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  • richardmitnick 9:38 am on January 11, 2021 Permalink | Reply
    Tags: "Astrochemist brings search for extraterrestrial life to Center for Astrophysics" Clara Sousa-Silva, A good biosignature has a final characteristic: It has limited or accountable false positives., , , , , , Phosphine has a unique spectral signature because the spectrum for phosphine is composed of the behavior of the bonds between hydrogen and phosphorus and that’s a very rare bond in gas molecules., SETI   

    From Harvard Gazette: “Astrochemist brings search for extraterrestrial life to Center for Astrophysics” Clara Sousa-Silva 

    Harvard University

    From Harvard Gazette

    January 4, 2021
    Alvin Powell

    Clara Sousa-Silva explores telltale biosignature gases on other planets.

    1
    Although the size and mass of Venus are similar to the Earth, its thick carbon-dioxide atmosphere has trapped heat so efficiently that the surface temperature usually exceeds 700 kelvins, hot enough to melt lead. Credit: SSV, MIPL, Magellan Team, NASA.

    In September, a team of astronomers announced a breathtaking finding: They had detected a molecule called phosphine high in the clouds of Venus, possibly indicating evidence of life [Nature Astronomy].

    That discovery shook the scientific establishment. Once thought of as Earth’s twin, Venus — though nearby and rocky — is now known to have a hellish environment, with a thick atmosphere that traps solar radiation, cranking surface temperatures high enough to melt metal, and accompanied by surface pressure akin to that thousands of feet below Earth’s ocean surface.

    But the detection, led by researchers from Cardiff University in Wales, the Massachusetts Institute of Technology, and the University of Manchester in England, was high in the atmosphere, where conditions are far more hospitable and the idea of microbial life more plausible. It was accomplished using spectroscopy, a method of determining the presence of different molecules in a planet’s atmosphere by analyzing how those molecules alter the light reflected from the planet. A key member of the team was fellow Clara Sousa-Silva, who had spent years studying the molecule’s spectroscopic signature and who believes that phosphine is a promising way to track the presence of extraterrestrial life.

    Sousa-Silva shifted her fellowship from MIT to the Center for Astrophysics | Harvard & Smithsonian and will spend the next two years advancing her work on biosignatures and life on other planets.

    She spoke with the Gazette about the recent discovery and what the future of the search for life may hold.

    Q&A
    Clara Sousa-Silva

    GAZETTE: You study biosignature gases, and your website says phosphine is your favorite. What is a biosignature gas and what’s so special about phosphine?

    SOUSA-SILVA: A biosignature gas is any gas in the planetary atmosphere that is produced by life. That by itself is not particularly interesting because molecules that can be produced by life can often be produced by many other things. So another question is: What is a good biosignature? And the answer to that also explains why phosphine is my favorite.

    A good biosignature isn’t just produced by life and released into an atmosphere. It is also able to survive in that atmosphere and be both detectable and distinguishable. So, if we’re looking at an atmosphere from far away, say from a different planet, and we detect an interesting molecule, that’s great. But maybe, because of low resolution in the instruments, lots of molecules look very similar to one another and the spectral signature also corresponds to a different molecule than one we thought we saw. So, you want a biosignature to be distinguishable.

    A good biosignature has a final characteristic: It has limited or accountable false positives. That means if it is produced by life, if it survives in the atmosphere, and you can detect it unambiguously, you still need to know if it was in fact produced by life or if it was accidentally produced by some other nonbiological process like photochemistry or volcanism. So, a good biosignature is all of these things: It is produced by life in large quantities and survives; it’s unambiguously detectable; and is unambiguously assigned to life.

    Famous biosignatures like oxygen and methane rank very well in the first few of these parameters. But methane, for example, looks an awful lot like every other hydrocarbon. And so knowing if you’re looking at methane versus a different molecule that also has carbons and hydrogens is quite hard. And even if you can unambiguously assign the thing you saw to methane, you don’t know if you can unambiguously assign it to life.

    Phosphine has a unique spectral signature, because the spectrum for phosphine is composed of the behavior of the bonds between hydrogen and phosphorus, and that’s a very rare bond in gas molecules. So phosphine is quite easy to distinguish, meaning it’s easy-ish to detect, and it is also produced by life. But it’s not produced by life in large quantities, so that’s a negative point for phosphine. But then, it’s so hard to produce without the intervention of life on rocky planets that it’s very low on false positives. I think phosphine is a well-balanced biosignature: produced in detectable quantities by life, being distinguishable, and having low false positives. That’s why it’s my favorite.

    2
    Clara Sousa-Silva, a fellow who grabbed headlines in September because of new findings of a potential signature for life on Venus, discusses that research. Credit: Kris Snibbe/Harvard.

    GAZETTE: Your site also says that phosphine is toxic to life that uses oxygen metabolism. So why is it a likely sign of life on Venus?

    SOUSA-SILVA: I don’t know if it’s likely. I wouldn’t dare put a probability on that. It is toxic to life on Earth that uses oxygen. And that is, obviously, us and everything we love. But lots of life on Earth does not rely on oxygen, and for the majority of time that life existed on Earth it also didn’t rely on oxygen. Granted, it wasn’t the most thrilling life. It wasn’t writing great works of literature, but it was nevertheless popular on Earth and seemingly very happy, thriving in forms that had no need for oxygen.

    The reason why phosphine on Venus, if it’s there, may signify life is more that we cannot explain it in any other way. We have no good explanation for the presence of phosphine on Venus, and we do know it can be produced by life. That doesn’t mean that’s what’s happening on Venus. That’s just, as extraordinary as it might sound, the best guess we have at this point.

    GAZETTE: Let’s talk specifically about the findings from September. What did you and your colleagues find on Venus?

    SOUSA-SILVA: It was an analysis of two separate observations done about 18 months apart. One was done with the JCMT, the James Clerk Maxwell Telescope, which is on Mauna Kea [in Hawaii].

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level.

    That observation has a tentative signal that could be assigned to phosphine. We then applied for time on ALMA [Atacama Large Millimeter/submillimeter Array in Chile], which is a much more powerful array of telescopes and which seemingly got a slightly stronger signal that also corresponded to phosphine.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    This is encouraging because the odds that a random signal will appear in the same place 18 months apart, using two different instruments, are very slim.

    The analysis was figuring out: One, is the signal real, because both of these instruments were collecting data very much at the limits of their capabilities. Two, if the signal is real, is the most plausible candidate phosphine rather than a different molecule? And three, if indeed the signal is real and it is phosphine, who or what is making it? Those are the three steps of the main article. This was about two years of work on top of my many years of work investigating phosphine as a biosignature.

    It took a long time and a large international team, including Anita [Richards, of the University of Manchester, U.K.] and Jane [Greaves, of Cardiff University (UK)]. Jane is the lead author of the paper that came out in September specifically extracting the signal from the data. Then lots of us were trying to figure out if the signal belongs to phosphine and if so, at what abundances. My contribution is that I know the pure spectroscopy of phosphine very well. My entire Ph.D. was dedicated to the spectroscopy of phosphine. So I was able to help figure out, if it was phosphine, what kind of abundances it was present in.

    I was also able to provide a list of other candidate molecules that could mimic the signal. The most promising one is phosphine, but the second-most-promising one is SO2 (sulphur dioxide), which would be a strange molecule to find in that location of Venus, but not anywhere near as strange as finding phosphine. So it was an important candidate to check. Then, if it is indeed phosphine and the signal is real, figuring out what is producing it was led by William Bains [at MIT]. It was also a large team, figuring out every process that might make phosphine and excluding a near-infinite list of negatives. It’s very, very hard to know if you’ve reached the end of that list.

    GAZETTE: So they’re working through the ways you might make phosphine that likely didn’t occur on Venus?

    SOUSA-SILVA: We’re trying to find an explanation, any explanation, and we did find a few methods that could produce small amounts of phosphine, but they were always quite trivial and always many orders of magnitude below what our estimates were for the signal detected in the clouds of Venus.

    GAZETTE: Is this discovery a warmup for finding phosphine and detecting biosignatures on planets around other stars?

    SOUSA-SILVA: I think it’s exactly a warmup for the search for life. It’s an excellent case study in the world of astrobiology.

    The odds that we find life beyond Earth from a booming, unambiguous, intelligent signal from the heavens is very slim. It’s likely, if we ever find life, that it is going to be something with quite a lot of uncertainty, and it will be really hard to even estimate that uncertainty. We won’t be able to say, “Oh, we found life with 80 percent certainty.” Those numbers are not ones we can do right now.

    What we can do is look at planets that have potentially habitable environments, look for molecules that can be associated with life, and then try to explain what’s going on there. We found a biomarker in a place that is potentially habitable. That’s a crucial first step, but it’s very far from the final step. We now need to figure out what other molecules would that biosphere produce? How will they interact with one another? How do we disentangle those behaviors from the spontaneous behaviors of a dead atmosphere?

    So, it’ll take a lot of work. We are very lucky to have Venus right next door so that we can use it as a lab. We can test all these theories in a way that we won’t be able to when we find a biomarker on an exoplanet, where there’s no hope of actually going in and probing the atmosphere to check. So this is a really important step.

    This has been reasonably controversial — and it should be — but we will have to do this many times. And every time we hope to be better prepared and have a better tool kit so that there’s less uncertainty. But it’ll take a long time before we can unambiguously confirm life elsewhere.

    GAZETTE: Before this discovery, Venus had been largely dismissed as a place for life because of its surface conditions. Your discovery has highlighted that a biosphere can be in places that may not immediately come to mind: high in the clouds where conditions are different. Is there a lesson here for thinking unconventionally when we evaluate places for life, especially since even here on Earth we’ve found life to be tough and enduring and in surprising places?

    SOUSA-SILVA: Life is very resilient and very resourceful on Earth and there’s no reason to think that’s some special characteristic of life on Earth rather than of life itself. We have ignored Venus because Venus is quite horrid to us. When we sent probes, they melted dramatically so we didn’t feel particularly welcome. It seems easier to imagine a place like Mars as habitable, even though actually there’s so little atmosphere and so little protection from the sun’s radiation that it’s really not an easily habitable surface.

    Mars is mostly uninhabitable, like Venus, just in a much quieter way. Mars will kill you, but it doesn’t melt you, so it feels more habitable, though I have no loyalty to either planet as a place to find life. This is hopefully going to help us think of habitability in a less anthropocentric way — or at least a less terra-centric way — and to think of habitability not just as a rocky planet with liquid water on the surface, but to think of subterranean habitats, moons of gas giants — something people already consider — and envelopes of an atmosphere as potentially habitable places in an otherwise uninhabitable planet.

    GAZETTE: What did you think when it became apparent that it might be life on Venus? Was that an exciting moment?

    SOUSA-SILVA: It was kind of a strange reversal. I had for years been working on this completely hypothetical investigation: If we found phosphine on a terrestrial planet what would it mean? I had concluded that because it has so few false positives on terrestrial planets that it could only mean life. I submitted the paper with this conclusion, and it was not controversial. The reviewers were fine with the idea — they had issues with other parts of the paper, but this didn’t bother them at all. No one cared because it was hypothetical: I was imagining this exotic, distant planet.

    When I was contacted by Jane, who had this tentative detection of phosphine on Venus, my not-so-controversial statement was now really extraordinary. And Venus is next door, so my hypothetical scenario became very concrete, very quickly. That was two years ago. We spent about a year and a half basically redoing and refining the analysis that we had done for my paper. This was, again, led by William Bains to try to figure out whether this is what happened on Venus. Venus is not your classic, potentially habitable exoplanet. It’s a pretty infernal place and maybe there phosphine could be made abiotically. So I never got to be as excited as I might at the first mention that phosphine had been found on a terrestrial planet. I expected this to happen hopefully before I die, but probably after I retire, not within months of submitting my hypothesis.

    I also immediately felt like I could not be trusted because I’m so biased. I’ve been working on phosphine for so long. I am a junior scientist without a permanent job. It would be so valuable to me for it to be life that I can’t be trusted to assess this accurately. So I was very careful to not get too excited. I had a strong glass of whiskey that evening, but that was it. Then I went and did the same work that we always do, which was to check every possible mechanism that can make phosphine, every possible molecule that can mimic the signal, and look again at everything I’ve done before and check for mistakes. It was nerve-racking to explore this expression of my prediction so nearby, so quickly.

    GAZETTE: Have you had a chance since the original paper was published?

    SOUSA-SILVA: Well, we did a good thing and paid a cost. Unlike a lot of observations of this kind, we published all our data and all our code. Everything was ready for people to come and tear it apart. So people did, which meant I never did get a little time off to enjoy it. It was great because they found a calibration mistake, and ALMA was able to rectify that, which allowed our team to reanalyze the data — they’re still doing it now. There was just way too much press and then way too much criticism, and I still haven’t taken time off.

    GAZETTE: About the scientific debate, how to you respond to the failure of other research groups to replicate the results?

    SOUSA-SILVA: This is the part of the work where I’m only tangentially involved, since I’m not doing any data reduction [of readings from Venus’ atmosphere]. This debate is a consequence of working at the edge of instrument capabilities, and the data are always going to be very noisy and delicate until we have better telescopes. Any discoveries made from these data, from the edges of our ability, are always going to be up for discussion. It’ll be nice when there’s a gold standard method for reducing these data, but there isn’t, so people disagree on the best way of extracting a signal without introducing spurious signals.

    The disagreement comes in a variety of forms, but the teams that didn’t replicate the results, don’t replicate the results in different ways. For example, the [Ignas] Snellen team [from Leiden University in the Netherlands] looked at the ALMA data before the calibration error had been corrected. I’m looking forward to seeing their revised analysis of the better data. The Villanueva team [led by Geronimo Villanueva at the NASA-Goddard Space Flight Center] that looked at both the ALMA data and the JCMT data, did find signals in the JCMT data, which, of course, begs the question of “Where does the signal go in the ALMA data?”

    They do disagree on the source of the JCMT signal, though. SO2 [sulfur dioxide], our second-most-plausible candidate, is their first-most-plausible candidate. And that is an even more complicated question of how you choose between two molecules that can simulate the same signal at these resolutions. Our team’s argument is that the SO2 [spectra] is a little off — you would expect SO2 to show up in different areas of the white bandpass. There also isn’t enough SO2 to justify the signal, so phosphine would need to complement the size of the signal. It’s a difficult argument to make — and we’re at the edge of the statistical significance of the signal — but it’s a totally valid argument.

    Then there’s the archival Pioneer data that was revisited and that they think could correspond to phosphine. It’s hard to bring all of this data to a place where they agree with one another, sadly, because people want to know the truth — I do, too. But the only real conclusion we have is that we don’t know Venus well enough, and we need more data. We need more observations that are not at the edge of instrument capabilities so that there’s no ambiguity in what we’re looking at.

    GAZETTE: Let’s talk a little bit about what you’ll be doing here at Harvard. You’ve been a fellow at MIT. Is the fellowship split between there and here?

    SOUSA-SILVA: No, I moved it. I am 100 percent Harvard — for the last two months, I think. It’s very new.

    GAZETTE: Who will you be working with and what will you be doing?

    SOUSA-SILVA: The 51 Pegasi b Fellowship is a wonderful three-year prize fellowship that is provided by the Heising-Simons Foundation. I did one year at MIT, and I’ve moved to Harvard for the last two years of the fellowship. My host is Dave Charbonneau — part of the reason I moved to Harvard is because of the expertise he has — and the team that surrounds him — on exoplanet atmospheres. There’s also the HITRAN [High resolution Transmission molecular absorption database] group, led by Iouli Gordon — and previously, Larry Rothman — who are world leaders in spectroscopic databases, which is the bread and butter of my work. So that combination of expertise made Harvard perfect.

    GAZETTE: Are you doing most of your work out of your home now or are you able to commute to the CfA physically?

    SOUSA-SILVA: No, I don’t even know where my office is yet. I would love to be commuting to the CfA, but because my work can be done remotely, it shall be done remotely.

    GAZETTE: Are you continuing to work on phosphine and Venus or are you moving on to other topics?

    SOUSA-SILVA: I’ll give it the same percentage of my time as I have in the past. Phosphine is very much my expert molecule, but 50 percent of my work is pushing against the notion of looking for single indicators of life. Because unless we get a radio signal in prime numbers or an unambiguous sign of CFCs [chlorofluorocarbons] or other really complex pollutants, we are going to need more than one molecule; we’re going to need a whole array of molecules that together paint the picture of a biosphere with all its complexity and interactions.

    So most of my work is trying to provide a tool kit that can detect every molecule that could potentially be in a habitable atmosphere. I started the work at MIT. They had come up with a list of all the possible molecules that could form in the context of a biosphere: 16,367. I know that number because I’ve been working on it for so long.

    Out of those thousands, we have spectra of some quality — and some of them are rough — for less than 4 percent of them. For the majority of molecules, we don’t even have even a crude ability to detect them. So most of my work is trying to simulate that spectra so we have at least some idea of what these molecules look like. That’s the connection to HITRAN. They have extremely high accuracy and extremely careful data on a handful of molecules, a little over 50. That is wonderful, but only a small dent in the list of 16,000-plus.

    I created a small program called RASCALL, for Rapid Approximate Spectral Calculations for All. The idea is to make really rough, very quick spectra for all of these molecules, and then build on it. Without RASCALL, the way I did my phosphine spectra took me a bit over four years and many extremely expensive supercomputers. I can’t repeat that for the 16,000 molecules. I calculated that it would take me over 62,000 years. I’m trying to shorten that timescale into something that resembles my lifetime, and that’s where RASCALL comes in.

    GAZETTE: Folks like you will be helping answer an interesting question in the decades to come: whether life is something rare or whether it’s not really that rare after all. It seems the thinking on that has been shifting in recent decades.

    SOUSA-SILVA: I do like that the shift is happening and that people are thinking that life is more common. I’m hoping that shift will go so far as thinking that life is not that special. It’s just an inevitable occurrence in a variety of contexts. If it can appear in places as different as Earth and Venus, which are at first glance similar because of their size and location but otherwise very different, then it must be extremely common because it would be the height of hubris to think that only the solar system can have life, but it has arisen twice in totally different environments.

    That seems really implausible. The sun is average, rocky planets are extremely common, the molecular cloud that formed the solar system was not special. Life on Earth came to be in a huge diversity of forms, and life changed Earth’s atmosphere many times. We only have one planet where we know life existed, but Earth has been many planets, which is something an astronomer colleague of mine, Sarah Rugheimer, likes to say. We have quite a lot of data points that basically show that life is pretty good at making itself happen in many ways throughout history.

    See the full article here .

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    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

     
  • richardmitnick 3:41 pm on November 10, 2020 Permalink | Reply
    Tags: "On 300 Million Habitable Zone Planets", , , , , , , SETI, The Drake Equation in various forms has continued to inform discussion., What catches the eye is the figure of 300 million which is the number the researchers give for potentially habitable planets in the Milky Way.   

    From Centauri Dreams: “On 300 Million Habitable Zone Planets” 

    From Centauri Dreams

    November 10, 2020
    Paul Gilster

    We’ve talked about the Drake Equation a good deal over the years, but I may not have mentioned before that when Frank Drake introduced it in 1961, it was for the purpose of stimulating discussion at a meeting at the National Radio Astronomy Observatory in Green Bank, West Virginia that was convening to discuss the nascent field of SETI.

    This was in the era of Drake’s Project Ozma and the terms of the SETI debate were hardly codified. Moreover, as Nadia Drake recounts in this absorbing look back at her father’s work in that era, Drake had spent the time immediately before the meeting trying to line up Champagne for UC-Berkeley biochemist Melvin Calvin, who was about to win the Nobel Prize.

    Frank Drake speaking at Cornell University in Schwartz Auditorium, 19 October 2017 by Amalex5

    Frank Drake with his Drake Equation. Credit Frank Drake.

    Drake Equation, Frank Drake, Seti Institute.

    So there was a certain ad hoc flavor to the equation, one that Drake assembled more or less on the fly to clarify the factors to be considered in looking for other civilizations. How Drake did all this while trying to locate a sufficient quantity of good Champagne in the rural West Virginia of 1961 is beyond me and adds to his mystique.

    Sparkling wine aside, the Drake Equation in various forms has continued to inform discussion. The likelihood of detecting alien civilizations could be approached by multiplying the seven factors Drake came up with, which are shown in the figure below. The number of detectable alien civilizations is N. The Drake Equation obviously relied on guesswork at the time, given that we knew little about the factors involved other than the rate of star formation.

    There’s still a lot of play in these numbers, of course, but it’s fascinating to watch the progress of exoplanetary science as we begin to fill in the numbers through actual observation. Notice in particular ne the number of planets, per star, that could support life. This value is what gets play in the recently released paper from Steve Bryson and a large number of colleagues at the SETI Institute, NASA and a variety of other organizations in The Astronomical Journal.

    What catches the eye is the figure of 300 million, which is the number the researchers give for potentially habitable planets in the Milky Way. Let’s drill into this a bit: The researchers are computing the occurrence of rocky worlds, defined here as planets within a certain range of radius (0.5 R⊕ ≤ r ≤ 1.5 R⊕), orbiting stars with effective temperatures of 4,800-6,300 K. The host stars cover main-sequence dwarf stars from Kepler’s DR25 planet candidate catalog as well as stars in data compiled by the European Space Agency’s Gaia mission.

    ESA (EU)/GAIA satellite .

    As the authors note: “We base our occurrence rates on differential population models dependent on radius, instellation flux and host star effective temperature.”

    This is a change of pace from the norm, so let’s turn to the paper:

    “Most of the existing literature on habitable zone occurrence rates are in terms of orbital period, where a single period range is adopted to represent the bounds of the habitable zone for the entire stellar population considered. However, no single period range covers the habitable zone for a wide variety of stars…While these period ranges cover much of the habitable zone for G stars, they miss significant portions of the habitable zones of K and F stars, and include regions outside the habitable zone even when restricted to G stars. This will be true for any fixed choice of orbital period range for the range of stellar effective temperatures required for good statistical analysis. Such coverage will not lead to accurate occurrence rates of planets in the habitable zone.”

    Hence the decision to work with instellation flux, which measures the photon flux on each planet as received from its host star. The authors say that this is the first paper on occurrence rates for habitable zone planets that operates on star-dependent photon output. In terms of effective temperature, G-class stars like the Sun are in the range of 5,200–6,000 K. F-class is 6,000–7,500 K, but as the paper notes, the paucity of F stars in the sampled data leads to the authors setting the temperature limits lower. K-class stars show up at effective temperatures of 3,700–5,200 K. The range used in this paper — 4,800-6,300 K — also excludes M-dwarfs, whose effective temperatures range from 2,400–3,700 K.

    Leaving out M-dwarfs could substantially under-count habitable zone worlds, but we also have enough concerns about tidal lock, stellar flare activity and atmospheric loss that we can’t assume M-dwarf planets are habitable. In any case, the authors have other reasons for the decision, including a very practical matter of future observation. After all, an analysis like this may well be useful as we ponder our target lists, and we also have to remember the limits of transit observation Kepler had to deal with:

    “The reason for limiting to Teff > 4800 K is two fold: (1) The inner working angle (IWA, the smallest angle on the sky at which a direct imaging telescope can reach its designed ratio of planet to star flux) for the LUVOIR coronagraph instrument ECLIPS falls off below 48 milliarc sec at 1 micron (3λ/D) for a planet at 10 pc for Teff ≤ 4800 K, and (2) Planets are likely tidal-locked or synchronously rotating below 4800 K that could potentially alter the inner HZ limit significantly…The upper limit of 6300 K is a result of planets in the HZs having longer orbital periods around early F-stars, where Kepler is not capable of detecting these planets…”

    So bear this in mind: Excluding what could be vast numbers of habitable planets in M-dwarf orbits, we still wind up with 300 million possibilities in the broad range of K-class through G-class stars. Co-author Jeff Coughlin is director of Kepler’s Science Office:

    “This is the first time that all of the pieces have been put together to provide a reliable measurement of the number of potentially habitable planets in the galaxy. This is a key term of the Drake Equation, used to estimate the number of communicable civilizations — we’re one step closer on the long road to finding out if we’re alone in the cosmos.”

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018.

    When you go through this paper, bear in mind what Centauri Dreams associate editor Alex Tolley pointed out to me — The Drake ne factor refers to the number of planets per star that can support life. What the Bryson et al. paper takes as its starting point is the number of rocky planets in the habitable zone, and this could mean that the figure of 300 million ‘habitable’ worlds takes in planets that resemble Venus more than Earth. It may also include water worlds, where the likelihood of technological civilization is unknown.

    So Drake’s term ne is not the same value as taken up in the new paper. Nonetheless, let’s return to that dazzling figure of 300 million, because when we’re dealing with that many planets of interest, we can afford to lose a number that turn out to be uninhabitable and still consider ourselves overwhelmed with possibilities for life.

    Numbers like these have implications for stars relatively near the Sun. The authors look at both the conservative and optimistic habitable zone, with the narrower ‘conservative habitable zone’ bounded by the ‘moist greenhouse’ and ‘maximum greenhouse’ limits, and the wider ‘optimistic habitable zone’ bounded by the ‘current Venus’ and ‘early Mars’ limits. I’m drawing this descrtiption from the Planetary Habitability Laboratory’s summary of work by Ravi kumar Kopparapu and colleagues.

    2
    Habitable Zone of around main sequence FGKM stars. The warm ‘habitable’ zone is divided into a ‘conservative habitable zone’ (light green) and an ‘optimistic habitable zone’ (dark green). Earth is at the inner edge of the ‘conservative habitable zone.’ Credit: PHL.

    Filtering their results using calculations for the conservative habitable zone, the authors maintain they can say with 95 percent confidence that the nearest rocky habitable zone planet around either a G- or K-class star is within 6 parsecs (roughly 20 light years). There could be four habitable zone rocky planets around G- and K-dwarfs within 10 parsecs of the Sun.

    How to build our small planet catalog to reduce uncertainties in the calculations? The answer is clearly more space-based observations even as new ground-based telescopes come online. Let’s also remember what we lost because of Kepler’s mechanical problems. While we did get a K2 extended mission, the original Kepler extended mission was meant to continue the ‘long stare’ at the original starfield, adding four more years of precision photometric data. The number of small planets in the habitable zone would have been significantly extended.

    “…by definition, Kepler planet candidates must have at least three observed transits. The longest orbital period with three transits that can be observed in the four years of Kepler data is 710 days (assuming fortuitous timing in when the transits occur). Given that the habitable zone of many F and late G stars require orbital periods longer than 710 days, Kepler is not capable of detecting all habitable-zone planets around these stars….”

    Given that upcoming missions like PLATO do not include such long stares on a single field of stars (PLATO plans no more than 3 years of continuous observation of a single field), we will need future missions to achieve what the original Kepler extended mission might have done, which would have been a doubling of the DR25 dataset and a large yield of small habitable zone planets.

    ESA PLATO spacecraft depiction

    The Kopparapu et al. paper is “Habitable Zones Around Main-Sequence Stars: New Estimates,” The Astrophysical Journal.

    See the full article here .

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    Tracking Research into Deep Space Exploration

    Alpha Centauri and other nearby stars seem impossible destinations not just for manned missions but even for robotic probes like Cassini or Galileo. Nonetheless, serious work on propulsion, communications, long-life electronics and spacecraft autonomy continues at NASA, ESA and many other venues, some in academia, some in private industry. The goal of reaching the stars is a distant one and the work remains low-key, but fascinating ideas continue to emerge. This site will track current research. I’ll also throw in the occasional musing about the literary and cultural implications of interstellar flight. Ultimately, the challenge may be as much philosophical as technological: to reassert the value of the long haul in a time of jittery short-term thinking.

     
  • richardmitnick 12:28 pm on October 26, 2019 Permalink | Reply
    Tags: I think it’s perfectly reasonable to examine how communications across interstellar space might play out should they exist., It seems that there is a built-in inevitability for life to cause and participate in information flow., , SETI, The bottom line is that we have not yet done enough to tell whether the cosmos is devoid of communicative species or crammed with them., We have to assume that really long-distance communications are actually possible at all., We would also have to assume that technologically inclined species can arise and survive for long enough to expend time and energy on any of these things.   

    From Scientific American: “Interstellar Conversations” 

    Scientific American

    From Scientific American

    Could there be information networks across the galaxy?

    October 19, 2019
    Caleb A. Scharf

    1
    Credit: C. Scharf 2019

    Let’s start by clearing something up. Whatever the ins and outs of the search for extraterrestrial intelligence over the years (that I’ll label as SETI) the bottom line is that we have not yet done enough to tell whether the cosmos is devoid of communicative species or crammed with them. Nowhere has this been articulated better than in the work by Jason Wright, Shubham Kanodia, and Emily Lubar of Penn State and their ‘Haystack equation’ [The Astronomical Journal]. This shows, unequivocally, that to date we’ve searched about as much as if we’d stared into a modest hot-tub’s worth of water from all of Earth’s oceans.

    Consequently, to say that ‘there’s clearly nothing out there’ is like looking in that hot tub, not finding a dolphin, and concluding that dolphins therefore do not exist anywhere on the planet.

    Given that fact, I think it’s perfectly reasonable to examine how communications across interstellar space might play out, should they exist. This does, of course, require a whole bunch of prior assumptions.

    We have to assume that really long-distance communications, whether by radio, laser, beams of neutrinos, massive engineering of weird stellar transit signals, or other barely imagined options are actually possible at all. We have to assume, or at least posit, that information might flow across interstellar space either as inadvertent side effects of a busy species (noisily broadcasting or carelessly pointing lasers, among other things) or as deliberate signals – seeking replies, establishing communications, or tracking a species’ own kind.

    We would also have to assume that technologically inclined species can arise and survive for long enough to expend time and energy on any of these things. That’s part of the depressing, although potentially realistic, Anthropocene mindset. But equally, simply shrugging our shoulders and saying that it’s all hopeless shuts down a discussion that could be very important.

    That importance could stem from the relevance of information itself. At all levels, information appears to be not just an integral part of the phenomenon of life on Earth [Chaos: An Interdiciplary Journal of Nonlinear Science], but the flow of information may represent a critical piece of what makes something alive versus not alive (that flow and informational influence might even be [Journal of the Royal Society Interface] of what life is).

    One small facet of this is very evident in how social animals deploy the flow of information. Imagine, for example, that humans didn’t communicate with each other in any way. It’s next to impossible to imagine that, right? We’re communicating even when we’re not speaking or touching. If I merely watch you walk down the street I’m accumulating information, adding that to my internal stash, analyzing, and incorporating it into my model of the world.

    There’s a much bigger discussion to be had there, but to come back to SETI. It seems that there is a built-in inevitability for life to cause and participate in information flow, and we should assume that extends across interstellar distances too. We ourselves have taken baby steps towards this – from our transmissions to our SETI efforts, to the fact that we maintain communications with our most distant robotic spacecraft, the Voyagers.

    As we’ve seen with studying the ideas of the so-called Fermi Paradox, in principle it’s pretty ‘easy’ for interstellar explorers to spread across the galaxy given a few million years. It therefore should be even easier for an information-bearing network to spread across the galaxy too. Signals can move at up to the speed of light, so the bottlenecks come from issues like the fading of signal strength with distance, the timescale of development of the infrastructure to receive and transmit, and the choices made on directionality (perhaps).

    The beautiful thing is that we can model hypotheses for this galactic information flow – even if we don’t know all the possible ifs, buts, and maybes. We can, in principle, test hypotheticals about the structure of information-bearing interstellar networks, which will also relate to the known physical distribution and dynamics of star systems and planets in our galaxy.

    Perhaps somewhere in there are clues about where we stand in relation to conversations that could be skittering by us all the time. Perhaps too are clues about what those conversations would entail, what the most valuable interstellar informational currencies really are.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 9:38 am on July 24, 2019 Permalink | Reply
    Tags: , , , SETI, , ,   

    From EarthSky: “Breakthrough Listen’s new search for alien lasers” 

    1

    From EarthSky

    July 24, 2019
    Paul Scott Anderson

    For the last few decades, the search for extraterrestrial intelligence has focused on detecting radio signals. But a new collaboration between Breakthrough Listen and VERITAS will focus on looking for laser-like flashes of light.

    1
    VERITAS will be used to help search for laser-like optical light pulses that could be beacons from an advanced alien civilization. Image via MIT/New Atlas.

    The Search for Extraterrestrial Intelligence (SETIInstitute) has traditionally looked for radio signals of artificial origin, i.e. coming from an alien civilization at least as advanced as our own.



    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

    We humans have been broadcasting radio waves into space for about 100 years now, since Marconi pioneered long-distance radio transmission. The reasoning has been that other civilizations might use radio, too. While that approach continues to be highly debated, there is another kind of search that is starting to be considered more seriously now as well: looking for optical signals – brief flashes of light like pulsing lasers – that could be used as beacons to communicate over interstellar distances.

    On July 17, 2019, Breakthrough Initiatives – founded in 2015 by entrepreneur Yuri Milner – announced a new partnership with the VERITAS Collaboration to focus on this strategy. VERITAS (the Very Energetic Radiation Imaging Telescope Array System) will search for such pulsed optical beacons, as well as radio signals, with its array of four 12-meter telescopes at the Whipple Observatory in Amado, Arizona.

    Breakthrough Listen Project

    1

    UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA




    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    Newly added

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

    CfA Whipple Observatory, located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    Breakthrough Listen, part of Breakthrough Initiatives, has already been conducting searches using its still-ongoing radio frequency survey and spectroscopic optical laser survey. But VERITAS can take the search to a new level. It was built to detect cosmic gamma rays and is the most powerful telescope array in the world for studying high energy astrophysics. As it turns out, it can also be used to look for “pulsed optical beacons” – laser-like pulses of light – that are very short in duration, only a few nanoseconds (one nanosecond is a billionth of a second).

    2
    Closer view of one of the 4 telescopes in the VERITAS array. Image via CfA/SciTechDaily.

    An advantage of this method is that any artificial pulses could outshine stars that happen to lie in the same direction. The use of all four telescopes would also help to eliminate false positives from any detections made. VERITAS will provide a unique way of expanding the search for alien intelligence beyond previous methods, as noted by Yuri Milner:

    “When it comes to intelligent life beyond Earth, we don’t know where it exists or how it communicates. So our philosophy is to look in as many places, and in as many ways, as we can. VERITAS expands our range of observation even further.”

    Andrew Siemion at the Berkeley SETI Research Center added:

    “Breakthrough Listen is already the most powerful, comprehensive, and intensive search yet undertaken for signs of intelligent life beyond Earth. Now, with the addition of VERITAS, we’re sensitive to an important new class of signals: fast optical pulses. Optical communication has already been used by NASA to transmit high definition images to Earth from the moon, so there’s reason to believe that an advanced civilization might use a scaled-up version of this technology for interstellar communication.”

    VERITAS will be able to detect very faint light signals, if any exist, according to Jamie Holder at the University of Delaware:

    Just how sensitive is VERITAS? The most powerful lasers on Earth can transmit a pulse of 500 terawatts lasting only a few nanoseconds. If one were placed at the distance of Tabby’s Star – that weird dimming star about 1,470 light-years away – then VERITAS could detect it. However, most of the stars that VERITAS will observe are 10-100 times closer than that, so feasibly a pulse of light 100-10,000 times fainter than that earthly laser could be found.

    VERITAS being able to search for alien light signals is a great bonus, since that is not what it was designed for. As David Williams at the University of California, Santa Cruz said:

    “It is impressive how well-suited the VERITAS telescopes are for this project, since they were built only with the purpose of studying very-high-energy gamma rays in mind.”

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    Laser SETI, the future of SETI Institute research

    In California, the SETI Institute is also using Lick Observatory‘s 40-inch Nickel Telescope on Mount Hamilton with a new pulse-detection system, to look for similar laser beacons from civilizations many light-years distant. Optical SETI has its advantages over radio SETI, such as no radio signal interference, according to Frank Drake, director of the Carl Sagan Center for Research:

    One great advantage of optical SETI is that there’s no terrestrial interference. It’s an exciting new field.

    This Lick experiment is unique as it uses three light detectors (photomultipliers) to search for bright pulses that arrive in a short period of time (less than a billionth of a second). Light from the star itself can also trigger the detectors as well, but seldom will all three photomultipliers be hit by photons within a billionth of a second time frame. This means few false alarms are expected, only about one per year.

    New and novel ways of looking for evidence of extraterrestrial intelligence are welcome, since the previous, traditional SETI method of just searching for radio signals is considered by many to be antiquated. Would a civilization thousands or millions of years more advanced then us still be using radio waves to communicate? SETI and other searches should be as broad as possible, and consider alternate possibilities for the best chance of success. With billions of stars in our galaxy alone, the hunt for such signals is like looking for a needle in a haystack. VERITAS is just one such alternate method, but it is a good start.

    Breakthrough Listen is a comprehensive initiative to search for evidence of intelligent, technological life from nearby stars to the universe at large. The objective is to examine one million nearby stars, all the stars in the galactic plane and 100 nearby galaxies, for both radio and optical signals. Not a small undertaking, but if there is to be any chance of finding an alien light show, then we must look.

    7
    This is how far human radio broadcasts have reached into the galaxy – not the black square – but the little blue dot at the center of that zoomed-in square. The ever-expanding bubble announcing humanity’s presence to anyone listening in the Milky Way is now only about 200 light-years wide, in contrast to our 100,000-light-year galaxy. Graphic created by Adam Grossman. Read more from Emily Lakdawalla at the Planetary Society.

    Search for extraterrestrial intelligence expands at Lick Observatory

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    New instrument scans the sky for pulses of infrared light

    March 23, 2015
    By Hilary Lebow

    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch)

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    5
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

    Optical SETI has its advantages over radio SETI, such as no radio signal interference, according to Frank Drake, director of the Carl Sagan Center for Research:

    “One great advantage of optical SETI is that there’s no terrestrial interference. It’s an exciting new field.”

    See the full article here .
    See the earlier blog post on Breakthrough Listen here.

    Not included in this far reaching article-

    seti@home


    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.orgin 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 11:29 am on July 21, 2019 Permalink | Reply
    Tags: , , , , , , , Is anyone out there?, , SETI, Shelley Wright of UCSD and Niroseti at UCSC Lick Observatory's Nickel Telescope,   

    From WIRED: “An Alien-Hunting Tech Mogul May Help Solve a Space Mystery” 

    Wired logo

    From WIRED

    07.21.19
    Katia Moskvitch

    1
    Yuri Milner. Billy H.C. Kwok/Getty Images

    In spring 2007, David Narkevic, a physics student at West Virginia University, was sifting through reams of data churned out by the Parkes telescope—a dish in Australia that had been tracking pulsars, the collapsed, rapidly spinning cores of once massive stars.

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    His professor, astrophysicist Duncan Lorimer, had asked him to search for a recently discovered type of ultra-rapid pulsar dubbed RRAT. But buried among the mountain of data, Narkevic found an odd signal that seemed to come from the direction of our neighboring galaxy, the Small Magellanic Cloud.

    smc

    Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

    The signal was unlike anything Lorimer had encountered before. Although it flashed only briefly, for just five milliseconds, it was 10 billion times brighter than a typical pulsar in the Milky Way galaxy. It was emitting in a millisecond as much energy as the sun emits in a month.

    What Narkevic and Lorimer found was the first of many bizarre, ultra-powerful flashes detected by our telescopes. For years the flashes first seemed either improbable or at least vanishingly rare. But now researchers have observed more than 80 of these Fast Radio Bursts, or FRBs. While astronomers once thought that what would be later dubbed the “Lorimer Burst” was a one-off, they now agree that there’s probably one FRB happening somewhere in the universe nearly every second.

    And the reason for this sudden glut of discoveries? Aliens. Well, not aliens per se, but the search for them. Among the scores of astronomers and researchers working tirelessly to uncover these enigmatic signals is an eccentric Russian billionaire who, in his relentless hunt for extraterrestrial life, has ended up partly bankrolling one of the most complex and far-reaching scans of our universe ever attempted.

    Ever since Narkevic spotted the first burst, scientists have been wondering what could produce these mesmerizing flashes in deep space. The list of possible sources is long, ranging from the theoretical to the simply unfathomable: colliding black holes, white holes, merging neutron stars, exploding stars, dark matter, rapidly spinning magnetars, and malfunctioning microwaves have all been proposed as possible sources.

    While some theories can now be rejected, many live on. Finally though, after more than a decade of searching, a new generation of telescopes is coming online that could help researchers to understand the mechanism that is producing these ultra-powerful bursts. In two recent back-to-back papers, one published last week and one today, two different arrays of radio antennas—the Australian Square Kilometer Array Pathfinder (ASKAP) and Caltech’s Deep Synoptic Array 10 at the Owens Valley Radio Observatory (OVRO) in the US—have for the first time ever been able to precisely locate two different examples of these mysterious one-off FRBs.

    Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

    Caltech’s Deep Synoptic Array 10 dish array at Owens Valley Radio Observatory, near Big Pine, California USA, Altitude 1,222 m (4,009 ft

    Physicists are now expecting that two other new telescopes—Chime (the Canadian Hydrogen Intensity Mapping Experiment) in Canada and MeerKAT in South Africa—will finally tell us what produces these powerful radio bursts.

    CHIME Canadian Hydrogen Intensity Mapping Experiment -A partnership between the University of British Columbia, the University of Toronto, McGill University, Yale and the National Research Council in British Columbia, at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, CA Altitude 545 m (1,788 ft)

    SKA Meerkat telescope(s), 90 km outside the small Northern Cape town of Carnarvon, SA

    But Narkevic’s and Lorimer’s discovery nearly got binned. For a few months after they first spotted the unusually bright burst, it looked like the findings wouldn’t make it any further than Lorimer’s office walls, just beyond the banks of the Monongahela River that slices through the city of Morgantown in West Virginia.

    Soon after detecting the burst, Lorimer asked his former graduate adviser Matthew Bailes, an astronomer at Swinburne University in Melbourne, to help him plot the signal—which to astronomers is now a famous and extremely bright energy peak, rising well above the power of any known pulsar. The burst seemed to come from much, much further away than where the Parkes telescope would usually find pulsars; in this case, probably from another galaxy, potentially billions of light-years away.

    “It just looked beautiful. I was like, ‘Whoa, that’s amazing.’ We nearly fell off our chairs,” recalls Bailes. “I had trouble sleeping that night because I thought if this thing is really that far away and that insanely bright, it’s an amazing discovery. But it better be right.”

    Within weeks, Lorimer and Bailes crafted a paper and sent it to Nature—and swiftly received a rejection. In a reply, a Nature editor raised concerns that there had been only one event, which appeared way brighter than seemed possible. Bailes was disappointed, but he had been in a worse situation before. Sixteen years earlier, he and fellow astronomer Andrew Lyne had submitted a paper claiming to have spotted the first ever planet orbiting another star—and not just any star but a pulsar. The scientific discovery turned out to be a fluke of their telescope. Months later, Lyne had to stand up in front of a large audience at an American Astronomical Society conference and announce their mistake. “It’s science. Anything can happen,” says Bailes. This time around, Bailes and Lorimer were certain that they had it right and decided to send their FRB paper to another journal, Science.

    After it was published, the paper immediately stirred interest; some scientists even wondered whether the mysterious flash was an alien communication. This wasn’t the first time that astronomers had reached for aliens as the answer for a seemingly inexplicable signal from space; in 1967, when researchers detected what turned out to be the first pulsar, they also wondered whether it could be a sign of intelligent life.

    Just like Narkevic decades later, Cambridge graduate student Jocelyn Bell had stumbled across a startling signal in the reams of data gathered by a radio array in rural Cambridgeshire.

    Women in STEM – Dame Susan Jocelyn Bell Burnell

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Dame Susan Jocelyn Bell Burnell at work on first plusar chart 1967 pictured working at the Four Acre Array in 1967. Image courtesy of Mullard Radio Astronomy Observatory.

    Dame Susan Jocelyn Bell Burnell 2009

    Dame Susan Jocelyn Bell Burnell (1943 – ), still working from http://www. famousirishscientists.weebly.com

    Not much of the array is left today; in the fields near the university where it once stood, there’s an overgrown hedge, hiding a collection of wonky, sad-looking wooden poles that were once covered in a web of copper wire designed to detect radio waves from faraway sources. The wire has long been stolen and sold on to scrap metal dealers.

    “We did seriously consider the possibility of aliens,” Bell says, now an emeritus professor at Oxford University. Tellingly, the first pulsar was half-jokingly dubbed LGM-1 —for little green men. With only half a year left until the defense of her PhD thesis, she was less than thrilled that “some silly lot of little green men” were using her telescope and her frequency to signal to planet Earth. Why would aliens “be using a daft technique signaling to what was probably still a rather inconspicuous planet?” she once wrote in an article for Cosmic Search Magazine.

    Just a few weeks later, however, Bell spotted a second pulsar, and then a third just as she got engaged, in January 1968. Then, as she was defending her thesis and days before her wedding, she discovered a fourth signal in yet another part of the sky. Proof that pulsars had to be a natural phenomenon of an astrophysical origin, not a signal from intelligent life. Each new signal made the prospect even more unlikely that groups of aliens, separated by the vastness of the space, were somehow coordinating their efforts to send a message to an uninteresting hunk of rock on the outskirts of the Milky Way.

    Lorimer wasn’t so lucky. After the first burst, six years would pass without another detection. Many scientists began to lose interest. The microwave explanation persisted for a while, says Lorimer, as skeptics sneered at the notion of finding a burst that was observed only once. It didn’t help that in 2010 Parkes detected 16 similar pulses, which were quickly proven to be indeed caused by the door of a nearby microwave oven that had been opened suddenly during its heating cycle.

    2
    Yuri Milner on stage with Mark Zuckerberg at a Breakthrough Prize event in 2017. Kimberly White/Getty Images

    When Avi Loeb first read of Lorimer’s unusual discovery, he too wondered if it was nothing more than the result of some errant wiring or miscalibrated computer. The chair of the astronomy department at Harvard happened to be in Melbourne in November 2007, just as Lorimer’s and Bailes’ paper appeared in Science, so he had a chance to discuss the odd burst with Bailes. Loeb thought the radio flash was a compelling enigma—but not much more than that.

    Still, that same year Loeb wrote a theoretical paper arguing that radio telescopes built to detect very specific hydrogen emissions from the early universe would also be able to eavesdrop on radio signals from alien civilizations up to about 10 light-years away. “We have been broadcasting for a century—so another civilization with the same arrays can see us from a distance out to 50 light-years,” was Loeb’s reasoning. He followed up with another paper on the search for artificial lights in the solar system. There, Loeb showed that a city as bright as Tokyo could be detected with the Hubble Space Telescope even if it was located right at the edge of the solar system. In yet another paper he argued how to detect industrial pollution in planetary atmospheres.

    Ever since he was a little boy growing up in Israel, Loeb has been fascinated with life—on Earth and elsewhere in the universe. “Currently, the search for microbial life is part of the mainstream in astronomy—people are looking for the chemical fingerprints of primitive life in the atmosphere of exoplanets,” says Loeb, who first dabbled in philosophy before his degree in physics.

    But the search for intelligent life beyond Earth should also be part of the mainstream, he argues. “There is a taboo, it’s a psychological and sociological problem that people have. It’s because there is the baggage of science fiction and UFO reports, both of which have nothing to do with what actually goes on out there in space,” he adds. He’s frustrated with having to explain—and defend—his point of view. After all, he says, billions have been poured into the search for dark matter over decades with zero results. Should the search for extraterrestrial intelligence, more commonly known as SETI, be regarded as even more fringe than this fruitless search?

    Lorimer didn’t follow Loeb’s SETI papers closely. After six long and frustrating years, his luck turned in 2013, when a group of his colleagues—including Bailes—spotted four other bright radio flashes in Parkes’ data. Lorimer felt vindicated and relieved. More detections followed and the researchers were on a roll: At long last, FRBs had been confirmed as a real thing. After the first event was dubbed “Lorimer’s Burst,” it swiftly made it onto the physics and astronomy curricula of universities around the globe. In physics circles, Lorimer was elevated to the position of a minor celebrity.

    Keeping an eye on events from a distance was Loeb. One evening in February 2014, at a dinner in Boston, he started chatting to a charismatic Russian-Israeli called Yuri Milner, a billionaire technology investor with a background in physics and a well-known name in Silicon Valley. Ever since he could remember, Milner had been fascinated with life beyond Earth, a subject close to Loeb’s heart; the two instantly hit it off.

    Milner came to see Loeb again in May the following year, at Harvard, and asked the academic how long it would take to travel to Alpha Centauri, the star system closest to Earth.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    Loeb replied he would need half a year to identify the technology that would allow humans to get there in their lifetime. Milner then asked Loeb to lead Breakthrough Starshot, one of five Breakthrough Initiatives the Russian oligarch was about to announce in a few weeks—backed by $100 million of his own money and all designed to support SETI.

    Breakthrough Starshot Initiative

    Breakthrough Starshot

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    SPACEOBS, the San Pedro de Atacama Celestial Explorations Observatory is located at 2450m above sea level, north of the Atacama Desert, in Chile, near to the village of San Pedro de Atacama and close to the border with Bolivia and Argentina

    SNO Sierra Nevada Observatory is a high elevation observatory 2900m above the sea level located in the Sierra Nevada mountain range in Granada Spain and operated maintained and supplied by IAC

    Teide Observatory in Tenerife Spain, home of two 40 cm LCO telescopes

    Observatori Astronòmic del Montsec (OAdM), located in the town of Sant Esteve de la Sarga (Pallars Jussà), 1,570 meters on the sea level

    Bayfordbury Observatory,approximately 6 miles from the main campus of the University of Hertfordshire

    Fast-forward six months, and at the end of December 2015 Loeb got a call asking him to prepare a presentation summarizing his recommended technology for the Alpha Centauri trip. Loeb was visiting Israel and about to head on a weekend trip to a goat farm in the southern part of the country. “The following morning, I was sitting next to the reception of the farm—the only location with internet connectivity—and typing the PowerPoint presentation that contemplated a lightsail technology for Yuri’s project,” says Loeb. He presented it at Milner’s home in Moscow two weeks later, and the Breakthrough Initiatives were announced with fanfare in July 2015.

    The initiatives were an adrenaline shot in the arm of the SETI movement—the largest ever private cash injection into the search for aliens. One of the five projects is Breakthrough Listen, which was championed, among others, by the famous astronomer Stephen Hawking (who has died since) and British astronomer royal Martin Rees.

    Breakthrough Listen Project

    1

    UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA




    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    Newly added

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

    Echoing the film Contact, with Jodie Foster playing an astronomer listening out for broadcasts from aliens (loosely based on real-life SETI astronomer Jill Tarter), the project uses radio telescopes around the world to look for any signals from extraterrestrial intelligence.

    Jill Tarter Image courtesy of Jill Tarter

    After the Breakthrough Initiatives were announced, Milner’s money quickly got invested into the deployment of cutting-edge technology—such as computer storage and new receivers—at existing radio telescopes, including Green Bank in West Virginia and Parkes in Australia; whether the astronomers using these observatories believed in alien life or not, they welcomed the investment with open arms. It didn’t take long to receive the first scientific returns.

    After the Breakthrough Initiatives were announced, Milner’s money quickly got invested into the deployment of cutting-edge technology—such as computer storage and new receivers—at existing radio telescopes, including Green Bank in West Virginia and Parkes in Australia; whether the astronomers using these observatories believed in alien life or not, they welcomed the investment with open arms. It didn’t take long to receive the first scientific returns.

    In August 2015 one of the previously spotted FRBs decided to make a repeat appearance, triggering headlines worldwide because it was so incredibly powerful, brighter than the Lorimer Burst and any other FRB. It was dubbed “the repeater” and is also known as the Spitler Burst, because it was first discovered by astronomer Laura Spitler of the Max Planck Institute for Radio Astronomy in Bonn, Germany.

    Max Planck Institute for Radio Astronomy

    Max Planck Institute for Radio Astronomy Bonn Germany

    Over the next few months, the burst flashed many more times, not regularly, but often enough to allow researchers to determine its host galaxy and consider its possible source—likely a highly magnetized, young, rapidly spinning neutron star (or magnetar).

    This localization was done with the Very Large Array (VLA), a group of 27 radio dishes in New Mexico that feature heavily in the film Contact. But the infrastructure at Green Bank Telescope upgraded by Breakthrough Listen caught the repeating flashes many more times, says Lorimer—allowing researchers to study its host galaxy more in detail. “It’s wonderful—they have a mission to find ET, but along the way they want to show that this is producing other useful results for the scientific community,” he adds. Detecting FRBs has quickly become one of the main objectives of Breakthrough Listen.

    Netting the repeater was both a boon and a hindrance—on the one hand, it eliminated models that cataclysmic events such as supernova explosions were causing FRBs; after all, these can happen only once. On the other hand, it deepened the mystery. The repeater lives in a small galaxy with a lot of star formation—the kind of environment where a neutron star could be born, hence the magnetar model. But what about all the other FRBs that don’t repeat?

    Researchers started to think that perhaps there were different types of these bursts, each with its own source. Scientific conferences still buzz with talks of mights and might-nots, with physicists eagerly debating possible sources of FRBs in corridors and at conference bars. In March 2017, Loeb caused a media frenzy by suggesting that FRBs could actually be of alien origin—solar-powered radio transmitters that might be interstellar light sails pushing huge spaceships across galaxies.

    That Parkes is part of the SETI project is obvious to any visitor. Walking up the flight of stairs to the circular operating tower below the dish, every button, every door, and every wall nostalgically screams 1960s, until you reach the control room full of modern screens where astronomers remotely control the antenna to observe pulsars.

    Up another flight of stairs is the data storage room, stacked with columns and columns of computer drives full of blinking lights. One thick column of hard drives is flashing neon blue, put there by Breakthrough Listen as part of a cutting-edge recording system designed to help astronomers search for every possible radio signal in 12 hours of data, much more than ever before. Bailes, who now splits his time between FRB search and Breakthrough Listen, takes a smiling selfie in front of Milner’s drives.

    While many early FRB discoveries were made with veteran telescopes—single mega dishes like Parkes and Green Bank—new telescopes, some with the financial backing of Breakthrough Listen, are now revolutionizing the FRB field.

    Deep in South African’s semi-desert region of the Karoo, eight hours by car from Cape Town, stands an array of 64 dishes, permanently tracking space. They are much smaller than their mega-dish cousins, and all work in unison. This is MeerKAT [above], another instrument in Breakthrough Listen’s growing worldwide network of giant telescopes. Together with a couple of other next-generation instruments, this observatory might hopefully tell us one day, probably in the next decade, what FRBs really are.

    The name MeerKAT means “More KAT,” a follow up to KAT 7, the Karoo Array Telescope of seven antennas—although real meerkats do lurk around the remote site, sharing the space with wild donkeys, horses, snakes, scorpions and kudus, moose-sized mammals with long, spiraling antlers. Visitors to MeerKAT are told to wear safety leather boots with steel toes as a precaution against snakes and scorpions. They’re also warned about the kudus, which are very protective of their calves and recently attacked the pickup truck of a security guard, turning him and his car over. Around MeerKAT there is total radio silence; all visitors have to switch off their phones and laptops. The only place with connectivity is an underground “bunker” shielded by 30-centimeter-thick walls and a heavy metal door to protect the sensitive antennas from any human-made interference.

    MeerKAT is one of the two precursors to a much bigger future radio observatory—the SKA, or Square Kilometer Array.

    SKA Square Kilometer Array

    SKA South Africa

    Once SKA is complete, scientists will have added another 131 antennas in the Karoo. The first SKA dish has just been shipped to the MeerKAT site from China. Each antenna will take several weeks to assemble, followed by a few more months of testing to see whether it actually works the way it should. If all goes well, more will be commissioned, built, and shipped to this faraway place, where during the day the dominant color is brown; as the sun sets, however, the MeerKAT dishes dance in an incredible palette of purples, reds, and pinks, as they welcome the Milky Way stretching its starry path just above. MeerKAT will soon be an incredible FRB machine, says Bailes.

    There is another SKA precursor—ASKAP in Australia.

    Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

    Back in 2007, when Lorimer was mulling over the Nature rejection, Ryan Shannon was finishing his PhD in physics at Cornell University in New York—sharing the office with Laura Spitler, who would later discover the Spitler Burst. Shannon had come to the US from Canada, growing up in a small town in British Columbia. About half an hour drive from his home is the Dominion and Radio Astronomical Observatory (DRAO)—a relatively small facility that was involved in building equipment for the VLA.

    5

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    Subconsciously, says Shannon, DRAO must have impacted his choice of career. And it was at DRAO that a few years later a totally new telescope—Chime [above]—would be built that would greatly impact the nascent field of FRB research. But in 2007 that was still to come. After graduating from Cornell in 2011, Shannon decided not to stay close to home—“something my mum would’ve wanted.” Instead, he moved to Australia and ultimately to Swinburne University on the outskirts of Melbourne.

    Shannon joined Bailes’ team in 2017—and by then astronomers had begun to understand why they weren’t detecting more FRBs, even though they were already estimating that these flashes were happening hundreds of times every day, if not more. “Our big radio telescopes don’t have wide fields of view, they can’t see the entire sky—that’s why we missed nearly all FRBs in the first decade of realizing these things exist,” says Shannon.

    When he, Bailes, and other FRB hunters saw the ultra-bright repeater, the Spitler Burst, they understood that there were fast radio bursts which could be found even without gigantic telescopes like Parkes, by using instruments that have a wider field of view. So they started building ASKAP [above]—a new observatory conceived in 2012 and recently completed in the remote Australian outback. It sports 36 dishes with a 12-meter diameter each, and just like with MeerKAT, they all work together.

    To get to ASKAP, in a very sparsely populated area in the Murchison Shire of Western Australia, one has to first fly to Perth, change for a smaller plane bound for Murchison, then squeeze into a really tiny single propeller plane, or drive for five hours across 150 kilometers of dirt roads. “When it rains, it turns to mud, and you can’t drive there,” says Shannon, who went to the ASKAP site twice, to introduce the local indigenous population to the new telescope constructed—with permission—on their land and see the remote, next-generation ultra-sensitive radio observatory for himself.

    MeerKAT and ASKAP bring two very different technological approaches to the hunt for FRBs. Both observatories look at the southern sky, which makes it possible to see the Milky Way’s bright core much better than in the northern hemisphere; they complement old but much upgraded observatories like Parkes and Arecibo in South America. But the MeerKAT dishes have highly sensitive receivers which are able to detect very distant objects, while ASKAP’s novel multi-pixel receivers on each dish offer a much wider field of view, enabling the telescope to find nearby FRBs more often.

    “ASKAP’s dishes are less sensitive, but we can observe a much larger portion of the sky,” says Shannon. “So ASKAP is going to be able to see things that are usually intrinsically brighter.” Together, the two precursors will be hunting for different parts of the FRB population—since “you want to understand the entire population to know the big picture.”

    MeerKAT only started taking data in February, but ASKAP has been busy scanning the universe for FRBs for a few years now. Not only has it already spotted about 30 new bursts, but in a new paper just released in Science, Shannon and colleagues have detailed a new way to localize them despite their short duration, which is a big and important step toward being able to determine what triggers this ultra-bright radiation. Think of ASKAP’s antennas as the eye of a fly; they can scan a wide patch of the sky to spot as many bursts as possible, but the antennas can all be made to point instantly in the same direction. This way, they make an image of the sky in real time, and spot a millisecond-long FRB as it washes over Earth. That’s what Shannon and his colleagues have done, and for the first time ever, managed to net one burst they named FRB 180924 and pinpoint its host galaxy, some 4 billion light-years away, all in real time.

    Another team, at Caltech’s Owens Valley Radio Observatory (OVRO) in the Sierra Nevada mountains in California, have also just caught a new burst and traced it back to its source, a galaxy 7.9 billion light years away.

    Caltech’s Deep Synoptic Array 10 dish array at Owens Valley Radio Observatory, near Big Pine, California USA, Altitude 1,222 m (4,009 ft

    And just like Shannon, they didn’t do it with a single dish telescope but a recently built array of 10 4.5-meter antennas called the Deep Synoptic Array-10. The antennas act together like a mile-wide dish to cover an area on the sky the size of 150 full moons. The telescope’s software then processes an amount of data equivalent to a DVD every second. The array is a precursor for the Deep Synoptic Array that, when built by 2021, will sport 110 radio dishes, and may be able to detect and locate more than 100 FRBs every year.

    What both ASKAP’s and OVRO’s teams found was that their presumably one-off bursts originated in galaxies very different from the home of the first FRB repeater. Both come from galaxies with very little star formation, similar to the Milky Way and very different from the home of the repeater, where stars are born at a rate of about a hundred times faster. The discoveries show that “every galaxy, even a run-of-the-mill galaxy like our Milky Way, can generate an FRB,” says Vikram Ravi, an astronomer at Caltech and part of the OVRO team.

    But the findings also mean that the magnetar model, accepted by many as the source of the repeating burst, does not really work for these one-off flashes. Perhaps, Shannon says, ASKAP’s burst could be the result of a merger of two neutron stars, similar to the one spotted two years ago by the gravitational wave detectors LIGO and Virgo in the US and Italy, because both host galaxies are very similar. “It’s a bit spooky that way,” says Shannon. One thing is clear though, he adds: The findings show that there is likely more than one type of FRBs.

    Back in Shannon’s hometown in Canada, the excitement has also been growing exponentially because of CHIME. Constructed at the same time as MeerKAT and ASKAP, this is a very different observatory; it has no dishes but antennas in the form of long buckets designed to capture light. In January, the CHIME team reported the detection of the second FRB repeater and 12 non-repeating FRBs. CHIME is expected to find many, many more bursts, and with ASKAP, MeerKAT and CHIME working together, astronomers hope to understand the true nature of the enigmatic radio flashes very soon.

    But will they fulfill Milner’s dream and successfully complete SETI, the search for extraterrestrial intelligence? Lorimer says that scientists hunting for FRBs and pulsars have for decades been working closely with colleagues involved in SETI projects.

    After all, Loeb’s models for different—alien—origins of FRBs are not fundamentally wrong. “The energetics when you consider what we know from the observations are consistent and there’s nothing wrong with that,” says Lorimer. “And as part of the scientific method, you definitely want to encourage those ideas.” He personally prefers to find the simplest natural explanation for the phenomena he observes in space—but until we manage to directly observe the source of these FRBs, all theoretical ideas should stand, as long as they are scientifically sound—whether they involve aliens or not.

    Any image repeats in this post were required for complete coverage.

    See the full article here .

    Totally missing from this article on SETI-

    SETI Institute


    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch).jpg

    Shelley Wright of UC San Diego, with NIROSETI, developed at U Toronto, at the 1-meter Nickel Telescope at Lick Observatory at UC Santa Cruz

    Laser SETI, the future of SETI Institute research

    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley

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  • richardmitnick 7:32 am on October 11, 2018 Permalink | Reply
    Tags: , , , , SETI, The Order of the Dolphin   

    From Discover Magazine: “The Order of the Dolphin: SETI’s Secret Origin Story” 

    DiscoverMag

    From Discover Magazine

    October 10, 2018
    John Wenz

    1
    (Credit: Theo Cobb)

    In 1961, when UFOs were all the rage, a group of top scientific minds met in secret at a rural observatory in West Virginia. At the time, the Green Bank Observatory was the biggest, baddest telescope in the burgeoning practice of radio astronomy.

    Green Bank Radio Telescope, West Virginia, USA

    While the list of meeting attendees now reads like a who’s who of the era’s luminaries, the reason they gathered covertly was because of the taboo nature of their topic of discussion. These scientists wanted to find, and talk to, aliens. They didn’t know it, but they were about to launch the modern Search for Extraterrestrial Intelligence, or SETI.



    Let’s back up a moment. In 1958, a newly minted Harvard PhD named Frank Drake came to Green Bank.

    Frank Drake speaking at Cornell University in Schwartz Auditorium, 19 October 2017 by Amalex5

    Usually he sought out typical radio astronomy targets — the Van Allen Belts around Earth, say, or the surface temperature of Venus, or the radiation belts of Jupiter.

    But one day in 1960, Drake and his colleagues instead tuned into two nearby stars, Tau Ceti and Epsilon Eridani. Their goal was simple: they were alien hunting, hoping to hear radio communications originating from intelligent extraterrestrials.

    UFOs were popular then, but Drake’s research was legitimate, one of the first dedicated scientific searches for aliens. Drake had been spurred on by Giuseppe Cocconi and Philip Morrison, who the previous year had co-authored a Nature paper with the provocative title “Searching for Interstellar Communications.” It remains a foundational SETI text.

    Much to Drake’s surprise, his team actually heard something in those first few experiments. Unfortunately, it ended up being just a high altitude plane. Project Ozma, as the research was called (after L Frank Baum’s fictional monarch of Oz), was both the first SETI experiment and the first SETI false alarm.

    “We had failed to detect a genuine alien signal, it was true, but we had succeeded in demonstrating that searching was a feasible, and even reasonable, thing to do,” Drake wrote in his book Is Anyone Out There?, co-written with science writer Dava Sobel.

    Talking to Dolphins

    While Drake was launching some of the first SETI programs, John Lilly — a physician, philosopher, writer and inventor — was attempting to communicate with his own alien intelligence. He just wasn’t looking quite as far.

    Humans are, in fact, surrounded by intelligence. Our fellow great apes understand the rudiments of language, and seem to possess highly organized social structures, tool-making skills and self-awareness. Creatures literally great and small — elephants and crows — have many of these qualities as well. (Alas, the pig is also remarkably intelligent; your bacon was likely self aware.)

    Intelligent life isn’t isolated to land, either. The octopus brain is one of the most remarkable on Earth, and its close cousin, the cuttlefish, is no slouch either. But the superstars of the sea, to most humans, are marine mammals, especially dolphins and whales.

    Lilly wanted to understand and communicate with dolphins — literally, to speak their language. And his ideas were taken seriously. He founded the Communication Research Institute in the late 1950s, and published research suggesting that his attempts to talk to dolphins were working.

    He also saw the experiments as a way to help efforts to contact aliens. If we can crack the code of dolphin language, Lilly thought, we might just have a shot at decoding other alien communication, too.

    The Stage Is Set

    Now, back to that clandestine 1961 meeting at Green Bank.

    The Space Science Board, a branch of the National Academy of Sciences, had tasked scientist and ballistics expert J.P.T. Pearman with putting together a meeting to expand the search for alien intelligence. While it wasn’t officially a secret meeting, it wasn’t well publicized either, since the topic was still considered one of the fringes of established research. No one wanted to put their career on the line to search for little green men.

    Counting Pearman, the gathering included 10 scientists. Drake and Lilly were there, of course, as well as Drake’s inspiration Morrison. Also in attendance were radio expert Dana Atchley,pre-eminent biochemist Melvin Calvin, optical astronomer Su-Shu Huang (who first conceived of stars having “habitable zones”), computing pioneer Barney Oliver and Russian radio astronomer Otto Struve. The final attendee was a young Carl Sagan, now perhaps the best known of the bunch.

    2

    (One more unofficial attendee: A supply of champagne to celebrate the likely announcement of a Nobel Prize for Calvin’s work on plant photosynthesis.)

    The biggest outcome of the conference was the Drake Equation. To know if aliens were out there, it helped to have an idea of how abundant they might be. The equation quantified estimates of star formation, planet formation, the likelihood of intelligent life arising and other factors necessary for intelligent life to exist.

    Drake Equation, Frank Drake, Seti Institute

    Despite its output of hard numbers, the Drake Equation is more symbolic than descriptive, a thoughtful tool to guide how scientists should think about looking for alien life. It set the tone for SETI and how it would be carried out in the subsequent decades, and offered a way forward for research that combined various legitimate scientific disciplines.

    Cause for Celebration

    As it happened, Calvin did win the Nobel, and the attendees indeed busted out the bubbly. But Lilly became another star of the show. Drake would write that, “Much of that first day, he regaled us with tales of his bottlenosed dolphins, whose brains, he said, were larger than ours and just as densely packed with neurons. Some parts of the dolphin brain looked even more complex than their human counterparts, he averred. Clearly, more than one intelligent species had evolved on Earth.”

    Lilly told the attendees he also heard signs of language, and empathy, in recordings of the dolphins. “In fact, if we slowed down the playback speed of the tape recorder enough, the squeaks and clicks sounded like human language,” Drake wrote. “We were all totally enthralled by these reports. We felt some of the excitement in store for us when we encounter nonhuman intelligence of extraterrestrial origin.”

    Lilly’s research generated so much excitement that, by the end of the conference, the attendees called themselves the Order of the Dolphin. Calvin, in his post-Nobel joy, even went on to send commemorative pins to the attendees. “He caused to be made these little pins which had silver dolphins on them, which he sent to all of us,” Morrison told David Swift, author of the book SETI Pioneers. “It wasn’t that we ever had meetings or chose officers of the Order of the Dolphin. It was just a souvenir of the particular time together.”

    Their excitement may have been a little hasty. “In retrospect,” Drake wrote, “I now think that Lilly’s work was poor science. He had probably distilled endless hours of recordings to select those little bits that sounded humanlike.” He wasn’t alone.

    “At that time we were quite enthusiastic about it because John Lilly came and told us about communications with dolphins,” Morrison told Swift. “Within a few years, the subject had pretty much dissipated, and Lilly’s work was not found to be reliable.”

    Shortly after the Order of the Dolphin meeting, Lilly began incorporating ketamine and LSD (legal at the time) into his experiments, hoping it would help him communicate better with dolphins. While Sagan visited the early experiments, reporting back to Drake on Lilly’s progress, as the science became hazier Sagan’s interest drifted as well. The work has tainted attempts to understand the intelligence of dolphins ever since.

    But while he may have veered into the realm of pseudo-science, Lilly did provide one useful guideline for future SETI efforts. “We came to a general conclusion … that in order to make any sense out of an alien language you had to hear a conversation between two of them,” Calvin told Swift. “You had to sit between them and hear a call and a response. You couldn’t just hear one side of the conversation, you couldn’t just receive.”

    3
    The Breakthrough Listen Initiative is training AI on massive data sets in hopes of discovering signals from an alien civilization. (Credit: Breakthrough Listen)

    Swimming Away

    Despite Lilly’s departure from legitimate science, the Order of the Dolphin’s legacy is assured. The Drake Equation remains a useful way to frame SETI research today, and the scientific advances we’ve made in quantifying its pieces are significant. We’ve found thousands of planets in other star systems and understand them better than ever — within the next few years, we’ll probably know not just if a world is in the habitable zone, but whether it’s truly habitable.

    And more resources than ever are pouring into SETI efforts, thanks in part to a $100 million project from Russian billionaire Yuri Milner called Breakthrough Listen.

    Breakthrough Listen Project

    1

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    Even if that effort fails to find intelligent aliens, increased exploration efforts by NASA and other agencies may just find evidence of life closer to home, either in Mars’s past, or today on the moons Enceladus, Europa, Titan or Triton.

    In other words, scientific literature on aliens may be a reality in the next few decades. While the man who gave the Order of the Dolphin its name may have descended into the fringes, the work of the order itself continues, vital as ever.

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)



    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley


    Laser SETI, the future of SETI Institute research

    See the full article here .

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  • richardmitnick 10:20 am on September 26, 2018 Permalink | Reply
    Tags: , , , , , NASA Is Taking a New Look at Searching for Life Beyond Earth, SETI   

    From NASA: “NASA Is Taking a New Look at Searching for Life Beyond Earth” 

    NASA image
    From NASA

    Sept. 25, 2018
    Editor: Tricia Talbert

    1
    A zoom into the Hubble Space Telescope photograph of an enormous, balloon-like bubble being blown into space by a super-hot, massive star. Astronomers trained the iconic telescope on this colorful feature, called the Bubble Nebula, or NGC 7635. Credits: NASA, ESA, and the Hubble Heritage Team (STScI/AURA), F. Summers, G. Bacon, Z. Levay, and L. Frattare (Viz 3D Team, STScI)

    NASA/ESA Hubble Telescope

    The explosion of knowledge of planets orbiting other stars, called exoplanets, and the results of decades of research on signatures of life – what scientists call biosignatures – have encouraged NASA to address, in a scientifically rigorous way, whether humanity is alone. Beyond searching for evidence of just microbial life, NASA now is exploring ways to search for life advanced enough to create technology.

    Technosignatures are signs or signals, which if observed, would allow us to infer the existence of technological life elsewhere in the universe. The best known technosignature are radio signals, but there are many others that have not been explored fully.

    In April 2018, new interest arose in Congress for NASA to begin supporting the scientific search for technosignatures as part of the agency’s search for life. As part of that effort, the agency is hosting the NASA Technosignatures Workshop in Houston on Sept. 26-28, 2018, with the purpose of assessing the current state of the field, the most promising avenues of research in technosignatures and where investments could be made to advance the science. A major goal is to identify how NASA could best support this endeavor through partnerships with private and philanthropic organizations.

    To view the workshop online, visit: http://www.ustream.tv/channel/asteroid-initiative-idea-synthesis—3

    On Thursday, Sept. 27 at 1 p.m. EDT, several of the workshop’s speakers will be answering questions in a Reddit AMA.

    What are Technosignatures?

    The term technosignatures has a broader meaning than the historically used “search for extraterrestrial intelligence,” or SETI, which has generally been limited to communication signals. Technosignatures like radio or laser emissions, signs of massive structures or an atmosphere full of pollutants could imply intelligence.

    In recent decades, the private and philanthropic sectors have carried out this research. They have used such methods as searching for patterns in low-band radio frequencies using radio telescopes.

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

    Breakthrough Listen Project

    1

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    Indeed, humanity’s own radio and television broadcasts have been drifting into space for a number of years. NASA’s SETI program was ended in 1993 after Congress, operating under a budget deficit and decreased political support, cancelled funding for a high-resolution microwave survey of the skies [SETI funding by governmental departments have not disappeared. Private funding has also supported SETI.

    Laser SETI, the future of SETI Institute research

    SETI has just embarked on a new project, Laser SETI, which is funded.]

    Since then, NASA’s efforts have been directed towards furthering our fundamental understanding of life itself, its origins and the habitability of other bodies in our solar system and galaxy.

    History of the Search for Technological Life

    Efforts to detect technologically advanced life predates the space age as early 20th century radio pioneers first foresaw the possibility of interplanetary communication. Theoretical work postulating the possibility of carrying signals on radio and microwave bands across vast distances in the galaxy with little interference led to first “listening” experiments in the 1960s.


    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley

    Thanks to NASA’s Kepler mission’s discovery of thousands of planets beyond our solar system,including some with key similarities to Earth, it’s now possible to not just imagine the science fiction of finding life on other worlds, but to one day scientifically prove life exists beyond our solar system.

    As NASA’s 2015 Astrobiology Strategy states: “Complex life may evolve into cognitive systems that can employ technology in ways that may be observable. Nobody knows the probability, but we know that it is not zero.” As we consider the environments of other planets, “technosignatures” could be included in the possible interpretations of data we get from other worlds.

    Debate about the probability of finding signals of advanced life varies widely. In 1961, astronomer Frank Drake created a formula estimating the number of potential intelligent civilizations in the galaxy, called the Drake equation, and calculated an answer of 10,000.

    Frank Drake, no image credit


    Drake Equation, Frank Drake, Seti Institute

    Most of the variables in the equation continue to be rough estimates, subject to uncertainties. Another famous speculation on the subject called the Fermi Paradox, posited by Italian physicist Enrico Fermi, asserted that if another intelligent life form was indeed out there, we would have met it by now.

    NASA’s SETI work began with a 1971 proposal by biomedical researcher John Billingham at NASA’s Ames Research Center for a 1,000-dish array of 100-meter telescopes that could pick up television and radio signals from other stars. “Project Cyclops” was not funded, but in 1976, Ames established a SETI branch to continue research in this area. NASA’s Jet Propulsion Laboratory (JPL) also began SETI work.

    In 1988, NASA Headquarters in Washington formally endorsed the SETI program leading to development of the High Resolution Microwave Survey. Announced on Columbus Day in 1992 – 500 years after Columbus landed in North America – this 10-year, $100 million project included a targeted search of stars led by Ames using the 300-meter radio telescope in Arecibo, Puerto Rico, and an all-sky survey led by JPL using its Deep Space Network dish.


    NAIC Arecibo Observatory operated by University of Central Florida, Yang Enterprises and UMET, Altitude 497 m (1,631 ft)

    NASA Deep Space Network dish, Goldstone, CA, USA

    The program lasted only a year before political opposition eliminated the project and effectively ended NASA’s research efforts in SETI.

    Why Start Looking at Technosignatures Now?

    Fueled by the discovery that our galaxy is teeming with planets, interest in detecting signs of technologically-advanced life is again bubbling up. Kepler’s discovery in 2015 of irregular fluctuations in brightness in what came to be known as Tabby’s Star led to speculation of an alien megastructure, though scientists have since concluded that a dust cloud is the likely cause. However, Tabby’s Star has demonstrated the potential usefulness of looking for anomalies in data collected from space, as signs of technologically-advanced life may appear as aberrations from the norm.

    Scientists caution that we will need more than an unexplained signal to definitively prove the existence of technological life. For example, there can be a lot of radio frequency interference from Earth-based sources.

    NASA will continue assessing promising current efforts of research in technosignatures and investigating where investments could be made to advance the science. Although we have yet to find signs of extraterrestrial life, NASA is amplifying exploring the solar system and beyond to help humanity answer whether we are alone in the universe.

    From studying water on Mars, probing promising “oceans worlds” such as Europa or Saturn’s moon Enceladus, to looking for biosignatures in the atmospheres of exoplanets, NASA’s science missions are working together with a goal to find unmistakable signs of life beyond Earth. And perhaps that life could indeed be more technologically advanced than our own.

    Fascinating.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 3:21 pm on September 3, 2017 Permalink | Reply
    Tags: "Everything Worth Knowing About ... Alien Contact" Almost, , SETI   

    From Discover: “Everything Worth Knowing About … Alien Contact” Almost 

    DiscoverMag

    Discover Magazine

    June 12, 2017 [Up in social media today 9.3.17]
    Sarah Scoles

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    The search for extraterrestrial intelligence (SETI) has been going for more than 50 years, with ever more sophisticated detection systems and creative ideas about how E.T. might come calling. Astronomers haven’t heard anything yet, but perhaps it’s only a matter of time. Check out what they’ve been looking for, how they would know if they found it and what the aftermath might be.

    How to Listen

    The universe emits many signals of its own. Black holes send out bursts of radio waves, X-rays and gamma rays. The dusty disks of forming planetary systems shine in infrared waves. Scientists must separate those so-called dumb signals from the smart signals that might come from extraterrestrials. Because of that necessary sifting, they assume that aliens would try to make their messages look different from the natural pings of the universe. In general, astronomers look for two hallmarks of technology.

    2
    Jay Smith

    Frequency compression: Narrowband signals come in on a small range of frequencies, like an individual radio station. Broadband signals spread across a wider range, like a broadcast that contains the whole FM band at once. Natural objects can only make signals so skinny, so if scientists see one that covers a tiny range of frequencies — like a laser or a satellite ping — they know it had to come from technology.

    Time compression: Scientists look for signals that last only for a flash and repeat, perhaps in a pattern that looks purposeful.

    BONUS! Almost-but-not-quite-natural-looking: Astronomers also keep their telescopes’ eyes out for anything that looks nearly natural. When researchers discovered fast radio bursts — superquick bursts that release at least as much energy in milliseconds as the sun does in a month — they threw around “aliens” as a (dim) possible explanation. And when astronomers discovered a star in 2015 whose light seems to occasionally get blocked by something big, one researcher proposed it was an alien megastructure. We still aren’t sure what causes either phenomenon, but scientists are studying them as natural emissions from the universe.

    Are We There Yet?

    You wouldn’t dip a glass in the ocean, come up with no fish inside and conclude, “No fish exist.” Astronomer Jill Tarter often says that’s where humans are with SETI.

    SETI’s Jill Tarter

    To fill enough glasses to get a good sense, researchers want to look at 1 million stars within 1,000 light-years of Earth and scan all the frequencies between 1 and 10 gigahertz. When they’ve done that, maybe they’ll have caught a fish or two — or will at least be able to say more about how many swim in the cosmic sea. Here’s how close they’ve gotten, proportionally, to that goal.

    99.959% How much searching astronomers still have to do to “cover” 1 million stars.

    0.041% How much of that search they have completed, for all radio SETI projects.

    3
    Jay Smith

    Cinematic SETI

    Sometimes, fictional film people meet extraterrestrial beings. When the encounters are good, they are very, very good. But when they are bad, they are horrid — and leave humans destabilized or dead. Here, we’ve ranked some of the most famous first-contact movies according to how naughty or nice the aliens are, as well as how realistic they, their technology and Earth’s response are.

    4
    No image caption or credit

    Our Best Bets

    Just as you wouldn’t bird-watch in interior Antarctica, you wouldn’t search for aliens in inhospitable environments. Astronomers have discovered thousands of planets, but only a few so far meet our basic requirements for possibly hosting life: being rocky and in the habitable zones around their stars (where water can stay liquid). Here are a few potentially life-friendly star systems where astronomers will aim their alien-seeking telescopes.

    Proxima Centauri

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The star system closest to our sun has a planet — Proxima b — similar to Earth’s mass. No one knows if it has any water, but it’s just 4 light-years away, so maybe we could find out in person someday.

    Wolf 1061

    4
    Wolf 1061. http://www.drewexmachina.com/2015/12/19/habitable-planet-reality-check-wolf-1061/

    The second planet in this star’s solar system is the next-closest Earth-ish-sized planet in a habitable zone, after Proxima b. It’s just 14 light-years from where you’re sitting right now.

    GJ 667

    5
    http://www.learnabouttravelmaps.info/pics/g/gliese-667-cb.html

    A mere 22 light-years away, this solar system has three super-Earth planets — between Earth’s and Uranus’ mass — in the habitable zone. And in the hunt for extraterrestrial life, every possibility counts.

    TRAPPIST-1

    Some 39 light-years away, this sun has three potentially rocky planets in its habitable zone and — bonus — four additional rocky planets. That’s seven Earth-ish-sized planets in one spot!

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    Kepler 186

    6
    NASA

    About 561 light-years away, the fifth planet discovered in this dwarf-star system circles its star’s habitable zone. The planet was the first astronomers found with a size similar to Earth’s.
    ____________________________________________________________________________

    Searches Past and Present

    1960 Astronomer Frank Drake performs the first modern SETI experiment, called Project Ozma (after a Wizard of Oz character). With an 85-foot radio telescope in Green Bank, W.Va., he looks at two sunlike stars for signs of alien technology.

    7
    In 1960, radioastronomer Frank D. Drake, then at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia, carried out humanity’s first attempt to detect interstellar radio transmissions. Project Ozma was named after the queen of L. Frank Baum’s imaginary land of Oz — a place “very far away, difficult to reach, and populated by strange and exotic beings.” The stars chosen by Drake for the first SETI search were Tau Ceti in the Constellation Cetus (the Whale) and Epsilon Eridani in the Constellation Eridanus (the River), some eleven light years (66 trillion miles) away. Both stars are about the same age as our sun.

    7
    Frank Drake

    1961 A small SETI conference takes place in Green Bank, at which Drake presents what’s now called the Drake Equation, which scientists use to estimate how many extraterrestrial civilizations may exist in our galaxy.

    Drake Equation, Frank Drake, Seti Institute

    1973 Ohio State University undertakes a SETI program with its Big Ear Observatory.

    Ohio State Big Ear Radio Telescope

    1979 The University of California, Berkeley, begins a long-lived project called SERENDIP — the Search for Extraterrestrial Radio from Nearby Developed Populations — at Hat Creek Observatory in Northern California.

    The most recently deployed SERENDIP spectrometer, SERENDIP V.v, was installed at the Arecibo Observatory in June 2009 and is currently operational.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    The digital back-end instrument is an FPGA-based 128 million-channel digital spectrometer covering 200 MHz of bandwidth. It takes data commensally with the seven-beam Arecibo L-band Feed Array[2] (ALFA).

    The next generation of SERENDIP experiments, SERENDIP VI, is in rapid development with a view to deploy it in early 2014 at both Arecibo and the Green Bank Telescope.

    GBO radio telescope, Green Bank, West Virginia, USA

    SERENDIP VI will also look for fast radio bursts.[3] SERENDIP VI receivers went into service in 2014-2015.

    1983 At Harvard University, astronomer Paul Horowitz launches Project Sentinel, using an 84-foot radio telescope.

    1988 NASA endorses its SETI studies, and scientists begin building the instruments they need to perform a search.

    1992 NASA’s SETI project, now the High Resolution Microwave Survey (HRMS), turns paperwork and plans into a physical project at Goldstone Observatory in California and the Arecibo radio telescope in Puerto Rico.

    1993 Just a year after its start, HRMS ends when Congress cancels its funding.

    1995 The private SETI Institute raises philanthropic funds and starts Project Phoenix, a reincarnated version of HRMS.

    1995 Horowitz continues his SETI work at Harvard with the Billion-Channel Extraterrestrial Assay (BETA).

    1999 Berkeley launches the citizen science project SETI@home, which lets your computer, in its downtime, dip into SERENDIP data.

    SETI@home, BOINC project at UC Berkeley Space Science Lab

    2004 Allen Telescope Array. First conceived by SETI pioneer Frank Drake, the idea has been a dream of the SETI Institute for years. However, it was not until early 2001 that research and development began, after a donation of $11.5 million by the Paul G. Allen Family Foundation. In March 2004, following the successful completion of a three-year research and development phase, the SETI Institute unveiled a three-tier construction plan for the telescope. Construction began immediately, thanks to the pledge of $13.5 million by Paul Allen (co-founder of Microsoft) to support the construction of the first and second phases. The SETI Institute named the telescope in Allen’s honor. 2005 The SETI Institute begins building a telescope dedicated to searches for aliens.Overall, Paul Allen has contributed more than $30 million to the project.

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA

    2015 METI (Messaging Extraterrestrial Intelligence) International begins an optical SETI program at the Boquete Observatory in Panama.

    7
    Boquete Observatory

    2016 The $100 million Breakthrough Listen project, sponsored by Russian magnate Yuri Milner, begins a 10-year search that includes both radio and optical strategies.

    Breakthrough Listen Project

    Telescopes:

    8
    100 Meter Robert C. Byrd Green Bank Telescope

    9
    64-metre diameter Parkes Telescope

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA


    Automated Planet Finder Telescope at Lick Observatory

    SETI Institute

    Still To Come:

    LASER SETI

    July 31, 2017
    New Laser SETI project will look for signals that most telescopes cannot see.
    Please visit https://www.indiegogo.com/projects/laser-seti-first-ever-all-sky-all-the-time-search-science#/ to learn all about Laser SETI.

    ____________________________________________________________________________

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 9:01 pm on July 21, 2017 Permalink | Reply
    Tags: , Messier 13, , , SETI, The Arecibo message,   

    From NYT: “Greetings, E.T. (Please Don’t Murder Us.)” 

    New York Times

    The New York Times

    JUNE 28, 2017
    STEVEN JOHNSON

    A new initiative to beam messages into space may be
    our best shot yet at learning whether we’re alone in the
    universe. There’s just one problem: What if we’re not?

    On Nov. 16, 1974, a few hundred astronomers, government officials and other dignitaries gathered in the tropical forests of Puerto Rico’s northwest interior, a four-hour drive from San Juan. The occasion was a rechristening of the Arecibo Observatory, at the time the largest radio telescope in the world.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    The mammoth structure — an immense concrete-and-aluminum saucer as wide as the Eiffel Tower is tall, planted implausibly inside a limestone sinkhole in the middle of a mountainous jungle — had been upgraded to ensure its ability to survive the volatile hurricane season and to increase its precision tenfold.

    To celebrate the reopening, the astronomers who maintained the observatory decided to take the most sensitive device yet constructed for listening to the cosmos and transform it, briefly, into a machine for talking back. After a series of speeches, the assembled crowd sat in silence at the edge of the telescope while the public-address system blasted nearly three minutes of two-tone noise through the muggy afternoon heat. To the listeners, the pattern was indecipherable, but somehow the experience of hearing those two notes oscillating in the air moved many in the crowd to tears.

    That 168 seconds of noise, now known as the Arecibo message, was the brainchild of the astronomer Frank Drake, then the director of the organization that oversaw the Arecibo facility.

    1
    Frank Drake

    The broadcast marked the first time a human being had intentionally transmitted a message targeting another solar system. The engineers had translated the missive into sound, so that the assembled group would have something to experience during the transmission. But its true medium was the silent, invisible pulse of radio waves, traveling at the speed of light.

    It seemed to most of the onlookers to be a hopeful act, if a largely symbolic one: a message in a bottle tossed into the sea of deep space. But within days, the Royal Astronomer of England, Martin Ryle, released a thunderous condemnation of Drake’s stunt. By alerting the cosmos of our existence, Ryle wrote, we were risking catastrophe. Arguing that ‘‘any creatures out there [might be] malevolent or hungry,’’ Ryle demanded that the International Astronomical Union denounce Drake’s message and explicitly forbid any further communications. It was irresponsible, Ryle fumed, to tinker with interstellar outreach when such gestures, however noble their intentions, might lead to the destruction of all life on earth.

    Today, more than four decades later, we still do not know if Ryle’s fears were warranted, because the Arecibo message is still eons away from its intended recipient, a cluster of roughly 300,000 stars known as Messier 13. If you find yourself in the Northern Hemisphere this summer on a clear night, locate the Hercules constellation in the sky, 21 stars that form the image of a man, arms outstretched, perhaps kneeling. Imagine hurtling 250 trillion miles toward those stars. Though you would have traveled far outside our solar system, you would only be a tiny fraction of the way to Messier 13. But if you were somehow able to turn on a ham radio receiver and tune it to 2,380 MHz, you might catch the message in flight: a long series of rhythmic pulses, 1,679 of them to be exact, with a clear, repetitive structure that would make them immediately detectable as a product of intelligent life.

    In its intended goal of communicating with life-forms outside our planet, the Arecibo message has surprisingly sparse company. Perhaps the most famous is housed aboard the Voyager 1 spacecraft — a gold-plated audiovisual disc, containing multilingual greetings and other evidence of human civilization — which slipped free of our solar system just a few years ago, traveling at a relatively sluggish 35,000 miles per hour. By contrast, at the end of the three-minute transmission of the Arecibo message, its initial pulses had already reached the orbit of Mars. The entire message took less than a day to leave the solar system.

    NASA/Voyager 1

    8
    Voyager – The Interstellar Mission. THE GOLDEN RECORD.

    True, some signals emanating from human activity have traveled much farther than even Arecibo, thanks to the incidental leakage of radio and television broadcasts. This was a key plot point in Carl Sagan’s novel, ‘‘Contact,’’ which imagined an alien civilization detecting the existence of humans through early television broadcasts from the Berlin Olympic Games, including clips of Hitler speaking at the opening ceremony.

    9

    Those grainy signals of Jesse Owens, and later of Howdy Doody and the McCarthy hearings, have ventured farther into space than the Arecibo pulses. But in the 40 years since Drake transmitted the message, just over a dozen intentional messages have been sent to the stars, most of them stunts of one fashion or another, including one broadcast of the Beatles’ ‘‘Across the Universe’’ to commemorate the 40th anniversary of that song’s recording. (We can only hope the aliens, if they exist, receive that message before they find the Hitler footage.)

    In the age of radio telescopes, scientists have spent far more energy trying to look for signs that other life might exist than they have signaling the existence of our own. Drake himself is now more famous for inaugurating the modern search for extraterrestrial intelligence (SETI) nearly 60 years ago, when he used a telescope in West Virginia to scan two stars for structured radio waves. Today the nonprofit SETI Institute oversees a network of telescopes and computers listening for signs of intelligence in deep space.

    SETI Institute

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA

    A new SETI-like project called Breakthrough Listen, funded by a $100 million grant from the Russian billionaire Yuri Milner, promises to radically increase our ability to detect signs of intelligent life.

    Breakthrough Listen Project

    1

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    As a species, we are gathered around more interstellar mailboxes than ever before, waiting eagerly for a letter to arrive. But we have, until recently, shown little interest in sending our own.

    Now this taciturn phase may be coming to an end, if a growing multidisciplinary group of scientists and amateur space enthusiasts have their way. A newly formed group known as METI (Messaging Extra Terrestrial Intelligence), led by the former SETI scientist Douglas Vakoch, is planning an ongoing series of messages to begin in 2018.

    9
    METI (Messaging Extraterrestrial Intelligence) International has announced plans to start sending signals into space

    And Milner’s Breakthrough Listen endeavor has also promised to support a ‘‘Breakthrough Message’’ companion project, including an open competition to design the messages that we will transmit to the stars. But as messaging schemes proliferate, they have been met with resistance. The intellectual descendants of Martin Ryle include luminaries like Elon Musk and Stephen Hawking, and they caution that an assumption of interstellar friendship is the wrong way to approach the question of extraterrestrial life. They argue that an advanced alien civilization might well respond to our interstellar greetings with the same graciousness that Cortés showed the Aztecs, making silence the more prudent option.

    If you believe that these broadcasts have a plausible chance of making contact with an alien intelligence, the choice to send them must rank as one of the most important decisions we will ever make as a species. Are we going to be galactic introverts, huddled behind the door and merely listening for signs of life outside? Or are we going to be extroverts, conversation-starters? And if it’s the latter, what should we say?

    Amid the decommissioned splendor of Fort Mason, on the northern edge of San Francisco, sits a bar and event space called the Interval. It’s run by the Long Now Foundation, an organization founded by Stewart Brand and Brian Eno, among others, to cultivate truly long-term thinking. The group is perhaps most famous for its plan to build a clock that will successfully keep time for 10,000 years. Long Now says the San Francisco space is designed to push the mind away from our attention-sapping present, and this is apparent from the 10,000-year clock prototypes to the menu of ‘‘extinct’’ cocktails.

    The Interval seemed like a fitting backdrop for my first meeting with Doug Vakoch, in part because Long Now has been advising METI on its message plans and in part because the whole concept of sending interstellar messages is the epitome of long-term decision-making. The choice to send a message into space is one that may well not generate a meaningful outcome for a thousand years, or a hundred thousand. It is hard to imagine any decision confronting humanity that has a longer time horizon.

    As Vakoch and I settled into a booth, I asked him how he found his way to his current vocation. ‘‘I liked science when I was a kid, but I couldn’t make up my mind which science,’’ he told me. Eventually, he found out about a burgeoning new field of study known as exobiology, or sometimes astrobiology, that examined the possible forms life could take on other planets. The field was speculative by nature: After all, its researchers had no actual specimens to study. To imagine other forms of life in the universe, exobiologists had to be versed in the astrophysics of stars and planets; the chemical reactions that could capture and store energy in these speculative organisms; the climate science that explains the weather systems on potentially life-compatible planets; the biological forms that might evolve in those different environments. With exobiology, Vakoch realized, he didn’t have to settle on one discipline: ‘‘When you think about life outside the earth, you get to dabble in all of them.’’

    As early as high school, Vakoch began thinking about how you might communicate with an organism that had evolved on another planet, the animating question of a relatively obscure subfield of exobiology known as exosemiotics. By the time Vakoch reached high school in the 1970s, radio astronomy had advanced far enough to turn exosemiotics from a glorified thought experiment into something slightly more practical. Vakoch did a science-fair project on interstellar languages, and he continued to follow the field during his college years, even as he was studying comparative religion at Carleton College in Minnesota. ‘‘The issue that really hit me early on, and that has stayed with me, is just the challenge of creating a message that would be understandable,’’ Vakoch says. Hedging his bets, he pursued a graduate degree in clinical psychology, thinking it might help him better understand the mind of some unknown organism across the universe. If the exosemiotics passion turned out to be a dead end professionally, he figured that he could always retreat back to a more traditional career path as a psychologist.

    During Vakoch’s graduate years, SETI was transforming itself from a NASA program sustained by government funding to an independent nonprofit organization, supported in part by the new fortunes of the tech sector. Vakoch moved to California and joined SETI in 1999. In the years that followed, Vakoch and other scientists involved in the program grew increasingly vocal in their argument for sending messages as well as listening for them. The ‘‘passive’’ approach was essential, they argued, but an ‘‘active’’ SETI — one targeting nearby star systems with high-powered radio signals — would increase the odds of contact. Concerned that embracing an active approach would imperil its funding, the SETI board resisted Vakoch’s efforts. Eventually Vakoch decided to form his own international organization, METI, with a multidisciplinary team that includes the former NASA chief historian Steven J. Dick, the French science historian Florence Raulin Cerceau, the Indian ecologist Abhik Gupta and the Canadian anthropologist Jerome H. Barkow.

    The newfound interest in messaging has been piqued in large part by an explosion of newly discovered planets. We now know that the universe is teeming with planets occupying what exobiologists call ‘‘the Goldilocks zone’’: not too hot and not too cold, with ‘‘just right’’ surface temperatures capable of supporting liquid water. At the start of Drake’s career in the 1950s, not a single planet outside our solar system had been observed. Today we can target a long list of potential Goldilocks-zone planets, not just distant clusters of stars. ‘‘Now we know that virtually all stars have planets,’’ Vakoch says, adding that, of these stars, ‘‘maybe one out of five have potentially habitable planets. So there’s a lot of real estate that could be inhabited.’’

    When Frank Drake and Carl Sagan first began thinking about message construction in the 1960s, their approach was genuinely equivalent to the proverbial message in a bottle. Now, we may not know the exact addresses of planets where life is likely, but we have identified many promising ZIP codes. The recent discovery of the Trappist-1 planets, three of which are potentially habitable, triggered such excitement in part because those planets were, relatively speaking, so close to home: just 40 light-years from Earth.

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    If the Arecibo message does somehow find its way to an advanced civilization in Messier 13, word would not come back for at least 50,000 years. But a targeted message sent to Trappist-1 could generate a reply before the end of the century.

    Frank Drake is now 87 and lives with his wife in a house nestled in an old-growth redwood forest, at the end of a narrow, winding road in the hills near Santa Cruz. His circular driveway wraps around the trunk of a redwood bigger than a pool table. As I left my car, I found myself thinking again of the long now: a man who sends messages with a potential life span of 50,000 years, living among trees that first took root a millennium ago.

    Drake has been retired for more than a decade, but when I asked him about the Arecibo message, his face lit up at the memory. ‘‘We had just finished a very big construction project at Arecibo, and I was director then, and so they said, ‘Can you please arrange a big ceremony?’ ’’ he recalled. ‘‘We had to have some kind of eye-catching event for this ceremony. What could we do that would be spectacular? We could send a message!’’

    But how can you send a message to a life-form that may or may not exist and that you know nothing at all about, other than the fact that it evolved somewhere in the Milky Way? You need to start by explaining how the message is supposed to be read, which is known in exosemiotics as the ‘‘primer.’’ You don’t need a primer on Earth: You point to a cow, and you say, ‘‘Cow.’’ The plaques that NASA sent into space with Pioneer and Voyager had the advantage of being physical objects that could convey visual information, which at least enables you to connect words with images of the objects they refer to. In other words, you draw a cow and then put the word ‘‘cow’’ next to the drawing and slowly, with enough pointing, a language comes into view. But physical objects can’t be moved fast enough to get to a potential recipient in useful time scales. You need electromagnetic waves if you want to reach across the Milky Way.

    But how do you point to something with a radio wave? Even if you figured out a way to somehow point to a cow with electromagnetic signals, the aliens aren’t going to have cows in their world, which means the reference will most likely be lost on them. Instead, you need to think hard about the things that our hypothetical friends in the Trappist-1 system will have in common with us. If their civilization is advanced enough to recognize structured data in radio waves, they must share many of our scientific and technological concepts. If they are hearing our message, that means they are capable of parsing structured disturbances in the electromagnetic spectrum, which means they understand the electromagnetic spectrum in some meaningful way.

    The trick, then, is just getting the conversation started. Drake figured that he could count on intelligent aliens possessing the concept of simple numbers: one, three, 10, etc. And if they have numbers, then they will also very likely have the rest of what we know as basic math: addition, subtraction, multiplication, division. Furthermore, Drake reasoned, if they have multiplication and division, then they are likely to understand the concept of prime numbers — the group of numbers that are divisible only by themselves and one. (In ‘‘Contact,’’ the intercepted alien message begins with a long string of primes: 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, and so on.) Many objects in space, like pulsars, send out radio signals with a certain periodicity: flashes of electromagnetic activity that switch on and off at regular rates. Primes, however, are a telltale sign of intelligent life. ‘‘Nature never uses prime numbers,’’ Drake says. ‘‘But mathematicians do.’’

    Drake’s Arecibo message drew upon a close relative of the prime numbers to construct its message. He chose to send exactly 1,679 pulses, because 1,679 is a semiprime number: a number that can be formed only by multiplying two prime numbers together, in this case 73 and 23. Drake used that mathematical quirk to turn his pulses of electromagnetic energy into a visual system. To simplify his approach, imagine I send you a message consisting of 10 X’s and 5 O’s: XOXOXXXXOXXOXOX. You notice that the number 15 is a semi-prime number, and so you organize the symbols in a 3-by-5 grid and leave the O’s as blank spaces. The result is this:

    4

    If you were an English speaker, you might just recognize a greeting in that message, the word ‘‘HI’’ mapped out using only a binary language of on-and-off states.

    Drake took the same approach, only using a much larger semiprime, which gave him a 23-by-73 grid to send a more complicated message. Because his imagined correspondents in Messier 13 were not likely to understand any human language, he filled the grid with a mix of mathematical and visual referents. The top of the grid counted from one to 10 in binary code — effectively announcing to the aliens that numbers will be represented using these symbols.

    Having established a way of counting, Drake then moved to connect the concept of numbers to some reference that the citizens of Messier 13 would likely share with us. For this step, he encoded the atomic numbers for five elements: hydrogen, carbon, nitrogen, oxygen and phosphorous, the building blocks of DNA. Other parts of the message were more visually oriented. Drake used the on-off pulses of the radio signal to ‘‘draw’’ a pixelated image of a human body. He also included a sketch of our solar system and of the Arecibo telescope itself. The message said, in effect: This is how we count; this is what we are made of; this is where we came from; this is what we look like; and this is the technology we are using to send this message to you.

    As inventive as Drake’s exosemiotics were in 1974, the Arecibo message was ultimately more of a proof-of-concept than a genuine attempt to make contact, as Drake himself is the first to admit. For starters, the 25,000 light-years that separate us from Messier 13 raise a legitimate question about whether humans will even be around — or recognizably human — by the time a message comes back. The choice of where to send it was almost entirely haphazard. The METI project intends to improve on the Arecibo model by directly targeting nearby Goldilocks-zone planets.

    One of the most recent planets added to that list orbits the star Gliese 411, a red dwarf located eight light-years away from Earth.

    On a spring evening in the Oakland hills, our own sun putting on a spectacular display as it slowly set over the Golden Gate Bridge, Vakoch and I met at one of the observatories at the Chabot Space and Science Center to take a peek at Gliese 411. A half moon overhead reduced our visibility but not so much that I couldn’t make out the faint tangerine glimmer of the star, a single blurred point of light that had traveled nearly 50 trillion miles across the universe to land on my retina. Even with the power of the Oakland telescope, there was no way to spot a planet orbiting the red dwarf. But in February of this year, a team of researchers using the Keck I telescope at the top of Mauna Kea in Hawaii announced that they had detected a ‘‘super-earth’’ in orbit around Gliese, a rocky and hot planet larger than our own.

    Keck Observatory, Maunakea, Hawaii, USA

    11
    Artist’s conceptions of the probable planet orbiting a star called GJ 411. Credit: Ricardo Ramirez.

    The METI group aims to improve on the Arecibo message not just by targeting specific planets, like that super-earth orbiting Gliese, but also by rethinking the nature of the message itself. ‘‘Drake’s original design plays into the bias that vision is universal among intelligent life,’’ Vakoch told me. Visual diagrams — whether formed through semiprime grids or engraved on plaques — seem like a compelling way to encode information to us because humans happen to have evolved an unusually acute sense of vision. But perhaps the aliens followed a different evolutionary path and found their way to a technologically advanced civilization with an intelligence that was rooted in some other sense: hearing, for example, or some other way of perceiving the world around them for which there is no earthly equivalent.

    Like so much of the SETI/METI debate, the question of visual messaging quickly spirals out into a deeper meditation, in this instance on the connection between intelligence and visual acuity. It is no accident that eyes developed independently so many times over the course of evolution on Earth, given the fact that light conveys information faster than any other conduit. That transmission-speed advantage would presumably apply on other planets in the Goldilocks zone, even if they happened to be on the other side of the Milky Way, and so it seems plausible that intelligent creatures would evolve some sort of visual system as well.

    But even more universal than sight would be the experience of time. Hans Freudenthal’s Lincos: Design of a Language for Cosmic Intercourse, a seminal book of exosemiotics published more than a half-century ago, relied heavily on temporal cues in its primer stage. Vakoch and his collaborators have been working with Freudenthal’s language in their early drafts for the message. In Lincos, duration is used as a key building block. A pulse that lasts for a certain stretch (say, in human terms, one second) is followed by a sequence of pulses that signify the ‘‘word’’ for one; a pulse that lasts for six seconds is followed by the word for six. The words for basic math properties can be conveyed by combining pulses of different lengths. You might demonstrate the property of addition by sending the word for ‘‘three’’ and ‘‘six’’ and then sending a pulse that lasts for nine seconds. ‘‘It’s a way of being able to point at objects when you don’t have anything right in front of you,’’ Vakoch explains.

    Other messaging enthusiasts think we needn’t bother worrying about primers and common referents. ‘‘Forget about sending mathematical relationships, the value of pi, prime numbers or the Fibonacci series,’’ the senior SETI astronomer, Seth Shostak, argued in a 2009 book.

    SETI astronomer Seth Shostak

    ‘‘No, if we want to broadcast a message from Earth, I propose that we just feed the Google servers into the transmitter. Send the aliens the World Wide Web. It would take half a year or less to transmit this in the microwave; using infrared lasers shortens the transmit time to no more than two days.’’ Shostak believes that the sheer magnitude of the transmitted data would enable the aliens to decipher it. There is some precedent for this in the history of archaeologists studying dead languages: The hardest code to crack is one with only a few fragments.

    Sending all of Google would be a logical continuation of Drake’s 1974 message, in terms of content if not encoding. ‘‘The thing about the Arecibo message is that, in a sense, it’s brief but its intent is encyclopedic,’’ Vakoch told me as we waited for the sky to darken in the Oakland hills. ‘‘One of the things that we are exploring for our transmission is the opposite extreme. Rather than being encyclopedic, being selective. Instead of this huge digital data dive, trying to do something elegant. Part of that is thinking about what are the most fundamental concepts we need.’’ There is something provocative about the question Vakoch is wrestling with here: Of all the many manifestations of our achievements as a species, what’s the simplest message we can create that will signal that we’re interesting, worthy of an interstellar reply?

    But to METI’s critics, what he should be worrying about instead is the form that the reply might take: a death ray, or an occupying army.

    6

    Before Doug Vakoch had even filed the papers to form the METI nonprofit organization in July 2015, a dozen or so science-and-tech luminaries, including SpaceX’s Elon Musk, signed a statement categorically opposing the project, at least without extensive further discussion, on a planetary scale. ‘‘Intentionally signaling other civilizations in the Milky Way Galaxy,’’ the statement argued, ‘‘raises concerns from all the people of Earth, about both the message and the consequences of contact. A worldwide scientific, political and humanitarian discussion must occur before any message is sent.’’

    One signatory to that statement was the astronomer and science-fiction author David Brin, who has been carrying on a spirited but collegial series of debates with Vakoch over the wisdom of his project. ‘‘I just don’t think anybody should give our children a fait accompli based on blithe assumptions and assertions that have been untested and not subjected to critical peer review,’’ he told me over a Skype call from his home office in Southern California. ‘‘If you are going to do something that is going to change some of the fundamental observable parameters of our solar system, then how about an environmental-impact statement?’’

    The anti-METI movement is predicated on a grim statistical likelihood: If we do ever manage to make contact with another intelligent life-form, then almost by definition, our new pen pals will be far more advanced than we are. The best way to understand this is to consider, on a percentage basis, just how young our own high-tech civilization actually is. We have been sending structured radio signals from Earth for only the last 100 years. If the universe were exactly 14 billion years old, then it would have taken 13,999,999,900 years for radio communication to be harnessed on our planet. The odds that our message would reach a society that had been tinkering with radio for a shorter, or even similar, period of time would be staggeringly long. Imagine another planet that deviates from our timetable by just a tenth of 1 percent: If they are more advanced than us, then they will have been using radio (and successor technologies) for 14 million years. Of course, depending on where they live in the universe, their signals might take millions of years to reach us. But even if you factor in that transmission lag, if we pick up a signal from another galaxy, we will almost certainly find ourselves in conversation with a more advanced civilization.

    7
    Carl Sagan holding the Pioneer plaque in Boston, in 1972. Credit Jeff Albertson Photograph Collection/UMass Amherst Libraries.

    It is this asymmetry that has convinced so many future-minded thinkers that METI is a bad idea. The history of colonialism here on Earth weighs particularly heavy on the imaginations of the METI critics. Stephen Hawking, for instance, made this observation in a 2010 documentary series: ‘‘If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.’’ David Brin echoes the Hawking critique: ‘‘Every single case we know of a more technologically advanced culture contacting a less technologically advanced culture resulted at least in pain.’’

    METI proponents counter the critics with two main arguments. The first is essentially that the horse has already left the barn: Given that we have been ‘‘leaking’’ radio waves in the form of Leave It to Beaver and the nightly news for decades, and given that other civilizations are likely to be far more advanced than we are, and thus capable of detecting even weak signals, then it seems likely that we are already visible to extraterrestrials. In other words, they know we’re here, but they haven’t considered us to be worthy of conversation yet. ‘‘Maybe in fact there are a lot more civilizations out there, and even nearby planets are populated, but they’re simply observing us,’’ Vakoch argues. ‘‘It’s as if we are in some galactic zoo, and if they’ve been watching us, it’s like watching zebras talking to one another. But what if one of those zebras suddenly turns toward you and with its hooves starts scratching out the prime numbers. You’d relate to that zebra differently!’’

    Brin thinks that argument dangerously underestimates the difference between a high-power, targeted METI transmission and the passive leakage of media signals, which are far more difficult to detect. ‘‘Think about it this way: If you want to communicate with a Boy Scout camp on the other side of the lake, you could kneel down at the end of the lake and slap the water in Morse code,’’ he says. ‘‘And if they are spectacularly technologically advanced Boy Scouts who happened also to be looking your way, they might build instruments that would be able to parse out your Morse code. But then you whip out your laser-pointer and point it at their dock. That is exactly the order of magnitude difference between picking up [reruns of] ‘I Love Lucy’ from the 1980s, when we were at our noisiest, and what these guys want to do.’’

    METI defenders also argue that the threat of some Klingon-style invasion is implausible, given the distances involved. If, in fact, advanced civilizations were capable of zipping around the galaxy at the speed of light, we would have already encountered them. The much more likely situation is that only communications can travel that fast, and so a malevolent presence on some distant planet will only be able to send us hate mail. But critics think that sense of security is unwarranted. Writing in Scientific American, the former chairman of SETI, John Gertz, argued that ‘‘a civilization with malign intent that is only modestly more advanced than we are might be able to annihilate Earth with ease by means of a small projectile filled with a self-replicating toxin or nano gray goo; a kinetic missile traveling at an appreciable percentage of the speed of light; or weaponry beyond our imagination.’’

    Brin looks to our own technological progress as a sign of where a more advanced civilization might be in terms of interstellar combat: ‘‘It is possible that within just 50 years, we could create an antimatter rocket that could propel a substantial pellet of several kilograms, at half the speed of light at times to intersect with the orbit of a planet within 10 light-years of us.’’ Even a few kilograms colliding at that speed would produce an explosion much greater than the Hiroshima and Nagasaki detonations combined. ‘‘And if we could do that in 50 years, imagine what anybody else could do, completely obeying Einstein and the laws of physics.’’

    Interestingly, Frank Drake himself is not a supporter of the METI efforts, though he does not share Hawking and Musk’s fear of interstellar conquistadors. ‘‘We send messages all the time, free of charge,’’ he says. ‘‘There’s a big shell out there now 80 light-years around us. A civilization only a little more advanced than we are can pick those things up. So the point is we are already sending copious amounts of information.’’ Drake believes that any other advanced civilization out there must be doing the same, so scientists like Vakoch should devote themselves to picking up on that chatter instead of trying to talk back. METI will consume resources, Drake says, that would be ‘‘better spent listening and not sending.’’

    METI critics, of course, might be right about the frightening sophistication of these other, presumably older civilizations but wrong about the likely nature of their response. Yes, they could be capable of sending projectiles across the galaxy at a quarter of the speed of light. But their longevity would also suggest that they have figured out how to avoid self-destruction on a planetary scale. As Steven Pinker has argued, human beings have become steadily less violent over the last 500 years; per capita deaths from military conflict are most likely at an all-time low. Could this be a recurring pattern throughout the universe, played out on much longer time scales: the older a civilization gets, the less warlike it becomes? In which case, if we do get a message to extraterrestrials, then perhaps they really will come in peace.

    These sorts of questions inevitably circle back to the two foundational thought experiments that SETI and METI are predicated upon: the Fermi Paradox and the Drake Equation. The paradox, first formulated by the Italian physicist and Nobel laureate Enrico Fermi, begins with the assumption that the universe contains an unthinkably large number of stars, with a significant percentage of them orbited by planets in the Goldilocks zone. If intelligent life arises on even a small fraction of those planets, then the universe should be teeming with advanced civilizations. And yet to date, we have seen no evidence of those civilizations, even after several decades of scanning the skies through SETI searches. Fermi’s question, apparently raised during a lunch conversation at Los Alamos in the early 1950s, was a simple one: ‘‘Where is everybody?’’

    The Drake Equation is an attempt to answer that question. The equation dates back to one of the great academic retreats in the history of scholarship: a 1961 meeting at the Green Bank observatory in West Virginia, which included Frank Drake, a 26-year-old Carl Sagan and the dolphin researcher (and later psychedelic explorer) John Lilly. During the session, Drake shared his musings on the Fermi Paradox, formulated as an equation. If we start scanning the cosmos for signs of intelligent life, Drake asked, how likely are we to actually detect something? The equation didn’t generate a clear answer, because almost all the variables were unknown at the time and continue to be largely unknown a half-century later. But the equation had a clarifying effect, nonetheless. In mathematical form, it looks like this:

    N= R* x ƒp x ne x ƒl x ƒi x ƒc x L

    N represents the number of extant, communicative civilizations in the Milky Way. The initial variable R* corresponds to the rate of star formation in the galaxy, effectively giving you the total number of potential suns that could support life. The remaining variables then serve as a kind of nested sequence of filters: Given the number of stars in the Milky Way, what fraction of those have planets, and how many of those have an environment that can support life? On those potentially hospitable planets, how often does life itself actually emerge, and what fraction of that life evolves into intelligent life, and what fraction of that life eventually leads to a civilization’s transmitting detectable signals into space? At the end of his equation, Drake placed the crucial variable L, which is the average length of time during which those civilizations emit those signals.

    What makes the Drake Equation so mesmerizing is in part the way it forces the mind to yoke together so many different intellectual disciplines in a single framework. As you move from left to right in the equation, you shift from astrophysics, to the biochemistry of life, to evolutionary theory, to cognitive science, all the way to theories of technological development. Your guess about each value in the Drake Equation winds up revealing a whole worldview: Perhaps you think life is rare, but when it does emerge, intelligent life usually follows; or perhaps you think microbial life is ubiquitous throughout the cosmos, but more complex organisms almost never form. The equation is notoriously vulnerable to very different outcomes, depending on the numbers you assign to each variable.

    The most provocative value is the last one: L, the average life span of a signal-transmitting civilization. You don’t have to be a Pollyanna to defend a relatively high L value. All you need is to believe that it is possible for civilizations to become fundamentally self-sustaining and survive for millions of years. Even if one in a thousand intelligent life-forms in space generates a million-year civilization, the value of L increases meaningfully. But if your L-value is low, that implies a further question: What is keeping it low? Do technological civilizations keep flickering on and off in the Milky Way, like so many fireflies in space? Do they run out of resources? Do they blow themselves up?

    Since Drake first sketched out the equation in 1961, two fundamental developments have reshaped our understanding of the problem. First, the numbers on the left-hand side of the equation (representing the amount of stars with habitable planets) have increased by several orders of magnitude. And second, we have been listening for signals for decades and heard nothing. As Brin puts it: ‘‘Something is keeping the Drake Equation small. And the difference between all the people in the SETI debates is not whether that’s true, but where in the Drake panoply the fault lies.’’

    If the left-hand values keep getting bigger and bigger, the question is which variables on the right-hand side are the filters. As Brin puts it, we want the filter to be behind us, not the one variable, L, that still lies ahead of us. We want the emergence of intelligent life to be astonishingly rare; if the opposite is true, and intelligent life is abundant in the Milky Way, then L values might be low, perhaps measured in centuries and not even millenniums. In that case, the adoption of a technologically advanced lifestyle might be effectively simultaneous with extinction. First you invent radio, then you invent technologies capable of destroying all life on your planet and shortly thereafter you push the button and your civilization goes dark.

    The L-value question explains why so many of METI’s opponents — like Musk and Hawking — are also concerned with the threat of extinction-level events triggered by other potential threats: superintelligent computers, runaway nanobots, nuclear weapons, asteroids. In a low L-value universe, planet-wide annihilation is an imminent possibility. Even if a small fraction of alien civilizations out there would be inclined to shoot a two-kilogram pellet toward us at half the speed of light, is it worth sending a message if there’s even the slightest chance that the reply could result in the destruction of all life on earth?

    Other, more benign, explanations for the Fermi Paradox exist. Drake himself is pessimistic about the L value, but not for dystopian reasons. ‘‘It’s because we’re getting better at technology,’’ he says. The modern descendants of the TV and radio towers that inadvertently sent Elvis to the stars are far more efficient in terms of the power they use, which means the ‘‘leaked’’ signals emanating from Earth are far fainter than they were in the 1950s. In fact, we increasingly share information via fiber optics and other terrestrial conduits that have zero leakage outside our atmosphere. Perhaps technologically advanced societies do flicker on and off like fireflies, but it’s not a sign that they’re self-destructive; it’s just a sign that they got cable.

    But to some METI critics, even a less-apocalyptic interpretation of the Fermi Paradox still suggests caution. Perhaps advanced civilizations tend to reach a point at which they decide, for some unknown reason, that it is in their collective best interest not to transmit any detectable signal to their neighbors in the Milky Way. ‘‘That’s the other answer for the Fermi Paradox,’’ Vakoch says with a smile. ‘‘There’s a Stephen Hawking on every planet, and that’s why we don’t hear from them.’’

    In his California home among the redwoods, Frank Drake has a version of the Arecibo message visually encoded in a very different format: not a series of radio-wave pulses but as a stained-glass window in his living room. A grid of pixels on a cerulean blue background, it almost resembles a game of Space Invaders. Stained glass is an appropriate medium, given the nature of the message: an offering dispatched to unknown beings residing somewhere in the sky.

    There is something about the METI question that forces the mind to stretch beyond its usual limits. You have to imagine some radically different form of intelligence, using only your human intelligence. You have to imagine time scales on which a decision made in 2017 might trigger momentous consequences 10,000 years from now. The sheer magnitude of those consequences challenges our usual measures of cause and effect. Whether you believe that the aliens are likely to be warriors or Zen masters, if you think that METI has a reasonable chance of making contact with another intelligent organism somewhere in the Milky Way, then you have to accept that this small group of astronomers and science-fiction authors and billionaire patrons debating semi-prime numbers and the ubiquity of visual intelligence may in fact be wrestling with a decision that could prove to be the most transformative one in the history of human civilization.

    8
    Frank Drake in front of the National Radio Astronomy Observatory Green Bank 300-foot radio telescope in West Virginia in the mid-1960’s.
    Credit National Radio Astronomy Observatory.

    All of which takes us back to a much more down-to-earth, but no less challenging, question: Who gets to decide? After many years of debate, the SETI community established an agreed-­upon procedure that scientists and government agencies should follow in the event that the SETI searches actually stumble upon an intelligible signal from space. The protocols specifically ordain that ‘‘no response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate international consultations have taken place.’’ But an equivalent set of guidelines does not yet exist to govern our own interstellar outreach.

    One of the most thoughtful participants in the METI debate, Kathryn Denning, an anthropologist at York University in Toronto, has argued that our decisions about extraterrestrial contact are ultimately more political than scientific. ‘‘If I had to take a position, I’d say that broad consultation regarding METI is essential, and so I greatly respect the efforts in that direction,’’ Denning says. ‘‘But no matter how much consultation there is, it’s inevitable that there will be significant disagreement about the advisability of transmitting, and I don’t think this is the sort of thing where a simple majority vote or even supermajority should carry the day . . . so this keeps bringing us back to the same key question: Is it O.K. for some people to transmit messages at significant power when other people don’t want them to?’’

    In a sense, the METI debate runs parallel to other existential decisions that we will be confronting in the coming decades, as our technological and scientific powers increase. Should we create superintelligent machines that exceed our own intellectual capabilities by such a wide margin that we cease to understand how their intelligence works? Should we ‘‘cure’’ death, as many technologists are proposing? Like METI, these are potentially among the most momentous decisions human beings will ever make, and yet the number of people actively participating in those decisions — or even aware such decisions are being made — is minuscule.

    ‘‘I think we need to rethink the message process so that we are sending a series of increasingly inclusive messages,’’ Vakoch says. ‘‘Any message that we initially send would be too narrow, too incomplete. But that’s O.K. Instead, what we should be doing is thinking about how to make the next round of messages better and more inclusive. We ideally want a way to incorporate both technical expertise — people who have been thinking about these issues from a range of different disciplines — and also getting lay input. I think it’s often been one or the other. One way we can get lay input in a way that makes a difference in terms of message content is to survey people about what sorts of things they would want to say. It’s important to see what the general themes are that people would want to say and then translate those into a Lincos-like message.’’

    When I asked Denning where she stands on the METI issue, she told me: ‘‘I have to answer that question with a question: Why are you asking me? Why should my opinion matter more than that of a 6-year-old girl in Namibia? We both have exactly the same amount at stake, arguably, she more than I, since the odds of being dead before any consequences of transmission occur are probably a bit higher for me, assuming she has access to clean water and decent health care and isn’t killed far too young in war.’’ She continued: ‘‘I think the METI debate may be one of those rare topics where scientific knowledge is highly relevant to the discussion, but its connection to obvious policy is tenuous at best, because in the final analysis, it’s all about how much risk the people of Earth are willing to tolerate. . . . And why exactly should astronomers, cosmologists, physicists, anthropologists, psychologists, sociologists, biologists, sci-fi authors or anyone else (in no particular order), get to decide what those tolerances should be?’’

    Wrestling with the METI question suggests, to me at least, that the one invention human society needs is more conceptual than technological: We need to define a special class of decisions that potentially create extinction-level risk. New technologies (like superintelligent computers) or interventions (like METI) that pose even the slightest risk of causing human extinction would require some novel form of global oversight. And part of that process would entail establishing, as Denning suggests, some measure of risk tolerance on a planetary level. If we don’t, then by default the gamblers will always set the agenda, and the rest of us will have to live with the consequences of their wagers.

    In 2017, the idea of global oversight on any issue, however existential the threat it poses, may sound naïve. It may also be that technologies have their own inevitability, and we can only rein them in for so long: If contact with aliens is technically possible, then someone, somewhere is going to do it soon enough. There is not a lot of historical precedent for humans voluntarily swearing off a new technological capability — or choosing not to make contact with another society — because of some threat that might not arrive for generations. But maybe it’s time that humans learned how to make that kind of choice. This turns out to be one of the surprising gifts of the METI debate, whichever side you happen to take. Thinking hard about what kinds of civilization we might be able to talk to ends up making us think even harder about what kind of civilization we want to be ourselves.

    Near the end of my conversation with Frank Drake, I came back to the question of our increasingly quiet planet: all those inefficient radio and television signals giving way to the undetectable transmissions of the internet age. Maybe that’s the long-term argument for sending intentional messages, I suggested; even if it fails in our lifetime, we will have created a signal that might enable an interstellar connection thousands of years from now.

    Drake leaned forward, nodding. ‘‘It raises a very interesting, nonscientific question, which is: Are extraterrestrial civilizations altruistic? Do they recognize this problem and establish a beacon for the benefit of the other folks out there? My answer is: I think it’s actually Darwinian; I think evolution favors altruistic societies. So my guess is yes. And that means there might be one powerful signal for each civilization.’’ Given the transit time across the universe, that signal might well outlast us as a species, in which case it might ultimately serve as a memorial as much as a message, like an interstellar version of the Great Pyramids: proof that a technologically advanced organism evolved on this planet, whatever that organism’s ultimate fate.

    As I stared at Drake’s stained-glass Arecibo message, in the middle of that redwood grove, it seemed to me that an altruistic civilization — one that wanted to reach across the cosmos in peace — would be something to aspire to, despite the potential for risk. Do we want to be the sort of civilization that boards up the windows and pretends that no one is home, for fear of some unknown threat lurking in the dark sky? Or do we want to be a beacon?

    Correction: June 30, 2017

    An earlier version of this article misstated the impact a few kilograms traveling half the speed of light would have if they collided with Earth. The impact would be less than that of the asteroid that killed off the dinosaurs, not more.

    See the full article here .

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  • richardmitnick 12:27 pm on October 12, 2016 Permalink | Reply
    Tags: , SETI   

    From ABC via SETI Institute: “Where is the search for extraterrestrial life up to?” 

    ABC News bloc

    ABC News

    10.11.16
    Mark Llewellyn

    1
    Photo: Scientists are stepping up their search to eavesdrop on ET. Facility not identified.

    Despite the headlines, no alleged signals from ET have ever been confirmed. Yet far from being put off their search, scientists are stepping it up.

    For decades scientists have been searching for evidence of life beyond Earth — intelligent or otherwise — using an array of methods.

    “If you are talking about life in the solar system, like life on Mars, or maybe Saturn’s moon Titan, or maybe one of Jupiter’s moons like Europa, then you just send a rocket and look for it,” said Seth Shostak, of the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California.

    There could be microbial life in all of these places, Dr Shostak said, “but you have to look hard, probably underneath the surfaces of these planets and moons”.

    As for finding life around other stars, scientists have to use really big telescopes to scan distant planets for chemicals — like oxygen, methane and water vapour.

    The challenge is that these kinds of molecular tracers for life could also indicate geological events.

    Scientists are still trying to pin down the exact chemical signature that would really prove life and not just the existence of volcanoes, Dr Shostak said.

    Other chemicals like ammonia, carbon and amino acids could also be signs of life.

    Meanwhile, the SETI Institute and others are focusing on another technique: looking for potential communication signals from ET.

    “You just do what Jodie Foster did in the movie Contact and eavesdrop on radio signals,” Dr Shostak explained.

    Optical laser transmissions as well as narrow-band radio signals are possible signs of intelligent life out there.

    But again it is hard to be sure where a signal really comes from, especially when you can’t pick it up more than once.

    False alarms and hoaxes

    Take the recent report that the giant Russian RATAN-600 radio telescope had picked up a signal while scanning a star called HD164595, in the constellation Hercules, the year before.

    “I’ve no doubt the signal was there, but the question was: is it ET, or just some satellite that’s just wheeling overhead and producing some radio emission that they picked up?” Dr Shostak said.

    He used SETI’s Allen Telescope Array in northern California, to zoom in on the star system.

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA
    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA

    “We didn’t find anything, the guys at the University of California Berkeley using their big telescope in West Virginia didn’t find anything. The Russians looked in this direction, I think 39 times, and only found this signal once,” Dr Shostak said.

    So, this looks very much like another false alarm — just like the claim last year that a giant alien engineering project had been set up on a planet orbiting a star called KIC 8462852.

    At least it wasn’t a hoax like the claim, by an amateur UK radio astronomer in 1998, that he had found radio signals coming from a system of two dwarf stars in the constellation Pegasus.

    The best candidate for an alien radio transmission remains the so-called WOW! signal, detected in 1977 by Ohio University’s Big Ear radio telescope, Dr Shostak said.

    Ohio State Big Ear Radio Telescope
    Ohio State Big Ear Radio Telescope

    The signal has not been heard again since so remains unconfirmed.

    Scientists step up the search

    Despite the lack of definitive evidence so far, the search for extraterrestrial life continues, and indeed scientists are stepping up the search.

    The European Space Agency’s ExoMars program is concentrating on Mars. An orbiter launched in March this year aims to examine the Martian atmosphere and a follow-up mission, featuring a rover vehicle, has a launch date of 2020.

    Looking outside our solar system is NASA’s Kepler space observatory, which lifted off in 2009. It has found thousands of planets, including dozens that could possibly support life.

    The number of planets has increased substantially over the past few years thanks to faster data processing.

    Meanwhile, the James Webb Space Telescope, planned for launch in 2018, will investigate the potential for extraterrestrial life by “sniffing” the atmospheric chemistry of Earth-like planets around other stars.

    Back on Earth, the world’s biggest single dish radio telescope, the 500-metre Aperture Spherical Radio Telescope (FAST), began operating in south-western China last month.

    FAST radio telescope located in the Dawodang depression in Pingtang county Guizhou Province, South China
    FAST radio telescope located in the Dawodang depression in Pingtang county Guizhou Province, South China

    Construction of the Square Kilometre Array (SKA), a giant multi radio telescope — made up of thousands of dishes and up to 1 million antennas — is also due to start in 2018.

    SKA Square Kilometer Array

    If it goes ahead, Australia will host more than 500 stations, each containing about 250 individual antennas.

    As part of a key science program, called Cradle of Life, SKA will focus on searching for carbon-containing chemicals in planetary atmospheres, while also trying to detect radio emissions from extraterrestrial civilisations.

    Parkes Observatory moves to centre stage

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia
    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    Meanwhile, the biggest-ever search for intelligent alien life ramps up this month when Parkes Observatory joins Green Bank Observatory in West Virginia in the $100 million Breakthrough Listen initiative.

    GBO radio telescope, West Virginia, USA
    GBO radio telescope, West Virginia, USA

    The project picks up fainter radio signals and covers 10 times more sky than previous hunts for alien life.

    Data is being analysed by computers belonging to volunteers of the citizen science project SETI@home.

    SETI@home, BOINC project at UC Berkeley Space Science Lab
    SETI@home, BOINC project at UC Berkeley Space Science Lab

    About 10 million people around the world have downloaded the free SETI@home software.

    While some scientists are sceptical about finding life on other planets, Dr Shostak said it was only a matter of time.

    He plans to buy everyone he knows a flat white coffee if SETI doesn’t find ET “within the next two decades”.

    “I might be wrong about that, and I may have to buy a lot of flat whites, but that’s my estimate of how long it will take,” he said.

    See the full article here .

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