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  • richardmitnick 10:28 am on August 2, 2017 Permalink | Reply
    Tags: , , , , METI, , , When Satellites Confuse SETI   

    From METI: “When Satellites Confuse SETI” 

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    METI International

    8.2.17
    Morris Jones

    SETI astronomers sometimes pick up strange signals.

    SETI Institute

    They don’t look like the regular type of radio transmissions we get from stars and other natural things in space. When this happens, they pay attention. These signals could be transmissions from extraterrestrials.

    There are protocols for dealing with a potential extraterrestrial discovery. You perform follow-up observations of the same source, or the same area of space. You ask other observatories to perform their own observations. You also avoid saying too much in public until you know the real source of the signal.

    SETI observations have gone down this path many times, and in all cases, no evidence of extraterrestrial intelligence was found. Sometimes, signals have come from aircraft. But an increasing source of strange signals comes from our own fleet of satellites.

    Recently, the red dwarf star Ross 128 was the subject of one such incident.

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    Image from Aaron Hamilton. http://www.orionsarm.com/eg-article/491700c65734d

    Astronomers from the famous Arecibo radio telescope picked up weird transmissions from the directions of this star, even though they were not actively conducting a SETI search.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    They alerted other astronomers and even published news of these investigations on a Web page. The media got hold of the story and published it. Much hype was made about the potential discovery, despite the fact that the astronomers had downplayed the likelihood of extraterrestrial involvement. But that doesn’t sound so juicy to journalists hunting for a big story.

    It was quickly shown that extraterrestrials were not beaming messages into space from Ross 128. But something else was certainly transmitting. The most likely cause, it seems, was a satellite orbiting the Earth. It just happened to be passing over the telescope’s field of view when these observations were taken.

    There’s a tremendous amount of artificial radio transmissions on Earth and in space. That’s how we sustain our information society. But the widespread use of radio waves causes problems for radio astronomers, SETI or otherwise. In the future, astronomers may need to go deeper into space, perhaps to the far side of the Moon, to escape the radio noise of Earth.

    That’s a luxury SETI astronomers can’t afford right now. All they can do is check any strange signals carefully, and accept that there will probably be more interference from satellites in the future.

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

    This also means that discipline needs to be practiced in reaching wild conclusions too quickly. Look before you leap. Check before you talk. In 2016, there was a torrent of publicity over a strange signal received by the RATAN-600 radio telescope, which was suspected of being an extraterrestrial transmission.

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    RATAN-600 (short for Radio Astronomical Telescope of the Academy of Sciences) is a radio telescope located near the village of Zelenchukskaya in the Caucasus Mountains, in Russia, at an altitude of 970 meters.

    Follow-up observations dispelled any chance of this, and it seems that once again, astronomers were tricked by a satellite. In this case, there was clearly too much talk before the signal had been properly investigated.

    These two incidents serve as lessons for SETI practitioners, the media and the public. Any strange signal detected by a SETI project is probably not from extraterrestrials. The most likely cause will probably be a satellite launched by humans from Earth. We all need to avoid leaping to wild conclusions without firm evidence. Getting that evidence takes time, and patience will be needed.

    We would all love to find evidence that humanity is not alone in the universe. It’s one of the most significant questions confronting science. But science shouldn’t run on emotions. It needs caution and deduction. SETI is mostly a well-run pursuit. But journalists and the public should still be cautious of any claims they encounter.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The primary objectives and purposes of METI International are to:

    Conduct scientific research and educational programs in Messaging Extraterrestrial Intelligence (METI) and the Search for Extraterrestrial Intelligence (SETI).

    Promote international cooperation and collaboration in METI, SETI, and astrobiology.

    Understand and communicate the societal implications and relevance of searching for life beyond Earth, even before detection of extraterrestrial life.

    Foster multidisciplinary research on the design and transmission of interstellar messages, building a global community of scholars from the natural sciences, social sciences, humanities, and arts.

    Research and communicate to the public the many factors that influence the origins, evolution, distribution, and future of life in the universe, with a special emphasis on the last three terms of the Drake Equation: (1) the fraction of life-bearing worlds on which intelligence evolves, (2) the fraction of intelligence-bearing worlds with civilizations having the capacity and motivation for interstellar communication, and (3) the longevity of such civilizations.

    Offer programs to the public and to the scholarly community that foster increased awareness of the challenges facing our civilization’s longevity, while encouraging individual and community activities that support the sustainability of human culture on multigenerational timescales, which is essential for long-term METI and SETI research.

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  • richardmitnick 10:32 am on May 18, 2017 Permalink | Reply
    Tags: , , , , Colossus project, , , METI,   

    From Centauri Dreams via METI International: “A ‘Census’ for Civilizations” 

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    METI International

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    Centauri Dreams

    May 17, 2017
    Paul Gilster

    We’ve been talking about the Colossus project, and the possibility that this huge (though remarkably lightweight) instrument could detect the waste heat of extraterrestrial civilizations.

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    But what are the chances of this, if we work out the numbers based on the calculations the Colossus team is working with? After all, Frank Drake put together his famous equation as a way of making back-of-the-envelope estimates of SETI’s chances for success, working the numbers even though most of them at that time had to be no more than guesses.

    Drake Equation, Frank Drake, Seti Institute

    SETI Institute

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

    Bear in mind as we talk about this that we’d like to arrive at a figure for the survival of a civilization, a useful calculation because we have no idea whether technology-driven cultures survive or destroy themselves. Civilizations may live forever, or they may die out relatively quickly, perhaps on a scale of thousands of years. Here Colossus can give us useful information.

    The intention, as discussed in a paper by Jeff Kuhn and Svetlana Berdyugina that we looked at yesterday (citation below), is to look out about 60 light years, a sphere within which we have numerous bright stars that a large instrument like Colossus can investigate for such detections. We’re making the assumption, by looking for waste heat, that civilizations living around such stars could be detected whether or not they intend to communicate.

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    Image: Figure 1 from Kuhn & Berdyugina, “Global Warming as a Detectable Thermodynamic Marker of Earth-like Extrasolar Civilizations: The case for a Telescope like Colossus.” Caption: Man-made visible light on the Earth in 2011. From DMPS/NASA. The brightest pixels in this 0.5 × 0.5 degree resolution map have a radiance of about 0.05 × 10−6 W/cm2/sr/micron. Credit: Jeff Kuhn/Svetlana Berdyugina.

    Let’s take the fraction of stars with planets as 0.5, and the fraction of those with planets in the habitable zone as 0.5, numbers that have the benefit of Kepler data as some justification, unlike Drake’s pre-exoplanet era calculations. Kuhn and Berdyugina have to make some Drake-like guesses as they run their own exercise, so let’s get really imaginative: Let’s put the fraction of those planets that develop civilizations at the same 0.5, and the fraction of those that are more advanced than our own likewise at 0.5. These numbers operate under the assumption that our own civilization is not inherently special but just one of many.

    Work all this out and we can come up with a figure for the fraction of civilizations that might be out there. But how many of them have survived their technological infancy?

    Let me cut straight to the paper on the outcome of the kind of survey contemplated for Colossus, which is designed to include “a quantifiably complete neighborhood cosmic survey for [Kardashev] Type I civilizations” within about 20 light years of the Sun, but one that extends out to 60 light years. In the section below, Ω stands for the ratio of power production by an extraterrestrial civilization to the amount of stellar power it receives (more on this in a moment).

    From the paper:

    “…current planet statistics suggest that out of 650 stars within 20 pc at least one quarter would have HZEs [Habitable Zone Earths]. Assuming that one quarter of those will develop Ω ≥ 0.01 civilizations, we arrive at the number of detectable civilizations in the Solar neighbourhood ND = 40fs, where fs is the fraction of survived civilizations (i.e., civilizations that form and survive). Hence, even if only one in 20 advanced civilizations survive (including us at the time of survey), we should get a detection. Taking into account the thermodynamic nature of our biomarker, this detection is largely independent of the sociology of detectable ETCs.”

    Independent because we are not relying on any intent to communicate with us, and are looking for civilizations that may in fact be advanced not far beyond our own level, as well as their more advanced counterparts, should they exist.

    Suppose we detect not a single extraterrestrial civilization. Within the parameters of the original assumptions, we could conclude that if a civilization does reach a certain level of technology, its probability of survival is low. That would be a null result of some consequence, because it would place the survival of our own civilization in context. We would, in other words, face old questions anew: What can we do to prevent catastrophe as a result of technology? We might also consider that our assumptions may have been too optimistic — perhaps the fraction of habitable zone planets developing civilizations is well below 0.5.

    But back to that interesting figure Ω. The discussion depends upon the idea that the marker of civilization using energy is infrared heat radiation. Take Earth’s current global power production to be some 15 terawatts. It turns out that this figure is some 0.04 percent of the total solar power Earth receives. In this Astronomy article from 2013, Kuhn and Berdyugina, along with Colossus backers David Halliday and Caisey Harlingten, point out that in Roman times, the figure for Ω was about 1/1000th of what it is today. Again, Ω stands for the ratio of power production by a civilization to the amount of solar power it receives.

    The authors see global planetary warming as setting a limit on the power a civilization can consume, because both sunlight from the parent star as well as a civilization’s own power production determine the global temperature. To produce maximum energy, a civilization would surely want to absorb the power of all the sunlight available, increasing Ω toward 1. Now we have a culture that is producing more and more waste heat radiation on its own world. And we could use an instrument like Colossus to locate civilizations that are on this course.

    In fact, we can do better than that, because within the 60 light year parameters being discussed, we can study the heat from such civilizations as the home planet rotates in and out of view of the Earth. Kuhn and Berdyugina liken the method to studying changes of brightness on a star. In this case, we are looking at time-varying brightness signals that can identify sources of heat on the planet, perhaps clustered into the extraterrestrial analog of cities. A large enough infrared telescope could observe civilizations that use as little as 1 percent of the total solar power they intercept by combining visible and infrared observations. A low value of Ω indeed.

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    Image: Figure 3 from the Kuhn/Berdyugina paper “Global Warming as a Detectable Thermodynamic Marker of Earth-like Extrasolar Civilizations: The case for a Telescope like Colossus.” Caption: Fig. 3. Expanded view of a representative North American region illustrating temperature perturbation due to cities (left, heated cities are seen in red) and corresponding surface albedo (right). From NEO/NASA.

    You can see what a challenge this kind of observation presents. It demands, if the telescope is on the ground, adaptive optics that can cancel out atmospheric distortion. It also demands coronagraph technology that can distinguish the glow of a working civilization from a star that could be many millions of times brighter. And because we are after the highest possible resolution, we need the largest possible collecting area. The contrast sensitivity at visible and infrared wavelengths of the instrument are likewise crucial factors.

    I’ll refer you to “New strategies for an extremely large telescope dedicated to extremely high contrast: The Colossus Project” (citation below) for the ways in which the Colossus team hopes to address all these issues. But I want to back out to the larger view: As a civilization, we are now capable of building technologies that can identify extraterrestrial cultures at work, and indeed, instruments like Colossus could be working for us within a decade if we fund them.

    We can add such capabilities to the detection of non-technological life as well, through the search for biomarkers that such large instruments can enable. More on that tomorrow, when I’ll wrap up this set on Colossus with a look at photosynthesis signatures on exoplanets. Because for all we know, life itself may be common to habitable zone planets, while technological civilization could be a rarity in the galaxy. Learning about our place in the universe is all about finding the answers to questions like these, answers now beginning to come into range.

    The Colossus description paper is Kuhn et al., “Looking Beyond 30m-class Telescopes: The Colossus Project,” SPIE Astronomical Telescopes and Instrumentation (2014). The paper on Colossus and waste heat is Kuhn & Berdyugina, “Global warming as a detectable thermodynamic marker of Earth-like extrasolar civilizations: the case for a telescope like Colossus,” International Journal of Astrobiology 14 (3): 401-410 (2015).

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The primary objectives and purposes of METI International are to:

    Conduct scientific research and educational programs in Messaging Extraterrestrial Intelligence (METI) and the Search for Extraterrestrial Intelligence (SETI).

    Promote international cooperation and collaboration in METI, SETI, and astrobiology.

    Understand and communicate the societal implications and relevance of searching for life beyond Earth, even before detection of extraterrestrial life.

    Foster multidisciplinary research on the design and transmission of interstellar messages, building a global community of scholars from the natural sciences, social sciences, humanities, and arts.

    Research and communicate to the public the many factors that influence the origins, evolution, distribution, and future of life in the universe, with a special emphasis on the last three terms of the Drake Equation: (1) the fraction of life-bearing worlds on which intelligence evolves, (2) the fraction of intelligence-bearing worlds with civilizations having the capacity and motivation for interstellar communication, and (3) the longevity of such civilizations.

    Offer programs to the public and to the scholarly community that foster increased awareness of the challenges facing our civilization’s longevity, while encouraging individual and community activities that support the sustainability of human culture on multigenerational timescales, which is essential for long-term METI and SETI research.

     
  • richardmitnick 3:51 pm on July 29, 2016 Permalink | Reply
    Tags: METI, , What would we look like to E.T.?   

    From METI: “SETI, Imagining Extraterrestrial Civilizations, and War” 

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    Illustration by Rlevente.

    METI

    7.29.16
    John Traphagan

    I’ve often thought it interesting that when SETI scientists imagine extraterrestrial civilizations, they usually think in terms of unified worlds that have one civilization. The image is very much unlike our world, in which we have multiple civilizations that are fractured and in conflict with other societies. The Brexit event of the past couple of days is a good example of just how fractured our world is as well as representing some solid data not in support of the idea that humans are becoming increasingly unified.

    When we imagine other worlds, we tend to take a distant view and create images that reflect a fictionalized, romanticized representation of life right here on Earth. Rather than fractured worlds with many civilizations like the one on which we actually live, many SETI scientists think in terms of what I call the Star Trek Imaginary, in which each world forms a civilization equivalent to a geopolitical unit on Earth. In other words, we think of alien worlds as unified political states or countries.

    There is a good chance that this is an inaccurate view of civilizations on other planets, but it still may be a useful way to think about extraterrestrial intelligence if only to deconstruct our assumptions about life on other worlds. Indeed, one way to use this image is to turn it around and think about Earth from the perspective of an alien world. This makes for an interesting thought experiment.

    Suppose ET planted some sort of observational device near Earth, say, 6,000 years ago. Somehow, they had noticed that there seemed to be an emerging civilization and thought it would be interesting to study how things evolved. ET doesn’t have a lot of time to spend on watching Earth and the observational device isn’t sensitive enough to show all the nuances of political machinations throughout human history. So the data are limited in detail. The result is a wide-angle picture of Earth throughout history that gives a general sense of what cultural evolution on Earth is like. ET will have learned quite a bit, actually, about how humans evolve and form societies over time, but a lot of the detail will be left out. They probably won’t get the nitty-gritties about the Brexit.

    So what would such a device tell ET? As I thought about this, I realized there would be one overwhelming image ET would get about Earth. And it’s an image we here—with our close-up picture of our own history—don’t usually associate with civilization on this planet.

    I think what ET might conclude is that Earth has been at war for about 5,000 years—pretty much non-stop. The first war in recorded history seems to have been in Mesopotamia around 2,700 BCE between Sumer and Elam, and from the outside it might look like it never stopped. Since that time, if one were to stand back a bit from Earth, there is a pretty good chance that warfare would be the dominant feature of human civilization. There is always war going on somewhere on Earth. It ebbs and flows in intensity. Sometimes it’s regional; sometimes it covers most of the planet. But it is always there and it might look like one long war from an outside perch. If you didn’t know all of the political and historical details, there would be no reason to assume that our history had been an endless string of wars rather than simply one really long one.

    From our perspective, this would not be a very accurate picture. Different societies have had on-and-off periods of war and peace. And we don’t tend to think about our civilization(s) as being characterized by a single war lasting 5,000 years, because we understand the geopolitical details in which there have been lots of wars over that time, not just one war. But if you look at Earth from the outside and treat human societies as a civilization, then it’s probably a reasonable conclusion about us. From the external—or in anthropology what we would call etic—perspective, human civilization might appear to be based on and characterized by a single war that has spanned almost 5,000 years.

    This raises the importance of seeing the difference between proximate and distant perspectives and the difficulties in imagining intelligent life and civilizations on other worlds when we don’t have a lot of data to work with (or in our current situation, without any data at all). SETI scientists often tend to impose their own assumptions about intelligence and civilization on imagined extraterrestrial worlds and those assumptions are shaped by ideas about the way our world is that: 1) may not be empirically accurate, and 2) are unlikely to reflect how we would look to outsiders.

    The devil is in the details, and we don’t have any of those, since we have no evidence of alien intelligence. But even if we do get evidence sometime, we probably won’t have much detail and we will need to be very careful to avoid imposing the Star Trek Imaginary—or any other set of assumptions—on what little data we receive. Standing back and trying to imagine what our world would look like to distant outsiders is a useful way of trying to control this tendency to imagine alien others in terms of romanticized images of ourselves.

    Perspective is important. It may well be that characterizing our world as being at war for 5,000 years is accurate, but it isn’t how we see ourselves and that, too, is an important piece of data about humans. Recognizing the potential disjuncture between how we see ourselves and how others might see us is a key component of trying to deflect, to the extent possible, our tendencies to infuse assumptions about intelligence and civilization drawn from our proximate understanding of and imagination about life on Earth into our speculations about intelligent life on other worlds.

     
    • Matthew Wright 4:16 pm on July 29, 2016 Permalink | Reply

      I agree. Our own situation is predictable given our nature as humans – arguably very much a product of our ape ancestry (chimps fight wars too) and of the way our species evolved. There’s a reasonably compelling argument that hunter-gatherer bands of around 150, the largest that a reasonable day’s walking could support, were cohesive. Larger bands were usually not and there was likely an evolutionary advantage in competition between bands of 150. Archaeological evidence points to wars in hunter-gatherer times, before agriculture emerged. It’s an interesting theory and if true, explains a fair amount including the way we’ve had to intellecualise stability into larger communities. Would aliens be the same? Highly unlikely. My take on aliens is that we might not even recognise them as such despite the way sci-fi often ideates them into better (human-style) societies.

      Like

    • Greg Long 7:56 pm on July 29, 2016 Permalink | Reply

      Completely agree.

      Like

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