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  • richardmitnick 6:13 am on December 21, 2014 Permalink | Reply
    Tags: , , , , Seth Shostak,   

    From Seth Shostak at SETI: “Mars Methane: Life at Last?” 


    SETI Institute

    Dec 20, 2014

    SETI Seth Shostak
    Dr. Seth Shostak, Senior Astronomer and Director of SETI Research

    m

    Mars is a tease.

    It seems that discoveries hinting at life on the Red Planet are as recurrent as Kansas hay fever. Open up the science section of any periodical, and you’ll invariably trip across new research encouraging us to believe that somewhere, skulking in the vast, dry landscapes of that desolate world, are small, wiggling creatures — fellow inhabitants of the solar system.

    Such enticing tidbits are nothing new. Their modern incarnation dates back to the early 1900s, when astronomer Percival Lowell promoted the existence of Martians who had trussed their planet with irrigation canals. This idea was well received by the public, but the astronomical community was at first skeptical, and eventually dismissive. By the First World War, these sluice-happy Martians were vaporware.

    As the century ground on, additional see-saw arguments for martian life made regular appearances. In the 1970s, the Viking Landers, with the best science instrumentation NASA could launch, went looking for life in the martian dirt. The verdict was that they didn’t find any. But one member of the Viking biology team doesn’t agree. Was it a hit or a whiff? We still can’t say for sure.

    NASA Viking
    NASA/Viking

    Then in 1996, claims of fossilized microbes in a meteorite known to come from Mars became the biggest science news story of the year. But were the seductive squiggles seen under the microscope really dead Red Planet microbes, or were they just inanimate features that mimicked croaked critters? Again, the jury has not returned to the court room.

    This litany of teases continues today with the saga of martian methane.

    Methane is best known on Earth as natural gas, and there’s a good chance it’s powering the device you’re using to read this. It’s the simplest of the organic molecules. “Organic,” by the way, doesn’t mean that it’s necessarily the product of biology, or that it was grown on a farm that shuns pesticides. It just means that the molecule incorporates carbon as one of its constituent elements. Since carbon has four covalent bonds, the simplest molecule you can make with this stuff is by attaching a hydrogen atom to each of these “chemical arms.” CH4 is the result, known to savvy 11th graders as methane.

    But in the context of extraterrestrial life, methane is important as a possible biomarker. It’s the exhaust gas of many forms of life on Earth — bacteria, most notably, but also slightly bulkier organisms such as cattle and pigs. If you detect methane in a planet’s atmosphere, you may have found pigs in space. Or more likely, microbes in space.

    In 2004, the Europeans launched the Mars Express orbiter, and did just that. They claimed that their spacecraft had spectroscopically sniffed clouds of methane wafting above the Red Planet. American astronomers, using ground-based telescopes, also thought they had sensed this gas. The claim was important, if true, because CH4 could be caused by underground, martian bacteria. If so, this would be the first detection of life beyond Earth.

    ESA Mars Express OrbiterESA Mars Express schematic
    ESA/Mars Express

    And even more, it would be living life. Not the dead microbes supposedly entombed in a meteorite, but metabolizing Martians that were still kicking. That’s because ultraviolet light from the Sun, untroubled by an ozone layer that Mars doesn’t have, would take apart any methane molecules in the atmosphere within 300 years or so. So if there’s methane around, it’s today’s methane (note to reader: for astronomers, 300 years ago is the same as “today”).

    Given this back story, you can imagine the considerable interest when NASA’s Curiosity rover bounced onto the sands of our little ruddy buddy in 2012, equipped with instruments that could also check for methane. The result, announced in September 2013, was that it couldn’t find any at a level under a part per billion, or roughly ten times lower than expected on the basis of the earlier measurements. You might guess that maybe Curiosity had the bad luck to land in a spot far from the madding, methane cloud. Sure, but scientists figure that — thanks to the circulation of its thin atmosphere — any gas spewed out in one spot would get spread around the entire planet within months. You should be able to detect it anywhere, if there’s enough of it.

    NASA Mars Curiosity Rover
    Curiosity

    The 2013 negative result from Curiosity was, indeed, both curious and a downer. But this week, researchers attending a conference of the American Geophysical Union in San Francisco heard of the detection of a sudden spike in methane. In a truly remarkable measurement by Curiosity, we find that the gas is back.

    That’s exciting news, but history cautions us not to party hearty just yet. Methane can be produced by geophysics as well as biology, when rocks and water interact chemically. Just because it smells like a duck, doesn’t mean it’s a duck.

    So what gives? No one’s sure yet; the obvious variability in the presence of methane suggests local sources, but the big question is whether the source is geophysical or biological.

    Nathalie Cabrol, a SETI Institute astrobiologist who is especially interested in the habitability of Mars, said, “The good news is that we now know sources of methane exist. This is something that we’ve measured.”

    Cabrol is cautious about concluding that these latest discoveries are even semi-solid evidence for biology, but there’s little doubt that such a scenario is possible.

    “There may not be an easy way to untangle whether the source of the gas is geophysical or biological,” Cabrol notes. “But if life evolved on Mars and survived eons of sudden and drastic climate changes, it might have evolved strategies analogous to dormant species on Earth. Bacteria can survive millions of years in terrestrial permafrost, awaiting the return of favorable conditions to start up their metabolism and multiply.”

    It might be life, or it might not be. But the good news is that we now have evidence of some sort of activity under the surface of Mars — phenomena subject to solid, repeatable measurement.

    Long everyone’s favorite place to search for extraterrestrial life, the Red Planet continues to taunt us a century after Percival Lowell assured us that it was both inhabited and cultivated. At least the first is still possible.

    See the full article here.

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  • richardmitnick 2:40 pm on September 26, 2014 Permalink | Reply
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    From Seth Shostak at SETI Institute: “So What Really Goes Down if We Find the Aliens?” 


    SETI Institute

    September 26, 2014
    By Seth Shostak, Senior Astronomer and Director of the Center for SETI Research

    SETI Seth Shostak
    Seth Shostak

    If we trip across life that’s not of this world, do we blast it or befriend it? What impact would it have on our society?

    This was the topic of a two-day symposium held at the John W. Kluge Center of the Library of Congress last week. Several dozen researchers — astronomers, philosophers, theologians, biologists, historians, and other tweed-jacketed specialists — opined on what might happen should we find we’re not alone.

    A lot of the discussion, unsurprisingly, was about discovering life that’s intelligent. This prompted a symposium leitmotiv that was dished out repeatedly: when thinking about aliens, beware of anthropocentrism. In other words, don’t assume that they will be similar to us ethically, culturally, or cognitively.

    Well sure, I can get down with that. I agree that we tend to view everything in the universe through the prism of our own natures. Mind you, I note that the squirrels in my front yard seem to do the same. They’re awfully squirrel-centric. That ensures that they attend to activities that are truly important (mostly acorn management). I don’t think less of them for that.

    Where this leitmotiv became more than a neo-Greek caution against hubris was when it was used to argue that SETI (the Search for Extraterrestrial Intelligence) is fatally flawed. We were told that our hunt for aliens assumes that they are like us. That kind of provincial attitude, it was said, will doom SETI to endless frustration. If we don’t think outside our own biological box, we’ll fail to find any company in the cosmos.

    But wait a minute: That’s akin to arguing that the 1976 Viking landers — with their complex instrumentation for sensing microbial Martians — were a clear non-starter because they were sensitive to carbon-based metabolism; in other words, life as we know it. Well, that’s true, but it was really hard to design experiments that were good at finding life as no-one-knows-it.

    Actually, when it comes to SETI experiments, we try not to make assumptions about the aliens’ cultural, ethical, or even biological makeup. We don’t assume they are similar to us. Rather, we assume that their physics is similar to ours — that they use radio transmitters or lasers to send information from wherever they are to wherever they need it. That’s no more anthropocentric than assuming that — if aliens use ground transportation — at least some of it is on wheels.

    Anthropocentrism is always a bugaboo, but to say that it might irretrievably cripple our efforts to find evidence for intelligence elsewhere is certainly arguable. So let’s consider that SETI experiments are not as myopic as some would aver. The big question then becomes, what happens if we pick up a ping?

    First, allow me to dispense with the false, but nonetheless ever-popular idea that the public wouldn’t be told. That’s goofier than Big Bird, and easily disproved by a cursory reference to SETI’s occasional false alarms. This paranoid idea probably derives from the widespread claim that 67 years ago some wayward aliens made a dismaying navigational error, and piloted their craft into the dirt near Roswell, New Mexico. The fact that this event is not the subject of much investigation by research scientists is often explained as the consequence of a government cover-up. The feds don’t want you to know about extraterrestrials.

    One could make the same argument about the lack of academic interest in leprechauns. Maybe the Irish government is hiding the bodies. I don’t find that a compelling argument. But I think the popular notion of secret evidence sparks the mistaken belief that a SETI detection would be hushed up. It won’t be.

    Of greater relevance to the subject of this symposium — preparing for discovery — was what would the signal reveal? What could we learn about the senders’ construction or culture?

    The most plausible answer is “not much.” Just as hearing a rustle in the forest provides precious little information on the flora or fauna that caused it, so too would an alien ping be largely uninformative, at least at first. There might be an accompanying message, but new and different instruments would be required to find it.

    What we could learn quickly are a few, mostly astronomical facts, to wit: (1) How far away is their solar system; (2) What type of star do they orbit? (3) The length of their day and their year.

    That might be it for a while. And “a while” would be years, at minimum.

    If we find intelligent beings elsewhere in our galaxy, you’ll not be quickly confronted with complex philosophical problems of understanding their mode of thinking or their biological blueprint — or even knowing whether they are biological. You won’t be misled by anthropocentric thinking, because there will be precious little information about whether they’re like us or not. For years, all we’ll be able to say is that there’s something out there that’s at least as technologically competent as we are.

    But of course, that’s still saying a lot.

    See the full article here.

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  • richardmitnick 7:42 pm on September 1, 2014 Permalink | Reply
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    Seth Shostak of SETI Institute at his Eloquent Best. 


    SETI Institute

    Seth Shostak. ’nuff said.

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  • richardmitnick 7:26 am on August 22, 2014 Permalink | Reply
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    From Seth Shostak via SPACE.com: “6 Most Likely Places for Alien Life in the Solar System” 

    space-dot-com logo

    SPACE.com

    SETI Seth Shostak
    Seth Shostak, Senior Astronomer, SETI Institute

    We still don’t have hard evidence for any life that’s not of this Earth, but across our solar system there are some tantalizing possibilities for primitive life to find a haven. Some moons of Jupiter and Saturn are intriguing, and there’s also the chance for some surprises somewhere on Mars.

    Here are my top six candidates for the best spots to search for primitive alien life in our solar system.

    FIRST STOP: Enceladus

    encl

    In 2005, NASA’s Cassini spacecraft photographed geysers of frozen water spewing from cracks in Enceladus’ southern hemisphere. Scientists think reservoirs of liquid water lie beneath the frozen surface and are warmed by gravitational interactions between Enceladus and other moons around Saturn. The necessities for life are there, and maybe Enceladans are as well. The moon has a mean radius of 156.6 miles (252.1 km).

    NASA Cassini Spacecraft
    NASA/Cassini

    NEXT STOP: Mars

    mars

    Mars remains perennially popular for those hunting for otherworldly protoplasm. Particularly intriguing are the dark stripes that appear in the Martian summertime at Horowitz crater. These are likely to be salty meltwater only inches beneath Mars’ dusty epidermis. A relatively simple probe could sample this muddy environment. Mars has a diameter of about 4,212 miles (6,779 km)

    NEXT STOP: Titan

    tit

    Titan is Saturn’s largest moon and the only world in the solar system (besides Earth) known to sport liquid lakes. These are lakes of ethane and methane — liquid natural gas — endlessly topped up by hydrocarbon rain. Despite the odd ingredients and Titan’s gelid temperatures (minus 290 Fahrenheit, or minus 179 Celsius), it is a world where chemistry’s a happening enterprise. Titan possesses diameter of 3,200 miles (5,150 km).

    NEXT STOP: Europa

    europa

    Many would grant Europa a higher potential-life rating than I have, since there’s probably more liquid water here than in all of Earth’s oceans. The downside is that Europa’s vast, salty seas lie beneath roughly 10 miles of ice. Not only is it difficult get a probe beneath this icy armor, but Europa’s oceans are darker than a cave — which means photosynthesis won’t work. However, something down there may subsist on geothermal heat or complex molecules from the surface. Europa possesses a mean radius of 970 miles (1,560.8 km).

    NEXT STOP: Venus, the Hellish Planet

    venus

    A surprise entry in the exobiology sweepstakes is our sister planet, Venus, with its scorching surface temperatures (850 F, or 454 C). The planet is generally assumed to be as sterile as a boiled mule.

    But planetary scientist David Grinspoon, astrobiology curator at the Denver Museum of Nature and Science, points out that high in the Venusian atmosphere temperatures are refreshingly tolerable. Atmospheric sulfur dioxide and carbon monoxide might serve as food for floating microbes. Venus is 7,521 miles wide (12,104 km).

    NEXT STOP: Callisto and Ganymede of Jupiter

    calisto

    I considered these two moons of Jupiter together, as I feel they’re neck-and-neck candidates for biology. Like their more celebrated neighbor Europa, Ganymede and Callisto may have buried, liquid oceans. However, in the case of these two satellite siblings, briny deeps would underlie at least 60 miles (100 km) of rock. Finding inhabitants here is a shovel-ready project for our grandkids. Callisto has a diameter of more than 2,985 miles (4,800 km); Ganymede’s diameter is 3,270 miles (5,262.4 km).

    See the full article here.


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  • richardmitnick 11:44 am on August 20, 2014 Permalink | Reply
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    From Seth Shostak of SETI Institute via Huff Post: “Forget Space Travel: Build This Telescope” 


    SETI Institute

    SETI Seth Shostak
    Seth Shostak,Senior Astronomer, SETI Institute

    The first telescopes were toys, charming amusements. Sure, there were a few practical uses, such as observing distant ships coming into harbor. Doing so allowed merchants to hurry down to the docks ahead of their telescope-free competitors, and snag all the better goods. Military commanders occasionally found telescopes handy as well. And when they weren’t being used for commerce or conflict, these simple devices were undoubtedly helpful for checking out the personal parameters of careless neighbors.

    In 1609, Galileo turned a telescope skyward — a move that no one else seems to have considered. His instruments had lenses about the size of a half-dollar coin, and magnifications that were only about 20 times. Their simple optics had more aberrations than Vlad the Impaler.

    Today, you wouldn’t give a kid a telescope this lousy, unless you’re inspiring her to forsake science in favor of a more lucrative occupation, like starching shirts. But these low-grade constructions were good enough to see the bigger moons of Jupiter, the craters of the moon, and stars making up the Milky Way. They were, despite their pitiful specifications, arguably the most important astronomical telescopes of all time.

    Modern researchers would find Galileo’s ‘scopes useful only for batting Whiffle balls. They’ve moved on to bigger and better, and today are building some truly impressive instruments: a new generation of titanic telescopes that sport primary mirrors larger than tennis courts.

    ESO E-ELT
    ESO E-ELT

    Thirty Meter Telescope
    Thirty Meter Telescope.

    Giant Magellan Telescope
    Giant Magellan Telescope

    These will snag a million times as much light as Galileo’s instrument, which is really the motivation for their construction. But, thanks to an ability to undo a lot of the distortions caused by Earth’s shuddering atmosphere [adaptive optices, active optics], these new outsized ‘scopes will be about as hawkeyed as the famed Hubble instrument — able to see detail at a level of about 0.1 seconds of arc. That’s enough to just make out a dime a dozen miles away.

    exo
    Exoplanet

    Impressive, yes, but no one cares about examining far-off dimes. What about inspecting worlds around other stars, the so-called exoplanets that dominate a lot of astronomy news these days? Well, with these new giant telescopes, any Earth-size exoplanet would be smaller than one pixel in size. It would be a thoroughly unresolved pinpoint of light.

    Useful, but not entirely gratifying.

    I think it’s fair to say that, given your ‘druthers, you’d want an instrument that could map exoplanets in the kind of detail you get with Google Earth, with enough resolution to actually see the Great Wall of the Klingons, in case they’ve built one.

    Could we construct such a telescope … ever?

    Here’s what it takes: Let’s assume that all the alien worlds you wish to view up close and personal are no more than 100 light-years away. That might sound pretty cramped to astronomy nerds, but there are probably several hundred thousand planets within that distance – enough to gratify even the most spirited voyeur.

    At 100 light-years, something the size of a Honda Accord — which I propose as a standard imaging test object — subtends an angle of a half-trillionth of a second of arc. In case that number doesn’t speak to you, it’s roughly the apparent size of a cell nucleus on Pluto, as viewed from Earth.

    You will not be stunned to hear that resolving something that minuscule requires a telescope with a honking size. At ordinary optical wavelengths, “honking” works out to a mirror 100 million miles across. You could nicely fit a reflector that large between the orbits of Mercury and Mars. Big, yes, but it would permit you to examine exoplanets in incredible detail.

    The down side is obvious: Who could ever construct such a thing? Well, fortunately, no one has to. Instead, you could field a phalanx of small mirrors in space, spread out over 100 million miles. They wouldn’t even have to maintain a fixed pattern, as long as you could accurately keep track of their relative positions.

    No huge mirror: just a manageable number of small ones. The ability to see detail would be the same. And, of course, it’s a heck of a lot easier to turn an array of small instruments to different places on the sky than to pivot a 100 million-mile monstrosity.

    Of course, there are a few small problems of principle here. You need to collect enough light to make the imaging possible, and correct for the fact that the target exoplanet is both rotating and sliding across the sky. Both problems can be dealt with, at least in theory — which suggests that they can also be dealt with in practice, given sufficient effort.

    But think of the implications. There’s a lot of talk about interstellar travel, and whether we will ever be capable of rocketing to other stars. It’s a tough thing to do.

    However, if the type of telescope described here can be built, then the tyranny of distance is vanquished. You can forget deep space probes and their long travel times. We could explore alien worlds in the comfort of our own homes, as our laptops scroll and zoom through data sets collected by a mammoth, space-based telescope array.

    It would also, quite obviously, be a whole new way to search for extraterrestrial life … just look for it, or its artifacts (like cities).

    This is, to my mind, the ultimate telescope. It’s not for our generation to build, or even the next two. But after that …?

    See the full article here.

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  • richardmitnick 4:59 pm on July 31, 2014 Permalink | Reply
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    From Seth Shostak at SETI Institute: “Why the Aliens Want Earth” 


    SETI Institute

    July 31, 2014
    SETI Seth Shostak
    Seth Shostak, Senior Astronomer, Director of SETI Research

    Expedia’s galaxy-wide website must be offering Earth at a major discount. In one movie after another, aliens decide to pass up competing Milky Way attractions — including neutron stars, antimatter clouds, hot Jupiters, and a 4 billion-trillion-trillion-ton central black hole — in favor of our planet. The small speck of rock we inhabit is more popular with tourists than Disneyland.

    Even an abbreviated laundry list of invasion films will give you the idea: Independence Day, War of the Worlds, Superman II, Mars Attacks, The Day the Earth Stood Still, Killer Clowns from Outer Space … They all share a common premise, namely that Earth is the bee’s knees, cosmically speaking.

    But really, you’ve got to wonder what would motivate creatures from other worlds to suffer a journey of hundreds of trillions of miles to visit our planet? It’s a trip so relentlessly devoid of scenery, their spacecraft wouldn’t need windows. Why bother?

    I’ve been asked this question at least a half-dozen times by Hollywood writers, and the best answer I can muster is “I don’t know.”

    My impoverished reply is clearly disappointing, and the usual response by the filmmakers is to resort to two hackneyed incentives to rope in the aliens, namely (1) a quest for natural resources, and (2) breeding experiments.

    Frankly, and not to rain on anyone’s parade, neither makes sense.

    Consider the idea that the extraterrestrials want materials for their industrial needs. It’s nice to imagine that Earth is valuable as a mining claim, but what do we have that they don’t?

    A frequent suggestion is water. But that’s silly: The universe is awash in water, thanks to the abundance of its two atomic ingredients, hydrogen and oxygen. Like Kimye and Kanye, these two elements are everywhere. Heck, there’s more water on some of the moons of Jupiter than on Earth, and no one’s going to get ruffled if you opt to remove it. But really, you can save the tanker costs by finding water in your own solar system. There’s bound to be plenty.

    Digging up other minerals and metals is similarly unnecessary and inconvenient. The entire cosmos is made of the same elements (and more or less in the same proportions) as is our local neighborhood. You don’t need to import this stuff from light-years away.

    Maybe they just need farmland? Like Captain Bligh, perhaps aliens are hoping to find a place to grow breadfruit, or whatever the galactic equivalent might be. Again, this is the kind of incentive that might work if you don’t first need to traverse interstellar space. If you do, consider building orbiting greenhouses at home. They’ll be cheaper, and the produce will be fresher. And honestly, if Earth’s countryside is that attractive, why didn’t someone plant a flag (or Klingon breadfruit) millions or billions of years ago? It seems that terrestrial real estate is a dog on the market.

    Breeding experiments are even less plausible, even if many movie-goers feel like participating. Anyone who’s made it through tenth-grade biology will recognize that breeding with other species here on Earth — all of whom are card-carrying members of the DNA club, and therefore closely related to you — is not only difficult, it’s guaranteed to be fruitless. And possibly illegal.

    Trendy scenarists will often invoke the social concern du jour, and suggest that the extraterrestrials are here to save us from ourselves. Aside from the obvious fact that they don’t know of such contemporary problems as climate change or nuclear proliferation (our newscasts haven’t reached them yet), why would they be interested? I bet the dinosaurs would have wished for a bit of alien help in giving an asteroid a nudge 66 million years ago, but it seems the extraterrestrials couldn’t be bothered. Are we that much more deserving?

    No, the bottom line is that the only truly special things about Earth are likely to be our biota and our culture. They could learn a lot about either one by merely analyzing the spectral signature of our atmosphere or tuning in to our TV broadcasts, and they would save a king’s ransom on fuel by avoiding actual travel.

    Despite the dramas played out at the local cineplex, real aliens won’t be itching to visit. What we’ve got, they’ve already seen, and the doorbell won’t ring. We’re not on their bucket list.

    See the full article here.

    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
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