Posted on 09/21/2017 4:33:12 PM PDT by LibWhacker
From blob-like jellyfish to rock-like lichens, our planet teems with such diversity of life that it is difficult to recognise some organisms as even being alive. That complexity hints at the challenge of searching for life as we don’t know it – the alien biology that might have taken hold on other planets, where conditions could be unlike anything we’ve seen before. ‘The Universe is a really big place. Chances are, if we can imagine it, it’s probably out there on a planet somewhere,’ said Morgan Cable, an astrochemist at the Jet Propulsion Laboratory in Pasadena, California. ‘The question is, will we be able to find it?’
For decades, astronomers have come at that question by confining their search to organisms broadly similar to the ones here. In 1976, NASA’s Viking landers examined soil samples on Mars, and tried to animate them using the kind of organic nutrients that Earth microbes like, with inconclusive results. Later this year, the European Space Agency’s ExoMars Trace Gas Orbiter will begin scoping out methane in the Martian atmosphere, which could be produced by Earth-like bacterial life. NASA’s Mars 2020 rover will likewise scan for carbon-based compounds from possible past or present Mars organisms.
But the environment on Mars isn’t much like that on Earth, and the exoplanets that astronomers are finding around other stars are stranger still – many of them quite unlike anything in our solar system. For that reason, it’s important to broaden the search for life. We need to open our minds to genuinely alien kinds of biological, chemical, geological and physical processes. ‘Everybody looks for “biosignatures”, but they’re meaningless because we don’t have any other examples of biology,’ said the chemist Lee Cronin at the University of Glasgow.
To open our minds, we need to go back to basics and consider the fundamental conditions that are necessary for life. First, it needs some form of energy, such as from volcanic hot springs or hydrothermal vents. That would seem to rule out any planets or moons lacking a strong source of internal heat. Life also needs protection from space radiation, such as an atmospheric ozone layer. Many newly discovered Earth-size worlds, including ones around TRAPPIST-1 and Proxima Centauri, orbit red dwarf stars whose powerful flares could strip away a planet’s atmosphere. Studies by the James Webb Space Telescope (JWST), set to launch next year, will reveal whether we should rule out these worlds, too.
Finally, everything we know about life indicates that it requires some kind of liquid solvent in which chemical interactions can lead to self-replicating molecules. Water is exceptionally effective in that regard. It facilitates making and breaking chemical bonds, assembling proteins or other structural molecules, and – for an actual organism – feeding and getting rid of waste. That’s why planetary scientists currently focus on the ‘habitable zone’ around stars, the locations where a world could have the right temperature for liquid water on its surface.
These constraints still leave a bewildering range of possibilities. Perhaps other liquids could take the place of water. Or a less exotic possibility: maybe biology could arise in the buried ocean on an ice-covered alien world. Such a setting could offer energy, protection and liquid water, yet provide almost no outward sign of life, making it tough to detect. For planets around other stars, we simply do not know enough yet to say what is (or is not) happening there. ‘It’s difficult to imagine that we could definitively find life on an exoplanet,’ conceded Jonathan Lunine, a planetary scientist at Cornell University. ‘But the outer solar system is accessible to us.’
The search for exotic life therefore must begin close to home. The moons of Saturn and Jupiter offer a test case of whether biology could exist without an atmosphere. Jupiter’s Europa and Saturn’s Enceladus both have inner oceans and internal heat sources. Enceladus spews huge geysers of water vapour from its south pole; Europa appears to puff off occasional plumes as well. Future space missions could fly through the plumes and study them for possible biochemicals. NASA’s proposed Europa lander, which could launch in about a decade, could seek out possible microbe-laced ocean water that seeped up or snowed back down onto the surface.
Meanwhile, another Saturn moon, Titan, could tell us whether life can arise without liquid water. Titan is dotted with lakes of methane and ethane, filled by a seasonal hydrocarbon rain. Lunine and his colleagues have speculated that life could arise in this frigid setting. Several well-formulated (but as-yet unfunded) concepts exist for a lander that could investigate Titan’s methane lakes, looking for microbial life.
For the motley bunch of exoplanets that have no analog in our solar system, however, scientists have to rely on laboratory experiments and sheer imagination. ‘We’re still looking for the basic physical and chemical requirements that we think life needs, but we’re trying to keep the net as broad as possible,’ Cable said. Exoplanet researchers such as Sara Seager at the Massachusetts Institute of Technology and Victoria Meadows at the University of Washington are modelling disparate types of possible planetary atmospheres and the kinds of chemical signatures that life might imprint onto them.
Now the onus is on NASA and other space agencies to design instruments capable of detecting as many signs of life as possible. Most current telescopes access only a limited range of wavelengths. ‘If you think of the spectrum like a set of venetian blinds, there are only a few slats removed. That’s not a very good way to get at the composition,’ Lunine said. In response, astronomers led by Seager and Scott Gaudi of the Ohio State University have proposed the Habitable Exoplanet Imaging Mission (HabEx) for NASA in the 2030s or 2040s. It would scan exoplanets over a wide range of optical and near-infrared wavelengths for signs of oxygen and water vapour.
Casting a wide search for ET won’t be easy and it won’t be cheap, but it will surely be transformative. Even if astrobiologists find nothing, that knowledge will tell us how special life is here on Earth. And any kind of success will be Earth-shattering. Finding terrestrial-style bacteria on Mars would tell us we’re not alone. Finding methane-swimming organisms on Titan would tell us, even more profoundly, that ours is not the only way to make life. Either way, we Earthlings will never look at the cosmos the same way again.
You are not going to explore “mircobial life” on some planet billions of miles away, WITH TELESCOPES.
If you are having difficulty seeing that I am simply messing with you then it must be my fault (look for the smiley face).
The internet is no place for serious discussion of anything larger than a donut.
Which reminds me: I’ll bet your rolly pollys haven’t even invented donuts, have they? Inferior, backwards species.
I remember (decades ago) a Disney piece on TV that theorized life on other planets might be based on some other element, eg, silicon, vice carbon. I’ve always wondered why we humans imagine alien life to be analogous to ours, only different: green skin, big eyes. etc.
Because human actors can only be made up into beings that at least vaguely resemble humans.
You almost certainly can. Microbial life created the lion’s share of earth’s oxygen and along with other forms of life altered the atmosphere in many other ways. So you can study planetary atmospheres to learn about the different kinds of life that are present on a given planet, even from hundreds of light years away.
Want aliens? Just visit Burning Man.
All you need is the ability to slip over into another universe. I can’t believe it’s taking so long.
“You almost certainly can. Microbial life created the lion’s share of earth’s oxygen and along with other forms of life altered the atmosphere in many other ways.”
Correlation is not causation. Why the earth’s atmosphere has oxygen is not proof of why another planet’s atmosphere has oxygen. In fact the theories of from where earth’s atmosphere got its oxygen is not “settled science”.
http://www.latimes.com/science/sciencenow/la-sci-sn-oxygen-from-carbon-dioxide-20141001-story.html
When and if we can actually travel beyond this solar system - 100, 200, 300,+ years - there will be plenty of time to “look for alien life” outside our solar system. Right now it’s a giant guessing game with adults given plenty of expensive toys to engage in what I call “scientific crystal ball gazing”. Government funding should be no where near these soothsayers.
Then again, we Earthlings could be unique in the whole universe
And, OF COURSE, it's not just about oxygen, but about everything life pumps into the atmosphere. The atmosphere is practically a living organism itself. Why not study it and learn what you can? To say that you can't learn anything about life by studying atmospheres is pure rubbish.
Horta! It’s that reoccurring nightmare about mom’s meatloaf!
You can mess around all you wish, and I don’t care. I can mess around just as much, in case you hadn’t noticed in my responses. But, I can also be serious with the content in my posts, in case you hadn’t noticed that either.
And, rolly polys are only inferior to those that don’t understand their purpose in the bigger picture of life on the entire planet.
BTW, they were still designed to roll up into a wheel-like form, for whatever purpose(s). The wheel is not a human invention, btw. For technical purposes, and for the engineering purposes that humans have, the wheel is a relatively new “invention”.
Just about everything in the universe can be seen as taking the shape of “wheels”. Whether you care or not, some things can’t be denied.
“Earthlings” is not strictly about “humans”, but about every living organism on the planet; that’s the way I interpret the word.
And, we may be unique as the most intelligent species in the entire universe, and we are uniquely human.
Extraterrestrials might exist, but to have evolved in the same fashion as “us”, would have taken mathematically prohibitive statistical challenges.
If “those” extraterrestrials do exist, they probably have or had the same origins; iow, we didn’t originate on this planet or on this sun’s region or on this galaxy. We might just be the accidental castaways from a different galaxy that merged with what we call the Milky Way. IN that sense, we might not be unique, but we might have the same origins and in that sense, we would be unique in that, we and those others in our “original home” are just about “the same”.
BTW, “distance between stars” does not mean that there was not contact in the past few billion years. We, as life, are relatively new to the universe, and it might be that life did start before it came to this region of the Milky Way. But, that life would still be “comparatively” the same as us.
Go ahead, spend YOUR money on it. For the near forseeable future it is not worthy of human endeavor other than to pay people with too much idle speculation time on their hands and expensive toys, paid for by someone else, to do it with.
“And, OF COURSE, it’s not just about oxygen, but about everything life pumps into the atmosphere. The atmosphere is practically a living organism itself.”
A very earth-centric view, as if every planet with an atmosphere has life. Total nonsense.
Haven’t paid attention to ST for years and years. I renounce it as a vehicle of evolutionary propaganda (and other “progressive” ideology). I do remember it’s episode about silicon based life, though. It was called “The Devil in The Dark”.
http://www.daviddarling.info/encyclopedia/S/siliconlife.html
https://en.wikipedia.org/wiki/The_Devil_in_the_Dark
That sentence WAS about earth’s atmosphere, not about every planet’s atmosphere, sheesh.
You're paying. If you're Mexican, you're paying for the wall. If you're American, you'll be paying for these new telescopes, particle accelerators, and all manner of basic scientific research projects. If there's waste, ferret it out, by all means, I'm with you. But this is not it.
Telescopes and particle accelerators have their good scientific purposes; looking for ET is not one of them.
There are a lot of reasons to study planetary atmospheres having nothing to do with ET.
Now... If an enterprising young SETI researcher wants to look at that data with something else in mind, I’m assuming you’d be okay with that? We could study exo-atmospheres for what you would call legitimate scientific reasons, while giving those scientists interested in ET a way to pursue that line of inquiry. Two birds with one stone, everyone’s happy.
That’s what I like about FR: Everyone working together to solve what seem to be intractable problems.
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