New research suggests life on other planets may fail to progress rapidly enough to keep a planet habitable:
Life on other planets would likely be brief and become extinct very quickly, say astrobiologists from The Australian National University (ANU).
In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.
"The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens," said Dr Aditya Chopra from the ANU Research School of Earth Sciences and lead author on the paper, which is published in Astrobiology.
"Early life is fragile, so we believe it rarely evolves quickly enough to survive."
"Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable."
[Continues.]
Abstract:
The prerequisites and ingredients for life seem to be abundantly available in the Universe. However, the Universe does not seem to be teeming with life. The most common explanation for this is a low probability for the emergence of life (an emergence bottleneck), notionally due to the intricacies of the molecular recipe. Here, we present an alternative Gaian bottleneck explanation: If life emerges on a planet, it only rarely evolves quickly enough to regulate greenhouse gases and albedo, thereby maintaining surface temperatures compatible with liquid water and habitability. Such a Gaian bottleneck suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surfaces of wet rocky planets in the Universe and (ii) rocky planets need to be inhabited to remain habitable. In the Gaian bottleneck model, the maintenance of planetary habitability is a property more associated with an unusually rapid evolution of biological regulation of surface volatiles than with the luminosity and distance to the host star. Key Words: Life—Habitability—Gaia—Abiogenesis habitable zone (AHZ)—Circumstellar habitable zone (CHZ). Astrobiology 16, 7–22.
Full article: http://www.mso.anu.edu.au/~aditya//pubs/ChopraLineweaver2016.pdf
(Score: 3, Insightful) by Anonymous Coward on Thursday January 28 2016, @06:39AM
I believe the article is assuming that the form of life in question is life as we know it. That may be the only kind of life there is, but we haven't traveled enough to determine that.
(Score: 3, Funny) by Anonymous Coward on Thursday January 28 2016, @06:45AM
This is clearly yet another bit of 'phony science' to convince us of global warming. Kappa.
(Score: -1, Offtopic) by Anonymous Coward on Thursday January 28 2016, @08:49AM
Indeed recent studies show that carbon dioxide or CO2, has 10 to 100 times less of an impact on the climate than previously estimated.
Meanwhile, globalist socialists want to institute a world wide tax on everything by taxing it's carbon footprint (that's just C). TFA is just more "Carbon Tax" propaganda to get us to buy into C being taxed, because "Carbon Bad!". Don't you just love how the goalposts shift to support their agendas regardless of reality.
Protip: The Medieval warming period was warmer than now. Earth's orbit is eccentric, it goes circular for a while then slightly elliptical, then back to circular then elliptical in a another direction. When the orbit is circular it's warmer, when it's elliptical it's an ice age. We've been coming out of an ice age for the past 10,500 years, almost to the peak. The ice is receding as it does. Don't you know how the Appalachian mountains were carved by glaciers? OH NO! THERE ARE NO GLACIERS in Appalachia! Derp. We don't care about that because it happened before we started "recording" history (but the marks are upon the Earth for us to ignore, they just don't fit the AGW -> Global Warming, -> Man Made Climate Change -> Climate Change -> Carbon Dioxide Greenhouse Gas -> Carbon Pollution agenda).
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @10:05AM
The globalists are most certainly not "socialists". They are purely capitalist, bent on a global race to the bottom in search of ever-more-concentrated wealth. We are not headed for a world "people's republic", just a trans-national corporate oligarchy.
(Score: -1, Troll) by Anonymous Coward on Thursday January 28 2016, @01:22PM
So that's all right then.
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @01:39PM
Only if you're rich.
(Score: 2) by Thexalon on Thursday January 28 2016, @03:43PM
Or, alternately, propaganda to convince us to dismantle all of those nuclear weapons that are collectively more than capable of wiping out the entire human race in a matter of hours because one world leader questioned the size of another world leader's dick.
Damn hippies, trying to ruin all the fun.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: -1, Redundant) by Anonymous Coward on Thursday January 28 2016, @06:30PM
And you know what happens when we make everyone give up nuclear weapons:
Mr. Chambers! Don't get on that ship! The rest of the book: 'To Serve Man' . . . It's . . . It's a cookbook!
(Score: -1, Redundant) by Anonymous Coward on Thursday January 28 2016, @06:37PM
Actually, I didn't mean to be so forward. I meant to pre-pend that comment with "Respectfully submitted for your perusal . . ."
(Score: -1, Offtopic) by Anonymous Coward on Thursday January 28 2016, @06:48AM
I'm a doctor, not an organic chemist! [youtube.com]
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @07:12PM
Actually, I was thinking this [youtube.com] would be more apropos.
(Score: 3, Interesting) by bzipitidoo on Thursday January 28 2016, @06:53AM
The usual arguments against an abundance of life all concern the difficulties in acquiring energy (food) and materials from the environment, and healing and maintenance of bodies against the steady ongoing erosive and damaging effects of most environments, and the development of a stable ecology. And those are not trivial problems. A broken leg is often deadly, and can happen so easily, just one wrong step, putting a foot in a hole, a bad landing after a jump, tripping, etc. There's also the competitive side of life, with the biggest threat to an animal often being other animals. There are so many ways for an animal to die its a wonder many survive for a whole year, let alone for decades.
However, I often wonder if boredom might ultimately prove to be an even deadlier problem. As we gain power and knowledge, life gets easier and easier. Too easy, perhaps. Paradise is within our grasp, and with careful management of limited resources, we all could have no more wars, no more want. And yet that might not be best for us. "Affluenza" anyone? We could of course screw it up and let paradise slip away, constantly teeter on the brink of nuclear war until one day someone pulls the trigger. Decisions, decisions.
(Score: -1, Offtopic) by Anonymous Coward on Thursday January 28 2016, @11:23AM
> Paradise is within our grasp, and with careful management of limited resources, we all could have no more wars, no more want. And yet that might not be best for us.
I'll trade with you. You can live in Russia and you'll have pleeenty of ways to have more works and wants.
(Score: 5, Insightful) by bradley13 on Thursday January 28 2016, @07:14AM
"Most early planetary environments are unstable."
Oh, bull pucky.
Mars is uninhabitable because life failed to regulate the water and CO2 cycle2? Um, no. Mars is uninhabitable because it's atmosphere was blown away by the solar wind. TFA page 12: "Why didn't Earth undergo a runaway greenhouse like Venus or a runaway glaciation like Mars?". Um, maybe because Earth receives only half as much solar radiation as Venus, but twice as much as Mars? Occam's Razor, baby.
Of course, life (at least on Earth) does regulate CO2, taking the C for building and dumping that useless O2 into the atmosphere. However, this was hardly decisive in making earth habitable in the first place. By the time photosynthesis came around, life had already existed for half-a-billion years.
Why is life rare in the universe? We don't know that it is. Fact is, we would be unable to detect another civilization equivalent to ours even on the nearest stars. Even the SETI efforts suppose a powerful, directional signal that just happens to be pointed our way in the moment that we are looking. Why hasn't the entire galaxy been colonized? Maybe because there is no FTL, no magic formula, and building generation ships to cross space is just too damned difficult?
This paper appears to be nothing but mental masturbation -
Everyone is somebody else's weirdo.
(Score: 4, Interesting) by Yog-Yogguth on Thursday January 28 2016, @10:49AM
Yeah it's a bad way to frame it for all sorts of reasons and geology will be massively more influential on both albedo and atmospheric composition than even a planet covered in life, it's not like we don't have multiple examples of exactly that happening here on "stable" Earth ("tiny" (lol) Krakatoa perhaps the most famous) and that's /without/ considering asteroid impacts etc.. It's not the only weirdness in the abstract and description of the paper either, or at least not the way I understood it.
Anyway they're throwing it out there so others can reference and/or correct something on it which can end up being helpful or useful even if it looks more like a publicity stunt :3
It could still be the case for some planet somewhere, i.e. as a more limited explanation (maybe I'm reading the abstract wrong and they're not taking a shot at identifying the Great Filter [wikipedia.org]). My impression is that despite the emphasis placed on it the paper underestimates pseudo-panspermia [wikipedia.org] in order to explain the assumed lack of life. It seems to me the paper contradicts itself.
Because considering how much pseudo-panspermia has been found it would otherwise appear as if the paper would require that all planets would have to have unstable environments all of the time that they could have been life-supporting. That's too much.
Maybe it could be the other way round and pseudo-panspermia is overrated, but then there's less to explain in the first place.
It's like the speculation about the star which varies erratically in brightness: the data¹ doesn't fit any explanation so we speculate and could continue to speculate for millennia without figuring anything new out unless something changes (new data).
If we ever get to check we might find a little life just about everywhere, just not in the quantity and diversity we're used to. Presently we were not even able to figure out the cause of that abnormal methane cloud which appeared on Mars, or even closer to home the very rare TLP [wikipedia.org] on the Moon likely to be luminescent gas of geological origin appearing and dissipating. Funnily enough around the Aristarchus crater/plateau. Aristarchus should stop farting on the Moon :D
¹ in the case of the star the data rules out everything including Dyson spheres (shoddy reporting gives the opposite impression) because there's nothing unusual going on in the heat signature/radiation according to the papers I've seen, so no aliens unless one uses them as a placeholder for $deity-or-anything-goes.
Bite harder Ouroboros, bite! tails.boum.org/ linux USB CD secure desktop IRC *crypt tor (not endorsements (XKeyScore))
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @12:40PM
Why is earth warmer than mars and colder than venus? I'll need a satellite network with 100% coverage and real time feed to answer that one sir, it is probably this molecule that makes up .01% of earth's atmosphere and 99% of the other two.
(Score: 1, Informative) by Anonymous Coward on Thursday January 28 2016, @01:38PM
Good start! I see you understand that
(http://www.umsl.edu/~orglab/documents/IR/IR2.html [umsl.edu])
By the by, the molecule you're studying now makes up 0.04% of Earth's atmosphere...seems your measurements aren't up-to-date. Carry on!
(Score: 2) by Immerman on Thursday January 28 2016, @06:50PM
Don't forget that absolute amounts are important, rather than percentages.
Mars has almost the same partial pressure of CO2 in it's atmosphere as Earth, so it should see similar CO2 greenhouse effects, but receives ~60% less sunlight density, so the expected temperature will be lower. Plus no atmospheric water, which is a complementary greenhouse gas (reflects a different wavelength of infrared - between the two they catch most thermal emissions) so even less heating.
Venus's atmosphere is *extremely* CO2 rich, and thus can be expected to see a far greater greenhouse effect than Earth. Add the much greater sunlight density and you can melt lead on the surface.
The clincher? Mercury - it's receiving far denser sunlight than Venus, but has no greenhouse gasses (or anything else) in its atmosphere, and is far, far cooler than Venus.
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @11:54PM
Venus is hot at the surface because the atmosphere is extremely thick. Compare the average temperature on Earth to that of Venus up where the pressure is at 1 atm and you see it is 348 K.[1] Compare to Earth at the same pressure: 283 K. The ratio is ~1.21. Venus is at ~0.723 AU from the sun. So it is 1/.723=1.38 times closer. Energy from the sun drops off by the square of distance, so Venus gets sqrt(1.38)=1.176 times as much energy as earth. It is just as hot as expected given the distance from the sun and thickness of atmosphere.
The relevant question to temperature is "Why does Venus have such a thick atmosphere?"
[1] https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Troposphere [wikipedia.org]
(Score: 0) by Anonymous Coward on Friday January 29 2016, @12:06AM
"sqrt(1.38)" is the temperature, not energy. Temperature is proportional to the fourth root of energy (stefan-boltzmann). So it should be (1.38^2)^.25.
(Score: 2) by Reziac on Friday January 29 2016, @06:28AM
Yeah, my first thought was ... have they noticed how life of some sort, even if just bacteria, cockroaches, and rats, populates every possible niche, and some we thought were impossible?? Just about anywhere there are reactive (vs. inert) chemicals, there's life. Life is fragile, my ass; more like adaptable, invasive, and tenacious.
Aside from the very narrow window SETI is able to examine, we're also kinda out in bumfuck nullspace, and even if aliens are also looking for us, tripping over one very minor star and a mere 150 light years worth of broadcast signals is an exercise in statistical noise.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by Runaway1956 on Friday January 29 2016, @03:24PM
I was agreeing with your, about 100%, right up to the end. Mental masturbation? That kicked it up to 1000%.
Fact is, we can't know what we don't know, until we learn more. There may be life on 90% of all planets, and there may be life on only .000000001% of all planets. Maybe MOST planets with life evolve intelligent life forms, and maybe less than one in a trillion planets with life ever evolve intelligence. We can't know. We've lived our entire life at the bottom of a well, and we simply can't imagine what life is like outside the well.
If/when we escape the well, and we are able to see the surrounding landscape, we'll have a better idea just how ignorant we are.
Abortion is the number one killed of children in the United States.
(Score: 4, Insightful) by tftp on Thursday January 28 2016, @07:15AM
However, the Universe does not seem to be teeming with life.
I wonder what evidence of nonexistence those scientists may have, outside of, you know, going to all those stars and checking in person. Life on Earth exists for millions of years, but it was sending RF into space only in the second half of the last century. (We largely stopped that waste now.) Other methods of detection, like spectroscopy of the atmosphere, are so far impossible for small planets, and not very informative. We don't even know if there is life on Mars right now, let alone in remote star systems.
(Score: 5, Interesting) by tonyPick on Thursday January 28 2016, @08:43AM
Even that's not practically detectable at the kind of distances we're talking about: See
http://www.centauri-dreams.org/?p=13340 [centauri-dreams.org]
And Google around "Benford Beacons" - basically a SETI-like sweep would have difficulty detecting us from the nearest stars, and certainly not the bulk of our output - any signals would be transient at best, and even then have a relatively short range (in interstellar terms): http://www.seti.org/faq#obs12 [seti.org]
(Score: 3, Informative) by VLM on Thursday January 28 2016, @02:01PM
Two other resources are the last chapter of Kraus's classic radio astronomy textbook and more recently some radar astronomy work. Also ham radio dudes with a serious investment of time/money can do radar astronomy bounce signals off the moon.
AFAIK unless there's been a new release even with a kilometer sized dish and megawatts and essentially infinite budget the best we've pulled off for planetary radar is Saturn. No further. Figure you can sniff a radar twice as far away or more than you can hear an echo. So maybe an alien space probe at Neptune could hear us... maybe.
If you have active devices with predefined agreed upon modulations and specifications on both ends like space probes we can barely communicate with them as they exit the solar system. Barely. If we ever sent a probe to a star we'd need to drop relay stations along the line unless we waited for the probe to come back.
The problem with SETI is the EE stuff gets in the way.
(Score: 2) by SecurityGuy on Thursday January 28 2016, @03:39PM
Yeah...I'm going to have to discount that FAQ as contradictory. It says other civilizations wouldn't be able to hear us, then a few questions later that we shouldn't worry about whether intentionally broadcasting to other potential civilizations is dangerous because we've been broadcasting for a long time and they'd already have heard us.
Can't have it both ways, guys.
(Score: 2) by Immerman on Thursday January 28 2016, @07:18PM
Actually I think we can, if you add the caveat that we're only worried about civilizations that might be a threat.
A civilization such as ours would be hard pressed to detect us even if we were intentionally signaling them from the nearest star. But even if we managed to get their attention with a powerful enough signal they still wouldn't be a threat because they're not remotely capable of launching an interstellar attack, and the only thing to worry about is fallout from cultural exchange.
On the other hand, any civilization advanced enough to launch an effective interstellar attack almost certainly also has far, far more sophisticated sensors than we do, and could already detect us. Sending a more powerful signal tells them nothing except that maybe we see them too, and that we're interested in communicating.
The only cause for worry is if we send a signal so powerful that that it stands clear enough of the noise that it gets picked up accidentally by a civilization so advanced it would be capable of interstellar travel, but that wasn't looking for evidence of other civilizations. In that case our signal might pique their curiosity, xenopobia, and/or bloodlust and lead to physical contact between our civilizations. But that seems somewhat unlikely.
The only other situation I can think of that would be cause for worry is if there's a galactic civilization out there that's intentionally avoiding contact with us until we send a sufficiently powerful signal to remove us from "protected planet" status and let the exploitative factions move in. But signal strength seems like a rather unlikely criteria to use for revoking such protection - after all once a civilization has discovered radio sending a more powerful signal is just a matter of having the will and resources to build a big enough transmitter. I suppose it says something about the amount of resources we're willing to spend on long-shots to contact aliens, but puts a resource-rich and contact-hungry low-tech civilization on the same level as a relatively uninterested high-tech civilization. Not impossible I suppose, but seems unlikely.
(Score: 2) by legont on Friday January 29 2016, @12:30AM
Let's assume for a second that speed of light holds as the limit. Then no matter how sophisticated, it would take intruders some more years to get here and start colonization. They are on the way, perhaps even from different places, but just not here yet. Besides, the powers of civilizations might not be that different. Perhaps, we are already rather close to the maximum capacity.
Given what we did to "discovered" cultures it seems irresponsible to advertise a ready for colonization place. It would make sense to be quiet and build military power of space kind; at least until some guarantees could be found.
I'd bet we don't hear them because they are hiding; and whoever was not hiding is not there any more.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by Immerman on Friday January 29 2016, @02:23AM
Sure, but on a galactic scale any species should be looking at centuries to millenia being the standard physical interaction frequency with another star - one of the reasons physical interstellar trade or warfare (short of total conquest by overwhelming forces) seems an unlikely prospect.
And I completely agree that our own history advises against advertising our presence. The point though, is that barring some sort of low-tech FTL transportation we've somehow managed to overlook, the only people we could possibly advertise our presence *to* would be those who are incapable of being a threat because of the ridiculous difficulties of interstellar travel. Unless we're actively hiding, everybody else will already know we exist.
Admittedly there is some nonzero risk of exposing ourselves to some comparable-level civilization who is then motivated to develop their tech and/or industry much faster than us and be capable of overwhelming us by the time they've crossed the endless void. But if that's the case then sooner or later they're bound to notice us anyway, and it doesn't seem like there's any reason to assume the risk would decrease with time.
As for us being anywhere near the maximum power a civilization could attain - that is patently absurd. Even if physics is limited to only what we already know as well-tested fact, our technology has only barely begun to exploit it. And for raw power available as a resource to reshape the universe to our will - we haven't even begun to build a Dyson's sphere yet, something that's well within reach of technologies currently in the laboratory. We harness so little of our sun's output that it's not even a rounding error. Any species with the will to do so could literally rebuild the solar system practically overnight, using nothing but the technologies we already have either in use or in the lab.
(Score: 2) by legont on Friday January 29 2016, @03:28AM
For the near maximum power I meant that we might already know most which is there to know and within a few decades, say millennia, will implement what you mentioned and so all other civilizations in the galaxy.
What I am trying to say is that if we believe in singularity, I agree it does not make sense to hide. If we think that there is a limit somewhere, it makes sense to get there first. The fact that we see nobody implies the later. If there exist a singularity, chances are we are already occupied, unless we are the first that is.
Regardless, pushing the progress as fast as we could appears to be the only viable strategy. Sorry the Earth conservation.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by Immerman on Friday January 29 2016, @06:42PM
If we're near the maximum level of science attainable, then interstellar warfare is pretty much doomed anyway. Unless you discover another species practically right next door, in the time it takes your invasion fleet to cross the void your target can easily have developed from having just discovered radio, to harnessing a fair fraction of their sun's output. In fact they may have already done so before you launch your fleet, after all you can only see their past, not their present. And at that point you have your piddly invasion fleet packed with what tiny power reserves they can carry between stars, versus a civilization on the defensive, backed by the harnessed power of their sun.
The only civilizations that need to worry are those that decide not to expand off their planet, or who get discovered long before they industrialize.
As for putting Earth conservation on the chopping block - sounds like a good idea to me, what better way to get a leg up in the war than destroying the only thing here worth fighting over? Stars without habitable planets are everywhere.
(Score: 2) by legont on Saturday January 30 2016, @07:43AM
One never knows - perhaps a little thing was not discovered yet. After all, Cortes came with 500 men and just 15 or so horses and they say the horses let him take over a civilisation of millions. He sure did not know he was so much more powerful - he just believed his god. As per isolation, Cortes destroyed his ships to create just that.
Anyway, the original article implies that we should take care about the earth because we don't see others. What seems more logical to me, we should forget about the earth preservation exactly because we don't see others. We should run ahead as quickly as possible to overcome whatever killed the others.
It appears to me that our overlords, whoever they might be, are destroying our planet deliberately to get our asses off somewhere else. Exactly like the nature does to her favourites.
Don't get me wrong - I personally hate this. Id' rather have a quiet live in a nice rural environment and if some bloody aliens come to kill me so be it. I just realise that nature pushes us this way. Should we resist?
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by Immerman on Saturday January 30 2016, @05:38PM
Well, the horses, and the gunpowder, and the steel weapons and armor. Unlike Eurasia, the Americas have no significant surface metal deposits, and as a result the natives were all essentially extremely sophisticated stone-age civilizations. There was a *massive* military technology gap. And then of course there was the *real* weapons - unintentional biological warfare thanks to the festering, disease ridden European cities. Estimates are that Columbus's voyage resulted in plagues killing 70-90% of the population of the Americas before Cortez ever got here. And alien diseases are probably nothing to worry about unless their world was somehow seeded by the same DNA as ours. Unless we happen to be based on the same amino acids we're probably inedible.
If there's a "little thing" we haven't discovered yet in science that would make that huge of a military difference, then it's probably not a "little thing", and we're nowhere near the "maximum power" science can attain.
As for assuming something killed the others, why would you do such a thing? We've barely looked at a tiny percentage of solar systems to see if they have planets, and only assume there's no life in most of them because they couldn't support life as we know it under the simplistic assumptions that we have on Earth. Europa-type moons aren't even considered. And there's no reason to expect we could "hear" other civilizations even if they exist - if we're any model to go on, then civilizations will only be radio-visible for a century or so, and even then our technology isn't sensitive enough to hear someone around the nearest star even if they were as loud as us at our loudest. The only way we could realistically detect another civilization is if they intentionally announced themselves, or started building a Dyson's sphere.
Also nature doesn't pick favorites, and rarely destroys anyone's ecosystem. And when she does, most of the species specialized for it go extinct, while the generalists had already spread anyway. Not sure where you were going with that.
(Score: 2) by Immerman on Thursday January 28 2016, @06:40PM
Actually spectroscopy could detect some major red flags about the presence of life. For example, detecting large quantities of free oxygen in the atmosphere is almost certainly an indicator of life - oxygen is much too volatile to remain in the atmosphere without some continuous process replacing it, and life is at the top of the list by a long shot.
Of course that only applies to oxygen-rich ecosystems, and we know that's not a requirement for life. Life was on Earth for hundreds of millions of years before photosynthesis was developed and began dumping oxygen into the atmosphere. And then it took over a billion years more for the available oxygen sinks to saturate so that oxygen could begin to build up in the atmosphere beyond trace amounts.
(Score: 1) by tftp on Friday January 29 2016, @12:16AM
We have no idea if there is life in water under Europa's ice. We do not know if there is oxygen, or any other gases, in that water. And that's on a large satellite of one of planets of our own star system. If you add to the mix the possibility that life elsewhere may be based on different elements, you simply do not have enough information; you don't receive enough, and you don't know enough to interpret it.
Even if we focus entirely on high-tech civilizations, what do you expect them to radiate away? Their home planets may have been destroyed long ago, or left far, far away, or lost the atmosphere due to explosion of their Sun (as this one is promising to do in 6 billion years...) They can be living on artificially created planets, or in spaceships of similar size; or they can become energy beings; or they can move entirely into neural nets of their machines and operate interchangeably as pure minds within crystals of silicon (for example) and as metal robots on surface of barren planets that, by all observations, do not support life.
(Score: 2) by Immerman on Friday January 29 2016, @03:34AM
Absolutely. I do not contest that life-as-we-don't-know-it could live unseen practically under our noses. Nor even that life-as-we-know-it could exist in places that wouldn't be visible to us. I only claim that there are some things we *could* see with current technology that would stand up and scream "Hey! Over here! We're alive!"
(Score: 1, Informative) by Anonymous Coward on Thursday January 28 2016, @08:00AM
Life on Earth is possibly unique, but not special. The assumption that we cannot detect life elsewhere in the universe with our immature technology pointed at a postage stamp sized portion of the sky means that other life doesn't exist is ludicrous. Some may have died out, and some are yet to start.
The reason we haven't encountered "aliens" in person - as far as we know - could be distance, or timing, or perhaps we are not the form of life they were looking for so they never knew we existed.
There's no need to declare Earth the only life in the universe just to make ourselves feel better. Life on Earth is possibly unique but it isn't the only life ... and may not even be the only life pondering this question.
(Score: 2) by Immerman on Thursday January 28 2016, @07:31PM
I wonder at your definitions of "unique" and "special".
If you mean unique in the sense of "sufficiently dissimilar that their aren't any aliens we could easily mistake for human" then I'd say that seems pretty likely, but also kind of pointless to mention - like saying every snowflakes is unique. It's simply a comment on the sheer number of options available to evolution. Barring humans being the result of some ancient race seeding the galaxy with their DNA, a Star Trek galaxy full of humanoids seems extremely unlikely.
As for special - unless the galaxy is absolutely teeming with life our existence seems pretty dang special to me. And it certainly seems from what we've seen so far that most stars don't host native life. Maybe there's actually thousands of independently arisen civilizations in the galaxy this moment, but given the scale of things that's still few enough that the existence of every one of them is something special.
(Score: 2, Insightful) by Anonymous Coward on Thursday January 28 2016, @08:26AM
Complex life has existed on this planet for around 500 million years, I wouldn't call that brief.
(Score: 2) by Yog-Yogguth on Thursday January 28 2016, @06:40PM
500000000 years = 0.5 Gya (gigayears [wikipedia.org]) = a lot of time for individual humans but little for many other things including in a lot of astronomy.
Bite harder Ouroboros, bite! tails.boum.org/ linux USB CD secure desktop IRC *crypt tor (not endorsements (XKeyScore))
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @10:05AM
The universe are big. In fact, most of the planets we find are merely "visible" as a faint shadow when they pass in front of their sun. We can not look for life on a planet we can barely see. Oh sure, there are some attempt at guessing from what we can detect about a planets atmosphere, but those guesses have one major limitation: They are based on the gasses (methane, CO2) that are released by life as we know it.
Even in our own solar system, we really don't have any clue about whether there is life or not in the one place most likely to contain life (outside of earth): Europa.
"There doesn't seem to be a lot of needles in these haystacks. We looked at one as we drove past it, and we can see the silhouette of a few hundred others".
(Score: 3, Informative) by takyon on Thursday January 28 2016, @01:12PM
Yes. I don't think our failure to detect alien communications is indicative of much. We will also have at least 1-2 better telescopes for examining exoplanets in the coming decades, James Webb [wikipedia.org] and possibly ATLAST [wikipedia.org] or HDST [wikipedia.org].
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 4, Interesting) by Dr Spin on Thursday January 28 2016, @10:36AM
There seems to be an assumption that life has to be carbon based and needs oxygen.
I think it is highly likely that it might not be like us. It might not be
made like us, and it might not behave like us. If its "clock rate" is a million times
slower, we probably could not detect it.
Read Fred Hoyle's "The Black Cloud" for the kind of thing I am talking about.
https://en.wikipedia.org/wiki/The_Black_Cloud/ [wikipedia.org]
Warning: Opening your mouth may invalidate your brain!
(Score: 5, Interesting) by TheRaven on Thursday January 28 2016, @12:22PM
There are lower bounds. Complex life has existed on this planet for about a tenth of the lifetime of the universe. For it to start evolving something with a significantly longer lifespan elsewhere, it would have had to reach complexity earlier (and the upper bound there is only a factor of ten) or had significantly greater mutations at each generation.
The key point is that a complex arrangement of matter capable of evolution is hard. Rats are among the most extreme examples on Earth: they have the highest mutation rate of any mammal, which gives the species a big evolutionary advantage (whatever you try to kill them with, there's a good chance that there will be one individual that can survive), but it's very unstable. The vast majority of rats die of cancer. For evolution, you need to have some mutation mechanism that generates different but survivable variations of the species. That's a very narrow window.
sudo mod me up
(Score: 0) by Anonymous Coward on Thursday January 28 2016, @08:41PM
There seems to be an assumption that life has to be carbon based and needs oxygen.
This is not an assumption but an educated guess based on the distribution of elements and the way they react. Carbon, Oxygen, Hydrogen and thus Water are all abundant and their chemical interactions favor complex molecular chains like nothing else at that complexity level. So, it is not a baseless assumption, but one rooted in basic "organic" chemistry. Organic chemistry isn't concerned with the elements it it because of us, but because those elements have the properities that support complexity and it just so happens they're abundant.
Our sun is an average sun. The elements in this solar system were forged in a Type 1A supernova (the most common kind). We have one example of life, and it just happens to use the most abundant chemicals reactions in the universe to create complexity. Thus, there is a good chance that if there is other life out there, it will use the same atomic building blocks, and thus similar chemical reactions for information storage (like our RNA / DNA), amino acids have been formed in labs via blasting basic elemental soup with electric arcing to simulate lightning, and clays / lipids have also been formed in similar chemical simulations / ovens. So, we have the very building blocks of our cells created in an eye blink by taking the most abundant chemicals and applying an energy cycle.
This is why we look for water and carbon and oxygen to narrow down our search for life. It's possible that silicon based life or some strange heavy metal based life with mercury for blood exists. However, it's a damn good bet that life made of rarer materials requiring more complex chemical reactions and more fragile and specific configurations should be far more rare. So, we look for life where life in the conditions that life is known to have emerged within the most abundant chemical soups and at temperatures conducive to energy gradients that encompass stability and reactivity of said chemicals.
To put it another way: For each instance of non-carbon based life out there there are very likely millions or billions of carbon based life forms. If we have limited funds, then we look for signs of life where it's more probable that it exists. It is not as if we're going into this on blind assumption based purely on our own existence. We've surveyed the distribution of atomic material for life to use, and tried to get various chemical complexity to emerge but as it turns out, C H O chains are the most conducive to complexity. And yet another way: We don't have a single indication that life based on other chemical reactions exists. And still another: If I fill a gum-ball machine universe with equal portions of red, green and blue candy, and only a tiny fraction of their total volume as pink and orange; Then I say, "Here are 9 coins to get 9 random gum-balls. Wanna bet that the only combinations of 3 different colors will be of red, green and blue?" Would you instead take the bet that you'll get a pink or orange, or even both a pink and orange to make combinations with? If so, I have some ocean front property in Nevada you may be interested in.
(Score: 2) by el_oscuro on Friday January 29 2016, @01:02AM
We've got life like that here, in hydro thermal vents. [whoi.edu]
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