Is Extraterrestrial Life More Whimsical Than Plausible? 344
coondoggie writes "Princeton University researchers are throwing some cold water on the hot notion that astrobiologists and other scientists expect to one day find life on other planets. Recent discoveries of planets similar to Earth in size and proximity to the planets' respective suns have sparked scientific and public excitement about the possibility of also finding Earth-like life on those worlds, but the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence."
It's not Optimism, (Score:5, Insightful)
They found intelligent life on Earth? (Score:4, Insightful)
In all seriousness, we haven't even got a foot on the next planet over. I think we can afford to not bicker and argue over the prospects for life elsewhere for a bit. Give science a chance to discover what it will.
Life is like a Cockroach (Score:2, Insightful)
Life is Like a cockroach, where there's one, there's a billion. The whimsical part is the notion that we will ever interact with one another. The distances and natural laws just won't allow it.
Where is my flying car? (Score:5, Insightful)
I think we are at a point where most adults have grown up their entire lives with the assumption that certain great discoveries and advancements will be made in their lifetime. Moon bases. Mars missions. Evidence (at least) of extra-terrestrial life. As these folks (I am one of them) hit the downward slope of their life expectancy (which itself hasn't seen the expected advancements), I expect much more wild speculation, straw-grasping and fallacious conclusions about what "must" exist.
If the universe is so immense that it is unlikely that extra-terrestrial life doesn't exist, then it is immense enough that we will probably never find it. Then there is the whole issue of whether that life evolved and died a billion years in the past.
Meanwhile, there are plenty of real problems to be solved and discoveries to be made here on Earth, if anyone is still interested.
Not saying don't look. Just saying be realistic.
observable data set - 1 planet with life (Score:5, Insightful)
The science is severly limited by the fact our observable data set of worlds with life consists of a single sample.
It is vary hard to do science with a single sample.
The same old tirade about wishful thinking (Score:2, Insightful)
Re:It's not Optimism, (Score:5, Insightful)
It's statistical probability, you Philistine!
"The researchers used a Bayesian analysis—which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist—to determine the probability of extraterrestrial life once the influence of these presumptions is minimized." Source [rdmag.com]
...possibility of also finding Earth-like life on those worlds
Whoever said extraterrestrial life had to be "Earth-like?"
Thus is the fallacy of the analysis.
Re:Some article links... (Score:2, Insightful)
I find it pretty stupid, to be honest.
By all counts, maths, physics, biology, chemistry, there is life anywhere else outside of Earth, period. Unless we really are in a magical fantasy world made by some bored deity playing Sims Universe.
Life develops easily with the right requirements, we know this from quite a lot of evidence. We even recreated genesis by accident, twice, and once on purpose just recently.
We see evolution right in front of us every day, and can even tweak it. We have been doing so for the past few thousand years with farming of crops and animals for the best traits, now we are doing it directly with DNA sculpting.
We know all the chemical and a considerable number of the biological interactions for life that make even the most basic life exist, and how easy it is for them to flourish given a food source.
We know that RNA and DNA are very easy and very stable structures to produce. (how the step from random chemicals to RNA world happened is still out there for now)
We are finding considerably more planets as the months go by, and even rocky ones now.
The solar system is huge, the galaxy is even bigger, the local cluster is MASSIVE, the universe as a whole is unfathomably big.
The maths and evidence quite clearly point to a very high percentage of there being life elsewhere.
In fact, it'd be better to state it as it is impossible for there NOT to be life out there. The numbers are just
It isn't just a hunch, it is basic math and rules that govern the whole of existence.
The only faith we have is faith that these laws exist far out there as well and that we aren't in a deities computer composed of bits.
We can only go with what we know, so it is almost certainly 99.9[repeating to a googol]% likely there is life out there. Complex, probably not as much, but almost certainly life regardless of complexity.
But one then wonders if non-complex life is even worthy of being called life and not just basic molecular interactions.
Would you call a Prion life? A virus? Some say yes, some say no. Either way, these are absolutely certain events outside of our little stars neighborhood.
Re:observable data set - 1 planet with life (Score:5, Insightful)
This. We can't even confirm or deny the existence of life on Venus or Mars.
WRONG FIELD (Score:2, Insightful)
This is once again more moronic bullcrap that says other planets are not like earth, so life can't evolve on them.
Most of the universe is composed of dark matter. We know nothing about dark matter, so saying you won't find life there is like saying you don't think there is any thing in a closed box before you even shake it.
Doing so just makes a fool out of the arrogant doctorate that thinks his Phd in one field of science makes him an expert in all.
The basic fact is the astrophysicists always make the SAME mistake - assuming life has to be earthlike. The definition of life is very broad and does not require DNA, water, or any of the rest of the stuff the astrophysicists look at.
Re:It's not Optimism, (Score:5, Insightful)
It's statistical probability, you Philistine!
"The researchers used a Bayesian analysis—which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist—to determine the probability of extraterrestrial life once the influence of these presumptions is minimized."
Source [rdmag.com]
Which amounts to, "my filter hasn't found any papers on extra-terrestrial life we've found yet, so clearly no evidence of extra-terrestrial life exists." I don't need a Bayesian filter to figure that one out, and it's actually pretty stupid to use one. We already know that we haven't found any life outside the Earth.
That said, the existence of life on Earth is all the evidence you need for life elsewhere. The chance of life arising is bigger than zero, and the amount of planets is large enough that for anything with probability not zero, it's going to happen more than once. The only valid question is just how full of life is the universe? Is it mostly lifeless or chock-full of it?
Actually it's based on statistics (Score:5, Insightful)
The idea of finding life on other planets is actually based on statistics. There are literally billions of Earth-like planets in the universe. The chances are that conditions on at least some of those planets has given rise to life.
There is also a very good statistical chance that there are non-carbon life-forms on other planets.
So unless you've got a "God created the Earth" mentality, there being life on other planets is a foregone conclusion.
Does that mean we'll encounter life from other planets? Perhaps not. That depends on whether any forms of FTL ever prove feasible, beyond which there's the roll of the dice of the rarity of planets with life. The odds are you'd have visit and explore a fair number of dead worlds before you'd encounter one with life.
Only those who think we are "created in God's image" would stick their heads in the sand and claim otherwise. God has no image, and it's form is the universe itself. To think we look anything like the universe is ludicrous!
Re:It's not Optimism, (Score:5, Insightful)
If you are willing to stipulate that God exists this actually makes for an awesome thought experiment.
Would God, being omnipotent and omnipresent want multiple worlds of beings?
What if he was curious* as to silicon based life, that would appear to be incompatible with a world configured for carbon life, so he would need to spin up another world.
What if God wanted a world of fire to play with creatures for whom consciousness existed in the flickering of flames?
There appears to be no reason why he wouldn't want other worlds, of course there is also no reason why he would either.
Imagine the possibilities, something akin to the final scene of MiB where the galaxy is really in a marble being played with, maybe there are other marbles?
Whether or not you choose to believe is a decision only you can make, doesn't mean you can't have fun with various viewpoints. That said, I think the God talk on /. is the new troll. Guaranteed to get a response every time ;)
-nB
* Of course being omnipotent means there is no curiosity, as God already knows everything... Thus why bother with the first world (assuming that's us) in the first place?
Re:Actually it's based on statistics (Score:5, Insightful)
The idea of finding life on other planets is actually based on statistics. There are literally billions of Earth-like planets in the universe. The chances are that conditions on at least some of those planets has given rise to life.
And what, if I may be so crass as to inquire, do you base that assessment on? The fact that "billions" is a large-seeming number? What if the probability of life (as we know it) forming on an earth-like planet is 1:10^12? The point of the article is that we simply don't know what that probability is, so arguments like the one you are making here are based on fantasy rather than evidence.
There is also a very good statistical chance that there are non-carbon life-forms on other planets.
Again: How do you know? Before, you were making a statistical argument from a sample size of one, which is bad. But now, since we know of zero planets that host non-carbon-based life, you are making an argument based on literally nothing but maybe old Star Trek episodes.
Re:Paywall ... (Score:5, Insightful)
What they ACTUALLY said (Score:4, Insightful)
The title is completely wrong. Nothing about this work suggests extraterrestrial life isn't plausible, nor that there's anything whimsical about it. Here is what they actually said.
We know that life appeared on earth very soon after the surface became cool enough to be habitable. People therefore assume the same would be true on other planets. But having only one data point doesn't give us enough evidence to actually conclude that with any confidence. In particular:
1. It took a few billion years after that for life to evolve to the point where it could wonder about the possibility of life on other planets.
2. If it had taken a few billion years for life to appear in the first place, we might never have reached this point.
3. Therefore this might just be an anthropic effect. Intelligent life forms will always find themselves on planets where life appeared quickly, but that doesn't tell you how often life actually does appear quickly.
Re:Some article links... (Score:2, Insightful)
Doesn't it seem that to believe the Earth is the ONLY place in the universe where sentient life has evolved shows extreme conceit?
But then these people are from Princeton University so they'd know a thing or two about conceit.
Pointless (and wrong) exercise in Statistics (Score:4, Insightful)
Sadly this article will be linked to a thousand times by the ID crowd shouting we need to stop wasting all this money looking for ET and realize how special and God chosen we are.
I’d also add Bayesian analysis sucks when it comes to these all or nothing analysis with such a small sample size. Bayesian analysis can be used to say we have approximately 50-100 years of civilization left. HOWEVER the same analysis 200 years ago would have given roughly the same result. These kinds of statistics mean nothing until you have a large data set that is properly categorized. We don’t even know for certainty our next nearest planetary neighbor is lifeless. Finding life on Mars would sudden explode Bayesian stats to near certainty that life is everywhere.
Re:It's not Optimism, (Score:1, Insightful)
Given that the universe is made for God's glory
What does that even mean? If God is omnipotent, why does he need the glory? And why does he seems to need everyone to love him? If this dude is real, he has one serious inferiority complex.
Nearly a certainty (Score:5, Insightful)
Neil DeGrasse Tyson gives a good talk on this, as usual with things related to astrophysics. He points out that the elements we find in our bodies are the same elements you find in the universe, and in the same order (hydrogen is the most common in the universe, and is the most common in us) and that you can trace the atoms in us to the crucible that formed stars. We are, literally, stardust. Well that is almost certainly not a coincidence. We are made of what we are made because the universe is made of what it is made. Same shit with carbon being our building block: Carbon is THE building block, you can make more molecules with it than with all other elements combined.
So looking at all that, we look pretty damn typical, pretty damn common. Thus when you have galaxies with hundreds of billions of stars, and 100-200 billion (observed) galaxies in the universe it becomes a near statistical certainty that such a thing would happen elsewhere. We aren't some special collection of elements that you are highly unlikely to see, we are precisely what you'd expect based on cosmic observation.
Re:Nearly a certainty (Score:5, Insightful)
But no one knows what the odds are of a getting all the conditions right for life to start.
If you assume that life must be everywhere, then you have to assume that those odds are pretty good.
If you assume that life isn't everywhere, then you have to assume that the odds are not very good.
So, In the end that little nugget of information doesn't really help at all. Its just more information that will be viewed through the colored lense of the beholder. In a small kind-of-sort of way, that's what this study is saying.The probability of life existing is determined in a large part by how much researchers assume it to be, rather than on any hard scientific method.
utter nonsense (Score:5, Insightful)
There is no support either for or against the existence of life on other planets. Bayesian analysis doesn't transform that lack of knowledge into evidence against life. After Bayesian analysis, people still don't have any facts.
However, I'd say things certainly look better now than they did a few decades ago, given that we have discovered both vast amounts of organic molecules in space, as well as lots of planets in the Goldilocks zone.
Re:It's not Optimism, (Score:5, Insightful)
Garbage in garbage out. There is currently insufficient data upon which to base any sort of 'estimate'. There is currently no way to know how many earth-like worlds there are in the galaxy. It certainly seems likely that the number of earth-like worlds in any galaxy would be a non-zero number, but currently all we can do is speculate wildly. So far we haven't found even one other earth-like world. All we have found is that there seem to be a large variety of planets orbiting many, perhaps most, stars at a large variety of orbital distances, including some in the goldilocks zones. Now we have some evidence from which we can conclude that planets are relatively common, but we simply cannot say how common earth-like water planets are.
What are the odds? (Score:4, Insightful)
Did life come about because of a confluence of circumstances unique to Earth or can it develop and thrive with a fairly broad set of conditions?
That's the fundamental question, because there are a variety of conditions on Earth that are relatively unique. But did live develop here specifically because of those conditions or was it only shaped because of them? I mean, if you examine life everything fits just right but what we have is a chicken and egg scenario.
Keep in mind that if life were as resilient and adaptable that we should be finding evidence of it surviving elsewhere within our own solar system. So far we haven't found anything which would imply that specific conditions are required. But how specific are the requirements. Earth isn't tidal locked, we've got a large satellite and a fairly stable star, plate tectonics, amongst countless other things. So who knows what the real odds are. I will concede, however, that it's far from being too late to find something on a neighboring planet.
I do like being optimistic about this, however, so I want to believe that life should be common. However, given the vastness of the universe "common" is an extremely relative term. What are the odds of finding complex multi-cellular life within a distance we can realistically travel? And what are the odds of finding life that is thriving within our time frame. Chances are that most life gets snuffed out long before it's able to evolve into anything noteworthy.
Comment removed (Score:5, Insightful)
Re:Paywall ... (Score:4, Insightful)
"We are made out of the most common elements in the universe. Only the height of arrogance would say that life couldn't happen anywhere but here".
It's not arrogance to say that you should only believe in the existence of something if there's evidence for it.
Otherwise it's just a form of religious faith.
To borrow a familiar example, Bertrnd Russell's teapot orbiting the Earth could be made out of common elements too. That doesn't mean it exists.
I don't see any way at present of estimating the likelihood of extraterrestial life existing somewhere. I'm sure it does, but that's only a belief in the absence of evidence..