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Is Extraterrestrial Life More Whimsical Than Plausible?
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 statistical probability, you Philistine!
An enigma, wrapped in a riddle, shrouded in bacon and cheese
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.
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.
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.
This. We can't even confirm or deny the existence of life on Venus or Mars.
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!
I do not fail; I succeed at finding out what does not work.
And having read the link, I can only say that my own statistical analysis shows with a high degree of confidence that every earth-centric or earth-is-unique argument made so far has been proven wrong. Therefore, expectations that this particular view will endure are probably based on optimism rather than evidence.
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.
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
Thousands of Exo-planets discovered. Viking’s life detection experiments are being reconsidered. Life has been found to have started very early in Earth’s evolution. Various Extremophiles discovered. For the last twenty years the evidence keeps tipping in favor of extraterrestrial life being more and more likely. That we haven’t yet discovered said life says more about our commitment to doing so than its likely-hood.
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.
Letter To Iran
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.
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.
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.
I think Neil DeGrasse Tyson explained it simply, I paraphrase "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". Of course the bigger problem would be that if you actually DID have a race that was able to master space and time what would you talk about? Check out his thoughts here, quite interesting.
ACs don't waste your time replying, your posts are never seen by me.
"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..
To have a right to do a thing is not at all the same as to be right in doing it