Discussion in 'Science, Math, History and Language Studies' started by BIV, Nov 29, 2012.
If only we could.
A good start?
When do we start?
Of course there's ice on the planet next to the sun.
This universe can't fucking BUY a second planet with an ocean. Sorry alien nuts, there's nothing out there.
Statistically there almost has to be other life out there. Unfortunately it is very unlikely we will ever find it.
Maybe not in our universe but the fact that water
exists as ice on a planet so close to the sun shows that
there are infinite possibilities. There is life out there.
I've always disagreed vehemently with that. In fact I think it's backwards, if anything. If we only knew of 2 planets, then we could say there's life on 1 out of 2 planets. 1/2, 50%. The more planets we find without life on them (the higher the X goes in 1/X), the more it suggests the 1 is going to stay 1.
And I know I've said it before but people might overestimate how long 14 billion years is. They might have never considered the perspective that relative to how long it can be expected for the first life to develop in a universe, it's actually a tiny amount of time. Like maybe in other universes the average time is like 10^12 years or 10^15.
How is that x number going up? We have discovered other planets but is there a way to tell if life exists on them?
Statistically speaking, when you look at all the things that had to go right for life to form, that number is ridiculously high as well. So statistically, it probably isn't as guaranteed as most people think. I learned this from Neon so I have to give him some credit.
No foolproof way, but there are lots of signs you can look for at a distance. One of the most obvious is the aforementioned presence or lack of oceans. That's relatively easy to determine and if they find one it would increase the shit out of the likelihood (which would still be infinitesimally small, but still).
The statistical strength of the number 1 is by far the biggest factor. For all we know earth could be the only instance of abiogenesis in 10^100000 universes in 10^100000 years. Do I think it is? I have no idea. But for having a rational grasp on the paradigm it's important to strongly consider the possibility.
Why would we assume there needs to be oceans present for life? I mean I understand we only know that life exists on our planet and we have oceans so it would work the same elsewhere. Even knowing that, it still seems like a silly assumption to make.
I never said needs. It's possible without them. But it's an enormous factor. Water is a unique substance and some of its special properties - hydrogen bonding, lower density as a solid, surface tension, heat retention et al - would seem magical to an intelligent species that's not familiar with it. All theories of abiogenesis have incorporated the ocean. Hell, it's called the primordial soup, not the promordial sandbox.
To me the pure size of our universe offsets that. Even if everything that happened to create life here was completely random and had a massive amount of luck, it seems likely to me that enough potential for life exists elsewhere that the random accident would have happened multiple times. Also, some other forms of life may have found "shortcuts" and not had to evolve as slowly as we did.
There are 200 billion stars in our galaxy, and 200 billion galaxies in our universe (and we don't know that our universe is the only one). That's a lot of opportunity for life to accidentally form elsewhere.
The other factor is time. We know that life was created by amino acids combining over millions of years into what we consider "life". This process is likely happening in millions of different places but at different speeds and with different catalysts starting the operation. So our quest for life began billions of years ago, this process might take trillions of years on other planets. I tend to think that whatever started our life happened similarly on other worlds, so their evolution has reached the same degree of advancement as us. Of course random acts may have occurred on other planets to cause a divergence of the evolutionary tree we know, and there might be a planet of intelligent bird people on one planet and fish-people on another.
If a planet has oceans, it has likely undergone the same evolutionary process as ours and that makes hunting for "life" much easier. We know what components make up a water-evolved life form.
My point was that the chance of life forming is so great that the size of the universe doesn't offset it or at least makes life elsewhere much less guaranteed. One in a million is a lot different than one in a quadrillion.
That seems crazy to me.
One thing you have to consider regarding the age of the universe... other life may have, by chance or through innovation, taking advantage of the relativity of time... thus having more opportunity to evolve.
I agree and disagree with both of you. True, the sheer number of potential locations is enough to multiply a teeny tiny chance by a massive amount, but there's no way to quantify that initial chance. There is literally zero way to do it, so it could be substantial or it could be mind-bogglingly small.
14 BYA - universe forms
4 BYA - earth forms
3 BYA - life synthesizes
o.0001 BYA - intelligent life evolves
These timeframes can argue equally in favor of both - that there's a good chance, and that there's a crazy small chance.
We know it's not zero.
True but can you really feel out the difference between 1 in 1e -10 and 1 in 1e -100? I think it's too much to comprehend. It's the same thing people often remind you about when they use the sheer number of galaxies/stars/planets argument. It works both ways, in terms of bigness and smallness.
In my mind the development of life is common enough that maybe there's a million "Earths" out there with life at some form of development. Which raises an additional point. How many have been wiped out by cataclysmic events? What if a "dinosaur killer" asteroid hit a planet that was in the same stage of development of life that we have reached now? It would be interesting if we could somehow monitor the effects.
The other factor in everyone's decision regarding life is that, due to the distances of the galaxies we are observing, we are seeing them thousands to millions of years ago. Who knows what level of advancement the planet has achieved between the time we observe it and now? Likewise, who know what some far off lifeform looking at Earth from 50 million light years away is seeing and saying. "Look at that primitive world. They only have dinosaurs walking around".
We aren't actually seeing anything other than a tiny dot so I'm not sure why that would matter.
We don't need to examine them closely to know quite a bit about them
And I was speaking more from a philosophical view as opposed to an observational view. The data we currently receive is delayed based on the distance from Earth they are.
BTW, to take a step back, as cool and meaningful as it would be to find a single instance of life that originated separately from us, and what it would suggest about the frequency of abiogenesis, what are the odds that even 1 out of 1000000 instances would be intelligent? That's a whole other argument, and it's very easy to argue that the cerebral cortex and its precursors and evolved forms are incredibly unusual. It's easy because you only have to compare the total number of species on earth that has existed with the number that has evolved a cerebral cortex.
I always worry that people assume evolution has something to do with progressing a species to some natural end-result where being super smart is the ultimate goal. It definitely does not work that way.