Which would surprise you more: Learning that life exists elsewhere in the Universe, or learning it does not?

Question

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Please explain why.

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Answer 1

The latter.

There are billions of stars in each galaxy, and there are billions of galaxies in the universe. We already know of several hundred extra-solar planets, so it appears (as expected) that stars with planets are ubiquitous. That means there must be countless trillions of other solar systems in the universe where there may have been planets with suitable conditions for abiogenesis.

Now, there must be a certain probability associated with abiogenesis - Maybe it's unlikely to happen even in a trillion solar systems (in which case why are we here?) or maybe it's only (say) one in a billion, in which case there ought to be hundreds of examples of extraterrestrial life in our galaxy alone, and billions in the universe as a whole.

However, what are the chances that the *probability* of abiogenesis exactly matches the number of *opportunities* it has to occur, so that it happened exactly once, and only once, in the entire universe? This, to me, seems incredibly unlikely - Either abiogenesis would be so unlikely that it would never happen, or it would be quite likely and it would happen billions of times. For it to occur just once, and only once, seems far more unlikely than either of these possibilities.

So... Given that we're here, my guess is that life has started in many other places in the universe too. How much of that would develop into intelligent species is another matter, of course.

The only caveat with this argument involves the idea of multiple universes: Suppose that there are many or an infinite number of universes, all with different characteristics, and that the probability of abiogenesis is so small that it's extremely unlikely to happen even in a trillion solar systems. In that case, maybe there are a vast number of other universes in which conditions suitable for life exist, but it never got started in those other universes - Our universe was the one place where this inconceivably unlikely event occurred, and it occurred only once. That's a possibility that we could perhaps be disappointed about, or inspired by, depending on your point of view.

Answer 2

I don't think I'd be surprised either way. Our definition of "life" is not all that precise to begin with, so the first evidence would need to be carefully evaluated. It could be a chemical reaction, contamination from Earth, or the real thing.

There are people re-evaluating the data from the Martian Viking probes of the 70s right now. They think they've found the evidence. Others disagree. The detection of intelligent life would be less ambiguous, but less likely.

The odds of finding other life in an effectively infinite universe are good, mitigated by the difficulty of getting around in it. But we simply don't know precisely how our own life arose, so we don't know what conditions are required to make it happen and how often those conditions occur. If we don't find life anywhere in our Solar system, the chances of finding it elsewhere will probably be low, but anything is possible.

Answer 3

Learning that it does. Even though the universe is huge, we really don't have any way of knowing just how rare an event it is for life to arise. Even if it did arise somewhere else in the universe, it may be too far away for us to send them a message before we become extinct. Or it may be too late -- they have already died out.

And all evidence up to now points to that there isn't life on other planets. So yes it would be more surprising to find out that this hypothesis was wrong.

Answer 4

It would surprise me to learn there is life elsewhere.

Learning of life elsewhere would indicate that humans had either figured out how to travel to these Places Where Life Exists But Not Advanced Enough To Make a Spaceship With Hyperdrive, or that the SETI cult reached a revelation. I'm not holding my breath for either event.

Until someone else proves me wrong, we're it.

Faith in life outside of earth is a religion, and I'm irreligious.

The Drake Equation is right up there with the Lord's Prayer.

Answer 5

I would be floored if anyone could offer conclusive proof of either scenario, but from a practical standpoint the chances of us accidentally receiving a signal sent into space by an interstellar intelligence would seem far more likely than the human species developing a way of examining every cubic parsec of the universe to emphatically declare there is "nothing" out there.

Of course, if a supreme creator appears and breaks it all down for us, well, that would be an altogether different story.

Answer 6

Learning life does not exist elsewhere would absolutely floor me.

Why? Life popped out of the Earth, so why not out of at least 1 other planet in the universe?

Answer 7

If I were to learn that there were positively no other life forms of any description out in the vastness of the universe would be staggering. As many people have written the universe has billions of stars all throughout millions of galaxies over billions of parsecs. For us on earth to believe that we are the only inhabited planet is not only naive but borders on insane.

Answer 8

If life were unique to Earth it would mean that abiogenesis is much less likely than it appears: on Earth it took place almost as soon as the planet was cool and wet enough.

Earth *is* rare, according to the Drake equation, but not at all unique in such a huge universe. No other life would be astounding.

CD

Answer 9

Learning that it does not.

It developed here, so why not elsewhere? Considering the number of planets in the universe, there's really no reason to think that life isn't out there somewhere.

Answer 10

I think that it would be disappointing to discover that it did not exist, because there is a possibility of it and we want it to be so. I would be surprised and elated to discover that there was life elsewhere in the universe because it would be a huge scientific discovery. I think finding out that there wasn't life elsewhere in the universe would surprise me more.

atheist