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by tsimionescu 2095 days ago
Think about it this way.

The Earth today is not capable of sprouting life (abiogenesis). In fact, from the fossil record and genetic studies, the Earth has almost certainly been unable to form new life (out of un living substances I mean) for billions of years.

Then, the same is true for multicellular life appearing from unicelular life. All of the living multi-cell organisms today seem to be descended from 1 common ancestor, 1 time that multicellular life has ever appeared in more than a billion years.

So right now, the very basic needs for life to even start seem to be staggeringly unlikely. Even at the huge scales of planets in the universe, it could be that the chances we'll ever meet another civilization are un conceivably low.

Of course, simple life could exist 'all over the place', and most scientists generally believe that. But life capable of interstellar communication like us may well be staggeringly rare in the universe.

We'll probably know a lot more about this in the coming decades/century, as we'll hopefully be able to send probes to look for life on Mars, Europa, Venus and other potential candidates in the Solar System. Perhaps we'll even be able to create abiogenesis in the lab and be able to learn more about the possible requirements that way.
1 comments
leto_ii 2094 days ago
> The Earth today is not capable of sprouting life (abiogenesis). In fact, from the fossil record and genetic studies, the Earth has almost certainly been unable to form new life (out of un living substances I mean) for billions of years.

Playing devil's advocate for a bit, how do you know that existing life, honed by evolution, doesn't simply outcompete life that is continuously born abiogenetically in places like hydrothermal vents [1]?

[1] https://en.m.wikipedia.org/wiki/Hydrothermal_vent

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tsimionescu 2094 days ago
Of course, we can't know for sure, but the fact that in all this time no other strain seems to have made it makes that theory implausible to me.

To be fair though, there is A LOT of life on earth, so we can't discount the possibility that we'll find some forms of life that come from a different tree than us.

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