[vmasto]

> 1 trillion chances per planet

Not meaning to be condescending, that's not how probability works or is expressed.

Also, the fact that the ocean "is a large place" says nothing about how probable or not the events to create and sustain life are.

I understand most people have this gut feeling that because the universe is vast and ancient there must be something out there (and I have it too), but we just don't know.

We just have no idea exactly how hard life is to develop and be sustained. We just started having theories (a handful at that) about how we transcended from chemistry to biology. The prevalent theory for example is that the moon's unusually big size and proximity was the catalyst for that to happen. How many planets have extremely big moons in such close proximity? How many million other factors played a role assuming the tide theory is even close to accurate?

It's just an infinitely complex problem and we just don't know.

[ShamelessC]

I'd love to know more about these moon theories. Got a good layman's article to cite?

[flukus]

There are a few effects but we don't know what is important and what isn't.

The moon stabilizes the earths rotation (due to orbital mechanics I don't understand), that's probably important for complex life.

Tides are probably important because they help mix up all the elements. Tidal pools also may have been critical for abiogenesis.

The creation of the moon be a huge planetoid hitting us may be responsible for plate tectonics that provide enough volcanism.