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0 pointsBaeocystin5y ago0 comments

No. We have a Last Universal Common Ancestor, but that says nothing about whether or not there were other independently-formed branches that were competing at the time.

My personal opinion is that life under early Earthlike conditions was/is almost a guarantee. There is compelling evidence that life already existed in and survived the Late Heavy Bombardment- that's very early in our planet's history. If it was truly a rare event that sparked things off, I would expect it to have occurred much later in the planet's history.

https://en.wikipedia.org/wiki/Late_Heavy_Bombardment#Geologi...

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tsimionescu5y ago

> My personal opinion is that life under early Earthlike conditions was/is almost a guarantee. There is compelling evidence that life already existed in and survived the Late Heavy Bombardment- that's very early in our planet's history. If it was truly a rare event that sparked things off, I would expect it to have occurred much later in the planet's history.

That is valid of course, but in the absence of evidence of its existence, the default assumption should be its unlikely.

rsynnott5y ago

Hmm, I'm not sure that that's correct. If you build an apartment block and it catches fire the week afterwards, then it's perhaps not reasonable to expect that if you build another one to exactly the same design it will never catch fire. At that point you might want to be reviewing your wiring plans.

That life showed up so early says... something. If life showing up was so fantastically difficult, we would arguably expect it to be later in geological time.

tsimionescu5y ago

Sure, but if you look at an extremely old building and find signs of fire only from its very early age, it's somewhat strange to say that it was very likely to catch fire.

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tomerico5y ago

Well, if it did show up in the late heavy bombardment, it could have also arrived from outer space.

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0 pointsBaeocystin5y ago0 comments

No. We have a Last Universal Common Ancestor, but that says nothing about whether or not there were other independently-formed branches that were competing at the time.

https://en.wikipedia.org/wiki/Late_Heavy_Bombardment#Geologi...

0 comments

tsimionescu5y ago

That is valid of course, but in the absence of evidence of its existence, the default assumption should be its unlikely.

rsynnott5y ago

That life showed up so early says... something. If life showing up was so fantastically difficult, we would arguably expect it to be later in geological time.

tsimionescu5y ago

Sure, but if you look at an extremely old building and find signs of fire only from its very early age, it's somewhat strange to say that it was very likely to catch fire.

1 more reply

tomerico5y ago

Well, if it did show up in the late heavy bombardment, it could have also arrived from outer space.

j / k navigate · click thread line to collapse