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> life appeared so soon after the Earth became solid It took hundreds of millions of years, possibly up to a billion years, for basic life to form on Earth. I
by quietbritishjim 8y ago
> life appeared so soon after the Earth became solid
It took hundreds of millions of years, possibly up to a billion years, for basic life to form on Earth. I would say that is not "soon"; it's a really long time.
The obvious response to that is, yes it seems like a long time, but it's not much on geological time scales. But it feels to me that there's an implicit circular argument here: the whole reason that geological time is measured in terms of such huge spans is because it took life such a vast amount of time to get to the point where humans exist to discuss it (understandably).
- neuronic 8y agoBut that's mostly because humans aren't an achievement of "life". We were never a development goal of "life" nor does the universe care very much about us - even if we built megastructures directly harnessing the energy of black holes and stars. If current knowledge is remotely correct, heat death will happen, no matter how immortal Homo deus will become. The quarks are against us. And if complex systems theory teaches us anything then it would be preposterous to assume any ultimate superiority in understanding the universe on our part. Who knows who wrote crazy alien versions of Hacker News posts 2 billion years ago in one of the other couple of thousands of galaxies seen in Hubble Deep Field alone...
- quietbritishjim 8y agoHumans are really just an example, I regret mentioning it. All significant developments in life (e.g. multi-cellular lifeforms, post-Cumbrian explosian animals) took hundreds of millions to billions of years.
- kamaal 8y agoIn fact given the fact evolution is a process without a goal. Intelligence could be even more rare among multicellular lifeforms.
- Brockenstein 8y agoOr the consequence of great intelligence is an evolutionary dead end. What if intelligent life becomes smart enough to destroy itself, but doesn't survive quite long enough to use that intelligence to save itself.
- JoeAltmaier 8y agoI remember reading that 4 or 5 intelligent hominids coexisted in Africa a million years ago. More or less intelligent. It can't be that rare then. In fact, dolphins. Octopi. Yeah, pretty much a given I'd imagine, in the right complex ecosystem, that intelligence is a thing.
- nickwalton00 8y agoEverything has some level of intelligence, but the intelligence to develop tools and civilization beyond tribes and sticks is something else.
- zeth___ 8y agoLife shows up in the fossil record more or less as soon as rocks on the Earths surface start forming. The first billions years on earth mostly involved the planet getting hit by large things and the surface melting. Repeat every millennium.
- throwaway5752 8y agoYou just explained why there's no fossil record from early earth, unless I'm misunderstanding you and that was your point. Ocean floor is continuously destroyed as it's subducted, and continents won't have fossils if they are under frequent bombardment.
- joshuahedlund 8y ago> continents won't have fossils if they are under frequent bombardment. Right, but if giant bombardments completely boil away the oceans and atmosphere to rain liquid rocks back down on the surface, there very very likely won't be life, either. So the claim is not just that "fossils only go back to X" but that X is so close to the end of the giant bombardments that there's almost no time left (geologically speaking - maybe 10-20MY) for "life but no fossils yet".
- deleted 8y ago[deleted]
- joshuahedlund 8y ago> It took hundreds of millions of years, possibly up to a billion years, for basic life to form on Earth. This is a common popular misconception. See something like Simon Conway Morris's book Life's Solution. There is evidence that life existed on earth almost as soon (geologically speaking) as the early bombardment stopped repeatedly boiling away the entire oceans and atmosphere, within something like 10-20 million years. Thus, all the interpretation about the implications of that.