:ok:

That strikes me as the main reason new life doesn't come into being. If it takes 100s of millions of years for it to "evolve" from non-living matter, we would never see it "pop" into extence. Even the simplist life is incredibly complex. That leaves a very big door open for development to be disrupted by other life or changed conditions. Seems like it would take a very long period of stable conditions to life to develop abiotically. — T Clark

We don't know how long it actually took to develop live from existing complex molecules, and i'm no biologist, but yes, that seems a plausible hypothesis.

Edit: I like that you put evolve in quotes there, because abiogenisis is not evolution. For evolution you need reproduction, and then you get a self-perpetuating proces. Molecules don't reproduce, so it seems to have been some random re-combination of complex molecules. And maybe this is a proces that doesn't built on itself (in that you have to start over each time)... And so it seems to be a chance event where a lot of time is not necessarily a prerequisite for it to happen (unlike say the evolution from a single cell to dinosaurs that does need a lot of generations). Say for example there is a 0,1% chance of that specific combination to happen given certain complex molecules, then it could happen anywhere between a day from now, a million years... or never, but the proces itself doesn't necessarily takes a lot of time.

:ok: Thanks

I like that you put evolve in quotes there, because abiogenisis is not evolution. For evolution you need reproduction, and then you get a self-perpetuating proces. Molecules don't reproduce, — ChatteringMonkey

I used "evolve" on purpose, because it seems to me there is probably a lot of a sort of evolution going on before something reaches the point we might call it alive. It isn't just chemicals combining until a chance leads to life. There is a very complex non-biological process of self-organization that leads to chemical cycles and the development of what they call "nanomachines." See "Life's Rachet." Somebody here on the forum recommended it. Was it you @StreetlightX? Maybe it was @apokrisis.

See the Wikipedia link for nanomachines. The first animation shows one of the naturally occuring nanomachines that Hoffman described. A living cell is full of these and other processes going on at all times.

I'm not certain that de novo proto-living forms could not arise now, are not arising now, and are developing towards sustainable life-forms, but it seems immensely unlikely that we would be aware of it if were happening.

a) we do not have a list of all the species that now exist.

It's quite complete for mammals and birds, but even for them, a new mammal or bird is discovered sometimes (not very often). For all of the creatures with six, eight, and more legs, or no legs, we have a long but incomplete list. For single celled creatures we do not know how many we are missing. Probably a lot.

b) we do not know where de novo proto-living life would appear, and the surface of the earth has many immensely inaccessible places on it. New life forms could be arising in the bucket of slop on your back porch.

c) we do not know what they would look like, because they would be... new. And they would be very small, smaller than viruses.

d) be careful what you wish for. Several scary science fiction novels inform me that new life forms may not like us, and we may not like them, either.

we do not know what they would look like — Bitter Crank

If a new organism did develop completely independent of existing life, it seems to me it would be unlikely to be DNA based. There is also speculation that the genetic material in the earliest life might have been based on RNA or even some other organic compound. I guess it's also possible that a new species could develop from a virus or other source of DNA that might look like our current life.

Somebody here on the forum recommended it. Was it you StreetlightX? Maybe it was @apokrisis. — T Clark

'Tis a fantastic book, but yeah, it was Apo. The best current book for the lay reader is Nick Lane's The Vital Question. Super in depth look at cutting edge research into how life might have come about. A bit more technical than some other pop-science books, but its emphasis on energy constraints and the role it plays in the development of life - something alot of people don't think about - is super eye opening and worth the trudge.

The best current book for the lay reader is Nick Lane's The Vital Question. — StreetlightX

Thanks. I'll take a look.

Your answer resonates with my feelings on the matter The "bucket of slop" sentence is terrific and your warning "they may not like us" must be taken seriously.

Thanks.