[forebirdo]

Did we have two Moons?

http://www.youtube.com/watch?v=xbZ4MlTw2JA

[Sotmoigma]

And since it obtained its Oceans after it solidified presumably, wouldn't the nutirients and minerals Paul spoke of have already been there? yes, but the point is that the tides would have acted like the water cycle does today, just faster and more intense. without either the dissolving of minerals into the water bodies would have been a lot slower.

[KhJOHbTM]

When did Earth obtain its Oceans? in the hadean period, as already posted. this is the same period that the collision is said to have taken place.

[Rnlvifov]

> Origin of Life on Earth Depended on the Moon?

No. To even suggest that is totally ludicrous. It's even a case of the reverse - the impact that created the Moon would have been a catastrophic extinction event if life had developed on Earth before then. Not just because of the impact itself but also because it resulted in the loss of life-giving hydrogen.

[TobaccoNUE]

in the hadean period, as already posted. this is the same period that the collision is said to have taken place.

That's my point. When the collision was supposed to have taken place, Earth's crust was supposedly still near molten. Wouldn't then the Oceans have evaporated?

[sEe]

http://en.wikipedia.org/wiki/Hadean

A sizeable quantity of water would have been in the material which formed the Earth. Water molecules would have escaped Earth's gravity more easily when it was less massive during its formation. Hydrogen and helium are expected to continually leak from the atmosphere[clarification needed].

Part of the ancient planet is theorized to have been disrupted by the impact that created the Moon, which should have caused melting of one or two large areas. Present composition does not match complete melting and it is hard to completely melt and mix huge rock masses. However, a fair fraction of material should have been vaporized by this impact, creating a rock vapor atmosphere around the young planet. The rock vapor would have condensed within two thousand years, leaving behind hot volatiles which probably resulted in a heavy CO2 atmosphere with hydrogen and water vapor. Liquid water oceans existed despite the surface temperature of 230 °C (446 °F) because of the atmospheric pressure of the heavy CO2 atmosphere. As cooling continued, subduction and dissolving in ocean water removed most CO2 from the atmosphere but levels oscillated wildly as new surface and mantle cycles appeared.

[CaseyFan]

> Origin of Life on Earth Depended on the Moon?

No. To even suggest that is totally ludicrous. It's even a case of the reverse - the impact that created the Moon would have been a catastrophic extinction event if life had developed on Earth before then. Not just because of the impact itself but also because it resulted in the loss of life-giving hydrogen.

It's not often I disagree with mollwollfumble, but in this case I do. Not so much that the moon may or may not have helped with the origin of life, but the statement that to "suggest that is totally ludicrous". We are not talking about if life could survive a moon formation impact, but the likelihood of life forming after the event. I personally think that the moon most likely did have a major influence on the beginning of life, due to it's tidal effects creating still pools of warm water of varying compositions at multiple places around the world every 12 hours for millions of years. That has to increase the possibility of various amino acids coming together in just the right combination. I am no scientist however, and can only go on what I read in various journals and websites. If mollwollfumble has some information to back up his assertion(which he invariably does ), then I would like to be able to read it and stay up with the current information.

[Dokescoonse]

To even suggest that is totally ludicrous +1

[caseferter]

There is though the simple fact that tides do influence and impact upon life. It isn't total supposition that they have always done so.

Agree with roughy. I don't know if the Moon was necessary for life to begin however the Moon's influence over the behaviour of water certainly was necessary for life as we know it to form. Whether this occurred at the Thea event or after, I don't know. It might have been something that became more important to life after any particular extinction event such as te K-T boundary. Even now, the tides in mangroves are responsible for the survival of several plants and animals.

[Trebbinsa]

Yes, I don't know what moll is on about. It is a long way from being settled science, but the possible relationship between the development of life on Earth and a large Moon has been widely discussed and appears in the literature. It might not be correct, but it's not "totally ludicrous".

Here's just one (popular) account of the science.

[intisgunkas]

meh

[wmhardware]

Without a moon, there would still be tides [though smaller] from the influence of the sun. This washing motion of the super tides that is proposed would still happen but over a longer period of time and if you add rainfall then that is even more washing. So, if the washing had an effect, having no moon would slow down the effect but it wouldn't stop it.

Though I have heard an alternative theory that the moon stabilises the earth's spin so that if this spin was not stable then the climate [or something] would be, well, unstable and not be settled enough in one place for anything to start off.

I am sure I am misquoting this theory horrendously, it is something in the back of my mind that I once saw on a documentary - about the moon I think...

[maxfieldj1]

i thought the warm tidal pools idea concerning abiogenesis had been superseded by the black smoker theory.

[avappyboalt]

I'll withdraw my meh when we have a reasonably large sample of biologically active planets so that we can make this kind of assessment.

[globjgtyf]

we have a reasonably large sample of biologically active planets so that we can make this kind of assessment I'm sure we have some Bayesians left around here...

Generalizing from large samples is not the only way that statistical conclusions can be drawn, let alone scientific inferences in general.

[Loolasant]

i thought the warm tidal pools idea concerning abiogenesis had been superseded by the black smoker theory. There is no consensus, nor is there likely to be any time soon. Both remain active possibilities.

[shashaffff]

I'm Bayesy for tryin', Bayesy for cryin'


You're right in abstract, but the fact that so little is known about abiogenesis means that in this case we can't assess these hypotheses without a larger set.

(Alternatively, I suppose, computational physical chemistry could improve a trillion times so that the matters could be tested in silico: this would be an unexpected development if it occurred in my lifetime but you'd see some qualified demehification under those circumstances.)

[prmwsinfo]

You're right in abstract, but the fact that so little is known about abiogenesis means that in this case we can't assess these hypotheses without a larger set. I was, indeed, disagreeing with your reasoning more than your conclusions. There are clearly insufficient bounds on our knowledge for us to be able to assess these ideas. While tighter constraints may well come from identifying life (or ex-life) elsewhere, it is also quite possible to imagine further knowledge from a purely terrestrial origin that would allow this as well (although not anytime real soon, I would think).