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A.DIM
2004-Dec-13, 02:57 PM
Life-Swapping Scenarios for Earth and Mars (http://www.space.com/scienceastronomy/mars_life_041213.html).

I, for one, agree with panspermia and think it likely that earth and mars have exchanged material.

But I can't help but wonder if the pertuerbing body that "flayed" mars was also responsible for the collision that resulted in the creation of earth's moon...

nah.

:wink:

Taibak
2004-Dec-13, 03:31 PM
Well, it's highly unlikely. Whatever hit the Earth released enough energy to liquify the planet's crust. Extremophile or not, I doubt anything could have survived that.

Gerrsun
2004-Dec-13, 04:04 PM
I don't know...those extremeophiles are pretty tough little buggers.

And what is the latests thinking on the biomass that exists UNDER the earth's crust? I have heard that there may be more life below the surface of the Earth than above in the form of bacteria.

http://www.resa.net/nasa/otherextreme.htm

Surley some of this would have survived any massive impact?

A.DIM
2004-Dec-13, 04:05 PM
Well, it's highly unlikely. Whatever hit the Earth released enough energy to liquify the planet's crust. Extremophile or not, I doubt anything could have survived that.

I agree, but wouldn't that body then also contain the same "life-giving" elements? And if Life had the chance to evolve there, would it not also be of similar genetic make-up?
Hmm... :-k
Fascinating! :D

Amadeus
2004-Dec-13, 05:20 PM
Well, it's highly unlikely. Whatever hit the Earth released enough energy to liquify the planet's crust. Extremophile or not, I doubt anything could have survived that.

was the whole surface liquid? I would expect some "islands" of material. Plus maybe some material that would have been ejected could be safe havens for extreamophiles. Microbes are small. You dont need a large safe area to help them going.

BTW this is a dumb question but what did hit the earth back then?

I'am guessing that it would have to have at least the same mass as that of the moon or had been going very fast to have been able to dislodge that amount of material.

You would think that something that big would still be hanging about and not af the enertia to escape the solar system espesialy after using all that energy in a colision with earth. I am not, btw talking about a certain planet x. [-X

Could it have been a large comet?

Gerrsun
2004-Dec-13, 06:00 PM
All true Dr. Who fans know that is was a Cyberman ship.

Poor poor Adric. :cry:

And I was actually starting to like the little nerd. :lol:

Taibak
2004-Dec-13, 07:21 PM
Well, it's highly unlikely. Whatever hit the Earth released enough energy to liquify the planet's crust. Extremophile or not, I doubt anything could have survived that.

was the whole surface liquid? I would expect some "islands" of material. Plus maybe some material that would have been ejected could be safe havens for extreamophiles. Microbes are small. You dont need a large safe area to help them going.

No idea. I'm just a little skeptical, in part because there's no evidence that whatever hit us was rich in water. Seems like if that were the case, there'd be some water present on the Moon.


BTW this is a dumb question

No such thing.


but what did hit the earth back then?

I'am guessing that it would have to have at least the same mass as that of the moon or had been going very fast to have been able to dislodge that amount of material.

You would think that something that big would still be hanging about and not af the enertia to escape the solar system espesialy after using all that energy in a colision with earth. I am not, btw talking about a certain planet x. [-X

Could it have been a large comet?

As I understand it, the current theory is that a planetoid the size of Mars collided with the Earth. It hit off-center and had enough momentum to go straight through the Earth's crust. It didn't, however, have enough momentum to escape the Earth's gravity so it eventually turned around and plowed into the Earth again. As a result of both collisions, a large amount of the planets' crusts was thrown into orbit where it eventually coalesced into the Moon. However, the majority of the planetoid's core stayed on Earth, sank to the center, and merged with our own.

Edymnion
2004-Dec-18, 10:41 PM
No idea. I'm just a little skeptical, in part because there's no evidence that whatever hit us was rich in water. Seems like if that were the case, there'd be some water present on the Moon.Well, there is water on the moon. There's not a lot of it there, granted, but there is water on the moon.

aurora
2004-Dec-20, 05:45 PM
As a result of both collisions, a large amount of the planets' crusts was thrown into orbit where it eventually coalesced into the Moon. However, the majority of the planetoid's core stayed on Earth, sank to the center, and merged with our own.

Which matches the observation that the Earth has an unusually large core (on a percentage basis, as compared to Venus or Mars) whereas the Moon has a small core.