On Jan 4, 4:23 pm, Phil Hays <[email protected]> wrote:
> On Mon, 2010-01-04 at 04:36 -0800, Alastair wrote:
> > Yes, as the major axis increases due to the gravitational pull of
> > Jupiter, the minor axis decreases until it reaches 1AU, then crash!
>
> The Earth has a much bigger "gravity well" than surface area. If a comet
> or other body comes close, then the Earth's gravity will much more
> likely deflect it into a different orbit than there be an impact. This
> different orbit might be an Earth impacting one, or also might be a
> Venus impacting one, but is more likely going to have multiple close
> passages with one or more planets before any impact, or before ejection
> from the solar system.
Well, I can't prove that it happened. Nor AFAIK can anyone.
But I saw an estimate of 5000 times the amount of water on Earth,
formed in the asteroid belt. So we ca let a few of the passing MLB
comets crash into Mars, the Sun, Jupiter, and off to space and still
have enough left over to fill the Earth. Mars is smaller than Earth,
and may only have served to help protect Venus rather than protect
Earth. In other words, even if Earth or Mars did not collide with the
comets they would probably distort their orbits enough to make a
collision with Venus unlikely.
But a model is required, and much more data.
Cheers, Alastair.
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