The Mosquito as space traveller

On a sunny day (Fri, 20 Feb 2009 03:32:48 -0800 (PST)) it happened Ian Parker
wrote in
:

Maybe the old earth was much smaller, with
hardly any water, and some big comet hit it,
driving the continents apart, creating oceans,
increasing gravity, that killing all the huge
animals.

If the Earth was smaller gravity would be HIGHER

No, no, smaller = less mass = less gravity.
If you were thinking the same mass, compressed in a smaller volume,
then at the surface you would be heavier.

The idea I was suggesting, is that if some huge comet did hit the earth,
it would get into the core, and increase the mass, causing volcanism all over the place,
and the swelling would push the continents, the solid surface layer fragments, apart.

The resulting increase in gravity due to increased mass, would kill only the big heavy lifeforms.