The fate of the Earth?

Hi.

I saw this discussion:
http://www.sciforums.com/archive/index.php/t-41880.html

One poster posted:
"Well I'm about to finish the book on that. Venus has stopped spinning
by an internal mechanism that was feeded by chaotic resonance in its
orbit. Consequently the planet heated up tremendously melting it
completely. This happened one to two billion years ago. We still see
the residual heat of that process and this has nothing to do with
greenhouse gas effect.

There are many details supporting that hypothesis, like the shaping
and geologic frequencies of the plains indicating melting, the
exponential declining of volcanic activity indicates strong cooling
etc. The new paradigm rthat is currently emerging is "radiogenic heat"
and a lot of it. But what is the source. The most likely element -
potassium40- (40K) is also much more rare on Venus?

It was the big brake."

Is any of this good theory? If so, what sort of implication would it
have for the far future of the Earth, when the Sun's luminosity
increases to the point it begins to evaporate the oceans from the
globe? (Note that this happens quite far in advance of the red giant
phase.) As it seems to suggest things other than greenhouse are
necessary to get the Venus-like environment. If melting it down is
required to keep it so hot, not just greenhouse, then could it be that
the Earth might instead of becoming like Venus become more like Mars
with a depleted, thin and wispy atmosphere? Or is this bad theory?
It's been about 5 years since this was posted, so I suppose more work
has been done now on this subject.