Sam McConnich wrote:

> depending on how the planet originally formed and from what,could
> radioactives within the planet contribute to maintaining heat

I think any sufficiently large terrestrial (rocky) planet will have
radioactives helping keep it warm. Mars isn't large enough, it's cooled
off too much. Earth is large enough; Venus may be.

The process by which *all* elements heavier than oxygen are formed, in
supernovae, will be the same everywhere. The dust out of which planets
are formed all comes from supernovae explosions, which will all produce
the heavier elements. I can think of no reason why the percentage of
radioactives in the dust should vary much from star to star, so we have
no good reason to believe the Earth is especially high in its percentage
of radioactives.

~~~~~~~~~~~~
Clear ether!
Lensman

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