Ok, one person says it's radiation that heats the earth.
Uranium in it's natural environment does not produce anywhere near that amount of heat, to melt the core of the earth, that is just stupid.
I think you all need to read a book or something.
[link to en.wikipedia.org
It was only discovered in 1936 that the earth has a molten core, and they still don't even know if Mars has a molten core or not.
If it was simply a matter of pressure and gravity, they would know if Mars has a molten core or not.
Mars has a dead electromagnetic field which would suggest it does not, if not, why is it's core not hot enough to be molten?
At least I don't pretend like I know everything, I can't stand these dumb fucks on here who pretend like they know everything and won't even click on a wikipedia article to study the matter a few seconds.