Why is the Earths core warm

Jim, the density of the Venetian atmosphere has everything to do with its higher surface temperature. The cause of the higher pressure is simply that Venus has more gas in its atmosphere (a lot more than Earth). The fact that there is more molecules means more gaseous collisions and hence more heat energy.
JIM: "Your post is about what is stated in books about this detail of Earth's systems."
MARK: So, not everything in a book is an attempt to distort the truth, I like to think that books contain observations and hypotheses that have been tested and supported. I call it science. Belief has no role in science.

Please don't make claims without proof. You also stated that Venus has a lower solar absorbtivity. Would you care to post what it is and not be so vague?

Venus is hot at its surface because its atmosphere traps solar heat and because the atmosphere's sheer mass is nearly that of continental land masses floating on magma. So we could use venus' atmosphere to study the movement of land plates (Brings into play the atmosphere of Jupiter which is denser than solid rock.)

Mark

Hi Mark, And can post a reference to the book that claims the atmosphere of Jupiter and Venus is as your last post says? I don't want to get in an "is too/is not" chat have it your way on the rest of these points. One thing about why the surface of Venus is hot is the atmosphere of Venus insulates much better than Earth's does. I'm sure we can agree on that anyway.