Jupiter and Saturn are cooling too rapidly to be old (Talk.Origins)

Claim CE231:


 * Jupiter and Saturn are cooling, giving off their internal heat at a rate too great for them to be billions of years old.

Source: Brown, Walt. 1995.In the Beginning: Compelling evidence for creation and the Flood. Phoenix, AZ: Center for Scientific Creation, p. 30.

CreationWiki response: It needs to be noted Talk.Origins seems to have ignored 3 of the 5 planets mentioned by Walt Brown. They are Neptune, Uranus and Venus. So even if they can explain Jupiter and Saturn, there are still 3 more.

This seems to be based on a uniform rate of decrease in temperature, but since the planet would cool by radiation to space, and the planet's radiation rate is driven by the fourth power of its surface temperature, the cooling rate would decrease as the body cools. According one of Dr. Brown's references, when this fact is considered in the calculations it shows that Jupiter is too hot to be 4.6 billion years old.

This is a nice theory, but can it start with first principles and produce Saturn's extra heat? It sounds like the type of theory that has enough unknowns that it can be adjusted to fit any related observation.