It's always bothered me when a radio program is called a "show". What exactly are you showing me?

They should have used Planet Express!

A few points of clarification.

1. The major heat-producing elements are all lithophiles, preferentially bounding to silicates. So there's virtually no radioactive decay in the core. It's all in the crust and mantle.

2. Thorium is an important heat source now due to its long half-life (14 Gy IIRC). But back in the day, Uranium and Potassium-40 were much more abundant, and produced the majority of the radioactive heating.

3. Assuming the Earth and Mars initially had similar bulk compositions, they would have similar rates of radioactive heating. But Mars surely cooled more quickly. The heat production scales as the mass, and therefore the volume. Heat loss scales as the surface area. So smaller planets have the lower surface to mass ratio and cool more quickly.

Earth already had its iron core at the time of the Moon forming impact. Most of the impactor accreted onto the Earth and the cores of the two bodies merged (Canup and Asphaug, 2001, Nature). A fraction of the silicate crust and mantle of the impactor and target was ejected into orbit. That debris accreted into the Moon. Since it is largely made of the silicate portion of the original bodies, it is depleted in metal, and has a relatively small core.

That's actually not an error. It's a contraction of "Space September", the name of a time unit in the early attempts at a Space Calendar or "Spalendar" that wouldn't be tied to solar or lunar cycles as viewed on Earth. It never caught on, which is too bad, because "Spock-tober" would be awesome.

"With Respect To"

Minor quibble: You cannot be on a light beam going half the speed of light because the light beam, by definition, is moving at the speed of light.

If not sooner.

Yes. At the inauguration for one. Unless you're suggesting that one of them was a replicant...

Jupiter's moons (with the notable exception of Io) are completely covered in ice tens to hundreds of km deep. They do not have ice "caps" that could be shrinking. If they were losing ice, it would be more like the south polar plumes of Enceladus. In that case, we'd be far more likely to observe the plume of escaping material than to measure the mass of ice remaining. No such plume has been observed on any of the Galileans. Io has no ice to speak of, and therefore cannot be losing any.

Moreover, the orbital period about the Sun is about twelve years, and the tidal periods about Jupiter are several days. Variations on an Earth year cycle would not be astronomically significant.

The lack of plate tectonics is precisely why the history is preserved. Unlike on the Earth, the crust never gets recycled.

That number has TRIPLED in the last year alone.

How can you have a "moderate leaning?" Would "moderate" imply you're not leaning in any direction (at least not much)? I know I'm being pedantic, but that's how my day's shaping up.

The impactor was in an extremely low earth orbit.

You've been moderated +5 Funny, but I fear this scenario is EXACTLY what is going to happen.