[Fish Hunter]

True,

You do seem to be open my doubt that anything in the solar system can remain stable for a billion years. The solar system is very active and a billion years is an incredibly long time, almost inconceivable to the human mind. Any constant perturbation of any size would effect things over a billion years. That was where I was going with my calculations, but I messed up when I did not throw the solar pressure into my initial condition for my exercise.

In my heart I just can't bring myself to believe in absolute constants, because the universe is dynamic and changing.

F H

[VadeRetro]

It's 4.5 billion years, and there have been changes. Early on things were very violent and unstable but they have settled down. Jupiter once ejected considerable mass from the system while its orbit slowed and degraded accordingly. (Conservation of momentum again.) The Earth survived massive bombardments early on and still takes the occasional whack. A poorly located planet-sized body broke up under tidal pressures (mostly from nearby Jupiter) to form the asteroid belt.

There are multiple, consistent, parallel lines of evidence pointing to the history of the solar system. It's in the orbital mechanics, the Herzprung-Russel stellar evolution model, the radiometric dates on the meteorites, etc. You don't make that go away inventing "Stump the Dummies" problems.