Expert: Philip Stahl - 7/28/2010

Question
Hi Philip, thanks for taking the time to look at my question.  I wanted to know what would have to be done to turn the moon into an interstellar comet?  A planetoid spaceship if you will.  Also, if the sun were dying would it be possible to use this new trajectory of the moon and fling it into the sun; like coal on a fire, to keep it ignited?  Thank you.

Answer
Hello,

Personally, I can't think of anything feasible OR desirable that we could do (or would wish to do) to turn the Moon into any kind of "planetoid spaceship". By that I mean a body detached from its present orbit and more or less under human supervision, direction.

You are dealing with a mass about 1/81 of the Earth's, and any alterations of the type that would render it a "directable planetoid" would not be conducive to us on Earth. Never mind our fancies for technology (as in the purported "fixes" for global warming in the book 'Superfreakonomics") which disclose a mind-boggling hubris for a species whose ambitions are definitely too big for its collective breeches.

So no, I'd not go there and wouldn't have clue one - given my conservative mindset and the possible consequences- why anyone would.

Obviously, then, "flinging the Moon" at the Sun is also out of the question! This is apart from the fact that it would have absolutely zero effect on keeping the Sun going- since nuclear fusion and coal burning are totally distinct processes, apart from the fact one can't thermodynamically apply the latter to the Sun.

Bear in mind here the Sun reaches its death throes (heading toward white dwarf status) because of the inexorable loss of energy efficiency in its successive, internal nuclear fusion reactions: going from proton-proton to triple alpha fusion and so on. Thus, its "end" is dictated by the diminishing 'Q'  (energy given off)from  nuclear fusion reactions via fundamental astrophysics.

The idea of hurling a tiny Moon at it would (analogously) make about as much difference as hurling a flea at a charging elephant to try and stop it.