Solar system objects

Re: Random moon questions

Centaur — Wed, 24 Sep 2008 22:23:22 GMT

zachsdad:

Hopefully someone else will weigh in if my numbers are off too badly.

You've got the right idea, zachsdad. I'd only add that the Moon's secular movement away from the Earth is decelerating, so it would theoretically take even longer to move that far out.

Re: Random moon questions

zachsdad — Wed, 24 Sep 2008 21:00:37 GMT

That's an interesting question. I did some very rough calculations assuming a constant rate of recession of 1.5 inches/year.

For the moon to move about 1/2 of it's current average distance further from the Earth (about 120,000 miles further out, enough to have a significant, but not catastrophic effect) would take just over 5 billion years. By that time a receeding moon will be the least of our worries, as we are heading for a merger with the Andromeda Galaxy in about 3 billion years, and our sun will run out of fuel and swell to a red giant phase -- toasting us, and the moon -- in about 4 billion years.

Hopefully someone else will weigh in if my numbers are off too badly.

Re: Random moon questions

chipdatajeffB — Wed, 24 Sep 2008 20:57:51 GMT

You may find this helpful:

http://cs.astronomy.com/asycs/forums/t/35379.aspx

Random moon questions

lostNtimeNspace — Wed, 24 Sep 2008 20:32:44 GMT

So I recently watched a program that said the moon is moving like an inch and some change away from us each year. So would it be safe to assume that eventually the moon would get far enough away from the earth that it would adversely change our tides if not our climate, due to the fact that the moon helps stabilize the earths tilt? Furthermore, with the moon moving away from earth, would that mean that eventually it would exceed the reach of the earth's gravitational pull? I'm just curious.