3/22/10

Tidbit of the Week--Tidal Locking



I've been doing a lot of tidbits on the moon lately. I wonder if it's because I've been thinking about the moon a lot lately. I guess so.

I never knew why only one side of the moon faces the Earth. I had some weird idea that maybe it was part of the Earth and it broke away and is still rotating at the same speed it's orbiting, or some such half-baked idea. But that's silly.

I was reading in 1001 Things Everyone Should Know About Science, and I read about land tides on the moon. Apparently, after hundreds of thousands of years these land tides have despun the moon, so now it only shows us one side. The book didn't go into much detail as to how this works, so I decided to dig deeper.

According to Wikipedia, these despinning land tide forces are called "tidal locking." In short, "The change in rotation rate necessary to tidally lock a body B to a larger body A is caused by the torque applied by A's gravity on bulges it has induced on B by tidal forces." That's enough explanation for me.

2 comments:

Professional Big Brother said...

DTHRocket,
If you want an explanation on those "bulges" that is easy to understand, you might want to try:
weeklysciencefact.blogspot.com/2010/02/mass-concentrations.html

R2K said...

You are a real lunatic!

But seriously, reading about MasCons on the moon is pretty interesting. There is a book called "How Apollo Flew to the Moon" by Springer Praxis. There is some wild stuff in there, it was actually harder than even I had appreciated before. Lots of navigation work.

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