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Moon's Bulge Explained

Posted by ryuzaki0 on from the put-some-cream-on-that dept.

anthemaniac writes "The moon has an unexplained bulge that astronomers have been trying to find a source for since 1799. Finally, an apparent answer: The equatorial bulge developed back when the developing moon was like molasses (and you thought it was cheese!) and, rather than today's nearly circular orbit, it 'moved in an eccentric oval-shaped orbit 100 million years after its violent formation.'"

6 of 204 comments (clear)

  1. Well by styryx · · Score: 2, Insightful

    Hey, way to suck the fun out of this with 'the cheese' joke in the description.

  2. Wait a minute... by The+Real+Toad+King · · Score: 2, Insightful

    Don't all circular/spherical objects bulge around the middle? take this o for example. The middle part of it is wide at the middle, and short at the top and bottom.

    1. Re:Wait a minute... by Mr.+Underbridge · · Score: 4, Insightful

      Right. I'd assume these guys accounted for the tendency of a rotating body to form an oblate spheroid, and that the moon's current orbit can't account for the degree of its oblacity (if that's a word). Thus it would need to have exhibited some more violent orbit in the past.

    2. Re:Wait a minute... by Billosaur · · Score: 4, Insightful

      Don't all circular/spherical objects bulge around the middle?

      If they are planets and they are spinning, yes. Just look at pics of the Jovian worlds, especially Saturn. And the Sun has a definite bulge. Of course, for most of the planets, the bulge is pronounced because they are still elastic to some degree. The Earth bulges owing to the fact that the continents are riding around on their crustal plates, which ooze on molten material, and the Moon is tugging on them as it goes aroudn us. The Moon's is more fascinating because it is a geologically dead world, so the bulge happened some time in the past and then got frozen in place.

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  3. Oblig... by Anonymous Coward · · Score: 2, Insightful

    That's no moon...

  4. How did Laplace find it? by helioquake · · Score: 2, Insightful

    How did Laplace determine the existence of the bulge?

    Was it a "simple" measurement of the shape of the Moon or something more sophisticated via his favorite mathematic tricks? Considering it is Laplace, he must have measured its eccentricity fairly accurately. I wonder what he used to do that in 1799.