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Angular Momentum and the Big Bang

  1. Nov 26, 2009 #1
    I've heard claims that the Big Bang defies the law of conservation of angular momentum. For example, not all planets spin in the same direction in our solar system. I think venus is an example. How does this defy CAM?
  2. jcsd
  3. Nov 27, 2009 #2


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    I've heard this claim. It just doesn't make any sense whatsoever. It's completely and utterly incoherent.

    First, the big bang theory really doesn't have much of anything at all to say about the formation of solar systems. The big bang theory is about the behavior of our universe on the largest of scales, beyond a few million light years. A solar system, by contrast, is just light-hours in size (and when we're talking about the parts of it that include Venus and Earth, we're just talking a few light-minutes).

    Second, the retrograde rotation of Venus is easily explained by a collision from a large object early in Venus' history.
  4. Nov 27, 2009 #3
    Erm, wouldn't you expect things to rotate in different directions if you assume that the initial angular momentum was zero? So you would assume that something fishy was going on if everything rotated in the same direction.
  5. Nov 27, 2009 #4


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    Well, in general, what happens is that if you have a cloud of randomly-moving particles that is collapsing, the total angular momentum will not be zero. But different clouds in different parts of the universe will have very different angular momenta.

    Furthermore, the reason why the planets are expected to have all had the same basic rotational direction originally is due to the dynamics of how the solar system formed: the friction in the disk of gas and dust around our young star that formed the planets sort of forces them to have the same angular momentum direction (to start with) as the solar system as a whole. The angular momenta can be changed later by collisions.
  6. Nov 27, 2009 #5
    lol, that's exactly what I was thinking. I couldn't make any sense out of the claim either. It was so bizarre that I couldn't tell if it was just ridiculous, or if it just was just over my head.
  7. Nov 28, 2009 #6
    Since it is considered a fact that NO information could have 'passed' through the initial Big Bang event, it sure is handy that we have the Atomic structure that we do, by pure chance. I would guess that I am only thinking this because that's what we are used to. There may well have been a near infinite number of matter structure possibilities that could have taken place for this particular Big Bang started Universe. NO, a funded program to investigate this, should NOT be started.
  8. Nov 28, 2009 #7


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    I don't see how these two statements are in any way related.

    Well, yes, this is most likely the case. And many physicists are looking into various possibilities related to this. It is difficult to test such theories, but not necessarily impossible.
  9. Nov 28, 2009 #8
    That's not considered a fact.
  10. Nov 28, 2009 #9

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    A quick google search shows that this claim is creationist claptrap. They are misconstruing (and I suspect intentionally so) what conservation of angular momentum says. Conservation of angular momentum does not say that the angular momentum of some non-isolated object such as Venus is constant.

    There is no consensus on why Venus rotates the way it does. It is easily explained without a collision. For example, see http://physicsworld.com/cws/article/news/2661.

    There is no correlation between the rotation of objects in the solar system and the initial rotation (or lack thereof) of the infant universe. Heck, there is no correlation between the rotation of objects in the solar system and the Milky Way. The angle between the ecliptic and galactic planes is about 62 degrees.
    Last edited by a moderator: Apr 24, 2017
  11. Nov 29, 2009 #10
    I was just going by what Hawking thought about it, that I subscribe to also.
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