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Gas/dust cloud physics.

  1. Mar 14, 2009 #1
    This is my first post here, so I'll start off by just saying hi. ^_^

    Anyway, I've been in a debate recently with somebody at another website and some interesting topics have come up that I would like to learn more about.

    The person I'm in the debate with clearly doesn't understand basic astronomy, saying with confidence that "gravity isn't enough to cause a cloud to collapse" and "Jupiter couldn't have formed unless there was already a large solid object to pull in all the gas". -_- I explained to him the concept of Jeans' length and Jeans' mass, and directed him to various web pages regarding the subject, and he has since disappeared completely.

    But there's one thing that came up that I still want to learn about, and any help in explaining it to me or directing me somewhere with an explanation would be nice.

    Well, the person said that "if planets were formed naturally then they wouldn't spin at all because collisions between particles in the protoplanetary disc would cause any rotation to be self-canceling. Clearly this person has lacking knowledge of angular momentum. Despite his leaving the debate I still want to learn about this. I know that the initial rotation of the cloud is the origin of the rotation of the subsequent stars and planets due to the conservation of angular momentum, but that's the extent of my knowledge on the matter. If possible I want to be able to know the math that shows his comment to be false, but overall I just want a deeper understanding on the topic.

    Can anybody help me out somehow?
  2. jcsd
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