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Cosmic Microwave Background Leans To Inflation Theory

Posted by Hemos on from the index-it-to-cpi dept.

Strigiform writes "Some of the questions about the early universe have been answered by the WMAP project as reported by New Scientist. The inflation theory of the early universe has been vindicated, as it correctly predicted the polarisation of microwaves observed. The earliest stars appeared only 200 million years after the Big Bang and the universe is about 13.7 billion years old"

1 of 37 comments (clear)

  1. Re:Q. Spherical expansion & Planet's Orbits by Omkar · · Score: 4, Insightful

    I'm not sure about relativistic orbits and stuff, but with Newtonian laws, you can prove orbits are planar (Kepler did this - orbit is an ellipse).

    Let r be the position vector of a planet, v=r' the velocity, and a=r'' be the acceleration.

    Now,
    a = GMr/|r|^3
    from Newton's Second Law and Newton's Law of Gravitation.

    So

    d(r X v/dt
    = r' X v + r X v'
    = r' X r' + r X a
    = 0 + r X GMr/|r|^3
    = 0
    ==> r X v = h, some vector constant ==> r and v are coplanar ==>The orbit of a planet is a plane curve

    Its fun and good practice to prove Kepler's Laws - my book outlines the proof. Try it.