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The Moon's Two Sides Look So Different Thanks To 4.5 Billion-Year-Old Physics (forbes.com)

Posted by samzenpus on from the good-side-bad-side dept.

StartsWithABang writes: 4.5 billion years ago, a giant object collided with our proto-Earth, kicking up debris that eventually coalesced into the Moon. While the near side contains dark maria and lunar lowlands, the far side is almost exclusive heavily cratered, high-mountainous regions. This was a mystery for a long time, but it appears that heating from the hot, young Earth caused a chemical and crustal difference between the two faces.

4 of 96 comments (clear)

  1. The moon could have been artificially created. by Anonymous Coward · · Score: 5, Funny

    Another, more plausible explanation is that the moon was actually an ancient artificial space station, placed in a very specific orbit around the earth. Over time, debris has collected on it, giving it its current appearance. The fact that it always faces the earth, and orbits the earth once every month is very intriguing. This isn't something we'd expect to happen were the moon a natural creation. That suggests that it likely was created as an artificial space station which has since become, for lack of a better term, dusty over a long span of time.

    1. Re:The moon could have been artificially created. by Anonymous Coward · · Score: 5, Funny

      That's no space station. It's a moon!

  2. Re:How could the Earth heat it? by Michael+Woodhams · · Score: 5, Interesting

    1 billion years ago the Earth had 100 to 1,000 foot tides as the Moon and the Earth were much closer

    My initial response is "I don't think so." My second response is to calculate, so here goes:
    Current distance to moon = 384,400 km = 4 x 10^8m
    Current rate of increase in distance to moon = 3.8 cm/year = 4 x 10^-2 m/year.
    If this rate were constant over a billion (10^9) years, then a billion years ago the distance to the moon was 4 x 10^-2m/year*10^9year = 4 x 10^7 m closer, or 10% closer. Tidal effect strengths are inverse-cube in distance, so a billion years ago, lunar tides would have been about 30% larger than now.

    This doesn't come close to "100 to 1000 foot tides."

    --
    Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
  3. Re:Please StopWithABang by jfdavis668 · · Score: 5, Informative

    The link could have gone straight to the Penn State news article Forbes was reporting on: http://news.psu.edu/story/3178...