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Ebb and Flow effects

  1. Dec 17, 2012 #1


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    OK, so the moon has a rather large mass (I found somewhere a comparison with earth which gave a value of about 75 billion trillion Kg/M3), but the spacecrafts Ebb and Flow are travelling rather fast with quite alot of momentum(132KG each, 6050km/s = around 800000Kg m/s). So what sort of things might happen when Ebb and Flow hit the Moon?

    I'm fairly sure that someone at NASA has already worked this out, but While my confidence in natural laws is high, my confidence in human beings is not as complete and it occurs to me that what NASA thinks will happen might be a little different to what does happen.

    While I'm sure any miscalculations or oversights will be very small, what are the implications of such an impact going wrong? could debris from the impact return to earth? if it does will it be spectacular, or terrifying? could the moon be rotated enough that we could see new areas with a telescope, or might it even begin to have a rotation like the earths?

    I can imagine a whole host of possibilities, but I'm afraid my astrophysics is very limited and am curious as to what more learned minds might postulate.
  2. jcsd
  3. Dec 17, 2012 #2


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    You've got that number wrong by the factor of 3600.
    In other words, it's per hour, not per second.

    but even if it was 6000km/s, the kinetic energy of the impactor would be ~2,5*10^15J, or the equivalent of a ~600 kiloton nuclear explosion(most warheads today have higher yelds, I believe).

    The actual speed they're going to hit the Moon at is ~4 times less than the escape velocity of Earth.
    For comparison, a typical meteor hits the atmosphere(or the Moon for that matter) at ~108000km/h(i.e.Earth's orbital speed).
    Last edited: Dec 17, 2012
  4. Dec 17, 2012 #3


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    Thanks. heh, After expecting it to be 6050km/s , 6050km/hr seems so slow!

    Ah well, still very interesting. (not as interesting as putting people there though)
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