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Increasing the mass of the moon (via pancake theory)

  1. Oct 20, 2011 #1
    Hello, I am an architect at UCL london and am currently looking at a hypothetical scene whereby the length of a day could be increased to something at least over a month (i.e. the earth would be spinning so slowly that it would be in contact with the sun for 30 days and darkness for 30 days).
    I am trying to see what it would be like to spatially and architecturally live in a nomadic fashion, whereby people would need to constantly follow the sun.

    I have also given myself a 250 million year deadline (by the way), when the tectonic plates collide to form Pangaea Ultima.

    In order for the moon to effect the spin of the earth in such a way, I realise that the mass of the moon would have to increase.

    What I would like to suggest is that over the course of 250 million years an asteroid could fall into earth's orbit and travel at such a slow speed that it would collide with the moon in pancake fashion, thereby increasing its mass to allow for the scenario to occur...

    [PLAIN]http://img546.imageshack.us/img546/6987/63graphichowasecondmoon.gif [Broken]

    My question is, is my scenario in any way plausible? Could this actually in a very rare circumstance occur?
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 20, 2011 #2
    One problem is that everyone would die in stage 1, so couldn't live in nomadic fashion... perhaps they could re-evolve.

    I don't think you need the moon to change as the earth isn't spinning due to the moon, the initial impact might be sufficient to change the earth's spin to a slower one that is a month long.
  4. Oct 20, 2011 #3
    Thanks for the reply. The thing is I don't need or want stage 1 to occur. I want stage 2 and onwards to occur, whereby an asteroid comes into our orbit and is absorbed by the moon. Nothing ever hits the earth.

    If there are any other ways in which the earth could start spinning slower I would also love to hear them btw
  5. Oct 21, 2011 #4
    Last edited by a moderator: Apr 26, 2017
  6. Oct 21, 2011 #5


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    Here's the problem. the increase in mass that the moon would have to undergo in order for it to be able to tidally lock the Earth to it in the time scale you want is several times the moon's present mass. Probably by about 5 to 6 times.
  7. Oct 21, 2011 #6
    Very interesting, thanks a lot, especially for the estimated increase in size.

    On a different note/perspective, could any other scenario cause the earth to spin as slowly as required? (30 days sunlight, 30 days darkness)? Thanks
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