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Changing Earth Orbit July 06! Is this for real?

  1. Jul 7, 2005 #1
    This site has a whole theory about changing the orbit of the earth by having 600 million people jumping at the same time.

    I am very skeptical about this. I mean it sounds like the violation of the conservation of energy/momentum if you can change the earth's orbit without any mass ejection or a collision of some asteroid with the earth.

    Can someone try to explain how this can be possible?
  2. jcsd
  3. Jul 7, 2005 #2


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  4. Jul 7, 2005 #3
    Well, there WOULD be a mass ejection: the 600,000,000 people.
    The problem is that this ejection returns.

    Consider this scenario... 300 passengers on a 747(which is going about smoothly) suddenly decide to stand up and jump up in concert. If done properly, a collective force will be exerted on the 747 pressing it down. Then, just afterwards, the 747 experiences a lack of weight equal to the 300 passengers, so the 747 rises. Then the 300 passengers hit the floor and the 747 experiences a sudden weight gain and thus moves down.
    On average, there is no net effect.
    However, perturbations of the craft during this time most certainly occur.
  5. Jul 7, 2005 #4
    Ok so basically if they gather enough people with no brains out there and they actually jump, it wouldn't help the earth's orbit at all but just result in some stupid earthquake! :surprised
  6. Jul 7, 2005 #5


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    Well, lets calculate the energy involved real quick: Lets say the average of these jumpers is a svelte high-jumper who has a mass of 50kg and jumps 1m (yeah, I'm lazy). 600 million times 50 times 1 is 30 billion (giga) joules or 0.03 TJ. According to http://www.geop.itu.edu.tr/~onur/seis/eq_energy/ [Broken] site, thats half the energy of a 4.0 magnitude earthquake and an insignificant fraction of the energy of a nuclear bomb. So it'd be detectable, but you probably wouldn't feel it.

    But there's a catch: earthquakes are localized. They happen in a pretty small area and the energy travels outward as a wave. So the energy of those 600 million jumpers would need to be concentrated either by having them all stand on the same football-field sized area or jump in a precise sequence to cause the waves to constructively interfere.
    Last edited by a moderator: May 2, 2017
  7. Jul 7, 2005 #6
    Ha ha! I like it! Can't wait for the 20th July of next year to watch a bunch of blisfully ignorant fools jumping thinking it's gonna do something!! :rofl:
  8. Jul 7, 2005 #7
    even if that small number of peole could cause such a force by jumping, it wouldn't do any good....the earth has gravity, so they will come back and counteract the force they made by jumping.
  9. Jul 8, 2005 #8
    What is the purpose of altering the Earth's orbit?
  10. Jul 8, 2005 #9
    If we can alter the earth's orbit to be slightly further from the sun, it could solve climate issues such as global warming etc..
  11. Jul 8, 2005 #10


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    I thought we already got this every november 2nd since the 60's :rofl: :rofl:
  12. Jul 8, 2005 #11
    Or we could investigate alleviations to pollution. Which one seems more sensible to you?
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