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So What would Happen if we all Jump at Once? 

By: Meghan Henseler

Maybe you've wondered it before, maybe you haven't.  What would happen if everyone in the world jumped at precisely the same moment?  Even with the amount of people on the earth, if everyone jumped at once in their own space, there would be no net force on the earth.  Everyone's jump starts and landings would cancel out each others.  This is perhaps less cool than many people would expect.  I was thinking that there would be more of a "the world would stop spinning answer," but according to studies done by Rhett Allain, this is not true.

The next logical question in a train of thought is "What would happen if everyone in the world jumped at precisely the same moment, in exactly the same spot?"  So picture this, everyone in the world flies into T.F. Green Airport, Providence.  Well really, in Warwick, but its PVD airport to make it easier for all the geniuses who think that Rhode Island is a part of New York.  (Fun fact: it's not) . The Earth is 6 TRILLION kg (thats a lot of kg), and there are 7 billion people on the earth, totaling about 363 billion kg.  Allain pondered this, and decided to physics it out to find the answer.  Assuming that all people could jump one foot in the air and that they were all jumping from the exact same spot, Allain used the laws of conservation of momentum and energy to find the answer.  
No, the world would not explode in a giant mushroom cloud.  In all reality, according to Allain's math, the jump would slightly push the world down (negative y axis, if you have everyone jumping up in line with the positive y axis).  By slightly push, it means that the Earth would have a recoil speed of 2.6*10^-13 m/s.  To put this into perspective, that's a hundredth of the radius of one hydrogen atom.  Woot.  Very exciting.  That is definitely what we thought would happen when we had the whole world fly to Providence.  
Some people might think that its cool that the Earth moved that little bit.  Well, I'm (really Allain and his math skills) are here to rain on your parade.  By the time everyone landed on Earth, it would have moved back into its original position.  Thus making this whole experiment unnecessary.  If I'm being honest, it would be cool to meet people from all over the world, and I'm pretty sure that this would make a pretty cool video that would go viral because everyone in the world was there to experience it happening.  

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