From the gravitation equation it is clear the earth gets pulled but we fall due to negligible mass. But, if each and every person on the earth takes a jet-pack and jumps to a height equivalent to 20 to 30 meters at the same instant of time, will the earth have any change in its motion? If yes then what could be the outcomes?


closed as off-topic by GdD, Brian Tompsett - 汤莱恩, called2voyage Apr 26 '16 at 15:24

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question is about other space sciences (physics, weather, astronomy, etc), and does not directly pertain to space exploration as outlined in the help center." – GdD, Brian Tompsett - 汤莱恩, called2voyage
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  • $\begingroup$ This is more of a speculative physics question than anything to do with space exploration as currently phrased. $\endgroup$ – called2voyage Apr 26 '16 at 15:25
  • 3
    $\begingroup$ It's not exactly a jetpack, but the result would be the same: what-if.xkcd.com/8 $\endgroup$ – Antzi Apr 26 '16 at 16:35

Unlikely any meaningful effect. Some napkin math...

Weight of average human: $62 kg$

Population Estimate: $7.4 \times 10^9$

Mass of combined population: $4.5 \times 10^{11} kg$.

The mass of Earth is estimated $5.972 \times 10^{24} kg$.

That's a huge order of magnitude in difference, and as such any gravity effects should be barely noticeable.

  • $\begingroup$ Phrased another way, the human population biomass on Earth ($10^{11}$ kg) is to the Earth ($10^{24}$ kg) roughly as a regular-sized bar of chocolate ($0.1 = 10^{-1}$ kg) is to the human population biomass on Earth ($10^{11}$ kg). $\endgroup$ – a CVn Aug 26 '16 at 14:36
  • $\begingroup$ I'm pretty sure if we rolled every human into a ball and collided it with the earth at 2000km/s we'd basically be able to take out a city, maybe a few cities nothing more. $\endgroup$ – Magic Octopus Urn Mar 28 at 13:17

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