Question: If everyone on the world jumped at the same time, would the earth move?

Iain Bethune answered on 23 Jun 2015:

The earth has a mass of 6×10^24 kg. There are about 7 billion people on the planet, with (say) an average mass of 70kg, so a total mass of about 5×10^11 kg.

Due to Newton’s 3rd Law (for every action there is an equal and opposite reaction), when we push down on the earth to jump, the earth pushes back at us with equal force. Whatever acceleration there is on us, the earth will accelerate about 10^13 times less – about 10 billion,billion times less. So yes it would move, but such a tiny move to be unmeasurable. And of course if everyone was spread out around the world, all of our forces would just serve to compress the Earth (a tiny little bit), rather than move it through space…