Michael Stevens of internet thingy VSauce investigates the foremost question in the minds of people who care about the Earth: How worried do we need to be that everyone on the planet is going to travel to Los Angeles and jump simultaneously? Would that cause an earthquake? Would it knock Earth off its axis? And how weird is it that the entire population of the planet could fit in L.A.?
As it turns out, everyone jumping at once wouldn’t have very much effect, although it’s fun to think about. If you want to do significant damage to the Earth, your best bet is to stay on the ground and just idle your car with the AC on instead.
What If Every Single Person on Earth Jumped at the Same Time?, Laughing Squid.