Did you know? It is possible we could move the Earth a tiny bit, if we all jumped at once.
There are roughly 7 billion people on Earth, with a total weight of approximately 800 billion pounds (363 billion kg).
Because people are spread somewhat equally around the planet’s spherical surface , if we all jumped in place, nothing much would happen — all our lift-offs and impacts would cancel each other out, resulting in zero net force on the Earth, according to work by physicist Rhett Allain.
Using the laws of conservation of momentum and energy, Allain, a physicist at the University of Southeastern Louisiana and blogger at Dot Physics, calculated what would happen to the 6-trillion-trillion-kilogram Earth under these circumstances.
“After all the people jump they would ‘fall’ back down — move towards the Earth. During this time, the Earth would move back up. All would be as it once was,” he told Life’s Little Mysteries.
The situation is much like two objects of very different masses connected by a spring. If you pull the masses apart and then let go, the force of the spring pulls them back together. The smaller mass moves much more than the larger mass, but both move. The Earth and the people are much like these two masses, Allain explained, except that “in this case, the spring is like gravity.”
So let’s imagine that everyone could congregate together in one place. Doing so would probably make it easier to synchronize our jump anyway. Some of that energy would go back into our shoes. The rest would disperse out into the air and ground, leading to some harrowing consequences:
- There would be a huge sound like an applause. At 200 decibels (the loudest possible sound ever created on Earth), it could shatter ear drums. For context, a jet engine produces 150 decibels of sound at takeoff, and our pain threshold is at 120 decibels.
- The ground would begin to shake, and if the jump happened near the coast, it could trigger a tsunami with 100-feet-tall waves.
- The shaking could also lead to an earthquake falling in the 4-8 magnitude range. That means it could be anywhere from a light shake to one that could cause some major destruction to bridges, railways, electric lines, and buildings.