When all the people on Earth gather and jump at the same time, it creates a significant force. So, can this force affect the Earth and cause any impact?
When mass moves toward the center of a rotating object, its rotational speed increases. For example, figure skaters often pull their arms in to gain speed during a spin. Therefore, theoretically, you could make the Earth spin faster, meaning a day could pass more quickly if a sufficient force is applied to the Earth’s surface.
All people on Earth gathering and jumping at the same time would create a tremendous force.
The massive earthquake in Japan in 2011 displaced a significant amount of earth toward the center of the Earth. In fact, this earthquake caused the Earth to spin faster, shortening each day by 0.0000018 seconds. So, could we replicate a similar effect by gathering the strength of everyone on Earth through a simultaneous jump?
Because humans are widely dispersed across the globe, if we all jumped in place, nothing would happen as the forces would cancel each other out. So, imagine if all humans on Earth concentrated in an area of about 1,200 km2. At that moment, when we all jump up, the force exerted would be focused at one point relative to the Earth. And this force could potentially make our Earth spin faster.
The effort of over 7 billion people on Earth would increase its rotational speed.
Using the laws of conservation of momentum and energy, physicist Rhett Allain at Louisiana University attempted to calculate what would happen to our Earth in this scenario. To simplify, he assumed each person could jump an average of 30 cm and that we all jumped exactly at the same time.
Allain concluded that the effort of over 7 billion people on Earth would increase its rotational speed by about 2.6×10^-13 m/s. This means that in one second, the Earth would move an additional fraction of the radius of a hydrogen atom. In other words, our day would pass a little faster, but it would likely be very difficult to notice this difference.
Since the weight of 7 billion people is minuscule compared to the colossal weight of the Earth, even if we repeated this action day after day, we would not be able to create a significant change like that caused by the earthquake in Japan, let alone produce a noticeable change.
In 2016, Business Insider invited astrophysicist Paul Sutter from Ohio State University and physicist Mark Boslough from Sandia National Laboratories (USA) to examine the potential impacts if this hypothesis were tested.
Firstly, a tremendous amount of energy would be released when billions of people land on the ground (at the same location, with each person instructed to jump on one foot at the same time). Some of that energy would bounce back to our shoes. The rest would disperse into the air and ground, leading to some notable effects.
For instance, the jumping of billions of people would produce a loud sound measuring 200 decibels (the loudest sound ever produced on Earth), which could rupture eardrums. To compare, a jet engine generates sound at 150 decibels during takeoff, while our pain threshold is 120 decibels. The ground would start to shake, and if the jump occurred near the coast, it could trigger a tsunami with waves as high as 30 meters.
The shaking could also lead to an earthquake registering around 4-8 on the Richter scale. It could create tremors ranging from light shakes to seismic jolts capable of destroying bridges, railways, power lines, and buildings. However, despite all these occurrences on the ground, the effects would not be felt in space. In other words, the hypothesis that billions of people jumping and landing at the same time could alter the Earth’s orbit or cause the planet to shift even slightly is impossible.
