What if the Whole World Jumped at Once? New Research Answers

Picture this: all 7.8 billion people on Earth gathered together, leaping in unison. It’s a wild thought experiment, but what would actually happen?

A recent study looked into the consequences of this improbable scenario.

Assembling the World in One Place

For this experiment to work, we would need to gather every single person on the planet into one location.

If we could somehow manage this incredible feat of logistics, the entire human race could fit within the confines of New York City, albeit snugly. This dense concentration of people sets the stage for the synchronized jump that follows.

Specifically, if the more than 7 billion humans stood jammed up against each other, we’d fill about 500 square miles, or a city the size of Los Angeles. However, even if we could all stand that close and still manage to jump all at once, the effects would be minimal compared to the Earth’s immense mass.

The Jump Heard ‘Round the World

At the signal, 7.8 billion people would need to leap one foot off the ground simultaneously. As billions of feet hit the earth at the same instant, a tremendous amount of energy would be released.

Some of this force would be absorbed by our shoes, while the rest would disperse into the ground and air, triggering a cascade of alarming effects.

According to physicist Rhett Allain, using the laws of conservation of momentum and energy, our collective jump would push on the Earth ever so slightly, giving it a recoil speed of 2.6 x 10^-13 m/s. That is, in one second, Earth would move about a hundredth of the radius of a single hydrogen atom. ^(ref) While this shift is infinitesimally small, it demonstrates the power of collective action on a global scale.

A Deafening Roar & Seismic Chaos

The collective landing would generate an ear-splitting noise, akin to thunderous applause, reaching an astounding 200 decibels. To put that into perspective, a jet engine at takeoff produces about 150 decibels, and our pain threshold sits at 120 decibels. 

The earth would start to tremble, potentially unleashing a tsunami with 100-foot waves if the jump occurred near a coastline. The seismic activity could also trigger an earthquake measuring between 4 and 8 on the Richter scale, causing varying degrees of damage to infrastructure.

In an experiment performed for BBC’s Earth Lab, science journalist Greg Foot attempted to answer this question by getting a crowd of 50,000 people to all jump up at the same time, measuring the resulting quake in the ground from 1.5 kilometers away.

The team detected an earthquake that read 0.6 on the Richter scale. However, scaling this up to the entire global population would still not be enough to significantly affect the Earth’s spin or orbit.^(ref)

Earth’s Orbit Remains Unaltered

Despite the ground-shaking consequences, the effects of our worldwide jump would not extend beyond Earth’s atmosphere. Unfortunately, the combined force of over 7 billion people leaping in unison would be insufficient to alter the planet’s orbit, as intriguing as that prospect may be.

Physicist Rhett Allain calculated that after the jump, everyone would fall back down toward the Earth, and during this time, the Earth would move back up to its original position. The situation is much like two objects of very different masses connected by a spring – the smaller mass (humans) moves much more than the larger mass (Earth), but both return to their initial positions.

While the idea of the entire world jumping at once is purely hypothetical, exploring its potential outcomes offers a fascinating glimpse into the power of collective action and the intricate balance of forces on our planet.