What if everyone jumped at once?

xkcd's What If?
16 Apr 202403:52


TLDRIn a hypothetical scenario where everyone on Earth gathers in Rhode Island and jumps in unison, the physical impact on the planet is negligible. Despite the collective force, the Earth's immense mass renders the jump insignificant, causing less than an atom's width of displacement. However, the social and infrastructural consequences are severe. Cell networks collapse under the strain, transportation systems are overwhelmed, and essential services like food and water become scarce, leading to a rapid societal breakdown. The aftermath would see a dramatic population decline and survivors struggling to rebuild civilization. The Earth's rotation and orbit remain unaffected, serving as a cautionary tale for future generations.


  • 🌍 The collective jump of all humans would not significantly affect the Earth due to its immense mass compared to human weight.
  • 🚀 Even if everyone jumped high enough, the Earth would only be displaced by less than the width of an atom.
  • 🏙️ The energy from everyone landing would be substantial but spread over a large area, causing minimal environmental impact.
  • 📡 The simultaneous landing would create a loud noise but would not have a lasting effect on the planet's structure.
  • 📵 The concentration of people would cause cell networks to collapse due to the unprecedented load.
  • 🛫 Transportation infrastructure would be overwhelmed, with airports and seaports unable to handle the volume of people needing to travel.
  • 🚗 Road networks would fail due to massive traffic jams, leaving cars abandoned and people to find alternative means of travel.
  • 🏪 Essential resources like food and water would be quickly depleted, and there would be no efficient system for distribution.
  • 🏥 Sanitation and healthcare would become dire issues, leading to a rapid decline in living conditions and a potential humanitarian crisis.
  • ⏳ Within weeks, the scenario could lead to the death of billions, turning the area into a graveyard and drastically reducing the global population.
  • 🌿 Survivors would face the challenge of rebuilding civilization and spreading out across the world.
  • 🪐 The Earth's rotation and orbit would remain unaffected by the event, continuing as they did prior to the jump.

Q & A

  • What is the scenario presented in the transcript where everyone on Earth stands close together and jumps?

    -The scenario involves magically transporting the entire Earth's population to one location, assumed to be Rhode Island, where they all jump and land simultaneously, and then face the challenges of returning to their homes and surviving.

  • How does the collective jump of the Earth's population affect the planet?

    -The collective jump does not significantly affect the Earth due to the planet's massive size compared to the force exerted by humans. The Earth would only be pushed down by less than an atom's width.

  • What is the immediate physical impact of everyone landing back on the ground?

    -The landing creates a loud, drawn-out roar from the impact of twelve billion feet hitting the ground, and a slight pulse of pressure that registers on a few local seismometers.

  • Why do cell phones display 'NO SIGNAL' after everyone lands?

    -The cell networks collapse under the unprecedented load of seven billion people trying to use them simultaneously, resulting in a 'NO SIGNAL' message on all phones.

  • What happens to the rest of the world outside of Rhode Island after everyone jumps?

    -Outside Rhode Island, abandoned machinery stops, airplanes continue on auto-pilot, food burns on unattended stoves, and there is a general sense of chaos and abandonment.

  • How does the situation in Rhode Island affect transportation and infrastructure?

    -Transportation is severely impacted, with massive traffic jams and insufficient public transportation. The infrastructure struggles to provide food, water, and sanitation for the concentrated population.

  • What are the long-term consequences for the people in Rhode Island?

    -The lack of food, water, and sanitation, along with the absence of healthcare, leads to a rapid decline in the population, with Rhode Island becoming a graveyard for billions.

  • How does this event affect the Earth's rotation and orbit?

    -The Earth's rotation and orbit remain completely unaffected by the event, as the mass and force of the human population are insufficient to alter these astronomical properties.

  • What is the final outcome for the survivors of this scenario?

    -The survivors spread out across the world and attempt to build a new civilization on the ruins of the old, with the human population greatly reduced.

  • What is the area that the crowd occupies at the start of the scenario?

    -The crowd occupies an area the size of Rhode Island, which is where they are assumed to be located.

  • What is the average height humans can jump vertically?

    -On average, humans can vertically jump about half a meter, especially when not constrained by being in a crowd.

  • What is the note to future civilizations at the end of the transcript?

    -The note advises against attempting such a global jump again, highlighting the disastrous consequences of the event.



🌏 The Hypothetical Earthwide Jump

This paragraph introduces a popular question pondering the consequences if every person on Earth gathered in one place, jumped, and landed simultaneously. It humorously starts by acknowledging the question's popularity and previous examinations, including a ScienceBlogs post and a Straight Dope article. The scenario begins with Earth's population magically transported to Rhode Island, where they collectively jump at noon. Despite the collective action, the Earth's immense mass means the jump has negligible physical impact, with the Earth only being pushed down by less than an atom's width. The energy from the fall is spread over a large area, causing minimal disturbance. However, the simultaneous landing creates a loud noise, and the crowd's cellphones all display 'NO SIGNAL' due to network overload. The paragraph concludes with the aftermath, including abandoned machinery, autopilot airplanes, and a traffic jam of epic proportions, leading to a grim outlook for the crowd's survival and the potential collapse of civilization.



💡Earth's population

The term 'Earth's population' refers to the total number of human beings living on the planet. In the context of the video, it is used to illustrate the hypothetical scenario where all people on Earth are gathered in one place, specifically Rhode Island, to jump and land simultaneously. This concept is central to the video's theme, as it sets the stage for the ensuing discussion on the physical and societal impacts of such an event.

💡Vertical jump

A 'vertical jump' is a physical action where a person propels themselves upward off the ground, typically measured in height. In the video, it is mentioned that humans can jump about half a meter on average, which becomes a point of comparison when considering the collective force exerted by the entire Earth's population jumping together.

💡Rhode Island

Rhode Island is a state in the northeastern United States, used in the video as the hypothetical location where all of Earth's population gathers. It serves as a geographical reference point for the scenario, allowing for the discussion of the spatial implications of concentrating billions of people in one area.

💡Energy delivery

The term 'energy delivery' refers to the transfer of energy from one system to another. In the video, it is used to describe the impact of everyone jumping and landing on the ground, which technically delivers a significant amount of energy into the Earth. However, the video explains that the energy is spread over a large area and has minimal effect beyond local seismometers.


Seismometers are scientific instruments that measure and record seismic waves caused by earthquakes or other ground movements. In the context of the video, it is mentioned that the collective landing of all people on Earth would cause a slight pulse of pressure that could be detected by seismometers, indicating the scale of the energy involved in the hypothetical scenario.

💡Cell networks

Cell networks are the infrastructure that enables mobile communication devices to connect and communicate with each other. The video discusses the collapse of cell networks under the unprecedented load if everyone on Earth were to use their phones simultaneously in one location, highlighting the strain on communication systems in such a scenario.

💡Traffic jam

A 'traffic jam' is a situation where a large number of vehicles are bumper-to-bumper, unable to move at a normal pace due to congestion. The video uses the concept of a traffic jam to illustrate the logistical nightmare of trying to transport the entire Earth's population away from Rhode Island after the hypothetical event, emphasizing the scale of the problem.


Sanitation refers to the hygienic disposal of human waste and the maintenance of clean and healthy environments. In the video, the lack of sanitation is highlighted as a major issue if all people were to gather in one place, as it would lead to unsanitary conditions and potential health crises.

💡Healthcare infrastructure

Healthcare infrastructure encompasses the systems, facilities, and professionals required to provide medical care to a population. The video points out that in the hypothetical scenario, the healthcare infrastructure would be nonexistent, leading to significant health risks for the concentrated population.

💡Earth's rotation and orbit

The 'Earth's rotation' is the spinning of the Earth on its axis, while the 'Earth's orbit' is its path around the Sun. The video emphasizes that despite the hypothetical scenario involving all humans jumping and landing simultaneously, these natural phenomena would remain unaffected, maintaining the regular course of the planet's movements.


The term 'survivors' refers to individuals who have lived through a catastrophic event. In the video, 'survivors' are mentioned in the context of the dire consequences of the hypothetical event, where the aftermath would leave only a fraction of the population alive to rebuild a new civilization.


A 'civilization' is a complex society characterized by urban development, social stratification, and a diverse cultural and technological framework. The video discusses the potential collapse of current civilization and the struggle of survivors to build a new one, highlighting the fragility and resilience of human societies.


The entire Earth's population is hypothetically gathered in one place, specifically Rhode Island.

The collective jump of all humans would not significantly affect the Earth due to its immense mass compared to humans.

An average human can jump about half a meter, and this would not move the Earth by more than an atom's width even if everyone jumped simultaneously.

The energy delivered to the Earth upon everyone landing would be substantial but spread out, causing minimal impact beyond local seismometers.

The sound of twelve billion feet hitting the ground would create a loud, drawn-out roar lasting several seconds.

Cell networks would collapse under the unprecedented load, leading to a 'NO SIGNAL' across all phones.

Abandoned machinery, airplanes, and kitchen appliances would lead to widespread disruption outside of Rhode Island.

The logistical challenge of returning seven billion people to their homes would be immense.

Transportation infrastructure, such as airports and light rail systems, would be insufficient to handle the crowd.

The largest traffic jam in history would occur as people attempt to use cars to disperse.

Electricity and fuel shortages would exacerbate the situation, leaving many people stranded.

Language barriers and lack of local knowledge would make cooperation and navigation difficult for the dispersed crowd.

Food and water scarcity, along with inadequate sanitation and healthcare, would lead to a rapid decline in population.

Within weeks, the scenario could result in Rhode Island becoming a graveyard for billions.

Survivors would face the daunting task of rebuilding civilization on the ruins of the old.

Despite the human catastrophe, the Earth's rotation and orbit would remain unaffected.

A cautionary note is given to future civilizations against attempting such an experiment again.



This question comes from Thomas and  many other people, who all asked:  


What would happen if everyone on earth stood  as close to each other as they could, jumped,  


and landed on the ground all at the same instant? This is one of the most popular questions  


submitted to What If. It’s been examined before,  including by a ScienceBlogs post and a Straight  


Dope article. They cover the physics pretty  well. However, they don’t tell the whole story. 


At the start of the scenario, the entirety  of Earth’s population has been magically  


transported together into one place. This crowd takes up an area the size  


of Rhode Island. In fact, let’s assume they  – I mean, we – are actually in Rhode Island. 


At the stroke of noon, everyone jumps. As discussed elsewhere, the jump doesn’t  


really affect the planet. Earth outweighs us  by a factor of over ten trillion. On average,  


we humans can vertically jump maybe half a meter  – and that’s when we’re not shoulder to shoulder  


in the middle of a crowd. Even if everyone did  jump that high, and the ground were rigid and  


responded instantly, the Earth would still only  be pushed down by less than an atom’s width. 


Next, everyone falls back to the ground. Technically, this delivers a lot of energy  


into the Earth, but it’s spread out over  a large enough area that it doesn’t do  


much more than leave footprints in a lot of  gardens. A slight pulse of pressure spreads  


through the North American continental crust and  dissipates with little effect beyond moving the  


needle of a few local seismometers. The sound of twelve billion feet  


hitting the ground does create a loud,  drawn-out roar which lasts many seconds. 


Eventually, the air grows quiet. Seconds pass. Everyone looks around. 


There are a lot of uncomfortable  glances. Someone coughs. 


A cell phone comes out of a pocket. Within  seconds, the rest of the world’s seven billion  


phones follow. All of them—even those compatible  with the region’s towers—are displaying some  


version of “NO SIGNAL”. The cell networks have  all collapsed under the unprecedented load. 


Outside Rhode Island, abandoned machinery begins  grinding to a halt, airplanes drift through the  


skies on auto-pilot trajectories, food starts  burning on abandoned kitchen stoves, soccer balls  


complete their trajectories into now-vacant goals,  and empty playground swings gradually drift to a  


halt. Back in Rhode Island, people – many people  – begin to wonder: how do we get everyone home? 


The T. F. Green airport in Warwick, Rhode Island  handles a few thousand passengers a day (I just  


flew out of there. They have the nicest bathrooms  of any airport I’ve ever seen. Very impressive.  


This is not part of the recording). Assuming  they got things organized (including sending  


out scouting missions to retrieve fuel),  they could run at 500% capacity for a hundred  


years without making a dent in the crowd. The addition of all the nearby airports  


doesn’t change the equation much. Nor does  the region’s light rail system. Crowds climb  


on board container ships in the deepwater port  of Providence, but stocking sufficient food and  


water for a long sea voyage proves a challenge. Rhode Island’s million cars are commandeered.  


Moments later, I-95, I-195, and I-295 become the  sites of the largest traffic jam in the history  


of the planet. Most of the cars are blocked  by the crowds, but a lucky few get out and  


begin wandering the abandoned road network. Some make it past New York or Boston before  


running out of fuel. Since the electricity is  probably not on at this point, rather than find  


a working gas pump, it’s easier to just abandon  the car and get in a new one. After all, who can  


stop you? All the cops are in Rhode Island. The edge of the crowd spreads outward into  


southern Massachusetts and Connecticut. Any two  people who meet are unlikely to have a language  


in common, and almost nobody knows the area. Even if people cooperate, everybody is hungry  


and thirsty. Grocery stores are immediately  emptied and woefully insufficient. Fresh water is  


hard to come by and there’s no efficient system  for distributing it. Sanitation is a disaster  


and healthcare infrastructure nonexistent. Within weeks, Rhode Island is a graveyard  


of billions (including most  of the people who submitted  


this question, and probably you and me, too). The survivors spread out across the face of the  


world and struggle to build a new civilization  atop the ruins of the old. Our species staggers  


on, but our population has been greatly reduced.  And most importantly: the Earth’s rotation and  


orbit are completely unaffected—it spins along  exactly as it did before our species-wide jump. 


Note to future civilizations:  let’s not try that again.