How the end of gravity would mean the end of the world
In this macabre thought experiment, we talk about what that apocalypse might look like.
American astronaut Bruce McCandless II floats above Earth during the first untethered EVA, or extravehicular activity, in space. February 1984.
(NASA / Space Frontiers / Getty Images)
Gravity is something we often take for granted — and why shouldn’t we? It’s been around since time immemorial (it’s probably been around since time itself) and doesn’t seem to be going anywhere anytime soon.
But what if it did? How would its disappearance impact our lives?
Images of astronauts in zero-gravity environments might come to mind. They’re floating around upside-down, having their hair rise all around their heads and are effortlessly doing somersaults.
It all sounds like an absolute hoot. But if gravity were to truly disappear, and not just dialed down, the results would be far less adorable.
In fact, it would actually spell the End. Of. The. World.
The disclaimer
A space tourist floats inside a zero-gravity simulator.
(Stringer / AFP / Getty Images)
Now, this article isn’t meant to be alarmist. It’s supposed to be as fun as those zero-gravity environments (okay, maybe not as fun).
Because, in actuality, you can rest assured that gravity will never go away.
"It would be something that would be far bizarrely beyond everything we've known about physics," says Philip Metzger, a planetary scientist at the University of Central Florida.
"But for fun, you know, you could imagine these things".
(Thanks, Phil!)
We’ll get into why gravity won’t ever disappear in a bit. For now, let’s go ahead and dive into this trippy thought experiment.
A rollercoaster ride for your body
Amusement park goers with their feet in the air as a rollercoaster ride turns upside down.
(Paul Ellis / AFP / Getty Images)
It’s a day like any other day. You’re going along on your merry way to work. Traffic was surprisingly forgiving, giving you time to treat yourself to a fancy cup of coffee.
Then, someone flips the gravity switch.
"The first thing you would notice would be the feeling that you're falling instantly," says Metzger. "Everybody all over the world would feel like they're falling, even though they're not going to be falling. They're actually going to be rising off the surface of the Earth."
"You would feel like you were in a rollercoaster going down that first hill or in an elevator that suddenly drops, because we're used to the feeling of gravity pulling all our blood and pulling our organs downward. And suddenly that would vanish."
Your body would feel like it’s falling, but your eyes would be able to see that you’re not. This disconnect between the physical and cognitive would likely result in something very akin to yet another rollercoaster ride experience: puking.
"The reason you throw up is because your body knows something is wrong," according to Metzger. "A lot of people get sick in these reduced-gravity flights. And so, the old NASA aircraft, they called it the ‘vomit comet’ because a lot of people would throw up."
Sheer destruction
A boy in mid-air at sunset.
(Ritesh Shukla / NurPhoto / Getty Images)
Outside of your body, things would become even more topsy-turvy.
Just about everything — chairs, tables, that cup of coffee you bought and other objects — would begin to rise off the ground. Your car would begin to float upward, having lost the friction with the ground that allowed it to move forward.
Parts of the environment would also begin to float.
"If gravity were to suddenly turn off, then the all the water in the world would start to rise off the surface of the Earth," according to Metzger. That includes water from the smallest puddles to vast oceans and everything in between.
This phenomenon would be particularly horrifying for people on boats or swimming in the water, as floating itself depends on gravity. According to Metzger, "Without gravity, you wouldn't float, you could just mix right into the water."
Freediving in clear water.
(Alexis Rosenfeld / Getty Images)
Within about a day, all the water from the planet’s surface would be flung way into space.
The atmosphere would also begin to rise and dissipate, as it depends on gravity to keep it anchored to the planet.
"The air would be getting thinner and thinner, almost immediately," says Metzger. "You would feel the air sucked out of your lungs. Your ears would pop like you've gone up to a high mountain."
The Earth’s crust and the layers beneath it would not be immune to the effects of gravity disappearing.
"One thing that would happen — that would be just devastating — would be the entire Earth ripping apart," according to Metzger.
"Earth is held into a round shape by gravity and the crust of the earth. These crustal plates are held down by gravity. So if the gravity disappeared, then as the Earth is rotating, those crustal plates would begin lifting off of the mantle of the Earth, and they would begin flying out into space as well."
A weather forecast for the apocalypse
A lightning storm above Miami Beach in Florida.
(Jeffrey Greenberg / UCG / Universal Images Group / Getty Images)
What does all this mean for the weather? Weather is the interconnectedness of earth, atmosphere and water, so with those elements being severely disrupted, what would some weather events look like?
(Sure, the weather might be small potatoes compared to the end of the world, but we’ve gone so far down this rabbit hole, there’s no turning back, baby!)
"The weather is driven in ways that we don't normally think about by gravity," says Metzger.
For example, gravity helps "stir" the atmosphere.
Cross section of jet streams flowing down toward the Earth before rising and then continuing the cycle.
(National Weather Service)
It pulls down dense cold air, forcing less dense warm air to move up. As it does, the warm air brings along moisture up to higher altitudes. There, the moist air cools, condenses, forms into ice and then falls back down to the Earth as rain.
"It's driven by gravity and by the heat of the sun," says Metzger. "So without the gravity, that wouldn't happen anymore. There would be all of these stirring effects in the atmosphere that would cease."
These stirring effects are also responsible for the creation and demise of major storms, so the disappearance of gravity would affect them as well.
Take, for instance, a hurricane.
Image of Hurricane Florence barreling through the Atlantic Ocean in September 2018.
(NASA / Getty Images)
"The rotary motion around it would continue. But at the same time, because the air would be expanding away from planet Earth, the density of the air would be lowering," says Metzger.
"I imagine that the water molecules in the clouds would begin evaporating because, as the pressure drops, that evaporation is more rapid and so the clouds would begin to get thinner."
The hurricane clouds wouldn’t be as contained, causing the hurricane’s tight swirl to loosen — but the swirl motion of the hurricane would not stop.
Why gravity is important
An astronaut floats above the Earth.
(HUM Images/Universal Images Group / Getty Images)
If by some freak incident that gravity switch were turned off, here’s something to calm your nerves (sort of): you wouldn’t notice it.
According to Metzger, "Within a rather short amount of time, the air pressure would become so low that we would lose consciousness."
Basically, we’d pass out, while the world falls apart around us.
Again, these events, as terrifying as they sound, will likely never come to pass.
Despite the significant role gravity plays in our world, gravity is actually the weakest force in the universe.
"But yet we feel it because the Earth is so large. There are so many particles in the Earth that it adds up," Metzger said. "All those little tiny amounts of gravity add up enough so that we can feel it, and it ends up making the world be what it is."
And by keeping the world – and our very existence grounded – gravity allows our minds and imaginations to float to the most fun, yet ridiculous, places.