Things would get pretty catastrophic.
There are enough things in this life to worry about. Like nuclear war, climate change, and whether or not you're brushing your teeth correctly. The Earth spinning too fast should not be high up on your list, simply because it's not very likely to happen anytime soon—and if it does, you'll probably be too dead to worry about it. Nevertheless, we talked to some experts to see how it would all go down.
First, let's talk about how fast the world is spinning now. That actually depends on where you are, because the planet spins fastest around its waistline. As Earth twirls around its axis, its circumference is widest at the equator. So a spot on the equator has to travel a lot farther in 24 hours to loop around to its starting position than, say, Chicago, which sits on a narrower cross-section of Earth. To make up for the extra distance, the equator spins at 1,037 mph, whereas Chicago takes a more leisurely (approximately 750 mph) pace.
If we could speed up Earth's rotation by one mile per hour, the sea level around the equator would rise by a few inches as water migrates there from the poles. "It might take a few years to notice it," says Witold Fraczek, an analyst at ESRI, a company that makes geographic information system (GIS) software.
What might be much more noticeable is that some of our satellites would be off-track. Geostationary satellites orbit our planet at a speed that matches the Earth's rotation, so that they can stay positioned over the same spot all the time. If the planet speeds up by 1 mph, then the satellites will no longer in their proper positions, meaning satellite communications, television broadcasting, and military and intelligence operations could be interrupted, at least temporarily. Some satellites carry fuel and may be able to adjust their positions and speeds accordingly, but others might have to be replaced, and that's expensive.
"These could disturb the life and comfort of some people," says Fraczek, "but should not be catastrophic to anybody."
Things would get more catastrophic the faster we spin.
Centrifugal force from the Earth's spin is constantly trying to fling you off the planet, sort of like a kid on the edge of a fast merry-go-round. For now, gravity is stronger and it keeps you grounded. But if Earth were to spin faster, the centrifugal force would get a boost, says NASA astronomer Sten Odenwald.
Currently, if you weigh about 150 pounds in the Arctic Circle, you might weigh 149 pounds at the equator. That's because of the extra centrifugal force that's generated as the equator spins faster combats gravity. Press fast-forward on that, and your weight would drop even further.
Odenwald calculates that eventually, if the equator revved up to 17,641 mph, the centrifugal force would be great enough that you would be essentially weightless. (That is, if you're still alive. More on that later.)
Constant jet lag
The faster the Earth spins, the shorter our days would become. With a 1 mph speed increase, the day would only get about a minute and a half shorter and our internal body clocks, which stick to a pretty strict 24-hour schedule, probably wouldn't notice.
But if we were rotating 100 mph faster than usual, a day would be about 22 hours long. For our bodies, that would be like Daylight Savings on crack. Instead of setting the clocks back by an hour, you'd be setting them back by two hours every single day, without a chance for your body to adjust. And the changing day length would probably mess up plants and animals too.
For our bodies, it would be like Daylight Savings on crack.
But all this is only if Earth speeds up all of a sudden. "If it gradually speeds up over millions of years, we would adapt to deal with that," says Odenwald.
If Earth's rotation picked up slowly, it would carry the atmosphere with it—and we wouldn't necessarily notice a big difference in the day-to-day winds and weather patterns. "Temperature difference is still going to be the main driver of winds," says Odenwald. However, extreme weather could become more destructive. "Hurricanes will spin faster," he says, "and there will be more energy in them."
The reason why goes back to that weird phenomenon we mentioned earlier: the Earth spins faster around the equator.
If the Earth wasn't spinning at all, winds from the north pole would blow in a straight line to the equator, and vice versa. But because we are spinning, the pathway of the winds gets deflected eastward. This curvature of the winds is called the Coriolis effect, and it's what gives a hurricane its spin. And if the Earth spun faster, the winds would be deflected further eastward. "That effectively makes the rotation more severe," says Odenwald.