What if the Earth Stopped Spinning?
If Earth stopped spinning all at once, it would be enormously catastrophic for much of the planet’s surface. Though we don’t feel it, we’re all moving along with the planet as it rotates; at the equator, this works out to around 1,000 miles per hour. Stop the planet suddenly, and everything sitting on top of it would go flying eastward. Imagine people, houses, trees, boulders and more being launched sideways at hundreds of miles an hour. In the aftermath, high speed winds, still rotating nearly as fast as the planet, would scour the surface clean.
If the slowdown happened more gradually, the effects would still be dramatic, but would unfold over a longer period of time. The first thing we might notice is that the Sun no longer travels across the sky over the course of a day. The apparent motion of the Sun comes from Earth’s rotation, so if the planet were stationary, it would cause a single day to last half a year long (though we could look forward to some very long-lasting sunsets).
Without the 24-hour days we’re used to, biological circadian rhythms would be thrown entirely out of whack. The rhythmic cellular processes that tell our bodies when to sleep and when to wake depend in part on regular changes in sunlight to function. Many creatures on Earth, from bees to trees, rely on circadian rhythms to carry out their lives. Changing these cycles could upend normal behavior patterns.