If the Earth suddenly stopped rotating, not only would cars, buildings, and people be affected, but also water and our atmosphere, causing giant tsunami waves and global windstorms. Areas near the equator, where the Earth’s rotational speed was the fastest, would be affected the strongest. Everything would continue to move forward at 1,600 kilometers per hour.
In the long-term, over billions of years, centripetal forces have made Earth a bit wider at the equator. Without rotation, these forces would vanish, and oceans would migrate to the poles, which are closer to the center of the Earth and have stronger gravity. This would result in dry land around the equator. Additionally, our usual day-night cycle would cease to exist, with one day lasting one year and six months each of daylight and darkness.
Earth’s magnetic field, which is partly generated by the rotation of our planet, might be altered once the Earth stops rotating. As a result, we might face higher exposure to deadly solar radiation, leading to quite dramatic changes.