Have you ever wondered what would happen if the Earth just stopped spinning? This Vsauce video will make you extremely grateful that the Earth has a spin (and hopefully will keep spinning).
If the Earth suddenly stopped spinning, we would probably all die, because everything that is on the Earth, but not the actual Earth, would keep moving. Everything would be flung due east at more than 1,000 mph. Clearly, this would cause widespread destruction. High speed winds would create unprecedented storms around the globe. The oceans would surge onto land in huge tsunamis. People on airplanes might have a chance of survival, but not for long since Earth’s magnetic field would cease to exist, allowing harmful radiation to reach the Earth. It seems like a second should be 1/60 of 1/60 of 1/24 of a day, but that’s actually not very accurate. The Earth’s rotation is really pretty irregular. A second is measured by the time it takes for the outermost electron on an atom of Cesium 133 to oscillate 9,192,631,770 times (this is how atomic clocks work). To keep time as accurately as possible, some scientists keep track of the Earth’s rotation by watching certain stars, while others keep track of the atomic time (as measured by an atomic clock, rather than the Earth’s rotation). Every few months this is compared and if it is close enough, a second is added or subtracted from the year’s total. This means that the time you see on your phone or other devices is “manufactured” so as to be accurate.