Slowing of Earth's Spin Revealed in Ancient Astronomers' Tablets

Each century, the length of the solar day, or the time it takes the planet to do a full rotation, grows by 1.8 milliseconds, according to a new study using astronomical observations going back to 750 B.C. Researchers have known that the planet's rotation is slowing because of friction caused by the tides, as water that's being tugged on by the moon's gravity sloshes against the solid Earth. The difference between 2.3 milliseconds and 1.8 milliseconds over a century may seem trivial, said study r