Earth Spins Faster

Earth Spins Faster

Does the day feel like it's passing by super quickly? It's not just in your head! Scientists say the Earth is actually spinning (快速旋转)a little faster than usual—about 1.3 to 1.5 milliseconds faster, to be exact. That means today will be just a tiny bit shorter than a normal day.

Experts from a group called the International Earth Rotation and Reference Systems Service carefully measure how fast the Earth travels. They use something called atomic clocks (原子钟), which are quite precise clocks, to check the planet's speed. Recently, they have noticed several instances(实例) of Earth speeding up.

The shortest day ever recorded on atomic clocks happened last year, on July 5. It was 1.66 milliseconds shorter than usual. Scientists also predicted that this summer would bring three extra-short days: July 9 (1.4milliseconds faster), today—July 22, and August 5.

So why is the Earth in such a hurry on these three days? Scientists aren't completely sure, but they have some ideas. The most likely reason has to do with the Moon's position. The distance between the Earth and the Moon changes all the time. When the Moon is farther away, the Earth tends to slow down a bit. Other factors like big earthquakes or extreme weather can also affect the Earth's spin. Climate change may play a role too—it's causing huge glaciers to melt, and NASA studies have found that this may change how fast the planet rotates(旋转).

Scientists say the speedy rotation is nothing to worry about.“We' ve known that the Earth's rotation changes a little for about a hundred years,” said Dennis McCarthy, a former time expert at the US Naval Observatory.“This is just one of those small, natural changes that happen from time to time.”