The Earth DOES rotate.
More Info: The Earth’s rotation is what gives us day and night. Rotation is the spin of the planet on its axis. The Earth completes a full rotation roughly every 24 hours. Many people know that the Earth’s rotation isn’t static. Scientists have determined that it wobbles slightly, like a top, along its axis. But what’s amazing about the Earth’s rotation is how dependent it is on a number of different circumstances– both cosmic and close to home.
Earth’s Rotation and the Moon
The Moon is the Earth’s sole natural satellite. It orbits around us due to the influence of our gravitational pull. However, gravity is a two-way street. Our gravitational pull affects how the moon will orbit around us. The moon’s gravitational pull determines the length of our days and how we rotate on our axis. We see this played out (in part) by the movement of the tides. As the tides are bulged out and in, it slows the rotation of the planet. We call this phenomenon “Tidal Acceleration.” However, for the most part, it is an acceleration in the negative value. The days are lengthened slightly due to the moon. This means that our rotation is slightly slowed.
Earth’s Rotation and Natural Disaster:
Earthquakes are literally Earth-shaking. These events are caused by plate tectonics and result in oft-destructive tremors. This much is already common knowledge. What isn’t so commonly known his how this affects the Earth’s rotation.
After particularly large Earthquakes, like the one in Japan in 2011, scientists have noticed something peculiar about the length of the day compared to stable atomic clocks. Some earthquakes actually cause the days to get shorter!
This difference is so miniscule that the average individual wouldn’t even notice. It takes precise scientific instruments to recognize it, but these events actually alter the very rotation of the Earth. Even if just in a small way.
Japan Quake Causes Day to Get a Wee Bit Shorter.” Japan Quake Causes Day to Get a Wee Bit Shorter. N.p., n.d. Web. 16 Jan. 2013. <http://phys.org/news/2011-03-japan-quake-day-wee-bit.html>.
Leap Seconds.” Naval Oceanography Portal. N.p., n.d. Web. 16 Jan. 2013. <http://www.usno.navy.mil/USNO/time/master-clock/leap-seconds