If this skater extended her arms as far away from her body as she could, she would spin more slowly. Similarly, the Earth would spin more slowly if the molecules of the atmosphere were clustered in high pressure systems near the equator.
Click on image for full size
Windows to the Universe
Can Earth’s Spin Be Changed by Wind?
News story originally written on March 19, 2003
Earth’s atmosphere is changing all the time. Winds and pressure patterns change over days, weeks, and years. Not only do those changes affect the weather, they affect the rotation of the Earth as well, causing changes to the length of days.
How does the air around us affect the spin of our planet? Earth is spinning like a skater spins on the ice. When a skater moves his or her arms out, mass is moved far from the axis of rotation (the skater’s body) and the skater spins more slowly. The spinning Earth works in the same way! When atmospheric pressure is high at the equator, mass is moved far away from Earth’s axis of rotation, and the planet spins more slowly.
There are other ways the atmosphere can affect Earth’s rotation too. For instance, strong winds in the atmosphere cause Earth to slow its spin because the total amount of movement must stay they same. “If the atmosphere speeds up then the solid Earth must slow down,” says David A. Salstein, the scientist who led the recent study to understand Earth’s rotation.
The research team compared wind and pressure measurements with measurements of Earth’s rotation. They found evidence that Earth’s spin is affected by the movements of air and can cause the length of days to change up to a small fraction of a second. (So if you feel like it’s been a very long day, you may be right!)
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates different pressures in the atmosphere which creates the winds around the globe. Since the Earth spins,...more
It was another exciting and frustrating year for the space science program. It seemed that every step forward led to one backwards. Either way, NASA led the way to a great century of discovery. Unfortunately,...more
The Space Shuttle Discovery lifted off from Kennedy Space Center on October 29th at 2:19 p.m. EST. The weather was great as Discovery took 8 1/2 minutes to reach orbit. This was the United States' 123rd...more
A moon was discovered orbiting the asteroid, Eugenia. This is only the second time in history that a satellite has been seen circling an asteroid. A special mirror allowed scientists to find the moon...more
Will Russia ever put the service module for the International Space Station in space? NASA officials want an answer from the Russian government. The necessary service module is currently waiting to be...more
A coronal mass ejection (CME) happened on the Sun early last month. The material that was thrown out from this explosion passed the ACE spacecraft. The SWICS instrument on ACE has produced a new and very...more
J.S. Maini of the Canadian Forest Service called forests the "heart and lungs of the world." This is because forests filter air and water pollution, absorb carbon dioxide, release oxygen, and maintain...more