How life could help atmospheric tides slow a planet's rotation

How life could help atmospheric tides slow a planet's rotation

5 years ago
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https://phys.org/news/2018-11-life-atmospheric-tides-planet-rotation.html

By contrast, atmospheric tides, sometimes called thermal or solar tides, occur when sunlight heats the surface and air on Earth's daytime side. That heating shifts the atmosphere's mass from the hottest point to cooler points on the planet. As with gravitational tides, atmospheric tides cause bulges that are vulnerable to gravitational pulls. Those bulges subtly change the shape of Earth's atmosphere, stretching it from a sphere to something slightly less symmetrical and more elliptical. Scharf suggests imagining a 'handle' on Earth, and that forces pulling on the atmospheric handle can then help speed up or slow down the planet's rotation.

Usually, the effects produced by these thermal tidal forces are relatively small, but the effects can be increased in certain circumstances, such as in resonances. These are natural vibrational frequencies that describe the undulating movement of bridges in the wind, or being pushed higher and higher on a swing. Atmospheric redistribution becomes amplified when the planet's rotation rate matches the natural frequency of the atmosphere's oscillation.