The Atmosphere and Earth's Orbit (Probably Easy Q)

[||spoon||]

Hi,

just wondering about a (probably) easy queation. Was learning about the coriolis effect today and how since the atmosphere is not rigidly connected to the Earth it appears to veer off a northerly/southerly course in a direction depending what hemisphere it occurs in... etc. Basically its effect on the atmosphere and winds.

I was wondering, if the atmosphere is free to be "left behind" (so to speak) while the Earth rotates, why is it not also left behind while the Earth orbits through space? Is it simply due to the force of gravity that the atmosphere remains around the Earth?

Thanks in advance,

-Spoon

 

[chriscolose]

With no gravity it's hard to have an atmosphere

 

[D H]

First off, the Earth's atmosphere is not entirely "free to be 'left behind'" while the Earth rotates. Because of friction between the atmosphere and the surface of the Earth, the Earth's atmosphere rotates pretty much with the Earth.

In the sense that the Earth's atmosphere is not rigidly coupled with the Earth, the atmosphere is to some extent "free to be 'left behind'" as the Earth orbits the Sun (and Moon). Just as friction with the Earth's surface restricts how much freedom the atmosphere has with respect to rotation, the Earth's gravity surface restricts how much freedom the atmosphere has with respect to orbiting the Sun.

 

[Brian H]

Gas molecules stick around on the surface for approximately the same reason you do. They would only escape Earth's gravity by achieving escape velocity, just like you. A few in the upper atmosphere get bashed hard enough by neighbours to make it, but most fall back.