Why does the atmosphere move with the earth?

[willem2]

(yes, I know this post is a couple of months old)

Are you sure you didn't calculate the speed of He at 25 kelvin? Helium should have a typical molecular speed of around a kilometer per second at typical temperatures in the lower atmosphere, with higher temperatures out in the thermosphere and exosphere (and correspondingly higher speeds). In addition, the typical speed doesn't need to exceed escape velocity for the gas to escape - if it's even somewhat close, the high-speed tail of the distribution will exceed the escape velocity, and the helium will gradually escape.

I think he used the 4 for the molar mass of helium, which is 4 gram, but you need to use 0,004 kg. So he's off by the squareroot of 1000.

 

[Buildafriend]

Why are there not chickens floating in the atmosphere? Are chickens not a gas?

 

[silkdaggers]

Hi , Just to gain some clarity: could someone chalk out for me all the forces acting on a gas molecule in the atmosphere which keeps it where it is and similarly the forces on a plane and moon. I am still unable visualize why plane in the air has to move along with the atmosphere but a satellite (Artificial or Natural) doesnt.

 

[russ_watters]

There are no such forces in either case!

 

[pete20r2]

So, do you guys get trolled often in these forums?

BTW, the atmosphere moves with us because of centripetal force (the same reason practically anything orbits anything else) combined with pressure and gravity, centripetal force pulls molecules inwards, so does gravity, and pressure pushes molecules apart. These forces are balanced. In the overall state of the atmosphere, there is no lateral force (parallel to the ground) only towards the centre of the Earth and directly away from it.