Recent content by Iseous

I don't think it really has anything to do with the shape of the cloud. The force of gravity can be simplified to a single point mass acting at a certain distance, regardless of the size or shape of the mass. The main thing that would matter is the size/shape of the object being pulled by this...

Your initial scenario is trivial. If it's already spinning it will keep spinning, that doesn't mean the gravitational force made it spin. It just didn't apply any moment to stop it or make it spin faster. Your second scenario is still relatively trivial unless you are talking about such a...

Okay, but that doesn't specify what forces actually caused that. You just keep going back further into the past and say that the thing before it had the spin already, but no explanation of the forces involved to actually do that. The big bang was basically an explosion outward, which would...

If this was part of a giant gas cloud, then the gas would have just been pulled toward Earth from gravity just like all the other mass. So yes, the atmosphere did not necessarily have to have its own spin initially. But gravity would not explain the initial spin of the Earth or other bodies...

Any object can be simplified to a center of mass for a gravitational force or sum of gravitational forces. That is why if you drop an object of any shape, it falls straight down (toward the center of mass of Earth) without any rotation about its own axis (because the gravity is acting at the...

Still to an outside observer who is not rotating with Earth. Regardless, once the sphere in that experiment started rotating and getting the gas to rotate with it, then it is no longer "still" either. So whether it started off not rotating, or you looked at a point once the sphere and gas...

So a spherical Earth rotating with an initially still atmosphere is nothing like a sphere rotating in an initially still gas?

In a fluid that was initially stationary, if that's what you mean.

I started to think about that and I think that would be correct. However, that's assuming those equations would even apply to a rotating sphere. I found a paper about boundary layers of a rotating sphere in a still fluid, and I'll try to look into it more to see what it says when I get a...

So if you were to take a ball, put it in the center of a large enclosed room, and keep it spinning constantly, the layer of air being rotated by the ball would increase in size over time?

Russ linked me to a page about boundary layers and I used those equations to get a very rough estimate of the size of that layer for Earth. Those equations weren't really for a sphere rotating, so I'm not sure if they really mean anything.

The Earth is rotating at a constant speed, so the molecules outside of the boundary layer will be moving at the freestream velocity (speed of rotation) relative to the Earth. And I'm not saying there is no friction between the molecules. The viscous forces are causing the boundary layer.

The constant rotation of the Earth essentially provides the relative motion.

For laminar boundary layers over a flat plate, the Blasius solution gives: For turbulent boundary layers over a flat plate, the boundary layer thickness is given by: where is the overall thickness (or height) of the boundary layer is the Reynolds Number is the density is the...

From your page "a boundary layer is the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant". Key words there are "immediate vicinity" and "significant". So sure the boundary layer goes on forever but it becomes negligible outside of...