Test to prove Earths spins:

Originally posted by apathist
Let's say the earth was all alone in the universe. Could it still be spinning? Wouldn't that invoke an aether?

If Earth was the only mass in the universe, if it was spinning it would still be measurably fatter around the equator than going from pole to pole. Plus there would still be Coriolis and that can be measured easily enough. Also a weight known to be very exact say measured at the poles would be slightly less weight at the equator for two reasons, one because of centrifugal force trying to fling it off into space and slightly less weight because the equator is bulging out a few miles so you are further from the center of mass so less gravity there.

Originally posted by apathist
Let's say the earth was all alone in the universe. Could it still be spinning? Wouldn't that invoke an aether?

https://en.wikipedia.org/wiki/Newton's_laws_of_motion

First law: In an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a net force.

Constant velocity is measured how? Objects don't move at constant velocity because they can sense the presence of some distant star. They do it in relation to the very structure of spacetime. So if that is what you are calling 'aether', then it is very much real.
It is possible that relativity changes this somewhat but even so, relativity requires you to be able to measure distance and hence structure although your actual measurements will vary depending on your relative velocity.

Originally posted by sonhouse
If Earth was the only mass in the universe, if it was spinning it would still be measurably fatter around the equator than going from pole to pole. Plus there would still be Coriolis and that can be measured easily enough. Also a weight known to be very exact say measured at the poles would be slightly less weight at the equator for two reasons, one because ...[text shortened]... tor is bulging out a few miles so you are further from the center of mass so less gravity there.

So, you say yes, a spinning earth means the aether exists.

I think we spin relative to the sun. No sun? No spin. The earth would settle for sphericality.

I don't entirely agree with myself here. We soak in a bath of radiation, not only from the sun. Surely the rest of the universe isn't whipping around us faster than light. Does the concept of truly empty space have any meaning?

I came across this:
YouTube
And it mentions another test for earths spin. A gyroscope. Which is actually where it gets its name.

https://en.wikipedia.org/wiki/Gyroscope
In 1852, Foucault used it in an experiment involving the rotation of the Earth.

Originally posted by Eladar
I think that everything is relative.

You can think what you like but it doesn't make it right.
Velocity is relative but acceleration isn't.
And spinning/rotation is acceleration.

Read a book.

Originally posted by Eladar
I think that everything is relative.

You could say that the earth is not spinning but everything is moving around the earth.

True formulas might now work but if we have no agreed upon center, how do we know we are the ones spinning?

Are you just playing devil's advocate or do you really have doubts Earth spins? There are so many lines of evidence Earth spins, you can just google earth spins. For one thing, you weigh slightly less on the equator than you do at the poles, for two reasons, one of which is a direct result of the spin, in that it bulges measurably at the equator so if you had a yardstick long enough if you drill a hole pole to pole it would measure a few miles shorter than drilling a hole from equator to the opposite side of Earth. So at the poles gravity is a bit stronger than at the equator, and that changes the apparent weight so that on a non-spinning Earth you would weigh slighly more than at the equator, since gravity follows the inverse square law but that is counterbalanced by the fact Earth spins and someone at the equator tends to get flung off into space. That doesn't happen because gravity way overcomes that effect but both effects can and has been measured many times.

Of course, if you are aligned with Freaky, you are in the non spinning Earth and would be a flatassser. Do you think Earth is flat and non-spinning? What leads you to this conclusion? Are you just parroting other people or do you have actual thoughts of your own on the subject? The bit about Coriolis not being true because you can't see a toilet flush spin in one direction is bogus because it effects large scale air movements and ocean currents. Also, it is well known if you shoot a rifle, a long range rifle, you better have a good handle on coriolis, the spin of Earth effects the apparent path the bullet takes over the ground, there is a big difference in a bullet shooting say 45 degrees to the right of north vs shooting the same rifle 45 degrees to the left of north, the same load of bullet and powder will put the bullets on a different path if not taken into account.

Plus the Foucault Pendulum swings around 360 degrees every day, you would have to explain how that can happen on a non-spinning Earth and the gyroscope experiments that show the angle of the rotating shaft changing 90 degrees in 6 hours if the shaft is pointed east-west but not if the shaft is pointed north-south.

There is no non-spinning Earth rational that can explain all those phenomena.

Also, I calculated how far away from Earth you would have to go to get the stuff spinning around a non-spinning Earth and at around 80 billion Km anything there would be spinning at the speed of light and of course at 800 billion Km, it would be spinning around ten times the speed of light, and that is just the close stuff astronomically, the nearest star would be spinning around Earth about 500 times the speed of light. That is just the closest one at 4 odd light years away, Alpha Centauri. Try to rationalize all that.