Moving Earth - Experimental facts.

[Obelix]

Could we please have a list of all known observational and/or experimental facts that prove Earth is moving? I can briefly recall the following:

 

1) Foucault's pendulum. How many times has it been repeated? What were the conditions?

 

2) Coriolis force, regarding winds and hurricanes.

 

3) Motion of ballistic misiles. Does anybody know details regarding the influence of Earth's rotation on the latter?

[DrP]

Could we please have a list of all known observational and/or experimental facts that prove Earth is moving?

 

 

We can look at the stars and see them move across the sky - as we can with the sun. The motion of the stars suggests that we are moving as well as them.

 

wrt the pendulum - as I mentioned before - we had one set up swinging over a hemispherical map in our physics foyer. This was constantly in opperation (ahem.. when it was actually working) and had a little battery at the top of the wire which gave teh pendulum a little extra push occasionally so it wouldn't slow down.

[swansont]

We can look at the stars and see them move across the sky - as we can with the sun. The motion of the stars suggests that we are moving as well as them.

 

I think that argument is more subtle, because one can argue that the stars are moving and we aren't. But there's parallax, and that's indicative of motion of earth. Also, all of the stars rotating about a fixed earth violates relativity, as it requires starts at some distance to travel faster than c in completing a revolution.

[D H]

it is important to note that all reference frames are equally valid. One can do physics entirely from the perspective of an Earth-fixed, Earth-centered reference (i.e., a frame with origin at the center of the Earth and rotating with the Earth). An ECEF reference is exactly what you want to use if you are modeling the Earth's atmosphere. It is of course exactly what you don't want to use if you are modeling the dynamics of some extrasolar star system. While all reference frames are equally valid, some reference frames are incredibly dumb choices for use in solving a particular problem and some are very good choices. Which frame is "best" depends on the problem at hand.

 

So, Is the Earth rotating? This begs a question: Rotating with respect to what? I'll assume you are talking about rotation with respect to some non-rotating frame. That in turn begs another question, what the F is this "non-rotating frame" business? Classical and general relativity have different concepts of what constitutes an inertial frame. Since we're talking about earhly motion, I'll use the classical definition: A non-rotating frame is a reference frame in which one only needs to account for the acceleration of the frame origin to make Newton's Laws appear to be valid. A non-rotating frame in classical mechanics is also a non-rotating frame (locally) in GR.

 

So, how can we tell if the Earth is rotating (with respect to inertial space)? Obelix, you missed one obvious test: The Sun. moon, and stars. We know how far the Sun, moon, and planets are from the Searth thanks to many different measurements, all of which agree with one another. Pluto's velocity, as measured by an Earth-fixed observer, always exceeds the speed of light. We can measure the distance to some stars by means of parallax. Even the closest star has an apparent velocity of 9,000 times the speed of light and is undergoing a near constant magnitude acceleration of 200,000 kilometers/second² toward the Earth. The problems with these non-physical velocities and accelerations disappear as soon as one incorporates the Earth's rotation into the mix.