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Name: Greg Capelle
Status: student
Age: 17
Location: N/A
Country: N/A
Date: Around 1999

How would you prove to someone that the earth is moving?

One of the simplest ways is to use a Foucault Pendulum. This is a long pendulum (small angular swing) in relatively low friction circumstances. Once it is set swinging, the plane of swing appears to shift relative to the room over time. The rate of shift is a function of latitude. At the poles of rotation, it takes about 24 hours for one complete shifting of the plane. As you move away from the poles of rotation toward the equator, the period of a complete 360 degree shift increases. Many museums have such a pendulum on display.

Other proofs are more subtle. This includes Coriolus Effect that is found in weather systems and ocean circulations, and Doppler measurements that can be made.

Good question!

Nathan A. Unterman

The best way to answer this I think is to just look at how this was all done. It took alot of arguing for hundreds of years. You can always come up with an explanation of how the earth is moving, the sun is moving, the planets etc, and keep the earth at the center of it all. But the explanation gets more and more complicated, circles inside of circles. Along comes Copernicus (spell?) and Kepler in the 1500's and they have a simpler model. But does that make it the "correct" model? It took a while. So while there are ways to make it clear that the earth is moving, someone can always argue with it.

I read all this once in a book called The Ascent of Man, by Jacob Bronowski (spell?), it was also a PBS TV show, and your library may have the tapes. Its pretty easy to find this story written down.

S Ross

If the person believes in gravity, show them the sun and point out the fact that we are not in the middle of it. There's a gravitational attraction between the earth and the sun, so we must be falling toward it, yet we never get there. This must be because we are moving sideways and falling toward the sun at the same time.

If the person doesn't believe in gravity, ask them to hop.

Tim Mooney

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