Proving the point (was: Carl Sagan quote of the...?)

From: Eugene Leitl (eugene.leitl@lrz.uni-muenchen.de)
Date: Mon Dec 20 1999 - 18:06:14 MST


Dan Fabulich writes:
> Say, does anybody here know how to demonstrate to a layman that the earth
> revolves around the sun rather than vice versa? I realized the other day
> that I didn't know how, and that this was arguably the sort of experiment
> which everybody ought to do/see/be aware of at some point in their lives.

By purely astronomical observation from Earth surface, afaik you
can't. Ellipses are aesthetically more pleasing than epicycles, but
that alone is no proof. Hey, it's just a big lamp dragged around by
angels. Focault's pendulum might also come to mind, but a true hard
case would argue the periode matching the solar day is just a
coincidence. Provided, one believes in gravitation (a very nice
gravitational balance basement experiment can be found here
http://www.fourmilab.ch/gravitation/foobar/ ), one might also construe
something from solar modulation of tides (few cm iirc) and the Solar
wobble due to Earth influence (which would require a high-precision
measurement).

It should be enough to convince anybody but the flat Earth people ;)



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