| MadSci Network: Astronomy |
Dear Mr. Hodapp,
We do live in a geocentric solar system. The epicycles of the second
century astronomer, Ptolemy, describe with accuracy commensurate with the
observing equipment of that time the loop-the-loop paths the planets
follow. With modern desktop computer planetarium programs ("The Sky" from
Software Bisque is one of the best) you can also live in a Martocentric,
Jovicentric or any other centric universe: Einstein taught us that there is
no absolute frame of reference, so just pick whatever one you want.
Computers make the math easy!
You posit a provocative hypothesis about a fast moving sun (it is
indeed moving through space as our Milky Way galaxy revolves every
250,000,000 years). Light from the sun travels about 186,000 miles per
second whether your view is heliocentric or geocentric. It takes about 8
minutes to travel to our Earth. There can be no "tail of light" in any
circumstance. The photons given off by the sun radiate in line of sight
directions no matter what.
As for who orbits around what, the actual case is that BOTH the sun
and our earth orbit around our mutual center of gravity. Can you visualize
a 93 million mile long teeter totter? We're at one end (very tiny) and the
huge sun is at the other. At a point deep within the sun, but NOT at its
center of gravity, is the "barycenter" of the earth-moon and sun system. We
are both orbiting around that point. Your next step is to contemplate how
complicated the mathematics become as astronomers keep track of the
barycenter of the solar system: sun, nine planets, a host of moons,
asteroids, the Kuiper belt and the Oort cloud! Whew. No less a genius than
Isaac Newton admitted thinking about orbits gave him a headache- and he was
just trying to keep track of earth, moon and sun. Keep your eyes on the
stars; there's a whole universe to explore out there.
Jim Foerch
Veen Observatory
Lowell, Michigan, USA
Try the links in the MadSci Library for more information on Astronomy.