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Posted to the UseNet Newsgroup "alt.astronomy" "FALLING FOR YOU" Planets are said to "fall" toward the Sun. This is how planets orbit the Sun. As a planet falls toward the Sun, the forward momentum of the planet's orbit around the Sun does not allow the planet to spiral down into the Sun. Satellites, all the moons in our Solar System, including Pluto's Charon, as they go around their planets, actually spend some of their time moving toward the Sun and the rest of their time moving away from the Sun. The Moon, however, *always* falls toward the Sun. There is always an "acceleration" of the Moon toward the Sun. The Moon never actually goes all the way completely "around" the Earth. The Moon's orbital pattern around the Sun is said to be "scalloped" just like Earth's orbit (rather than "looped" like true satellite orbits). http://www.math.nus.edu.sg/aslaksen/teaching/convex.html http://www.astronomycafe.net/qadir/q1665.html http://nineplanets.org/luna.html (It is here that i will inject Barry's important objection to this argument. If the Earth and the Moon were orbiting farther away from the Sun, the Moon would orbit Earth like other satellites, some of the time moving away from the Sun and some of the time moving toward it. My thought here is that Earth and Selene *don't* happen to be farther away from the Sun. So to me, Asimov's "Moon always falling toward the Sun" argument is still a good reason to think of Selene, the Moon, as a major planet. And especially when this reason is included with all the other reasons that Isaac Asimov listed and described.) Are any of you fans of Isaac Asimov? Me? I'm a big fan of his, a *huge* fan, especially of his non-fiction articles and books. Asimov wrote a lot of material on the Moon, and it was his stance that the Moon is really a planet and not just a satellite. In fact, he was the one who first convinced me that Selene, the Moon, is a full-fledged major planet in its own right! This might be a good time to note that terms like "binary planet system", "double planet system", and "sister planet" originated with Asimov. He first coined these terms long before Charon, Pluto's satellite, was discovered. Another thing to look for in a major planet would be how it "fits in" with other major planets. Next we'll look at just how well our Moon fits in with the rest of the planets in our Solar System. happy days and... starry starry nights! -- Indelibly yours, Paine P.S. Thank YOU for reading! P.P.S. Some secret sites (shh)... http://painellsworth.net http://savethechildren.org http://eBook-eDen.secretsgolden.com |