> > Hello List, I am taking a risk of ridicule again, but.... If an asteroid can > have an orbit like this, why do the scientist think the moon could not have > been caught up in an orbit around earth after being in a orbit similar to > that of this asteroid?
Asteroid 2002 AA29 never gets captured into Earth orbit. In about 600 years from now, it drifts near the Earth, and gets into a situation where the Earth and the asteroid pass each as they travel around the Sun, and does this for about 50 years. >From the Earth perspective, it would appear the asteroid is in an elongated 1-year >orbit around the Earth, But it is not a true satellite, it just appears as one because of the viewing perspective. Hence, we call it a 'quasi-satellite' during this time. It has this strange behavior because it is in the same orbit as the Earth (co-orbital) but inclinced at 11 degrees, and because of the combined gravity pulls of both the Sun and Earth. This URL shows two animations side-by-side of the same orbit from two different viewing perspective: http://neo/2002aa29/2002aa29f.gif The animation on the left is from a Sun-centered (heliocentric) perspective, and the one on the right from a Earth-centered (geocentric) perspective). They are the same orbit show in different ways. Note in the heliocentric perspective, the asteroid crosses the Earth's orbit twice within the year. When the asteroid is inside of Earth's orbit, it is traveling faster and it passes the Earth. Once it crosses over the Earth's orbit, it slows down relative to the Earth, and this allows the Earth to then pass the asteroid. This is repeated for about 50 years, and then the asteroid returns back to its libration motion, where it ping pongs back and forth along the Earth's orbit, taking about 95 years for each trip. Ron Baalke ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
