3753 Cruithne
Though 3753 Cruithne is sometimes called our second moon, it does not actually orbit the Earth. Its eccentric orbit just happens to be in 1:1 resonance with ours, taking a year to go once around the Sun. From our frame of reference, Cruithne appears to be moving in a bean-shaped orbit about the Earth. This animation shows a similar orbit, and how the two motions can combine to give the illusion of the oddly shaped orbit.
Read more about this:
http://en.wikipedia.org/wiki/3753_Cruithne#Dimensions_and_orbit
Never heard of this before.
ReplyDeleteThe call it the great lonely bean of the cosmos, a bean fit for a giant's tooth. Squuuuiiiiish!
ReplyDeleteVery nice
ReplyDeleteIf Ptolemy had known about this object, I wonder how epicycles it would take for him to model its motion?
ReplyDeleteVery interesting question.. with potential new ideas =)
ReplyDeleteThanks Rozni Yusof
we need 3D models for those sort of things.
ReplyDeleteWikipedia gives a slightly different orbit, Cruithne doesn't quite go "around" Earth, it's more like it's "dive-bombing" Earth.
ReplyDeletehttp://en.wikipedia.org/wiki/File:Horseshoe_orbit_of_Cruithne_from_the_perspective_of_Earth.gif