Cruithne, also known as asteroid 3735, is a planet discovered the 10th of October 1986. Cruithne is 130,000,000,000,000kg. It is about two degrees Celsius on Cruithne. Cruithne takes about 364 days to revolve around the Sun. Cruithne is locked in a 1:1 resonance with Earth, meaning for every orbit around the Sun the Earth makes, Cruithne makes one as well. Cruithne is 5 kilometers wide and it never comes closer to the Earth than 0.1 AU (40 moons length.) Cruithne is one of several thousands of asteroids that cross the Earth’s orbit. However if you look from Earth’s surface, Cruithne appears to be orbiting the Earth. For this reason some people have mistakenly nominated Cruithne as “Earth’s second moon.” However, if you look down from above the solar system, (Please check out this image – http://earthsky.org/wp-content/uploads/2002/10/cruithne_orbit_300.jpg) you can easily see that Cruithne orbits the Sun. Cruithne’s orbit is however locked to the earth’s orbit. Cruithne’s orbit is greatly affected by Earth’s Gravitational force. Earth and this asteroid return every year to nearly the same place in their orbit to “meet” each other. But not for long… Recent discovery tells us that Cruithne’s orbit is not stable at all. Computer model simulations currently indicates that Cruithne would spend 5000 more years in its current orbit and then very possibly start orbiting the Earth, truly becoming an Earth’s moon, however it would not be for long. In another 3000 thousand years, the little ball for filth shall go back to orbiting the Sun. I will look forward to an Earth with two moons. (Hopefully I will still be alive because of some new technology.) However some people who have posted on rather unreliable sites have a different opinion on this matter. As a matter of fact, this site (http://scienceray.com/astronomy/the-earths-second-moon-cruithne/) says that Cruithne is seriously a moon of the Earth. He first told us that he thinks that Earth has 2 moons. And then went on saying that the second moon is called Cruithne. He says in his article that Cruithne orbits the Earth every 770 years, and that Cruithne has no chance of colliding with the Earth. He then went on saying about the Earth possibly orbiting around Cruithne, because of Cruithne’s speed. (Seriously? A huge planet like earth orbiting around an asteroid 5 kilometers wide!) He then finished by talking about how Earth’s last series of close interactions with Cruithne was in 1902. And their next set of close interactions would happen sometime in 2292.