While all of us are familiar with the moon that hangs in the night sky, many are unaware that the Earth is circled by other natural satellites, including one, Cruithne, which orbits in an exceedingly strange pattern that may reveal the secrets of planetary formation.
Discovered in 1997, 3753 Cruithne can best be described as a “quasi-orbital” satellite of Earth. Unlike the moon that we all know, which orbits our planet in an ellipsoid fashion, Cruithne moves about the inner solar system in a “horseshoe” orbit, wobbling and swinging through its path. Though horseshoe orbits are not uncommon and can be observed in the moons of Saturn, Cruithne is unique, in that the three-mile-long asteroid displays a complexity in its orbit, which is tilted out of the plane of the solar system.
As it moves through the system, this moon swings wildly, circling messily around Earth’s orbit. Cruithne moves so far away from the Earth, in fact, that its path can often bring it into the domains of Mars or Venus, our nearest planetary neighbors. As IFLScience points out, Cruithne orbits the Sun once a year, yet in order to make its way around the Earth’s orbit, the moon requires nearly 800 years.
Did you know that Earth has a second moon called Cruithne? I didn’t! @VirtualAstro https://t.co/YN83lTrWbr pic.twitter.com/6yfyIxG30b
— SpireWeather (@SpireWeather) February 25, 2015
Scientists hope that Cruithne’s odd orbit can reveal to them some of the gravitational interactions that occurred during the formation of the solar system. It was only in the later part of the 20th century that researchers began to understand that objects could become trapped in horseshoe orbits for lengthy periods, adding another variable to their understanding of planetary formation. Scientists believe that terrestrial planets grow from collisions between objects of Cruithne’s size and larger.
Researchers also assert that the asteroid could be useful as a landing site for astronauts. As the Inquisitr has previously reported, NASA is actively pursuing the concept of asteroid mining, and the proximity of Cruithne during certain points of its orbit could make it an ideal test site for such technologies.
Cruithne isn’t alone as a quasi-orbital satellite of Earth, however. Several other similar objects have been noted by researchers, including one, 2014 OL339, that could also masquerade as a moon of Earth. As the New Scientist points out, the 490-foot-long asteroid is in a resonant orbit with the Earth, having followed us closely for the last 775 years.
Cruithne will be at its closest approach to Earth in 2,750 years. In roughly 8,000 years, Cruithne is expected to move very close to Venus, an event that may well push the small moon out of the solar system.
[Image via Above Top Secret ]
