Earth Officially Has A Tiny Second Moon

(Photo : Getty Images/Matt Cardy) The Earth's Moon.

It's official. Earth has a second moon. Well, not quite. It's a tiny second moon.

NASA spotted a small asteroid that has been orbiting Earth for nearly a century. The asteroid is 120 feet to 300 feet in diameter, and it also orbits the sun in the same fashion as our planet.

Named "asteroid 2016 HO3," the small moon was found on April 27 by the University of Hawaii's Institute for Astronomy. They used their Pan-STARRS 1 asteroid survey telescope to make the find. Scientists believe that unlike our moon, this new second moon may eventually drift away from Earth in a few hundred years.

"The asteroid's loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth's gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon," commented Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California via Mother Nature Network. Chodas said that the tiny second moon is "caught in a little dance" with Earth.

NASA previously found another asteroid orbiting Earth, named "2013 YN107." It was not considered a moon, however, and it eventually drifted away from Earth. Another object found that has been considered a quasi-orbital satellite of Earth is 3753 Cruithne, found in 1997. It was not considered a moon because it did not orbit Earth in an elliptical fashion.

Cruithne has not yet left Earth, and according to Pulse Headlines, it will take about 800 years for the rock to complete its "unstable ring shape around our orbit." What makes "Asteroid 2016 HO3" special is that it completes that very process in just a year

NASA astronomers are keeping their eyes out for other satellites orbiting our planet.