Earth’s new ‘mini moon’ has been made official after almost 100 years of orbiting the Sun and Earth. The tiny asteroid, which is somewhere between 120 and 300 feet in diameter, has been slowly circling the Sun on a similar orbit to that of Earth’s, but NASA only just announced that this small rock also orbits Earth--just like our first beloved moon.
“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,” says Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies.
“The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth.”
The asteroid, known as “asteroid 2016 HO3,” is believed to have been caught in this dance for at least the last century. The Pan-STARRS 1 asteroid survey telescope, located on Haleakala in Hawaii, first discovered the mini moon on April 27th. It is expected to continue its dance for at least the next few hundred years or so.
While there have been numerous other asteroids caught in a similar dance with Earth, all of them lasted only a short while, eventually leaving Earth’s orbit. Chodas says asteroid 2003 YN107 was discovered orbiting Earth in a similar way about 10 years ago, but it is now long gone.
“This new asteroid is much more locked onto us,” Chodas says.
How cool would it be to have another moon visible in our skies?