A little asteroid has been tagging along in Earth’s orbit for at least a century — and it’ll probably follow along for at least a few hundred years more.
Scientists at the Pan-STARRS 1 telescope on Haleakala, Hawaii spotted the little asteroid, known as 2016 HO3, in April. They estimate that the asteroid is only about 130-330 feet wide, making it a tiny speck in the vastness of space. Even at its closest point, 2016 HO3 is at least about 9 million miles away.
“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 NASA’s Centre for Near-Earth Object 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.”