According to a new research by NASA, moon isn’t the only celestial body orbiting Earth. For the last 100 years or so, a small asteroid, which they are calling 2016 HO3, has been revolving around our planet. And if the astronomers are correct, it will be a constant companion of Earth for several centuries to come.
Discovered on April 27 of this year as part of the Pan-STARRS 1 asteroid survey held in Hawaii, the asteroid has been found to orbit around the sun, while at the same time going around Earth. Although situated too far to be called an actual satellite of our planet, it is being described as a “quasi-satellite”. Speaking about the find, Paul Chodas of the Center For Near-Earth Object (NEO) Studies at NASA’s Jet Propulsion Laboratory said:
Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth. One other asteroid — 2003 YN107 — followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth’s companion for centuries to come.
2016 HO3, according to the researchers, follows an elliptical orbit, spending half of each revolution closer to the sun than our planet. Thanks to its highly-angled orbit, the asteroid jounces up and down Earth’s orbital plane exactly once a year. At its closest position from our planet, it floats at a no mere distance of around 9 million miles (or 14 million kilometers). By comparison, moon is located at only about 239,000 miles (approx. 384,600 km) from Earth. Chodas added:
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. 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.
While the exact size of the asteroid has not yet been determined, scientists believe that it is somewhere between 120 feet (around 40 meters) and 300 feet (or 100 meters) across. Given its distance from our planet, very little is actually known about 2016 HO3, including its composition.