A mountain-sized asteroid has been located by a Russian astrophysicist and his team. They say this mammoth asteroid crosses paths with Earth every three years, according to Christian Science Monitor.

UR116 is not a collision threat, but just finding it proves how unpredictable asteroids can be.

A short documentary, "Asteroid Attack," highlights the discovery by Vladimir Lipunov, a professor at Moscow State University, according to Christian Science Monitor. The asteroid is 370 meters in diameter, and would hit the Earth 1,000 times harder than the bus-sized meteor that slammed Russia in 2013.

The orbit of such a large object is hard to predict, Lipunov says. Planets that the asteroid passes have gravitational forces which could alter the trajectory.

"We need to permanently track this asteroid, because even a small mistake in calculations could have serious consequences," he said.

UR116 shouldn't hit the Earth, at least in the next few decades, but an expert with the official Space Research Institute in Moscow says there are 100,000 other objects near Earth that are threats. Only 11,000 have been tracked and catalogued, according to Christian Science Monitor.

"Every couple of days new ones are being discovered," Natan Esmant said. "Scientists have increasingly powerful tools to do this work, but there's a lot still to be done. Every object that crosses the Earth's path can be a potential threat."