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October 17, 2015

A couple of small asteroids will sneak past Earth tomorrow. There’s no chance of either of them hitting our planet. But they show that the space around us isn’t empty — space rocks frequently fly within a few million miles.

The first encounter comes in the wee hours of the morning, when asteroid 2014 UR slips less than a million miles from us — about four times the distance from Earth to the Moon. The asteroid is between the size of a large house and a small office building.

The second encounter comes a few hours later, when 2011 SE97 flies less than three million miles from Earth. It is somewhat bigger — between the size of a small office building and a football stadium.

Both of these objects are Near-Earth Asteroids — their orbits periodically bring them close to Earth’s orbit around the Sun. So far, astronomers have discovered about 13,000 Near-Earth Asteroids. Plots of their orbits show that there’s almost no chance of collisions with any of them in the foreseeable future.

Still, there’s always the chance that an asteroid that hasn’t been discovered could be headed our way. So several searches are underway to find and plot every asteroid that’s a potential threat. Most of these projects use automated telescopes that scan large sections of the sky every night. Repeated scans not only reveal new objects, but provide enough data to calculate their orbits — giving us a better picture of our planet’s busy neighborhood.

Script by Damond Benningfield, Copyright 2015

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