A small asteroid will pass about 30,000 miles from Earth late tonight. Astronomers are tracking it to learn more about the asteroid and its orbit around the Sun. Plotting its orbit will let us know if the asteroid could hit Earth over the next few decades.

Asteroid 2012 TC4 is about the size of a house. That’s not as big as the asteroid that exploded over Russia back in 2013. So it most likely wouldn’t do much damage even if it did hit us — it would burn up or explode high in the atmosphere.

Many other asteroids that pass close to Earth are much bigger. If one of them hit us, it could cause damage on a local, regional, or even global scale. So astronomers have been scanning the skies for such asteroids for a quarter of a century.

They say they’ve found most of the ones that could cause global damage. Now they’re trying to find the ones that could cause more localized problems. Finding an asteroid long before it hits Earth could give us time to deflect it; more about that tomorrow.

2012 TC4 gives the asteroid-tracking networks a chance to refine their skills. So astronomers have been monitoring it since it got close enough and bright enough for them to see it clearly.

The asteroid will pass closest to Earth at 12:42 a.m. Central Time tomorrow. As astronomers track it, they’ll learn more about its size, mass, and composition — critical factors in determining how much of a threat any space rock poses to our planet.

Script by Damond Benningfield