An asteroid is going to fly right by Earth in October, and scientists are pumped
On Oct. 12, asteroid 2012 TC4 will be as close as 4,200 miles from from Earth. NASA/JPL-Caltech

Pretty soon, an asteroid is going to zip right past the Earth, but you shouldn’t be alarmed. Everything is going to be fine — and even better, NASA is going to use the opportunity to make sure we can protect ourselves from asteroids that could actually hit us.

Here’s the deal: An Italian astronomer spotted the asteroid, known as 2012 TC4, in 2012, when it flew past the Earth. At its closest approach, it was as close as a quarter of the distance between the Earth and the moon. Then its orbit took it too far from Earth for telescopes to watch it.

Now, it’s back, and on Oct. 12, it will again pass close to Earth. Astronomers haven’t pinned down its orbit precisely enough to say just how close it will get, since they only had a week of data from its 2012 visit. But they know it definitely won’t come closer than 4,200 miles away and expect it to stay much farther away than that.

The Oct. 12 flyby, shown not even remotely close to scale.
The Oct. 12 flyby, shown not even remotely close to scale. NASA/JPL-Caltech

2012 TC4 is between 30 and 100 feet across. For comparison, the asteroid that drew headlines in 2013 for turning into a meteor over Chelyabinsk, Russia, was likely about 65 feet across before its dramatic downfall.

But while NASA isn’t concerned about 2012 TC4 pulling the same trick, it does intend to use the asteroid’s flyby to test its preparedness for other near-Earth objects. This summer and fall, the agency’s Center for Near-Earth Object Studies will turn a network of telescopes to the asteroid. Each telescope will gather detailed observations of the asteroid’s path, allowing NASA to improve its predictions for future flybys.

Monitoring is just one piece of NASA’s asteroid strategy. In case it does spot a large enough rock coming uncomfortably close, it’s also working on developing spacecraft that can bump asteroids off-course.