DEEP IMPACT: NASA’s New ‘Intruder Alert’ System Spots An Incoming Asteroid.

A large space rock came fairly close to Earth on Sunday night. Astronomers knew it wasn’t going to hit Earth, thanks in part to a new tool NASA is developing for detecting potentially dangerous asteroids.

The tool is a computer program called Scout, and it’s being tested at NASA Jet Propulsion Laboratory in Pasadena, Calif. Think of Scout as a celestial intruder alert system. It’s constantly scanning data from telescopes to see if there are any reports of so-called Near Earth Objects. If it finds one, it makes a quick calculation of whether Earth is at risk, and instructs other telescopes to make follow-up observations to see if any risk is real.

NASA pays for several telescopes around the planet to scan the skies on a nightly basis, looking for these objects. “The NASA surveys are finding something like at least five asteroids every night,” says astronomer Paul Chodas of JPL.

But then the trick is to figure out which new objects might hit Earth.

The ability to deflect or destroy them might be nice, too.