It was amazing to see today the videos from NASA showing a direct hit by their spacecraft DART (an acronym for “Double Asteroid Redirection Test”) on the asteroid Dimorphos.

Here are some amazing statistics on this astounding feat of physics:

• DART traveled 56,000 miles to accomplish its $330 million suicidal mission against the 560-foot diameter Dimorphos.
• DART came in at 1,260 pounds to impact the 11-billion-pound Dimorphos, similar in scale to a house-fly smashing into an NFL running back. This seems harmless if not for the fact that the fly is going 15,000 miles per hour!
• NASA’s boffins predict that the impact will shift the orbit of Dimorphos around its bigger sibling Didymos by 1%–reducing it by 7 minutes from the current rate of about 12 hours per revolution.

The big question is: Could we really deflect an asteroid heading for Earth? Given the success of DART, I am now a lot more optimistic that, by the time a planet-threatening object comes our way, a defense system will be in place.

“We do not currently know of any object of “moderate” size which has a chance of impact in the next 100 years. …Please keep in mind that anything smaller than about 30 meters in size will have an airburst and is unlikely to reach ground (excluding metallic NEAs). Our atmosphere is very efficient at protecting us from small impacts.”

–  Asteroid scientist Marina Brozovic