Nasa's deflect-asteriod offensive to avoid future catastrophes on Earth

Dimorphos doesn't pose any threat to Earth, but the DART mission is the first physical test in space of one of NASA's primary tenets: planetary defense.

On Monday evening, a robotic NASA spacecraft is programmed to ram itself into a distant asteroid at 14,000 miles per hour (25,500 kilometers per hour) in deep space to demonstrate the agency’s future ability to defend Earth from hazardous space rocks. 
 

It’s a fast action scene straight out of a sci-fi movie:  The spacecraft, named DART, will first spot an asteroid the size of a football stadium named Dimorphos as a single pixel in its camera. About an hour later, if all goes as planned, DART will smash into its target with enough force to nudge the big space rock