NASA knocked an asteroid off course in 2022 in a pioneering test of humanity's ability to defend Earth. Its spacecraft's impact pushed the space rock into a slightly different orbit around the Sun, according… Four years ago, NASA purposely smashed a spacecraft into a small asteroid to see if they could deflect it – a test to prove humanity could protect Earth from threatening space rocks. The experiment pushed the moonlet asteroid Dimorphos into a smaller... [2252 chars]