“For the first time ever, humanity has changed the orbit of a planetary body,” said NASA planetary science division director Lori Glaze.https://www.sciencenews.org/article/dart-mission-deflected-asteroid-for-planetary-defense
A change of 32 minutes in orbit — but only 4% of the total orbital period. To deflect an asteroid away from Earth, it’d better be done several years in advance. 🌏
Still, it can be done. An amazing first.