NASA deliberately crashed a spacecraft into a small, nonthreatening asteroid on Monday in an experiment to change the space object's orbit around a larger space rock.
Why it matters: The first-of-its-kind mission — called the Double Asteroid Redirection Test (DART) — was designed to determine whether the technology could one day be used to defend Earth from hazardous asteroids or comets by deflecting them off their collision course with the planet.
