Scientists say the Late Heavy Bombardment was triggered in our solar system by the migration of our outer planets, which jostled icy comets about, sending some of them flying inward. The incoming comets scarred our moon and pummeled our inner planets. They may have even brought materials to Earth that helped kick start life. This artist’s conception illustrates a storm of comets around a star near our own, called Eta Corvi. – Image credit: NASA/JPL-Caltech

Related channels: COMETS, ASTROBIOLOGY, PLANET MARS, EXOPLANETS, TRAPPIST-1