Panspermia (from Ancient Greek πᾶν (pan) 'all', and σπέρμα (sperma) 'seed') is the hypothesis that life exists throughout the Universe, distributed by space dust,[1] meteoroids,[2] asteroids, comets,[3] and planetoids,[4] as well as by spacecraft carrying unintended contamination by microorganisms,[5][6][7] known as directed panspermia. The theory argues that life did not originate on Earth, but instead evolved somewhere else and seeded life as we know it.