Two scientists from Harvard University created a model of how life might have spread from planet to planet. Henry Lin and Abraham Leob believe that life was spread across the galaxy by aliens, similar to how a virus spreads an epidemic.
That kind of thinking is called panspermia, a controversial theory that suggests the building blocks of life reached Earth from some faraway alien world, reports Tech Times. The two researchers then built a model that theorizes life on one planet spreads outward in all direction. It then takes root if it finds a habitable planet while going around a neighboring star.