One million alien visitors from another star system could already be lurking in the solar system. We aren't talking about "little green men" here, however — more "little (and not so little) gray rocks," asteroids from the triple star system Alpha Centauri.
Alpha Centauri is the closest star system to our own, lying around 4.3 light-years away. New research has indicated that, if Alpha Centauri ejects as much material as the solar system, then as many as one million space rocks larger than 328 feet (100 meters) wide could be lurking in the Oort Cloud, a band of icy material at the edge of our solar system. Some of these alien visitors could even make their way into the inner solar system.
