This is from a scientific point of view. For aliens in popular culture see extraterrestrial life (popular culture). For other uses, see Extraterrestrial (disambiguation).

Extraterrestrial life is life that may exist and originate outside the planet Earth, the only place in the Universe known to support life. Its existence is currently hypothetical; there is as yet no evidence of extraterrestrial life that has been widely accepted by scientists.

Most scientists hold that if extraterrestrial life exists, its evolution would have occurred independently in different places in the universe. An alternative hypothesis, held by a minority, is panspermia, which suggests that life in the universe could have stemmed from a smaller number of points of origin, and then spread across the universe, from habitable planet to habitable planet. These two hypotheses are not mutually exclusive.

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NPR Topics: Space

Astronomers See A New Class of Black Hole
Fri, 03 Jul 2009 13:00:00 -0400
Scientists say X-ray data collected by the European Space Agency's XMM-Newton spacecraft show evidence of a new type of black hole in a galaxy about 290 million light years from Earth. Astronomer Sean Farrell explains what the discovery might tell us about galaxy evolution.
Salty Sea May Lurk Under Saturn Moon
Thu, 25 Jun 2009 13:00:00 -0400
Salty ice grains inside in Saturn's outer ring point to a possible underground ocean on the moon Enceladus.
Breaking Ground On The First Spaceport
Sat, 20 Jun 2009 12:13:00 -0400
Out in the wilds of New Mexico, they're marketing a new kind of commercial space — as in, outer space. On Friday, New Mexico broke ground on what's billed as the world's first commercial spaceport.
Summer Sky Highlights What's Missing
Fri, 19 Jun 2009 13:00:00 -0400
This season's astronomical highlights are about what won't be visible in the night sky. Astronomer Paul Rao discusses what he describes as "the eclipse of the century," Jupiter's mysterious missing moons, the vanishing rings of Saturn and the forthcoming Perseid meteor shower.
NASA Moon Missions To Search For Water
Thu, 18 Jun 2009 00:48:00 -0400
A rocket is scheduled to blast off for the moon Thursday afternoon carrying two probes that will gather data to prepare for possible future manned missions. One probe will map the moon, and the other will search for water ice.
NASA To Launch Two Moon Missions
Wed, 17 Jun 2009 16:00:00 -0400
NASA will launch Thursday two missions to the moon. One spacecraft will orbit the moon and create an unprecedented high-resolution map of the lunar surface. The other mission will send a spent rocket part on a collision course with a permanently shadowed lunar crater.

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Carl Sagan on Search for Extraterrestrial Intelligence -1979: Carl Sagan speaks about the search for extraterrestrial intelligence. Cosmos series, episode 12 "The Enciclopaedia Galactica"