NASA scientist: Aliens may have already visited Earth

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A NASA scientist says we may have already been visited by aliens - we just didn't notice.

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Silvano Colombano, a researcher at NASA's Ames Research Center in Mountain View, California, argued in a paper published Monday that scientists in the search for extraterrestrial intelligence, or SETI, need to rethink some commonly held assumptions about extraterrestrial life - including that aliens would be carbon-based.

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“I simply want to point out the fact that the intelligence we might find and that might choose to find us (if it hasn’t already) might not be at all produced by carbon-based organisms like us,” Colombano wrote. He goes on to argue that the extraterrestrials could be “an extremely tiny super-intelligent entity."

In an email to Newsweek, Colombano clarified that the aliens could "ultimately be robotic" in nature.

Other assumptions Colombano calls on scientists to question are that "interstellar travel is impossible or highly unlikely," that we have not been visited by aliens already and that aliens would use radio waves to communicate.

“If we adopt a new set of assumptions about what forms of higher intelligence and technology we might find, some of those phenomena might fit specific hypotheses, and we could start some serious inquiry.”

As part of his conclusion, Colombano proposed scientists "stretch possibilities as to the nature of space-time and energy" in future SETI research.

The paper was submitted as part of SETI’s Decoding Alien Intelligence workshop.