According to Silvano P Colombano, a scientist at the NASA Ames Research Centre in Mountain View, California, aliens might have already visited the earth in the past. However, he notes that the aliens might not look similar to what we visualize them.
Colombano, in his research paper, suggests that humans may have failed to see extraterrestrial beings that visited our planet. He believes that the aliens who came to Earth might not be similar to carbon-based organisms, according to a report by the Independent. His research paper was submitted as part of SETI's Decoding Alien Intelligence workshop.
"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 in the paper.
Colombano also said that the scientific community either avoids or overlooks research on UFO phenomena because they assume that the likelihood of extraterrestrial travel is low and the likelihood of hoaxes is high. The scientist further said that humans must reconsider how civilization might in the future considering the rapid technological development.
