Business Insider A theory called panspermia, which dates back to the 5th century BC, posits that certain life forms can hop between planets, and even star systems, to fertilize them with life. By Jessica Orwig
'This kind of discovery, however, won't come suddenly, according to Linda Billings, the consultant to NASA's Astrobiology and Near Earth Object Programs. "As is the case with most scientific discoveries, the discovery of extraterrestrial life will likely be a prolonged process," Billings told Business Insider. "Claims of evidence of extraterrestrial life will be subjected to peer review, and other scientists will continue to look for further evidence."
'One example of this prolonged process took place in the mid-90's when a team of scientists announced that they found convincing evidence for extraterrestrial life inside of a Martian meteorite — a rock that formed on Mars, were ejected into space after a powerful impact by an asteroid or comet, and eventually landed on Earth. To date, scientists have identified 132 Martian meteorites.
'In 2013, [Steven] Benner said during a talk at the Goldschmidt conference for geochemists that Mars might have been a better place for life to begin than Earth. That's because ancient Martian meteorites contain more boron and molybdenum — important precursors to the formation of RNA — than early Earth.
Moreover, Christopher Adcock and Elizabeth Hausrath, both researchers at the University of Nevada in 2013, discovered that phosphates — another important chemical in the formation of RNA, DNA, and essential proteins — in Martian meteorites are more water-soluble than those on early Earth.'