Very interesting study by NASA. Could this be yet another passive way of preparing us for an official announcement sometime in the future which confirms the existence of extraterrestrial life? aia Sputniknews: Most scientists currently prefer to focus on exploring distant star systems, not Earth, in their search for intelligent extraterrestrial organisms. The latest NASA study seems to prove research on Earth could prove more useful than previously thought. Our planet is a place which may hide an array of alien "artefacts", with some of them possibly created by extinct civilisations which existed on Mars, Venus or even Earth itself, according to the latest NASA study. "Because the geological, paleontological, and archaeological records on Earth are so incomplete, it is even possible that the Earth itself hosts such artefacts, although, again, this idea is often conflated with unscientific popular imaginings and science fiction stories about alien visitation, and so must be approached