Aliens could listen in to Earth with predicted first human contact made by 2029
Aliens could soon be listening in on Earth, with the first human contact set to be made by the end of 2029.
Extra-terrestrials listening in on spacecraft signals will be able to send responses thanks to radio wave transmissions sent to interstellar NASA probes, scientists report.
Aliens might have intercepted radio wave transmission and subsequently made a reply - which is expected to reach Earth before the decade is out according to new research.
Scientists are hopeful waves have been intercepted by lifeforms who have chosen to respond - meaning that humans will have alien contact.
Co-author Dr Howard Isaacson, of California University in Berkeley, who has conduct the research, said: "This is a famous idea from Carl Sagan who used it as a plot theme in the movie Contact.
Green comet last seen by Neanderthals 50,000 years ago to fly past earth tonightThe 1997 film tells the story of a SETI scientist played by Jodie Foster who discovers evidence of extra-terrestrial life on a planet 26 light-years away - and opts to make first contact using radio wave signals.
The team of researchers examined signals sent from Earth to the Voyager 1, Voyager 2, Pioneer 10, Pioneer 11, and New Horizons spacecraft.
They created a map illustrating where the signals may have spread upon being released into the universe.
These spacecraft have been communicating with the Deep Station Network (DSN) radio antennas, downloading scientific and telemetry data.
The DSN is NASA’s international network of massive radio antennas that support interplanetary spacecraft missions as well as a few Earth-orbiting satellites.
The researchers found that transmissions sent to Voyager 2, Pioneer 10, and Pioneer 11 have already come into contact with at least one star.
Since 1972, NASA has used a system of radio antennae called the Deep Space Network (DSN) to track spacecraft and send powerful radio signals towards them, reports New Scientist.
Dr Isaacson and colleagues have worked out which stars these radio signals may have reached and when responses could be received here.
He said: "In the search for extraterrestrial intelligence we're always thinking about the best places to look because we can't look at every single place at once."
They mapped out the paths of five spacecraft – Voyager 1 and Voyager 2, which have left our solar system, and Pioneer 10, Pioneer 11 and New Horizons, which are heading that way – and the radio signals sent to those spacecraft during their travels.
Snow moon visible in UK tonight - best time to look into night skyThey then used the Gaia catalogue of stars to see when those signals would have reached systems in our local neighbourhood.
They found that the DSN signals have already reached four stars. Aliens living near one of them - which lay in the path of Pioneer 10’s received signals - could theoretically have sent a response that would reach Earth by 2029.
Replies from aliens near two more star systems - reached by Voyager 2's signals - could reach us in 2031 and 2033.
Dr Isaacson said: "We know little about whether these stars host planets or could be hospitable for life because they are much fainter than our own sun so any exoplanets would be hard to detect.
"But statistically planets seem relatively common and there should still be many undiscovered ones."
The study is in Publications of the Astronomical Society of the Pacific.