In a best case scenario it could be around two millennia, the experts from Beijing Normal University estimate, while a pessimistic view is far longer - 400,000 years to be precise.
Stephen Hawking s chilling warning about aliens ignored dailystar.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from dailystar.co.uk Daily Mail and Mail on Sunday newspapers.
Called the Beacon in the Galaxy (BITG) message, it is essentially an updated version of the famous Arecibo message, which was first transmitted from Puerto Rico in 1974 for the same purpose.