The known universe is estimated to contain more than one trillion billion stars and 40 billion planets – so it’s a fair bet one of these is home to intelligent lifeforms. But despite the high likelihood of aliens existing somewhere out in space, humanity has been unable to find them…

Source: https://metro.co.uk/2019/06/12/humanity-will-discover-alien-artifacts-built-by-advanced-extraterrestrial-civilisations-9886664/