This week, NASA astronomers announced they’d discovered seven Earth-like planets around a star labelled Trappist-1, which is 40 light years away. That means that the view we have of that solar system is how it looked 40 years ago.
Conversely, if they could get a good look at Earth, the scientists on those planets would see us as we were in 1977 — wearing leisure suits and disco duds — and probably determine there’s no intelligent life here.