In his TED talk, Brian Greene makes a startling point. In addition to the fascinating idea that there may be many more universes than just ours, he notes that at some point in the future, the stars are going to disappear.
They won’t disappear because the stars have been destroyed. They will disappear from view because the universe is expanding, and it’s expanding at a faster and faster rate. Eventually it will be expanding so fast that the light from the stars will never reach astronomer eyes on our planet earth. So when these far-into-the-future astronomers look into space, all they will see is inky blackness and no evidence of stars or other galaxies we can now see. Which means those astronomers won’t have the opportunity to observe, measure, and think about the many phenomena our current astronomers can observe, measure and think about.
This is likely to have a dramatic impact on how those future astronomers understand and appreciate the universe they live in. These future astronomers will simply NOT be able to make the same observations and reach the same conclusions about space and the universe that we can right now.
While we live in a precious time when we can make amazing observations, whose to say we have not also lost the ability to make other observations that earlier astronomers, if they existed, would have been able to make? No way to know.