I stumble across this bit of information in the newspaper, in an article about the « expansion » of the universe; the report asserts that as the universe expands, galaxies will be pulled farther and farther away from Earth:
« Light emitted by such galaxies will therefore fight a losing battle to traverse the rapidly widening gulf that separates us. The light will never reach Earth and so the galaxies will slip permanently beyond our capacity to see, regardless of how powerful our telescopes may become. Because of this, when future astronomers look to the sky, they will no longer witness the past. The past will have drifted beyond the cliffs of space. Observations will reveal nothing but an endless stretch of inky black stillness. »
Surprising that the writer says astronomers « will no longer witness the past. »
What is witnessed has never been the past and it never will be; what is witnessed is only the present, endlessly here and now. Whatever changes for astronomers, as for the rest of us, has never been the past; what changes is always the present.