Here is another related one I quite like, from a writer named Harry Mulisch. It is the idea of an "historiscope". Since as we look farther away, we are looking backward in time, the idea is to exploit this to look backward in time right where we are, aka to literally see our own history. All it would require is something shiny and reflective enough at a great enough distance, combined with a powerfully enough telescope to see the reflection.
Imagine a giant mirror 1000 light years away, directly aligned to face us, and a monster telescope array the size of a whole solar system or something similar. Focus the telescope on the mirror. Then the light impacting the telescope this instant, will be photons that left the mirror 1000 years ago. But some of those are photons that left earth 1000 years before *that*, travel to the mirror for a thousand years, hit it and bounced, and have now spent another thousand years on the return journey. So as you looked in the mirror, you would literally see the earth 2000 years ago.
The beautiful thought involved in this is that the past is not gone. Information about it is streaking off into space at the speed of light, and bouncing in ripples off everything it touches, and some of those ripples can come right back here. The past is in principle directly observable. Not just the light years distant, astronomical past, but in principle even local happenings.
Of course the practicalities of actually exploiting this are daunting. Very few photons hit any given object a long way away, most things aren't that shiny and aren't aligned, few of the scattered photons come back to any local detector, etc. But the principle of the thing is still mindblowing, in my humble opinion, and indescribably beautiful.
For what it is worth...
Cheers!