I saw a passage in my son's homework book, constructing a scenario in which a person standing on a planet 65 million light years away from Earth, with an extremely powerful telescope pointed at Earth, would be able to see the dinosaurs.
I understand the time reference, since the dinosaurs purportedly lived on the earth 65 million years ago. Does this really happen though? Does looking at faraway objects show past versions of that object?
Best Answer
Yes, that's true, though whether you could actually see dinosaurs is debatable because from 65 million light years away they'd be pretty small :-)
The reason is very simple. When you look at a dinosaur you're seeing the light reflected from the dinosaur's skin. That light travels at a finite speed, so it takes a finite time to get from the dinosaur's skin to you. If you're a light year away from the dinosaur what you're seeing is the light reflected off the dinosaur's skin a year ago.