Looking back in time from another galaxy towards earth?

Question

What if an advanced civilization from another galaxy had the technology of high resolution telescopes beyond the realm of anything we currently have, and they could see detail on a planets surface, would they be able to see let's say the dinosaurs or our early ancestors walking about? In theory this would seem possible

Answer 1

It would be wonderful. But to see how later on the earth developes more and moer into the garbage bin (as it is today) of the universe would not be that nice.

Answer 2

Theoretically, yes. If the observer is say 100 million light years away from the earth the light of our planet reaching him at any time would have left the earth 100 million years ago and would show the events during that time. In the same manner if he would be listening/looking for radio signals he wouldn't be able to receive any artificial radio waves since radio, and later televisions, was only invented 80 years ago.

Answer 3

In theory that is true. But that would mean the aliens must be millions of light years away to see millions of years in our past, which means the magnification required would be incredible. A super-huge telescope, millions of times bigger than a solar system, would be needed to see dinosaurs. They couldn't use a small telescope because of diffraction (see link, scroll down to diffraction limit of telescopes).

Answer 4

If they were at least 250 million light years away they could watch the dinosaurs going about their daily routine.

Answer 5

They could gather light that was that old,
but at the resolutions you're talking about,
you come up against some hard physical
limits so ...no, you wouldn't see the dinos.

Answer 6

Viewing Earth from another galaxy would be impossible.