For example if the Betelgeuze system had a planet, with a theoretical large telescope on that planet and looked back at earth. It would see life and civilizations from the 15th century a.d. (~500 light years distance)
For example if the Betelgeuze system had a planet, with a theoretical large telescope on that planet and looked back at earth. It would see life and civilizations from the 15th century a.d. (~500 light years distance)
I think this is plausible. The only problem is finding the inhabited planet to look at. But the telescope itself is kind of already in the heads of people. We would send one or probably several spacecraft into the far reaches of our solar system and use the sun as a massive gravitational lense.
It would just take ages to get a new target into focus.
Alternatively, they could get useful resolution if they had a telescope the size of the solar system, something that’s doable with interferometry.