There isn't any intelligent life possible on a planet that that far from our sun. It's too cold for life to evolve. So, no 'they' can't look back. This planet is so far away from the sun, the light can beraly reach it. My guess is that our telescopes aren't able to see this planet because it's simply too dark. Other planets, light years away from here, can be seen because of the sun the planet is orbiting. Eveytime the planet would pass the sun in the line of field of a telescope we would see a black dot. For the planet is in the way of the light that's coming from the sun. I hope I answered some question right, it's only from what I know. Which of course could be wrong. I am sorry for my bad english, it's not my native language.