When you look at the stars, the light that you see is probably hundreds of years old. Which means that you don't know if they still exist.
Does all this mean, that if you fly in a speed faster than the light, more far and far away from something, you can see how it looked back in time?
This is a reasonable enough question. Imagine that you are looking at the object and behind you, you have a very large mass of clear, but very high index of refraction material (with index of refraction $n$). Then you could easily say "I wonder how this looked 100 years ago", and then very quickly run behind your large block of material at some speed $c/n < v < c$, and look through the material at the object you are viewing. You would see it at a time prior to what you originally saw it at, and this doesn't violate special relativity or anything. You should make sure not to stand directly behind where you were, because then you would be blocking your own view.
But the theory of relativity tells us that you need a lot of energy to reach the speed of light and when you won't be able to travel at the speed of light no question arises of looking back in time
