I often wondered how big space really is, but after watching the videos in class I am actually a bit overwhelmed. It is crazy to think about the size of the universe or perhaps the universes. How do we actually know what is all looks like as shown in the videos? They proved that it would take millions of lightyears to even experience the sight of some stars and black holes, so how do we know that they are there? In one of the videos where the size of the planets and stars and black holes kept getting bigger with exact measurements, I was wondering how we actually know the sizes and even that they exist if we can never reach them. Quite interesting.