What are some of the problems with space travel?

One problem with space travel is that space is huge. How huge? Unimaginably huge. It is Billions of Billions of Billions of miles across. Our Earth is only 9,000 miles across. So, it'll take a long time to go anywhere. Also, if you go near something with gravity, you'll be pulled in.Either a planet, or a star. Anyway, you'll need tons of oxygen to keep you alive for who knows how many years in space. But that is now. Who knows, maybe we'll find something to make us travel anywhere in a blink of an eye?