The Universe is very, very big: we are one planet amongst nine in the solar system, revolving around a star.
This star is one of 200 million in a galaxy 100,000 light years across. Our galaxy is one of 100's of millions that exist or did exist in the cosmos. Even if we take a minimal approach, we can still see neighboring galaxies that man can never in all our existence ever visit, possibilities of hyperspatial travel in the far future notwithstanding.
The nearest, Andromeda, is 2 million light years away..
Star size comparison:馃憞