And your beliefs are based on rocks and assumptions.
It's not like there are a few scientist sitting around an office making up stuff. Any assumption is based using precise measurements and other scientific data. I'll give you an example:
It's like one very small part of a piece of paper is covered. You can't say the entire piece of paper is white because you can't see all of it, but you know that most of the paper is white, so you assume. The part that is covered
could be any color, but white is the most likely color it could be.