To revist this article, visit My Profile, then View saved stories. It's fun to think about how we know stuff. For instance, the sun has a mass of about 2 x 10 30 kilograms. That is such an enormous mass that it's difficult to comprehend. And if it's so difficult for us to even imagine numbers that large, how would we go about finding those values? Well, the original method was to use some small masses, a stick, and a string. Yes, this is one of the important steps in determining masses of both the sun and all the planets in our solar system. It's called the Cavendish experimentâfirst performed by Henry Cavendish in 1798. It's really cool, so I'm going to explain how it works.