How the Earth moves, and how do we know?
"Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not." -Galileo Galilei All of science is rooted in the idea that natural phenomena can be explained naturally, and that if we want to know how anything in the Universe works, all we need to do is ask the Universe the right questions, and the answers will appear.
Source: scienceblogs.com