We live in a world of physical reality. You can drive at 80 miles per hour (kids, don't try this at home!), and feel the acceleration. Even having never driven that fast, we can imagine what it would be like -- from our experience, which comes from a multitude of places (such as riding roller coasters, etc.). Relativity is a bit different.
We can imagine what will happen if we go at speeds close to the speed light travels, but only in our heads -- we don't know what it will feel like. There are so many changes, from the way we perceive light to how time works, that it is unlike anything in our experience. All of quantum physics is like this; it goes against intuition. We ask you not to worry. Physicists have grappled with this problem for centuries. Some Physicists never develop an intuition for it. If you can, kudos to you! We will try to help you develop that intuition, and tell you what you need to know.
In the following pages you will find information about what the physicists thought in order to come up with the theory of relativity, what mathematic formulas did the use and what other theories and studies they used as a basis for their work. After you finish, you will probably think in a different way about our world. Good luck, and enjoy the ride!