I, Albert Einstein, was born in Germany in 1879. I have become famous for my theory of relativity, which was published in 1905. My theory of relativity is based on two main principles: the principle of relativity and the principle of the constancy of the speed of light. The principle of relativity states that all physical laws appear the same to any observer, no matter how he moves relative to other observers. This means that the laws of physics do not change if we move or accelerate. The sec...