Albert Einstein had described the special theory of relativity in 1905. The result of Einstein's thinking about light, this theory introduced brand-new ideas to science. It opened up an entire ...

In the same way that he had used light’s constant speed to construct the special theory of relativity, Einstein declared this a principle of nature: the equivalence principle. Armed with this ...

Einstein’s motivation to understand the nature of light began when he was just 16 years old. His theory of special relativity ...