After Albert Einstein published his special theory of relativity in 1905, he spent the next decade trying to come up with a theory of gravity. But for years, he kept running up against a problem. He ...

On November 25, 1915, 35-year old German-born Albert Einstein presented a series of equations to the Prussian Academy of ...

A new solution to Albert Einstein's theory of general relativity suggests hypothetical gravitational stars that look like black holes could be nested within one another. When you purchase through ...