On 14 September 2015, a new age of astronomy began. Since then, we have been observing the universe in a completely new way: with gravitational waves. [more]

Albert Einstein's theory of relativity is one of the pillars of modern physics. Inititally developed from thought experiments, it is now supported by a large number of different experiments and observations. It is therefore one of the most stringently tested physical theories. We take a look at the foundations and observed predictions of this theory. [more]