The existence of dark matter has been discussed for more than a century. In the 1970s, astronomers and cosmologists have then began to build what is today a compelling body of evidence for this elusive component of the universe. The Standard Model of particle physics contains no suitable particle to explain these observations, and thus dark matter arguably represents a glimpse of physics beyond the Standard Model. The nature of dark matter remains today poorly constrained, with proposed candidates spanning 90 orders of magnitude in mass, ranging from ultra-light bosons to massive primordial black holes. Here, we discuss what we have learned about the nature of dark matter from past experiments, and the implications for planned dark matter searches in the next decade.

We argue that diversifying the experimental effort, incorporating astronomical surveys and gravitational wave observations, is our best hope to make progress on the dark matter problem.