Modern particle physics relies on the Standard Model, an extremely successful theory that describes the basic building blocks of visible matter and the forces that act between them. However, despite this success, strong evidence points to a Universe in which most matter is not made of the particles already known.

In fact, about 25% of the Universe appears to be made of dark matter: an invisible form of matter that has not been detected directly so far. Its presence is revealed through gravity: from the way galaxies rotate to the way large cosmic structures form and evolve, dark matter plays a huge part in shaping the Universe as we observe it today.

The lack of direct detection makes the study of dark matter difficult and raises a fundamental question: what does it mean to study something that cannot be observed directly? Part of the answer lies in how theorists turn ideas into predictions that can be tested, connecting observations of the Universe with experiments in the lab. But the scientific process does not always go from theory to experiment: sometimes an unexpected observation, or a new measurement comes first and leads to the need for a new theoretical framework.