What is the universe made of? Is most of the visible matter just atoms, or is there something like dark matter? Do we know all the particles that are out there? Why do galaxies rotate at their observed speed? These and other questions are part of what we think about every day.

Did you know that the answer to these questions can be studied with detectors not in space, but on Earth? In our lab we have built Xenoscope, a prototype for a future detector with 50 tons of liquid xenon. It will be installed deep inside a mountain. The prototype is 2.6 m long and contains almost half a ton of xenon. It will allow us to study the purification of xenon to have a clean target material and how to detect the light and electrons produced in xenon detectors.