Laura Baudis, Professor of Particle Physics at the University of Zurich, recently talked about the extremely difficult search for Dark Matter at the TEDxCERN event in Geneva. In the talk, which is available as a video recording, she gives a well understandable insight into one of the hotest topics of current particle physics research.
"We know today that what we see is not the whole picture." With this statement, the particle physicist Laura Baudis opened her presentation at the TEDxCERN event on 5 November. TEDxCERN is a series of lectures by outstanding scientists, which took place this year for the fourth time at the European Particle Physics Laboratory (CERN) in Meyrin, near Geneva.
Fritz Zwicky's finding
Laura Baudis was one of twelve speakers. As she opened her lecture, on the backdrop of the CERN auditorium's stage a disturbingly beautiful picture of our Milky Way was presented. As bright as the stars glitter - the picture does not show "the whole picture," as Baudis noted, because the universe does not consist only of the matter visible to us humans. Modern physics rather assumes that 85% of the matter present in the universe is invisible to the eye.
The Swiss-American physicist Fritz Zwicky, who was the first to identify this invisible form of matter in the 1930s, called it dark matter. Many physicists have been thinking about the nature of dark matter since then. So far without success, as Laura Baudis stated: "Even 80 years after Fritz Zwicky's discovery, we still do not know what dark matter is."
But now there is a hope for new discoveries – due to a great experiment in the Italian Alps, in which Laura Baudis played a major role: the XENON experiment at the Gran Sasso underground laboratory. There, the physicists involved want to track down the particles that make up dark matter. This particles, which are not more than theoretical concepts until now, are called WIMPs (for: weakly interacting massive particles).
Laura Baudis stretched out her hand during her lecture. 10 million WIMPs traverse a hand per second, physicists have calculated. But it is enormously difficult to find even a few of these WIMPs. "With the XENON experiment, we will be able to detect a few of these particles per year, and perhaps even not more than a single one."
Author: Benedikt Vogel