Scientists are trying to measure its temperature of dark matter

A team of researchers at the University of California at Davis is trying to measure the temperature of dark matter, the imperceptible substance that should make up at least a quarter of everything in our universe.

Although we still don’t know what the dark matter is composed of, according to the researchers, it is possible to detect its temperature level. At least it is of this opinion Chris Fassnacht, a physics professor who, together with colleagues, is trying to analyze the distortion that happens when dark matter distorts light coming from distant objects. This is the effect called “gravitational lensing,” an effect that allows us to observe very distant objects in some cases otherwise imperceptible.

According to the standard model, dark matter should be “cold”, in the sense that it should be composed of particles that move relatively slowly, at least with respect to the speed of light. According to Fassnacht, however, this model does not work well on the scale of individual galaxies but only on the cosmic scale. Dark matter could be “hot”: the particles that compose it could be lighter and could move fast.

Analyzing the gravitational lens produced by seven distant quasars, the researchers examined the changes in the dark matter that produced the effect. The results showed a lower limit to the potential mass of a dark matter particle. This limit does not entirely exclude cold dark matter.

“We need to look at about 50 objects to get a good idea of how hot dark matter can be,” says the researcher, convinced that this study may be useful to understand the temperature level of dark matter.