As such, it’s been a challenge to detect this matter using traditional techniques and telescopes. However, the research team was finally able to locate the missing matter by leveraging the phenomenon of FRBs — brief flashes of energy that come from random directions in the sky and last for milliseconds. Scientists don’t yet know what causes them, and their randomness makes them difficult to detect.
But as Professor Macquart explained, by using these FRBs as “cosmic weigh stations” the team was able to detect the missing matter. “The radiation from fast radio bursts gets spread out by the missing matter in the same way that you see the colours of sunlight being separated in a prism,” he said. “We’ve now been able to measure the distances to enough fast radio bursts to determine the density of the universe.” Amazingly, the team only needed to observe six of these to account for all the missing matter, yielding a measured density close to pre-existing estimates for how much there should be floating around the universe — and giving astrophysicists answers to a frustrating mystery they’ve been pursuing for decades.