Scientists May Have Finally Detected A Dark Matter Signal
by Justine Alford
Photo credit: Ecole Polytechnique Fédérale de Lausanne
Could scientists have finally spotted a signal from dark matter—the elusive, theoretical substance that’s thought to make up much of the universe? After laboriously scouring through X-ray data collected from one of the European Space Agency’s telescopes, astronomers spotted a weird spike in emissions that can’t be explained by any known particle or atom, leading the team to believe that it may have come from dark matter. The work will be published next week in Physical Review Letters, but you can read a preprint version here.
Dark matter is a mysterious substance that’s eluded astronomers for decades. It can’t be directly observed because it doesn’t absorb or emit light, hence the name. Scientists have only been able to infer its existence because it seems to exert gravitational effects on normal, visible matter.
When scientists observe the speed at which galaxies are rotating, they are confronted with something strange: They are spinning so fast that they should have been ripped apart long ago because the gravity produced by observable matter is insufficient to glue them together. That’s why scientists think something invisible is giving them that extra gravity they need to remain intact. These observations have led astronomers to estimate that the dark stuff could make up as much as 80% of all matter in the universe.
While scientists have never managed to detect or measure dark matter, newly gathered observations suggest we may finally have some tangible evidence for its existence. The data came from the ESA’s XMM-Newton spacecraft, which was analyzed by an international team of researchers. After scouring through thousands of signals, they spotted a weird spike in X-ray emissions coming from two different spots in the universe: the Andromeda galaxy and the Perseus galaxy cluster. The signal doesn’t correspond to any known particle or atom, and is unlikely to be the result of a measurement or instrument error, which is why, tantalizingly, the team thinks it could have been produced by a dark matter particle.
“The signal’s distribution within the galaxy corresponds exactly to what we were expecting with dark matter, that is, concentrated and intense in the center of objects and weaker and diffuse on the edges,” study author Oleg Ruchayskiy said in a news release.
“With the goal of verifying our findings, we then looked at data from our own galaxy, the Milky Way, and made the same observations,” added co-author Alexey Boyarsky.
The researchers think that the signal could have come from the destruction of a dark matter candidate particle, possibly the hypothetical sterile neutrino. That’s because it is believed the decay of these particles, which are cousins of electron-like particles called neutrinos, could produce X-rays.
If scientists can confirm this discovery, the team believes it could spur a new era in astronomy, and may lead to the development of telescopes specially designed for studying signals coming from dark matter particles.
“We will know where to look in order to trace dark structures in space and will be able to reconstruct how the universe has formed,” added Boyarsky.
Via Ecole Polytechnique Fédérale de Lausanne