Dark matter discovered? What the new WIMP signal means
What's the story
A team of scientists has made a possible breakthrough in the search for dark matter, the mysterious substance that makes up most of the universe's mass. The researchers observed a potential interaction with a particle called weakly interacting massive particle (WIMP) during an experiment at the Sanford Underground Research Facility in South Dakota. However, they have yet to confirm its existence definitively.
Cosmic enigma
What is dark matter?
Dark matter is thought to make up about 85% of all the matter in the universe.
Unlike ordinary matter, which forms stars, planets, and people, dark matter neither emits nor reflects light.
This makes it invisible to both the human eye and telescopes.
However, scientists are confident of its existence due to its gravitational effects on a galactic scale.
Particle candidates
What are WIMPs?
WIMPs are among the candidate in the hunt for dark matter particles.
The LUX-ZEPLIN (LZ) experiment, where this observation was made, is specifically designed to detect such interactions and look for WIMPs.
It employs 10 ton of liquid xenon in a detector device managed by the US Department of Energy's Lawrence Berkeley National Laboratory.
Interaction details
Possible interaction observed
The researchers reported a possible interaction between a xenon atom and another particle that seemed to behave like a WIMP.
They theorized that this could be a WIMP colliding with the nucleus of a xenon atom, transferring some energy and creating a faint flash of UV light detected during the experiment.
The collision also caused what is known as nuclear recoil in the xenon atom's nucleus.
Discovery caution
Not yet a discovery of dark matter
Despite the interaction behaving as expected for a WIMP, the researchers have cautioned that this observation doesn't meet the statistical threshold required to declare a discovery of dark matter.
"Importantly, as it's just a single event, we are not claiming that it is dark matter," said Sam Eriksen from the University of Bristol in England.
The team is now working to rule out other explanations for their finding.
Cosmic glue
Dark matter's role in universe formation
Alvine Kamaha, an astrophysicist at UCLA and co-author of the study, explained dark matter's role in the universe.
"You can think of dark matter as the cosmic glue that helped enable the formation of galaxies like our Milky Way," she said.
Without dark matter, Kamaha added, "the universe would have evolved very differently," potentially altering how structures leading to our solar system formed.