In the ongoing quest to understand dark matter, researchers are now wondering if a strange phenomenon occurring at the heart of the Milky Way galaxy could be from a different form of dark matter.
Dark matter is a mysterious substance that could make up 85 percent of the Universe’s mass, and researchers have been working endlessly to find and understand it. Now, a new study published in Physical Review Letters is looking at a new candidate for dark matter that could be causing unexplained chemical reactions within the Milky Way.
From Neutral to a Positive Charge
For this study, researchers from King’s College London first noticed something strange about the clouds at the center of the Milky Way.
“At the centre of our galaxy sit huge clouds of positively charged hydrogen, a mystery to scientists for decades because normally the gas is neutral. So, what is supplying enough energy to knock the negatively charged electrons out of them?” said Shyam Balaji, postdoctoral research fellow at King’s College London, in a press release.
“The energy signatures radiating from this part of our Galaxy suggest that there is a constant, roiling source of energy doing just that, and our data says it might come from a much lighter form of dark matter than current models consider,” Balaji continued in a press release.
Read More: How Astronomers Define Where a Galaxy Ends and Interstellar Space Begins
Hard-to-Find Particles
According to the study, the main consensus on dark matter is that it consists of a group of particles known as Weakly Interacting Massive Particles (WIMPs). These particles pass through regular matter with barely any interaction, which is why they’re so hard to detect.
However, the research team may have identified a different type of dark matter with a lower mass than WIMPs. According to the researchers, these tinier particles are likely crashing into each other and producing new charged particles through what is known as annihilation. The charged particles could possibly be ionizing the hydrogen clouds.
Slower and Lighter
In past studies, researchers tried to explain the hydrogen ionization through cosmic rays — fast, energetic particles that move through the Universe. However, there were challenges to this explanation. The energy signatures recorded and observed at the Central Molecular Zone (CMZ) — where the ionization was happening — didn’t seem large enough to coincide with cosmic rays. Because of this, the research team believes that the source causing the annihilation weighs less than WIMPs and is slower than cosmic rays.
“The search for dark matter is science’s biggest manhunt, but a lot of experiments are based on Earth. By using gas at the CMZ for a different kind of observation, we can get straight to the source. The data is telling us that dark matter could potentially be a lot lighter than we thought,” Balaji said in a press release.
The research team also believes that these findings could correspond with other galactic mysteries, such as the discovery of the 511-keV emission line — an X-ray observation seen at the center of the Milky Way. The 511-keV emission line could be caused by this new, lower-mass type of dark matter.
Read More: How Vera C. Rubin Revolutionized Dark Matter
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Physical Review Letters. Anomalous Ionization in the Central Molecular Zone by Sub-GeV Dark Matter
A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
