A NASA telescope may have detected evidence of dark matter, enabling it to be “‘seen” for the first time.
Since dark matter was conceptualized nearly 100 years ago by Swiss astronomer Fritz Zwicky, the invisible substance theorized to hold galaxies together that is supposedly all around us has largely remained a mystery.
Dark matter does not absorb, reflect or emit light, making it hard to observe directly and understand what it truly is. One theory suggests that they are “WIMPS”, “Weakly Interacting Massive Particles”, which are heavier than protons but, as the name implies, interact very little with other forms of matter.
Despite their shy nature, when two WIMPS collide they are predicted to annihilate, releasing other particles—including gamma ray photons—as they do so.
Researchers have long been trying to exploit this to reveal dark matter, looking at regions where dark matter is expected to be concentrated—like the center of the Milky Way—in search of the telltale gamma ray signals.
At last, researchers from the University of Tokyo may have found what they were looking for in the latest data from the Fermi Gamma-ray Space Telescope.
“Numerous studies have previously attempted dark matter searches using Fermi satellite data. The key factors behind the success of this research were the exploration of the halo—a region that had previously received little attention, located away from the galactic center—and the use of the latest data accumulated over 15 years,” study author and astronomer professor Tomonori Totani told Newsweek.
“We detected gamma rays with a photon energy of 20 gigaelectronvolts (or 20 billion electronvolts, an extremely large amount of energy) extending in a halo-like structure toward the center of the Milky Way galaxy. The gamma-ray emission component closely matches the shape expected from the dark matter halo,” said Totani in a statement.
“If this is correct, to the extent of my knowledge, it would mark the first time humanity has ‘seen’ dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics. This signifies a major development in astronomy and physics,” he added.
The energy spectrum or range of gamma-ray emission intensities observed matches the emission predicted by the annihilation of theoretical dark matter particles, with a mass of around 500 times that of a proton, according to the researchers.
The frequency of the WIMPs annihilation estimated from the measured gamma-ray intensity also falls within the range of theoretical predictions.
As the gamma-ray measurements aren’t easily explained by other more common astronomical phenomena or emissions, Totani believes this data is a strong indication of gamma-ray emission from dark matter.
Totani also told that us if the findings are correct, “It would mean we have identified WIMPs as the true nature of dark matter, the greatest mystery in cosmology.
“Furthermore, it would signify the discovery of a new elementary particle not in the Standard Model of particle physics, representing a major advancement in fundamental physics.”
However, the results must be verified through independent analysis by other researchers, while scientists will require further evidence to confirm the findings.
“For everyone to be convinced that this is truly dark matter, the decisive factor will be the detection of gamma rays with the same spectrum from other regions, such as dwarf galaxies,” Totani explained to Newsweek.
“The accumulation of further data from the Fermi satellite and large ground-based gamma-ray telescopes such as CTAO will be crucial.”
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Reference
Totani, T. (2025). 20 GeV halo-like excess of the Galactic diffuse emission and implications for dark matter annihilation. Journal of Cosmology and Astroparticle Physics.