A new study suggests that a mysterious gamma-ray glow at the center of the Milky Way could be indirect evidence of dark matter, with advanced simulations showing that dark matter collisions could produce the observed asymmetric shape, reviving a long-standing hypothesis.
The gamma-ray excess at the galactic center, first detected by NASA’s Fermi Gamma-ray Space Telescope in 2009, has baffled astronomers for years. This diffuse glow of high-energy radiation could originate from pulsars—rapidly spinning neutron stars—or from the annihilation of dark matter particles. For over a decade, the debate has centered on which explanation better fits the data, with the glow’s bulge-like shape initially favoring pulsars.
Recent research, published in Physical Review Letters on October 16, 2025, challenges this assumption. Using supercomputer simulations that incorporate the Milky Way’s formation history, a team led by Joseph Silk of Johns Hopkins University found that dark matter distributions are not spherical but asymmetric, matching the gamma-ray excess’s shape. This finding elevates the dark matter theory to equal footing with the pulsar hypothesis.
Dark matter, which constitutes about 27% of the universe, remains undetected directly despite its gravitational effects. Scientists have long hunted for Weakly Interacting Massive Particles (WIMPs), a leading candidate, which could annihilate upon collision and emit gamma rays. The new simulations provide a plausible mechanism for how dark matter could cause the observed glow, without requiring a spherical distribution.
The pulsar theory posits that numerous unseen pulsars in the galactic bulge emit the gamma rays. However, astronomers have not observed enough pulsars to account for the excess, leaving room for alternative explanations. The new study does not disprove the pulsar idea but shows that dark matter is equally consistent with the data, as Silk noted a “50% chance” for either theory.
Confirmation may come from future observatories, such as the Cherenkov Telescope Array (CTAO), scheduled to begin operations in 2027. With higher resolution, CTAO could distinguish between point sources like pulsars and diffuse emissions from dark matter, potentially settling the debate. If dark matter is confirmed, it would be a monumental breakthrough in physics.
Experts not involved in the study, like Tracy Slatyer of MIT, caution that while the research strengthens the dark matter case, it does not provide definitive proof. The ambiguity persists, and the scientific community remains divided, emphasizing the need for more data.
The pursuit of dark matter is a fundamental quest in modern science, with implications for understanding the universe’s composition and evolution. This study reinvigorates the search and highlights the importance of computational models in astrophysics.
In conclusion, the mysterious glow continues to captivate scientists, serving as a potential window into dark matter. Whether it stems from pulsars or dark matter, resolving this enigma will advance our knowledge of the cosmos, with upcoming telescopes offering hope for clarity.