D_O_IC_R_E_D#Dark Matter
Imagine that dark matter, that invisible substance that makes up most of the mass of the Universe, is not made of a single type of particle, as many scientists thought
A bold new hypothesis suggests that it may exist in two distinct forms.
This would help solve a cosmic enigma that has intrigued astronomers for years.
The problem is this: telescopes like Fermi have detected an excess of gamma rays (a type of radiation) coming from the center of the Milky Way.
This signal could be produced when dark matter particles meet and annihilate each other, releasing energy.
However, in dwarf galaxies-which are rich in dark matter and have little “noise” from other sources-this same excess of gamma rays simply does not appear.
If dark matter were the same everywhere, the signal should be seen everywhere.
But it isn’t.
According to researchers, including Gordan Krnjaic from Fermilab, the explanation may lie in the very nature of dark matter.
Instead of a single particle, it could be formed by two different particles.
These two can only annihilate each other when they are present in balanced quantities and manage to “meet.”
In the Milky Way, especially in the galactic center, the proportions of the two forms would be more balanced.
Therefore, annihilations occur more frequently and produce the observed excess of gamma rays.
In dwarf galaxies, one form may dominate almost completely, leaving the other in smaller quantities.
Without the encounter between the two, annihilations become very rare and the signal disappears.
Interestingly, this idea does not require changing the basic laws of physics.
The probability of annihilation between the particles remains the same when they meet.
What changes is the environment: it depends on the local “mixture” of the two components.
This creates different predictions for each type of galaxy, explaining why we see the signal in one place and not in another.
This hypothesis, recently published in the Journal of Cosmology and Astroparticle Physics, opens a new way of looking at dark matter.
It doesn’t invalidate previous observations, but offers an elegant explanation for a contradiction that seemed complicated.
Future observations with the Fermi telescope and other instruments may test this idea: if the signal remains absent in dwarf galaxies or appears in new locations, scientists will have more clues to confirm or adjust the model.
Meanwhile, the mystery of dark matter becomes even more fascinating-and perhaps a little closer to being solved.
Published in 04/16/2026 13h22
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
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