The mini-halos of dark matter scattered throughout the Cosmos could function as highly sensitive probes of primordial magnetic fields. This is what emerges from a theoretical study conducted by SISSA and published in Physical Review Letters. Present on immense scales, magnetic fields are found everywhere in the Universe. However, their origin are still subjects of debate among scholars. An intriguing possibility is that magnetic fields originated near the birth of the universe itself, that is they are primordial magnetic fields. In the study, researchers showed that if magnetic fields are indeed primordial then it could cause an increase in dark matter density perturbations on small scales. The ultimate effect of this process is the formation of mini-halos of dark matter, which, if detected would hint towards a primordial nature of magnetic fields. Thus, in an apparent paradox, the invisible part of our Universe could be useful in resolving the nature of a component of the visible one.
Image by Lucie Chrastecka