A groundbreaking study suggests that dark matter, the elusive substance that makes up the majority of the universe’s matter, may have a slight interaction with regular matter, challenging our traditional understanding of this mysterious component of the cosmos.
The Invisible Puzzle
Dark matter is a phenomenon that has puzzled astrophysicists for decades. Due to dark matter being invisible to our telescopes and detectors; regular matter is made of atoms, interacting with light.
We never did call it ‘dark’ because it is some shadowy stuff; it simply doesn’t interact with the electromagnetic force, which includes light. Although ordinary matter absorbs, emits or scatters light, dark matter is invisible because it gleams with an eerie light of one kind that only tells extraordinary tales.
Rather, it is the effect of gravity that dark matter has on galaxies and galaxy clusters in which we infer its presence. By watching how light bends and distorts as it travels through areas rich in dark matter, scientists have managed to chart the way this enigmatic material is spread throughout the cosmos.
A Surprising Interaction
However, a new study published in the Astrophysical Journal Letters argues that dark matter may not be entirely disconnected from normal matter. Other evidence of unknown connections between dark matter and ordinary matter has since been found by researchers, led by Jorge Sánchez Almeida.
The team homed in on ultra-faint dwarf galaxies (UFDs) — minor satellite galaxies of the Milky Way. The main body of these galaxies, where the faint stars reside and are visible, is believed to be dominated by dark matter.
For their simulations, the researchers modeled two scenarios: one in which dark and regular matter are assumed to interact gravitationally only and another in which they have a direct interaction. When dark and regular matter rather only interact through gravity, as the simulations pretended to be true, then the distribution of stars we would expect within them follows a specific pattern: they should have denser centers in which there are more stars per unit volume than at the edges.
But when the team compared these models with observations of the six UFDs they studied, they found that an ‘interacting’ model, in which dark and normal matter interact directly–such as through collisions between dark photons and regular electrons–provided a better match to observed data. This is consistent with an additional interaction mechanism between the baryons and dark matter affecting the distribution of stars in model galaxies.
Conclusion
This surprising discovery runs counter to our standard understanding of dark matter, and how it interacts with normal matter. If validated, it could open a new field of study and possibly provide ways to detect dark matter directly. The still enigmatic nature of the interactions involved, nevertheless this research is a fundamental step in explaining the mystery that dark matter represents and its influence on the Universe.
