Dark matter, comprising approximately 85% of the matter in the universe, remains one of cosmology's most significant mysteries. Unlike ordinary matter, dark matter does not interact with light, making it invisible to telescopes. Its existence is inferred from its gravitational effects on visible matter, such as the rotation of galaxies and the bending of light ("What is Dark Matter?" - NASA).
In a paper published in May 2025, Stefano Profumo proposed that dark matter originated in a "dark mirror" universe, a parallel realm with its own set of particles and forces ("dark Matter may have Originated in a 'Dark Mirror' Universe" - University of California, Santa Cruz). This dark sector would contain dark versions of protons and neutrons, interacting with each other but largely invisible to our universe.
The concept of a dark mirror universe isn't entirely new, stemming from theories attempting to explain the matter-antimatter asymmetry in our own universe. Profumo's work provides a specific mechanism for how dark matter could have formed within this framework, potentially explaining its abundance and properties.