“Mirror world may provide clues to dark matter mystery”
The dark matter, which makes up most of the mass of the universe, continues to be a mystery that defies decades of search. Now, a researcher proposes two explanations that break with tradition: a “mirror world” and a quantum mechanism linked to the origins of the cosmos.
Beyond invisible particles
For years, physicists have been tracking possible candidates for dark matter: from the coveted WIMPs to the hypothetical axions. However, experiments continue to return stubborn silence, eroding confidence in the classical model of exotic particles. Faced with this scenario, Stefano Profumo, from the University of California, Santa Cruz, proposes to do away with dark matter and look towards phenomena that may have naturally emerged in the first seconds of the universe.
A dark reflection in the origin of the cosmos
Profumo introduces the idea of a “mirror world” based on quantum chromodynamics, the same theory that holds protons and neutrons together. In this invisible parallel universe would exist dark quarks and gluons, capable of forming heavy particles that, in the extreme conditions of the early cosmos, would have collapsed into tiny objects similar to black holes. Imperceptible to our instruments, they would interact only through gravity and, if abundant, explain the gravitational traces attributed to dark matter.
A quantum residue of the cosmic horizon
Profumo takes an even more abstract direction. Inspired by Hawking radiation, it suggests that the universe’s horizon – its observable limit – could have generated dark matter during a phase of accelerated expansion following the Big Bang. This process would have produced stable particles that do not interact with ordinary matter, except through gravity. Although both ideas are speculative, they are supported by established theories such as quantum physics in curved space-time.
Profumo’s theories, coherent and rigorously formulated, are part of the cosmological tradition of UC Santa Cruz, responsible for key advances in the Lambda-CDM model. However, the enigma persists: we know that gravity in the universe exceeds what galaxies and visible stars explain, but we ignore what substance exerts that force. For now, dark matter remains hidden… perhaps, in a mirror that we have not yet learned to look into.
