A New Theory of Dark Matter Could Solve Three Cosmic Mysteries

Key Points:

• A new study led by UC Riverside professor Hai-Bo Yu proposes that dense clumps of Self-Interacting Dark Matter (SIDM) can explain three distinct astrophysical phenomena, including gravitational lenses, stellar streams, and satellite galaxies.
• Unlike Cold Dark Matter (CDM), which is collisionless, SIDM particles collide and exchange energy, leading to "gravothermal collapse" and the formation of extremely dense, compact cores within dark matter halos.
• The SIDM model accounts for the ultra-dense object in the gravitational lens system JVAS B1938+666, perturbations in the GD-1 stellar stream, and the unusual properties of the Fornax 6 globular star cluster in the Fornax dwarf galaxy.
• This unified explanation across vastly different cosmic environments challenges the standard CDM model and supports SIDM as a more comprehensive framework for understanding dark matter's role in the universe.
• The research was published in *Physical Review Letters* and funded by the John Templeton Foundation and the U.S. Department of Energy.