Shedding Light on the Dark Matter Universe
The existence of dark matter is one of the Universe’s great mysteries. All stars, planets and interstellar gases are made from atoms—yet atomic matter represents only 15 percent of the total matter in the Universe. The remaining 85 percent is dark matter.
Dark matter provides the cosmic foundation for galaxies to form, but its microphysical properties remain unknown. Dr. Sean Tulin, Canada Research Chair in Particle Physics and Cosmology, is investigating the unknown particle physics of dark matter.
The total mass of galaxies and galaxy clusters is mostly composed of dark matter. Its gravity causes light rays to bend and influences the motion of stars. We can observe dark matter’s presence through its gravity even though we cannot see it directly.
Although it may not be possible to create a dark matter particle collider in the laboratory—as we have done for other types of particles to learn more about their properties—galaxies and clusters of galaxies have vast reservoirs of energetic dark matter particles that can act as “natural” particle colliders. Whether or not dark matter particles collide leaves an imprint on the shape of a galaxy or cluster, which in turn can be measured by its gravity through astrophysical observations.
Such observations by Tulin and his research team will make it possible to combine theoretical ideas of the microphysics of dark matter particles with astrophysical measurements spanning systems up to 100 times bigger than our galaxy. Ultimately, Tulin’s work will reveal more about this mysterious form of matter that dominates our Universe.