Dark matter is the mysterious substance that makes up roughly a quarter of the Universe.

Physicists suspect that dark matter is made of unseen particles that neither reflect nor absorb light, but are able to exert gravity.

Experiments around the world are attempting to detect and study such particles. The leading candidates include WIMPs (weakly interacting massive particles) and axions.

“We still don’t know what dark matter is. The primary candidate for a long time was the WIMP, but it looks like that’s almost completely ruled out,” Professor Terning said.

An alternative to the WIMP model of dark matter calls for a form of ‘dark electromagnetism’ including ‘dark photons’ and other particles. Dark photons would have some weak coupling with ‘regular’ photons.

Professor Terning and Dr. Verhaaren add a twist to this idea: a dark magnetic monopole that would interact with the dark photon.

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