Dim light emanating from the purgatory between galaxies could illuminate the most shadowy constituents of the cosmos.

Dark matter, an unidentified type of particle that interacts gravitationally but otherwise shuns normal matter, lurks throughout clusters of galaxies. Because the elusive substance emits no light, it’s difficult to pin down how it is distributed, even though it makes up the majority of a cluster’s mass. But a feeble glow known as intracluster light could reveal dark matter’s whereabouts, researchers suggest July 30 at arXiv.org. The intermediary could eventually help scientists get a better handle on what dark matter is and how it behaves.  Stacy Kim, graduate research associate, astronomy, joins the conversation.

Image Credit: J. LOTZ/STSCL, ESA, NASA