Galactic Collision May Contain Clues About Dark Matter
A newly discovered galactic smash-up may give astronomers insight into the behavior of galaxy collisions and the nature of dark matter.
The Musket Ball Cluster, located about 5.23 billion light-years from Earth in the constellation Cancer, is about 8 million light-years across. Scientists have previously seen about half a dozen such collisions, which occur when galaxy clusters — groups of galaxies gravitationally bound together - violently crash together. The textbook case is the Bullet Cluster, where one galaxy cluster is seen shooting through the other.
Many of the most basic questions about dark matter remain unanswered. No one yet knows if dark matter can collide with itself, though current evidence suggests dark matter particles interact little with other dark matter. Knowing the details of galaxy-collision processes may help scientists determine the characteristics of dark matter particles and narrow down the list of possible particles that could be dark matter.