Mirabilis, one of the pairs of dwarf galaxies detected. (NASA/CXC/University of Alabama/M. Micic et al./International Gemini Observatory/NOIRLab/NSF/AURA) For the first time, astronomers have spotted evidence of a pair of dwarf galaxies featuring giant black holes on a collision course with each other. In fact, they haven't just found just one pair – they've found two. The first pair of merging dwarf galaxies is in the cluster Abell 133, about 760 million light-years away from Earth, and the other is in the Abell 1758S galaxy cluster, which is about 3.2 billion light-years away. It's hoped that these sightings and further investigations...