"Collision Course: Massive Black Holes and Galaxies on the Move"

Two pairs of gigantic black holes, each in a different dwarf galaxy, are speeding towards each other, and they're set for two separate, never-before-seen collisions. Astronomers used NASA's Chandra X-ray Observatory to spot the four dwarf galaxy black holes racing towards each other, dragging an enormous train of gas and stars in their wake. They are set to collide and merge to form even larger galaxies, and studying them as they approach each other could help astronomers understand how the cosmic monsters lurking across the universe came to grow so large.