"Collision Course: Two Pairs of Ringing Black Holes in Violent Encounter"

Astronomers have observed two pairs of colliding black holes in separate dwarf galaxies, providing the first observational evidence of such a cosmic clash. As the black holes head for a collision and merger, the dwarf galaxies they sit in will also merge and form a larger galaxy, shedding light on how these cosmic titans and the galaxies they inhabit grew in the early universe. The scientists used NASA's Chandra X-ray Observatory to examine the colliding black hole pairings and found that the dwarf galaxies are pulling in gas that is "feeding" their inhabitant black holes, causing them to grow even before the merger.