When Black Holes Collide

What happens when two black holes collide? This extreme scenario occurs in the centers of many merging galaxies and multiple star systems. The featured video shows a computer animation of the final stages of such a merger, while highlighting the gravitational lensing effects that would appear on a background starfield . The black regions indicate the event horizons of the dynamic duo , while a surrounding ring of shifting background stars indicates the position of their combined Einstein ring . All background stars not only have images visible outside of this Einstein ring , but also have one or more companion images visible on the inside. Eventually the two black hole s coalesce . The end stages of such a merger is now known to produce a strong blast of gravitational radiation , providing a new way to see our universe. This Week is: Black Hole Week at NASA