From www.youtube.com - December 16, 2011 3:46 PM

This animation compares the X-ray 'heartbeats' of GRS 1915 and IGR J17091, two This animation compares the X-ray 'heartbeats' of GRS 1915 and IGR J17091, two black holes that ingest gas from companion stars. GRS 1915 has nearly five times the mass of IGR J17091, which at three solar masses may be the smallest black hole known. A fly-through relates the heartbeats to hypothesized changes in the black hole's jet and disk.