Ansky, a once-dormant black hole, is now emitting powerful X-ray bursts, giving scientists a rare chance to study its activity in real time.

Learn why a black hole is becoming active and why experts still can't explain the source of its regular, periodic pattern of X-ray energy flashes.

Although we know that supermassive black holes (millions of times the mass of our sun) lurk at the center of most galaxies, their very nature makes them difficult to spot and study. In contrast to the popular idea of black holes constantly "gobbling up" matter,