This diagram illustrates a possible explanation for a series of intense bursts of energy seen by the NASA Swift satellite's Burst Alert Telescope on March 28, 2011. Subsequent Hubble Space Telescope observations showed that the blasts originated from the center of a dwarf spheroidal galaxy located nearly 4 billion light-years away. The unusual string of powerful outbursts likely arose when a star wandered too close to its galaxy's central black hole, weighing perhaps as much as 1 million times the mass of our Sun. Intense gravitational tidal forces tore the star apart, and the infalling gas continues to stream toward the hole. The black hole formed a jet along its spin axis. Because the jet is pointed toward Earth, astronomers see a powerful blast of X-rays and gamma rays.
