Nicole M. Ford

A radio telescope picks up a signal from the center of the Milky Way. The source MAXI J1744-294 flares in X-rays and radio waves, but where it actually resides is a mystery. It could be near the black hole, or it could just lie along the same line of sight, thousands of light-years away.

A giant cauldron that barely smolders most of the time, but occasionally spits out showers of sparks. That is roughly how the supermassive black hole at the center of our galaxy — Sagittarius A*—behaves. It weighs four million times as much as the Sun and lies 26,000 light-years away.