Black hole boldly goes where no black hole has gone before

Black holes are, by definition, invisible. But the region around them can flare up periodically when the black hole feeds. As gas falls into a black hole, it will heat to high temperatures and radiate brightly, particularly in X-rays. Thanks to ESA’s XMM-Newton data, astronomers found one stellar-mass black hole by chance feeding in a globular star cluster in a galaxy named NGC 4472 (or M49), about fifty million light-years away in the Virgo Cluster. Credits: ESA, NASA and Felix Mirabel