Eclipsing a black hole

A chance eclipse has enabled astronomers for the first time to measure the width of a disk of swirling, hot matter around a supermassive black hole.

BLOCKING BLACKNESS. These X rays come from the supermassive black hole at the core of the spiral galaxy NGC 1365. Last year, a cloud obscured them. CXC, NASA

The black hole lies at the center of the galaxy NGC 1365, some 60 million light-years from Earth.