Astronomers Weighed a Sleeping Black Hole 6 Billion Suns Heavy

The black hole gives off almost no light, yet astronomers measured its mass at about 6 billion Suns.

It sits over 10 billion light-years away, seen as it was when the universe was a quarter of its age.

JWST clocked the mass by watching how fast stars race around the galaxy's dark core.

It is the most distant 'sleeping' black hole ever weighed this way — about 15 times farther than the old record.

The black hole looks oddly heavy for its galaxy, hinting it grew fast and early as a quasar.