Measuring a black hole's spin rate

Supermassive black holes -- incredibly dense objects thought to be at the center of spiral galaxies, such as this one depicted in an artist's illustration -- have a mass millions to billions times the mass of our sun.

At the center is an accretion disk, created by matter being pulled toward the center of the galaxy, attracted by gravity. At the core is a region of compact, high energy X-ray radiation thought to originate from the base of jets of the outflowing energetic particles, depicted in blue.

This high energy X-radiation produced by iron atoms lights up the disk, and now data observed from spiral galaxy NGC 1365 in July 2012 by the European Space Agency’s XMM-Newton and NASA's NuSTAR space telescopes has enabled astronomers to see just how speedily matter is swirling in the inner region of the disk, thus accurately confirming the rate of spin for black holes for the first time.