Nasa has its best evidence yet that black holes exist.
Until now they have never been observed because they are thought to suck in everything around them.
But a powerful orbiting telescope has seen X-rays escaping from the edge of one.
Astronomers using the Chandra X-ray Observatory found that suspected black hole systems threw out only 1% as much energy as others.
Scientists think the energy they observed was from the very "rim" of the black hole or event horizon. Their findings have been backed up by the Hubble Space Telescope.
Michael Garcia, of the Harvard-Smithsonian Centre for Astrophysics, in Massachusetts, said: "It's a bit odd to say we've discovered something by seeing almost nothing, but, in essence, this is what we have done ."