In the heart of MCG-6-30-15, a galaxy 130 million light-years away,there is a hole. It's as big around as the orbit of Mars. Into thishole stars and star-stuff are always falling—a lot of stuff, theequivalent of a hundred million suns so far. From this hole nothing
escapes, not even light; it is perfectly black, like the mouth of along tunnel. If you were to get into a spaceship and put it into orbitaround this perfect blackness, you would find, once you got closeenough, and even before you started your final descent into darkness,that you were no longer in control. You would be swept along by anirresistible current, not of swirling gas or stardust but of space-timeitself.
That's because the black hole in MCG-6-30-15 is spinning. And as it spins, it drags space-time around with it.
No spaceship has been there to check it out, of course. And none ofthis is directly visible from Earth. From Earth, MCG-6-30-15 doesn'tlook like much: It's a lenticular galaxy, a lens-shaped blob of starswithout the photogenic spiral arms that typify our Milky Way galaxy."It's very undistinguished," says Cambridge University astronomerAndrew Fabian, who has been studying it for a decade. "If you were touse an optical telescope and just look at images, you wouldn't jump upand down." But if you look at the galaxy with a different kind oftelescope, it comes alive. As gas falls toward the central black hole,before it disappears from the universe forever, it becomes so hot thatit emits X rays, which astronomers can collect and plot on a spectrum.
