If you want to feel a shiver of cosmic menace, just ponder black
holes. Venture a bit too close to one of these voracious
monsters, and you’ll never get out — although it hardly matters,
since you’ll be torn to shreds and flash-heated to millions of
degrees along the way. Star-size black holes are bad enough, but
the supermassive holes that lurk at the centers of most galaxies
are millions of times more powerful. When they swallow a star or
a giant gas cloud, we call the resulting flare of energy a
quasar, which can be visible halfway across the universe. Now
it’s about to happen — albeit with less spectacular fireworks —
right in our backyard. Back in 2011, astronomers spotted an
interstellar gas cloud plunging more or less toward the Milky
Way’s own supermassive black hole, which is about the mass of 4
million suns. And by the scientists’ calculations, the cloud
will meet its doom this coming September or October. “The impact
will be deeper and more exciting than we thought,” says Stefan
Gillessen of the Ma