Theorists had suspected that such enormous black holes existed just a billion years after the big bang, since most if not all of mature large galaxies have the matter-gobbling monsters at their centers.

(Related: "Immaculate Black Holes Found Near Universe's Conception.")

Matter falling in to black holes collides at blinding speeds and bleeds energy, ultimately generating bright x-rays, so scientists turned to the space-based Chandra X-ray Observatory to provide proof for very distant—and therefore very early—black holes.

But at first even a 45-day stare into deep space—the longest and deepest yet in the x-ray spectrum—didn't provide compelling evidence.

Now, by pooling those Chandra images and looking for correlations in the