As a rule of thumb, the more massive a black hole is, the bigger
its surrounding galaxy will be. That's why there's something so
fundamentally wrong about NGC 1277, a tiny galaxy home to
possibly the biggest black hole yet. Galaxy NGC 1277 is only
about a tenth the size of our Milky Way. That isn't ridiculously
tiny for a galaxy — our galactic neighbor the Large Magellanic
Cloud is only a hundredth our size, for instance — but it does
mean that its black hole should be significantly smaller than
Sagittarius-A*, the supermassive black hole at the center of our
galaxy. And that emphatically isn't the case. The black hole at
the center of NGC 1277 is thought to be about 17 billion times
as massive as our Sun, compared to just about 4.3 million solar
masses for Sagittarius-A*. What's more, the NGC 1277 black hole
takes up a volume whose diameter is 4 light-days across, meaning
it spans a distance over 338 times that of the diameter of
Earth's orbit around the Sun. Even Neptune's outermost orbit,
with a diameter o