Lurking deep in the heart of our Milky Way galaxy, in the direction of Sagittarius A, is a super-massive black hole, the ‘Eater of All Things’. Out here in the galactic ‘burbs, we’re relatively safe… for now. But when our lovely neighbour galaxy Andromeda comes a-callin’ in a few billion years, all bets are OFF!
The more we look, the more we see these gravitational gargantuans in the centers of galaxies. My guess is we’ll find that these beasts are absolutely intrinsic to galaxy formation. No giant Black Holes – No big galaxies. Just an informed guess.
Here’s a very good PBS/NOVɅ programme on the topic: