It's a dangerous universe. To the right is a picture of one of the more worrying phenomena. The 3C321 system.
(Parapharased from Yahoo News):
"The telescope images show a massive black hole in the "perp" galaxy (lower left pink blob) shooting a stream of deadly radiation particles into the lower section of the other galaxy (smaller pink blob slightly right and above, still in lower left quadrant). They're about 1.4 billion ly from here, orbiting around each other at a distance of 24,000 ly. The jet gets deflected after passing through, and dissipates (shown in blue on the image).
Any Earthlike planet in the third of the target galaxy that's affected would have the ozone layer removed, and the magnetosphere that protects the surface from charged particle bombardment severely compromised. The result? Sterilisation."
One hopes it's a natural phenomenon. I'm sure it is. Any civilisation that could manipulate supermassive galactic black holes like that no doubt has far more subtle means of dealing with problems. Unless they're trying to make a point. Anyway, it all happened 1.4 billion years ago.