[Hebrews 11:6]

Because there are indeed closer galaxies than 11 mly (e.g., Andromeda at 2.5 mly), I'm confused by APOD's appellation "closest active galaxy." I clicked on the website's "active galaxy" link and received no enlightenment. Active in star formation? Active in evolving? Active in ejecting high-energy particles? Can you clear that up for me, please?

[Conan the Librarian]

I think they ment RADIO-active. It is a high energy radio source. Very noisy.

There is a lot going on in there hidden by that gas cloud.

[SunkenCiv]

Active Galaxies and Quasars
http://imagine.gsfc.nasa.gov/science/objects/active_galaxies1.html

Active galaxies are galaxies which have a small core of emission embedded in an otherwise typical galaxy. This core may be highly variable and very bright compared to the rest of the galaxy... For “normal” galaxies, we can think of the total energy they emit as the sum of the emission from each of the stars found in the galaxy. For the “active” galaxies, this is not true. There is a great deal more emitted energy than there should be... and this excess energy is found in the infrared, radio, UV, and X-ray regions of the electromagnetic spectrum.