In the mid-1830s in colonial South Africa, visiting British astronomer John Herschel spotted an object that perhaps no one had ever seen before: A round, fuzzy little nebula, curious in that it seemed to have a broad dark band across its middle but otherwise unremarkable.

Herschel, who was in South Africa to catalog fuzzy objects like this, logged it in his books and later listed it in his catalog of celestial objects. This particular object didnt seem special in any way and didnt even merit a name, but only a numerical catalog designation. It eventually becomes known by its updated catalog number, NGC 5128.

A few years later, spaceborne X-ray detectors provide our first view of the X-ray sky and they discover that Centaurus A is also a prominent source of powerful X-rays. When gamma-ray detectors are lofted into space, Centaurus A is again found to be a strong source of this ultra-powerful type of radiation. It seems there is something very strange and mysterious going on in Lord Herschels fuzzy little object.

In the past 50 years, conventional telescopes also have examined Centaurus A, and theyve found it to have a very strange appearance. It appears to be a large elliptical galaxy encircled by a thick dark band of material. The odd thing about that is that large elliptical galaxies typically do not have such dark bands of dust and debris (known as "dust lanes"). Spiral galaxies typically do have such dust lanes, but Centaurus A is obviously not a spiral galaxy. It is this strange juxtaposition of characteristics that led to a theory that explains the odd characteristics of Centaurus A: Its the scene of an accident.

A giant cosmic collision is certainly a dramatic event, but it turns out there is another fascinating aspect of Centaurus A: Recent radio and X-ray studies of Centaurus A reveal enormously powerful jets of superheated material being shot out of the galaxy in opposite directions at near light speed (see photos).

These spinning jets of material are thousands of light years in length, and it is the tremendous blast of energy from these jets that is generating much of the radio and X-ray radiation that makes Centaurus A such a strong source of radio noise and X-rays.

Such powerful jets have been spotted in some other galaxies as well, and their source is now well known: Such jets are the signature of a super-massive black hole in the center of the galaxy, a black hole with a mass millions of times greater than our sun. The gravitational pull of such a black hole is so powerful that material is sucked into it and around it at tremendous speeds. As the material is spinning around the black hole it can be entwined into twisting jets shooting away from the poles of the black hole, much like a cotton-candy machine can spin long twisted tendrils as the cotton ball is pulled away.

Crashing galaxies, a giant spinning black hole, powerful glowing jets flying out of the galactic core all of these add up to what astronomers call an "active galaxy." These are galaxies that have undergone some sort of catastrophic disturbance and are now producing powerful outbursts of energy and star formation.

Most such galaxies are very distant, but Centaurus A is unique in that it is a relatively close (about 10 million light years, which is "just down the street" as galaxies go). That makes it a unique "cosmic laboratory" for studying the strange effects and high-energy physics that accompany such powerful outbursts and collisions.

All its blast and thunder aside, Centaurus A is rewarding another way: Its an easy object for anyone to see, needing only a pair of binoculars or small telescope, visible low on the southern horizon in springtime (for observers in the northern hemisphere). Amateur astronomers often dub Centaurus A "the hamburger galaxy" for its curious appearance in the eyepiece. (Squint your eyes and look at the photo to understand why.)

The peaceful appearance of Centaurus A in a small telescope is a reminder of two complementary truths: That behind much of the beauty of the sky lies incomprehensible power and fury, and that maelstrom and destruction can produce a very tranquil beauty. Its our great luxury to be snug and safe a great distance from Centaurus A, enjoying its beauty and learning its mysteries without having to fear its power.