Artwork based on an optical photograph of the Centaurus A galaxy (NGC 5128). Centaurus A's most distinctive feature is the great lane of dust (here appearing purple) which bisects the galaxy. Astronomers now believe the dust lane is a great disc of dust, yet to be formed into stars, which surrounds the galaxy's core and which we see edge- on. Centaurus A is so called because it is the brightest source of radio emission in the constellation of Centaurus. Located some 16 million light years away, it is the nearest active galaxy to Earth.