Astronomy Picture of the Day

Explanation: A bird? A plane? No, but pictured here is something physically much larger, flying much higher, and moving much faster than either of these. It is, in fact, a Seyfert type 2 spiral galaxy. The "S" is actually a lane of stars, gas and dust circling the core. Designated NGC 3393, the bright core makes this galaxy a Seyfert and the infrared glow of central dust help distinguish it as "type 2." Seyfert galaxies have extremely energetic nuclei similar to more powerful quasars. Seyferts are thought to have black holes in their centres. Most of the lines and small spots in this image are due to cosmic rays striking the imager and are unrelated to structure in the galaxy.