NGC 247 - The Needle's Eye

NGC 247 is a much more interesting galaxy than it might first appear to be. Classified as a dwarf spiral galaxy, it is much more spread out than most dwarf galaxies at 93,000 light years in diameter. But even though it rivals larger galaxies in size (e.g., our own galaxy is thought to be around 100,000 light years in diameter), it is not nearly as dense as typical spiral galaxies. In fact, our Milky Way has five times as much free hydrogen in it as does NGC 247.

It also contains a rather mysterious hole in it—a place largely bereft of gas and stars. This gives the galaxy its colloquial name, the Needle’s Eye Galaxy. The prevailing theory is that this hole formed as the result of interaction with a smaller galaxy in the past, but no candidate for such an interaction appears to still be in the vicinity.

NGC 247 is roughly eleven million light years away in the Cetus Constellation and is part of the Sculptor Galaxy Group—the closest galaxy group to our own Local Group (in astronomy, “local” is a relative term).

One oddity regarding NGC 247 is that it contains a superluminous x-ray source, which could be a long-sought-after intermediate-mass black hole. If scientists could ever confirm this, it would be a significant discovery because to date, we can confirm only the existence of stellar-mass black holes, such as Cygnus X-1, and supermassive black holes that reside at the centers of galaxies.

In the lower left of the frame, you can see four tiny galaxies marching in a straight line. This collection of galaxies goes by the name the Burbidge Chain—so named for Geoffery and Margaret Burbidge, who discovered it in 1963. This small collection of galaxies is more than 290 million light years away from us.