This spectacular image from the NASA / ESA Hubble Space Telescope shows the trailing arms of NGC 2276, a spiral galaxy 120 million light years away in the constellation of Cepheus. At first glance, the delicate tracery of bright spiral arms and dark dust lanes resembles countless other spiral galaxies. A closer look reveals a strangely one-sided galaxy shaped by gravitational interaction and intense star formation. ESA / Hubble & NASA, P. Sales confirmation: L. Shatz
Most spiral galaxies, like our own Milky Way, tend to be symmetrical. However, sometimes a dramatic event can happen to a galaxy and pull it into an asymmetrical shape, like that with galaxy NGC 2276 in the constellation of Cepheus. This galaxy was recently captured by the Hubble Space Telescope, and although if you look closely it might look like a typical spiral galaxy, if you look closer you can see that it is unusually wobbly in shape.
There are actually two oddities about this particular galaxy caused by two different types of interactions. At the top right of the picture you can see that one of the spiral arms seems to be detaching from the main body of the galaxy. This is due to a nearby companion galaxy, NCG 2300. This companion galaxy has an attraction for NCG 2276 and has thrown it out of shape. In fact, it has twisted the galaxy so much that it faces us on Earth, but in fact the galaxy is obliquely gone.
The other curiosity is on the left side of the picture. You can see that there are a lot more blue areas in this region than in the rest of the galaxy. These blue regions are areas of star formation where new, young stars grow brightly. This star formation is particularly intense in this area due to the interaction of the galaxy with the hot gas that lies between galaxy clusters and is known as the intracluster medium.
Although we usually think of the space between galaxies as empty nothing, gases like hydrogen and helium and even heavier elements like iron can actually be present there. When it approaches a galaxy like NCG 2276, this matter can clump under gravity and provide material for new stars.