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The Large Magellanic Cloud, an irregular galaxy.
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© Loke Kun Tan (StarryScapes)

Irregular Galaxies

Irregular galaxies are appropriately named. This class includes any galaxy which cannot be classified as either spiral or elliptical. Thus in some sense every irregular galaxy is unique in it's appearance. There are, however, two general types of irregulars. Irr I galaxies are similar to spirals because they have lots of gas and young stars. But they lack well-defined spiral structure. Irr II galaxies look as if they have collided with another galaxy or experienced some other violent event which may have led to their distorted, asymmetrical shape.

If you live south of the Equator, you may be able to see two irregular type galaxies in your night sky. The Large and Small Magellanic Clouds are two very nearby irregular galaxies which are orbitting the Milky Way. Because they are nearby and fairly bright, they can be seen with the unaided eye.

A Matter of Scale - interactive showing the sizes of things, from very tiny to huge - from NSF

Last modified December 21, 2005 by Travis Metcalfe.

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