They can look like anything and have many different characteristics. Irregular galaxies have no rotational symmetry.
Many irregular galaxies probably used to be spiral, or elliptical until they had some kind of accident which changed them such as crashing with another galaxy.
Many other irregular galaxies probably were never spiral or elliptical; they simply didn't evolve that way.
Irregular galaxies get their odd shapes in many ways. One way irregular galaxies are formed is when galaxies collide or come close to one another, and their gravitational forces interact. Another source of irregular galaxies may be very young galaxies that have not yet reached a symmetrical state. Also, in some irregular galaxies, like M82, young stars eject energetic bubbles of gas, giving the galaxy a blobby look.
The Large Magellanic Cloud (LMC) is an irregular-shaped galaxy in the Local Group. The irregular shape may be the result of a disturbance, perhaps a collision of two galaxies. The Large Magellanic Cloud (LMC) is near the constellation Dorado, and is 163,000 light-years away.
Large Magellanic Cloud
Large Magellanic Cloud
The Cartwheel Galaxy is an irregular galaxy that has a ring-like structure that is the result of a head-on collision of two galaxies! It started out as a regular spiral galaxy that was hit by a smaller galaxy. The ring-like band of stars formed much like ripples form in water when a rock is tossed into it. The Cartwheel Galaxy is about 500 million light-years from Earth in the constellation Sculptor.
Cartwheel Galaxy
Cartwheel Galaxy
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