To some, it looks like the wheel of a cart. In fact, because of its outward oval appearance, the presence of a central galaxy , and their connection with what looks like the spokes of a wheel, the galaxy on the right is known as the Cartwheel Galaxy . To others, however, it looks like a complicated interaction between galaxies awaiting explanation. Along with the two galaxies on the left, the Cartwheel is part of a group of galaxies about 400 million light years away in the constellation Sculptor . The large galaxy's rim spans over 100,000 light years and is composed of star forming regions filled with extremely bright and massive stars. Pictured , the Cartwheel's ring-like shape is the result of gravitational disruption caused by a smaller galaxy passing through a large one, compressing the interstellar gas and dust and causing a star formation wave to move out like a ripple across the surface of a pond.
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