“For me, the study of these laws is inseparable from a love of Nature in all its manifestations.” – Murray Gell-Mann
When you take a glimpse into the deep Universe, beyond the gas, dust, stars and planets of our own galaxy, you enter the realm of the galaxies. In general, they come in two types: the spirals, with neat, orderly arms, and the ellipticals, with a symmetric, bulging shape. But for everything that exists in the Universe a particular way in general, there are exceptions.
In the 1960s, astronomer Halton Arp became fascinated with these exceptions, creating a catalog of 338 examples: the Atlas of Peculiar Galaxies. We now know that most of these are galaxy pairs or triplets in the process of major mergers, displaying features such as tidal disruption, stellar bridges, starbursts and occasionally a rare, ring shape.