There are all kinds of odd things in the sky. Things that defy our naming conventions, and our attempts to understand them. For instance, NGC 4618, the one-armed galaxy.
A spiral galaxy with only one arm may not top the list of cosmic oddities, but it does capture the minds of curious astronomers. The obvious question is: why does it only have one arm? Well, nobody’s absolutely certain yet.
William Herschel discovered NGC 4618 in 1787, about 6 years after his most famous discovery, Uranus. He built powerful telescopes that allowed him to make these discoveries. Herschel made numerous other discoveries as well.
