APOD 4.1

Today I am writing about Island Universe NGC 5584. This is a spiral galaxy similar to our own Milky Way, but it has several interesting features. Among these features are a recently exploded Type I Supernova and over 250 Cepheid Variable Stars. Other amazing facts about this galaxy is its size, which is over 50,000 light years, and its distance which is over 72 million light years away. Another interesting fact about this galaxy is that it was used as data for part of a recent study which helped to improve the accuracy of the Hubble constant, which states how fast the Universe is expanding. Even more amazing than this is that this study actually supports the theory of dark matter, which so far is the only theory that explains why the Universe is expanding even faster.