APOD: 9/14/13 - Hubble Spots a Lone Neutron Star

In this old image, which was released back in the late 90's, Hubble spied with its right eye something... well. What is it? As it turns - pictured near the center (where the small arrow points) is a lone neutron star, wandering about the interstellar medium. This is incredible for several reasons, but lets just start with the discovery of the object at all. Neutron stars - the remnants of massive stars that went supernova, without having the appropriate mass to collapse into a singularity - are very small - typically only a few kilometers in diameter. This particular one is believed to be merely 16.8 miles (or about 28 kilometers) across, with its location coming in at an estimated 400 light-years from Earth (it can be found in the constellation of Coronae Australis). Despite being so small and distant, the compact object is still very hot and quite bright; making it stick out like a sore thumb from its immediate surroundings. With that in mind, take a moment to appreciate the fact that Hubble can resolve such an extraordinarily unlikely find. That - paired with the fact that Hubble experienced several major problems during the first ten years of its mission - make a seemingly uninteresting object fascinating.

References, sources, and further reading can be found here: http://www.fromquarkstoquasars.com/apod-91413-hubble-spots-a-lone-neutron-star/