Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 April 14 RX J185635-375: Candidate Quark Star Picture Credit: M. van Kerkwijk (Institute of Astronomy, Utrecht), S. Kulkarni (Caltech), VLT Kueyen, ESO Explanation: Why is RJX J185635-375 so cool and so dim? Previously, this compact star held claim to being the closest neutron star -- only 150 light-years away. Now new observations and analysis indicate not only a cool temperature for RXJ J185635-375, pictured above, but also...