Comet C/2011 L4 (Pan-STARRS, right) and the Andromeda galaxy (left), April 2013. Comets are bodies of ice and dust that enter the inner solar system from the outer solar system. As they approach the Sun, the heat boils the ice, producing a coma around the nucleus, along with a tail stretching out behind it. Comet C/2011 L4 was discovered on 6 June 2011 by the Pan-STARRS telescope on Maui, Hawaii. A bright comet, it peaked at magnitude 0 near perihelion in March. It faded slowly and developed a wide tail and anti-tail, one of the longest such seen for over 50 years. Photographed on 3 April 2013, from Kustavi, Finland.