... ESA , NASA , NOAO Explanation: While chasing the spectrum of a mysterious arc in a cluster of galaxies within the obscure northerly constellation Lynx , astronomers have stumbled upon the most massive and distant star-forming region ever discovered . ... While the galaxy cluster lies about 5 billion light-years distant, spectroscopic studies show that the arc itself is actually a distorted image of an even more distant but enormous star-forming region. ... A Galactic Star Forming Region in Infrared ...