This image shows one of the largest known single objects in the universe, the Lyman-alpha blob LAB-1. This picture is a composite of two different images taken with the FORS instrument on the Very Large Telescope — a wider image showing the surrounding galaxies and a much deeper observation of the blob itself at the center made to detect its polarization. The intense Lyman-alpha ultraviolet radiation from the blob appears green after it has been stretched by the expansion of the universe during its long journey to Earth. These new observations show for the first time that the light from this object is polarized. This means that the giant "blob" must be powered by galaxies embedded within the cloud.
Image credit: ESO/M. Hayes