Comet Enthusiast

A new wide-field image released today by ESO is both a wide-field and long-exposure one, revealing thousands of distant galaxies and more, particularly a large group belonging to the massive galaxy cluster known as Abell 315. As crowded as it may appear, this assembly of galaxies is  the proverbial “tip of the iceberg”, as Abell 315 — like most galaxy clusters — is dominated by dark matter. The huge mass of this cluster deflects light from background galaxies, distorting their observed shapes slightly.