The Planck space telescope operated by the European Space Agency (ESA) this week unveiled a spectacular image of a bridge of hot gases connecting a pair of galaxy clusters across millions of light years of space.
Bridging Cities of Galaxies: Planck has discovered a bridge of hot gas that connects galaxy clusters Abell 399 (lower center) & Abell 401 (top left). The galaxy pair is located about a billion light-years from Earth. The gas bridge extends approximately 10 million light-years between them. The image shows the 2 galaxy clusters as seen at optical wavelengths with ground-based telescopes & through the Sunyaev-Zel'dovich effect (in orange) with the Planck satellite.