A vast bridge of superheated gas, spanning 10 million light years and linking two clusters consisting of thousands of galaxies, has been identified by star-gazing scientists, tangled remnants of the universe's infancy. The discovery was made by the European Space Agency team wielding the Planck space telescope, part of the mission to explore the most ancient light in the cosmos and better understand the origins of the universe and what it contains.
"In the early Universe, filaments of gaseous matter pervaded the cosmos in a giant web, with clusters eventually forming in the densest nodes" the ESA said in a statement about the discovery. "Much of this tenuous, filamentary gas remains undetected, but astronomers expect that it could most likely be found between interacting galaxy clusters, where the filaments are compressed and heated up, making them easier to spot."
Evidence of a hot gas bridge was first identified by XMM-Newton, an X-ray telescope also operated by the ESA. That was confirmed by the Planck data, and crunching information from the two allowed scientists to figure out the temperature of the gases involved.
In fact, the huge strand of inter-cluster gas is believed to be approximately 80 million degrees Celsius, and made up of "the elusive filaments of the cosmic web mixed with gas originating from the clusters." Further analysis of this and other such bridges will be required to confirm that, however.
The identification of the bridge - which spans clusters Abell 399 and Abell 401, each of which is made up of hundreds of individual galaxies - is the first to use the so-called Sunyaev–Zel’dovich (SZ) effect to reach a positive conclusion. That technique takes advantage of the fact that Cosmic Microwave Background light - the ancient light the Planck telescope is designed to track - is modified as it passes through the hot gases in a very particular way.