A cosmic aurora between two clusters of galaxies
The cosmic web
In the Universe, matter is distributed as a "cosmic web", consisting of filamentary structures at the intersection of which are formed huge concentrations, called clusters, of thousands of galaxies. Clusters of galaxies can be considered the largest gravitational bound objects in the Universe. The observations made so far with radio telescopes show in the central areas of some clusters a "halo" of radio emission that confirms the existence of a magnetic field, probably amplified by fusion processes and progressive incorporation of smaller structures.