Newly discovered cosmic megastructure challenges theories of the universe

Artistic impression of what the Big Ring (shown in blue) and Giant Arc (shown in red) would look like in the sky if you could see them. Photograph: Stellarium/University of Central Lancashire/PA

Astronomers have discovered a ring-shaped cosmic megastructure, the proportions of which challenge existing theories of the universe.

The so-called Big Ring has a diameter of about 1.3bn light years, making it among the largest structures ever observed. At more than 9bn light years from Earth, it is too faint to see directly, but its diameter on the night sky would be equivalent to 15 full moons.