Astronomers have discovered a distant quasar illuminating a vast nebula of diffuse gas, revealing for the first time part of the network of filaments thought to connect galaxies in a cosmic web. Cosmologists generally believe that matter in intergalactic space is distributed in a vast network of interconnected filamentary structures of gas known as the cosmic web. The vast majority of atoms in the Universe reside in this web as primordial hydrogen — vestigial matter left over from the Big Bang. Researchers from the University of California at Santa Cruz and the Max Planck Institute for Astronomy have now captured an image of these filamentary structures for the first time. To achieve this, they exploited the intense radiation generated by a supermassive black hole in a quasar.