Gamma-Ray Bursts Found a Cosmic Wall
The night sky looks as smooth as the surface of a calm lake. But if you look at gamma-ray bursts (brief, blinding explosions visible across the entire universe) you'll find ripples in that smoothness.
Scientists took a catalog of such bursts and divided the sky into two hemispheres. In the southern one, they found a tiny group: 4–5 bursts huddled together.