From a telescope on the southern tip of Africa, astronomers have learned to listen to the oldest whisper in the cosmos — the radio hum of hydrogen, stretched thin across billions of light-years of expanding space. A team led by the Universities of Manchester and the Western Cape has demonstrated that this signal, long theorized but maddeningly elusive, can now be captured not galaxy by galaxy, but as a vast collective glow that maps the architecture of the Universe itself. The technique, called hydrogen intensity mapping, transforms ancient light into a three-dimensional portrait of how matter