This fuzzy mass of glowing green gas is one of the largest – and oldest – objects in the Universe. Called, rather cutely, Lyman-Alpha Blob One this cloud of elemental hydrogen lies at least eleven and a half billion light years back in space-time, in the constellation Aquarius. Astronomers have known about LAB-1since 2000, but no one knew exactly what made it glow. Now the European Southern Observatory’s Very Large Telescope has illuminated the mystery: 15 hours of telescope work saw – for the 1st time – that the 300,000 light-year wide LAB-1 glows, not by its own luminosity, but because several brilliant galaxies deep within the cloud light it from the inside like multiple filaments in a frosted light-bulb. Those galaxies are probably producing young hot blue stars vigorously – just what we might expect back then, in the childhood of the Universe. For SDC I’m DB