Call it a cosmic growth spurt. A young galaxy is making stars over 100 times as vigorously as the Milky Way.

SMM J21350-0102 is shrouded in dust, which hides it from most telescopes. But the Atacama Pathfinder Experiment (APEX) in Chile, spotted the galaxy via sub-millimetre radio waves emitted by the dust. Light from the galaxy is absorbed by the dust, emitted as infrared and stretched to radio waves as the universe expands.

Its brightness and size is boosted by the magnification of a galaxy cluster that lies in front. This allowed a team led by Mark Swinbank of the University of Durham, UK, to resolve individual clouds of star formation. They calculated that the galaxy was churning out 250 suns a year.

The team thinks a merger of galaxies is driving star formation, “but we do not yet understand the physics”, says Swinbank.

Journal Reference: Nature, DOI:10.1038/nature08880