Scientists solve cosmological puzzle

It is a picture of a dwarf galaxy forming one billion years after the Big Bang. The background image shows the large-scale cosmic context (the panel is approximately 100,000 light years across); the inset shows the central 2,000 light years of the dwarf galaxy where powerful feedback from newly born star clusters drives bulk motions in the gas. Stars are shown in yellow; colours from violet to blue to green to white correspond to gas of increasing density. Credit: S. Mashchenko, J. Wadsley, and H. M. P. Couchman