Witnessing cosmic dawn

Credit: Dr Harley Katz, Beecroft Fellow, Department of Physics, University of Oxford. The video shows the formation and evolution of the first stars and galaxies in a virtual universe similar to our own. The simulation begins just before cosmic dawn, when the universe is devoid of starlight, and runs to the epoch 550 million years after the Big Bang. The age of the universe in millions of years is shown in the upper left. The inset focuses on the evolution of a galaxy. Purple regions display the filamentary distribution of gas, composed mostly of hydrogen. White regions represent starlight and the yellow regions depict energetic radiation from the most massive stars.