Space began to recover from the Big Bang when the first stars formed, according to a new study by researchers from University College London (UCL) and the University of Cambridge, between 250 and 350 million years later.
The research team studied six of the most distant galaxies, from which light has traveled to Earth for most of their lives. The authors found that it takes 13 billion years to get from these galaxies to the Earth: at the time when light was just beginning its journey towards our planet, the universe was only 550 million years old.
Analyzing images from the Hubble and Spitzer space telescopes, the researchers calculated the ages of these galaxies in the range from 200 to 300 million years: this allows us to estimate the period when their stars first formed.
Lead author, Dr. Nicholas Laporte of the University of Cambridge, noted that the universe was likely dark for the first several hundred million years, before the first stars and galaxies formed.
Our observations indicate that the cosmic dawn occurred 250–350 million years after the beginning of the formation of the Universe.
The authors of the new work note that their knowledge may not yet be complete, so they are awaiting the start of the James Webb telescope mission.