Stars formed only 250 million years after the Big Bang

Stars in a galaxy 13.28 billion light years away formed only 250 million years after the Big Bang, finds a team of international astronomers led by groups at UCL and Osaka Sangyo University in Japan. The discovery shows that stars in the galaxy - called MACS1149-JD1 - formed at an unexpectedly early stage in the age of the Universe and the new observations break the team's own record for detecting the most distant known source of oxygen. The team confirmed the distance of the galaxy through observations undertaken with the Atacama Large Millimetre/Submillimetre Array (ALMA) and the European Southern Observatory's Very Large Telescope (VLT); the distance corresponds to looking back to a time when the Universe was only 500 million years old, which is 3.5% of its present age. Although the presence of galaxies at this epoch is not necessarily surprising, the detection of oxygen in MACS1149-JD1 indicates a more remarkable conclusion. Oxygen is only created in stars and then released into the gas clouds in galaxies when those stars die. The presence of oxygen in MACS1149-JD1 therefore indicates that a previous generation of stars had already formed and died at an even earlier time. "This is an exciting discovery as this galaxy is seen at a time when the Universe was only 500 million years old and yet it already has a population of mature stars.