Free Astronomy Magazine March-April 2018

17 MARCH-APRIL 2018 SPACE CHRONICLES D ata visualization – Hubble Tele- scope image of the night sky where the galaxies were found and two zoomed in panels of the ALMA data. [Hubble (NASA/ESA), ALMA (ESO/NAOJ/NRAO), P. Oesch (Uni- versity of Geneva) and R. Smit (Uni- versity of Cambridge)] ! tail, and we’ve never been able to measure the movement of gas in galaxies so early in the Universe’s history,” said co-author Dr Stefano Carniani, from Cambridge’s Caven- dish Laboratory and Kavli Institute of Cosmology. The researchers found that the gas in these newborn galaxies swirled and rotated in a whirlpool motion, similar to our own galaxy and other, more mature galaxies much later in the Universe’s history. Despite their relatively small size – about five times smaller than the Milky Way – these galaxies were forming stars at a higher rate than other young galaxies, but the researchers were surprised to discover that the galax- ies were not as chaotic as expected. “In the early Universe, gravity caused gas to flow rapidly into the galaxies, stirring them up and form- ing lots of new stars – violent super- nova explosions from these stars also made the gas turbulent,” said Smit, who is a Rubicon Fellow at Cambridge, sponsored by the Netherlands Organization for Scien- tific Research. “We expected that young galaxies would be dynam- ically ‘messy’, due to the havoc caused by exploding young stars, but these mini-galaxies show the ability to retain order and appear well regulated. Despite their small size, they are already rapidly grow- ing to become one of the ‘adult’ galaxies like we live in today.” The data from this project on small galaxies paves the way for larger studies of galaxies during the first billion years of cosmic time.