The early universe, between 13.5 and 10 billion years ago, was teeming with galaxies: they were much more evolved than predicted by current theoretical models, so much so that they often show an appearance similar to those of today.
This is demonstrated by the results of the Alpine project (the Alma Large Program to Investigate CII at Early Times), the largest study of distant galaxies, published in eight different articles in the journal Astronomy & Astrophysics.
The observations lead to reconsider the current knowledge on the formation and evolution of galaxies.
Among the authors of the studies also the Italian researchers of the National Institute of Astrophysics (INAF) of Bologna, Florence and Padua.
In particular, as part of the Alpine project, the astrophysicists studied 118 very distant galaxies, some never observed before, through the network of Alma radio telescopes (Atacama Large Millimeter / submillimeter Array) in Chile, managed by the Southern European Observatory (Eso) .
Thanks to Alma, they managed to penetrate the thick blanket of gas and dust that surrounds these primitive galaxies, allowing them to reveal some secrets.
Galaxies in the early universe did not have enough time to produce stars in large quantities, which is why astronomers did not expect to find so much dust and metals inside them.
“Instead, we have discovered that the early universe is a true forge of galaxies”, explains Paolo Cassata, researcher of Inaf and of the University of Padua, one of the signatories of the studies.
“Some of these galaxies, the most common, are starting to accumulate dust and metals.
Others instead - he concludes - are already so dusty as to be completely invisible to optical telescopes ”, even to Hubble, used to scrutinizing the deeper universe.
