University of Geneva researchers have helped find a galaxy emitting a large number of ionizing photons. The discovery marks an important step towards increasing our understanding of how the early Universe was created, they say. After the Big Bang, the Universe expanded and, by cooling down, matter began to take shape progressively. The first stars and galaxies formed several hundred thousand years later. Around one billion years after the Big Bang, the Universe entered what is known as the Epoch of Reionization, in which the Universe was reheated and hydrogen, the most abundant element, was re-ionized. Astronomers have been puzzled over how this important transformation, called cosmic ionization – about which little is known – was possible. The hypothesis was that galaxies were responsible for this phenomenon, said a University of Geneva statement. Stars and star clusters were born of gas, thus forming the first galaxies. UV radiation emitting from these stars ...
