When the universe was created, there were no stars to illuminate it. It took millions of years before conditions allowed the first suns to form. When the total blackness of the cosmos ceased to be so due to the gradual appearance of those bright dots that were the first stars, what is usually described somewhat poetically as the “cosmic dawn” took place. Recent research has made it possible to find out, with more precision and security than in previous studies, the time when the cosmic dawn occurred.
The international team of Nicolas Laporte, from the University College London, and now at the University of Cambridge, both institutions in the United Kingdom, examined six of the most distant galaxies currently known, whose light has taken most of the time of the existence of the universe to reach us.
Laporte and his colleagues found that the distance of these galaxies from Earth means that we now see them as they were more than 13 billion years ago, specifically when the universe was only 550 million years old.
Analyzing images from the Hubble and Spitzer space telescopes, the researchers calculated that the age of these galaxies at that distant time ranged from 200 to 300 million years, which has made it possible to deduce when their first stars formed.
According to the results of these analyzes, the cosmic dawn occurred between 250 million years and 350 million years after the creation of the universe.
Simulation of the formation of some of the first stars in the fledgling galaxies, a few hundred million years after the Big Bang, the “explosion” with which the universe was born. (Image: Harley Katz, Beecroft Fellow, Department of Physics, University of Oxford)
It is very likely that this cosmic sunrise can be observed directly with the James Webb space telescope, capable of seeing further and therefore of going further back in time. The launch of this telescope into space is scheduled for the end of the year. The study authors estimate that at the time when the galaxies they investigated formed, they and others like them must have been bright enough so that the light they emitted can be seen in our time with the James Webb Space Telescope. (Source: NCYT from Amazings)