The new analysis of the data obtained using the James Webb Space Telescope (JWST) has provided a unique opportunity to investigate the end of the dark ages in space, approximately 550 million years after the Big Bang. This era marks the transition of the universe from a state where neutral atoms blocked starlight to a period where starlight could be observed.
In the early stages, even though the first stars and galaxies were forming, their light remained invisible due to the absorption by neutral atoms. The situation changed when the ionization of these atoms began as a result of ultraviolet radiation emitted by massive and hot stars. These stars, which were tens, hundreds, and sometimes thousands of times more massive than our Sun, played a significant role in ionizing hydrogen, which in turn made the universe transparent to starlight.
This ionization process was not uniform and depended on the density of matter distribution throughout the universe, spanning hundreds of millions of years. Some regions of the universe became transparent to visible light earlier, while others retained neutral gas for billions of years.
The JWST, operating in the infrared range, has allowed astronomers to observe the earliest galaxies and star systems that were previously not observable in visible light. So far, the JWST has made groundbreaking discoveries, including the identification of a record number of distant galaxies, black holes, protoclusters of galaxies, and quasars, which have opened up new understandings of the universe’s evolution.
These findings not only confirm the uneven formation of structures in the early universe but also raise hopes for the detection of even earlier objects. The significance of these observations lies in uncovering the role of the first stars and galaxies in the ionization of matter, which made the universe transparent to starlight of all wavelengths.
Thanks to advanced technologies and the observations made possible by the JWST, scientists now have a unique opportunity to explore the distant past, unravel the mysteries of the early universe, and gain a better understanding of its evolution.