More Difficult for Light to Get Through the Cosmic Void with Lower than Expected Number of Galaxies

More Difficult for Light to Get Through the Cosmic Void with Lower than Expected Number of Galaxies

A team of researchers used the world’s largest telescope to look into a 12 billion years old volume of space for galaxies that may provide answers to the lower degree of transparency in the universe at that point in its timeline.

The study was published in The Astrophysical Journal under the title “Evidence for Large-scale Fluctuations in the Metagalactic Ionizing Background near Redshift Six” and was led by Professor George D. Becker of University of California Riverside, with members from UCLA and UCSB.

The study

Scientists took into consideration two opposite models that could shed light on the differences in transparency observed in that cosmic period. One would explain how starlight could not travel very far due to the small number of galaxies in that area. The other – that if it encompassed an unusually large number of galaxies, the region had cooled considerably over the previous several hundred million years.

Even though the expected outcome was the second model, the team found that the region had fewer galaxies and reached the conclusion that the lack of galaxies is a cause for opacity, and not the other way around.

Its significance for our understanding of the Universe

These findings also explain how in regions with more galaxies the ultraviolet light allowed for the gas found in deep space to become transparent earlier than in regions with fewer galaxies, accounting for the variations in transparency.

The team of scientists hopes to find further clues on the illumination of the Universe by the first galaxies. More information on the evolution of the early Universe is expected as well, and with the help of continually developing instruments that enable scientists to look further back in time, we may come closer to comprehending how existence as we know it came to be.


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