When Galaxies Were Born

More about the book

Approximately 300,000 years after the Big Bang, the universe was composed of hydrogen, helium, and a small amount of lithium. As it expanded and cooled, matter spread out, leading to the ignition of the first stars and the formation of primordial galaxies through gravitational clustering. These early galaxies, emerging within the first few hundred million years, contained stars made solely of hydrogen and helium. They produced vast amounts of ultraviolet radiation, re-ionizing hydrogen in deep space and marking a significant phase transition known as the reionization era. The narrative explores efforts to uncover the oldest, most distant stars and galaxies, enhancing our understanding of the universe's early evolution. Research into this largely uncharted "cosmic dawn" is challenging and involves major observatories like ESO's Very Large Telescope, the Atacama Large Millimetre Array, the twin Keck telescopes, and the Hubble Space Telescope. Future advancements will come from the Extremely Large Telescope, Giant Magellan Telescope, Thirty-Meter Telescope, and NASA's James Webb Space Telescope, set to launch in December 2021. Alongside detailing the field's progress, the author shares personal insights and experiences from observatories worldwide, illuminating the origins of the first stars and galaxies and their role in the universe's cosmic structure.