Hydrogen, constituting a significant portion of the universe's matter, was prevalent on early Earth due to geological activities. Similar to stars, early life forms utilized hydrogen for energy through chemical reactions. Archaea, discovered in the 1970s, represent a unique form of life thriving in diverse environments by harnessing energy from hydrogen gas using hydrogenases. These microorganisms survive in hostile conditions like acidic hot springs and deep underground by converting hydrogen. Methanogenic archaea play a role in methane production by consuming hydrogen in animal intestines, affecting greenhouse gas levels. Archaeal hydrogenases, efficient biological catalysts, drive research in eco-friendly hydrogen production, potentially replacing expensive metal catalysts. The "hydrogen hypothesis" suggests that early eukaryotic evolution was influenced by a symbiotic relationship between archaeal and bacterial cells, highlighting the pivotal role of hydrogen in evolutionary history.