Scientists have made a groundbreaking discovery by studying archaea, ancient microorganisms that date back two billion years and are considered microbial ancestors to humans. The focus of the research was on how these archaea utilize hydrogen gas for energy production, surviving in extreme environments on Earth by consuming and generating hydrogen via specific enzymes called hydrogenases. The study revealed that some archaea possess unique hydrogen-using enzymes, [FeFe]-hydrogenases, previously thought to be limited to eukaryotes and bacteria. These findings offer insights into the evolution of eukaryotes, suggesting that humans may have evolved from a fusion of archaeal and bacterial cells facilitated by hydrogen exchange. Furthermore, the study indicates the potential for industrial hydrogen production inspired by archaea, as they have been utilizing hydrogen for energy for billions of years, presenting a greener pathway for various industries. Researchers believe that by understanding how archaea employ hydrogen, there is an opportunity to develop more efficient methods for biological hydrogen production, contributing to the transition towards a sustainable green economy. This study challenges previous beliefs about the distribution of hydrogenases in different life domains, showcasing the remarkable diversity and complexity of these enzymes in archaea.