Yes, hydrogen is the most abundant gas in the universe. It is found in vast quantities in stars, including our own Sun, where it plays a crucial role in the process of nuclear fusion. In stars, hydrogen nuclei combine under extreme temperatures and pressures to form helium through a series of fusion reactions, releasing a tremendous amount of energy in the process. This fusion process is what powers stars and allows them to emit light and heat. Due to the abundance of hydrogen and its fundamental role in stellar fusion, it is considered the most common element in the universe.