What percentage of baryonic (quark-based particle) matter in the universe is Hydrogen?
Hydrogen is the most abundant element in the universe. It accounts for about 75 percent of all baryonic (quark-based particle) matter in the universe, which was created in the Big Bang. The remaining baryonic matter (25 percent) is helium. Experts note that baryonic matter should only include matter composed of baryons. In other words, it should include protons, neutrons and all the objects composed of them (i.e. atomic nuclei), but exclude things such as electrons and neutrinos which are leptons.
The element Hydrogen has only one proton and one electron and is the only element which has no neutrons. Therefore it is considered the simplest element in the universe and properly has a very valid reason for being the most abundant and most common element in the universe.
Because of research by scientists and other experts, we know that hydrogen is an essential element for life. It is present in water and in almost all the molecules of living things. It does not however play a particularly active role with any concerned molecules. Hydrogen is an item that will strictly remain bonded to carbon and oxygen atoms.
According to Oracle Encyclopædia, hydrogen is found in the sun and most stars in the universe. On Earth, hydrogen is found in the greatest quantities as water. It is present as a gas in the atmosphere only in tiny amounts – less than 1 part per million by volume. Any hydrogen that does enter the atmosphere quickly escapes the Earth’s gravity into outer space.