Hydrogen is the most abundant element in the universe. Roughly 75 percent of the entire universe is composed of hydrogen. On Earth, hydrogen is the third most abundant element, found in water and organic matter.

Hydrogen is a gardener’s best friend. Hydrogen is one of the two chief elements involved in the chemical and physical reactions constantly taking place in the sun – reactions which generate heat and light that can make begonias and hydrangeas grow, even if they’re 93 million miles away.

Hydrogen is the simplest element on the periodic table. Whether it’s solid hydrogen, liquid hydrogen or hydrogen gas, the atoms are all the same: One proton and one electron.

You probably won’t find much pure hydrogen gas on Earth. Hydrogen is a gas in its most common form. And because of its simplicity, hydrogen gas happens to be the lightest element in the universe – lighter than air, in fact. This means that without a way to keep it anchored, the vast majority of the hydrogen gas on Earth escapes the atmosphere.

Hydrogen gas is perfectly safe – despite the history associated with it. Hydrogen gas is flammable, as workers at a New Jersey airfield found in 1937 discovered when the airship Hindenburg exploded. While historians are still unsure what caused the disaster, they agree on one thing: Keeping two hundred thousand square meters of hydrogen gas just a few feet above the passenger cabin is unsafe. Today, blimps are filled with helium gas, which is heavier than hydrogen. (And hydrogen is less flammable than gasoline!)

Hydrogen gas is safer than gasoline. In its common gaseous state, hydrogen has no color, odor or taste – and it’s completely non-toxic.

If we ever colonize the outer solar system, we’ll have a near-constant supply of hydrogen gas. All of the gas-giant planets – Jupiter, Saturn, Uranus and Neptune – have abundant hydrogen gas in their atmospheres. Jupiter and Saturn both have tremendous amounts of both hydrogen gas and helium throughout their atmospheres, whereas the hydrogen gas on Neptune and Uranus stays close to the outermost regions.

Hydrogen may be the future of alternative fuels. Scientists and economists talk about an impending “hydrogen economy,” in which a substantial amount of our energy needs are met by hydrogen. Gas is getting more expensive as crude oil becomes more expensive, and soon we’ll need a variety of alternative energy sources and renewable fuels to replace our dwindling (and polluting) supply of fossil fuels.

Hydrogen is non-polluting. Water is the only by-product of a hydrogen fuel cell car.