The most abundant element, making up an incredible 75 percent of the known mass of the universe, is hydrogen. It also might be the energy fuel of the future.

For more than 4 billion years, hydrogen has fueled our sun, a nuclear fusion reactor that fuses hydrogen into helium to light up our solar system.

Hydrogen has also fueled our rockets. It’s very lightweight, a huge advantage for space travel. Under extreme pressure, or at extremely low temperatures, it becomes liquid.

Without a spark and an oxidizer, liquid hydrogen is stable. So rockets also carry liquid oxygen and an ignition source. Once lit, hydrogen packs a serious punch, burning at more than 5,000 degrees Fahrenheit.

Hydrogen may one day power our earthbound transportation, too. In most fuel cells, hydrogen is forced through a membrane. It splits off an electron as electricity, which can run an electric motor to propel a vehicle.

To fill the tank of a fuel-cell car, hydrogen has to be highly compressed—but in that state, it contains three times the energy, pound for pound, as gasoline.

And when processed through a fuel cell, the only emissions are water vapor.

On Earth, hydrogen doesn’t often exist in a pure gas form. But it can be separated from water by electric current.

Whether used in cars, rockets, or even fusion reactors, this essential element could, and probably should, play an ever-more-important role in powering the world.