Beyond Earth, plasmas are certainly abundant. About 99% of the visible universe is plasma, including most of the matter in stars and the region of space around Earth. This plasma near Earth is controlled by Earth’s magnetic field, or magnetosphere, This magnetic shield is particularly important since it helps insulate Earth from the solar wind, the stream of protons and electrons that flows out into space from the sun.

The inside of a star is an extremely hot, dense plasma. The hydrogen nuclei in this plasma fuel the stellar fusion processes that provide the star’s energy. Harnessing this same process here on Earth would meet our energy needs indefinitely. The raw materials, two isotopes of hydrogen, are readily available, and the by-product, helium, is an inert gas. The great challenge is sustaining here on Earth the high temperatures found at the centers of stars. We are not quite there yet, but fusion researchers have made steady progress over the last few decades.