1924-1928 Plasma

The book of science

Tom Sharp

Irving Langmuir physics Plasma


The fourth state of matter happens when electrons, energized enough to escape their atomic nuclei, collectively generate electric and magnetic fields and become conductive. Irving Langmuir studied when thermionic emission ionizes a gas in a vacuum tube to change the behavior of the gas, and, because it reminded him of blood plasma, called it “plasma.”


Lightning strikes, sprites, and Saint Elmo’s fires are glowing plasmas from natural electrostatic discharges. The solar wind is a plasma of electrons, protons, and alpha particles that stream through space. Polar aurorae are from interactions of the earth’s magnetic field with solar and magnetospheric plasmas. The sun and the stars are luminous spheres of plasma. Interstellar nebulae are plasma clouds. Interplanetary, interstellar, and intergalactic spaces are permeated with plasmas. * Fluorescent and neon lights contain plasmas. Large TV diplays contain many small plasma cells. Arc lamps and arc welders create plasmas. Even static electric sparks are plasmas.

Langmuir probe

Electrons in a plasma have a temperature and a density, and the plasma has an electric potential measured with a Langmuir probe, bearing in mind that the probe itself affects plasma properties.

It doesn’t exist

It takes a while for reality to set in, like almost a thousand years. We used to be able to count the cases, simple as A, B, C. Maybe eventually our senses will register it. Maybe eventually we will all mature in our sensibilities. Maybe eventually we will make our lives as deliberate as fairy tales.

It’s always a good idea, as a scientist, to look at the cases that we cannot explain. Some things are so obvious that it may take some genius to see them.

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