Modeling the Invisible

The Van Allen Radiation Belts

Al Cikas

The Van Allen Radiation Belts were the first discovery made in space, made by the very first American satellite, Explorer 1. Its Geiger counter was designed to register some 25,000 counts per second, yet it immediately encountered counts of nearly four times that. Shown here is the Doughnut Model, the earliest depiction of what a radiation belt might look like. Later refinements produced the Magnetic Bottle version we now accept as accurate today.

This project was made with educators in mind, and designed for universities, planetariums, museums, etc. It's a throwback to the Doughnut Model of the late 1050s, and provides a physical wire model one can examine by walking around it. Life Magazine, in late October 1958, depicted a single belt, tinted reddish pink. That notion has been preserved here. Later, when a second belt was defined, many drawings rendered it in green, also done here. In reality, Solar particles from the sun enter the Earth's magnetic field, where electrons are stripped from their host protons and part in opposite directions. Protons sink to the inner belt (pink), while electrons are flung to the outer belt (green). On occasion, these particles overflow the belts, corkscrew around the Earth's magnetic field lines, and are deposited in the polar regions, forming colorful Auroras. Colored crinkle paper (flammable) forms the Aurora and is made to wave with a small computer fan, providing a somewhat realistic view. LED strip lights illuminate the magnetic field lines. Push buttons and a 12 volt wall wart allow visitors to activate either the lights or the fan. Clear Krylon coats the crinkle for strength and safety.

Nearly any materials available may be considered. Pictured here is the final design, after several differing concepts were evaluated. The individual photo captions point out the necessary details. When it was finished, it was donated to a nearby Space Museum, also shown here.

Click on the image to start the 'slideshow' of how Al created the model of the Van Allen belts for The Space Museum.

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Sven Knudson