Little Bits of History

Belting One Out

Posted in History by patriciahysell on January 31, 2013
Van Allen Belts

Van Allen Belts

January 31, 1958: The means for defining bands of radiation around Earth become available to James Van Allen. Van Allen was an American scientist from the University of Iowa where he earned a PhD in nuclear physics in 1939. He went first to the Carnegie Institution and then joined Applied Physics Laboratory (APL) where he worked on proximity fuses used to detonate explosive devices automatically. In 1942 he joined the Navy and served as an assistant gunnery officer.

After the war, he returned to APL and began to be interested in the study of the upper atmosphere. The Explorer I was the US answer to the Sputnik launches. It was the first successfully launched US spacecraft rising into space on this date. The cigar-shaped satellite orbited the Earth every 115 minutes 220 miles above the surface. It carried instruments to measure cosmic rays, micrometeors, and its own temperature. On board, at Van Allen’s insistence, was a Geiger counter, an instrument to measure radiation.

The possibility of trapped ionized radiation was already under investigation. The radiation belts were confirmed from the Explorer 1 and Explorer 3 missions. The actual mapping of the belts was done by Sputnik 3, Explorer 4, Pioneer 3, and Luna 1. There are two distinct radiation belts of energetic electrons with protons forming a single belt. There is an inner and outer belt. While similar radiation bands have been discovered around other planets, the Van Allen Belts refer specifically to Earth’s radiation bands.

The two belts are formed by different processes. They are harmful to satellites and can cause damage to sensitive equipment. Humans are also susceptible to the radiation which is difficult to shield against. While we don’t know exactly how the belts are formed, there is one company claiming they can drain the inner belt to 1% of its natural energy level within a year. They would use High Voltage Orbiting Long Tethers which would be long strands of highly charged cables. The radiation in the belts would intercept the cables, change directions, and dissipate into space. The lessened radiation would make the region far safer for space jockeys.

“I don’t think the human race will survive the next thousand years, unless we spread into space. There are too many accidents that can befall life on a single planet. But I’m an optimist. We will reach out to the stars.” – Stephen Hawking

“The Earth is just too small and fragile a basket for the human race to keep all its eggs in.” – Robert Heinlein

“There are so many benefits to be derived from space exploration and exploitation; why not take what seems to me the only chance of escaping what is otherwise the sure destruction of all that humanity has struggled to achieve for 50,000 years?” – Isaac Asimov

“The dinosaurs became extinct because they didn’t have a space program. And if we become extinct because we don’t have a space program, it’ll serve us right!” – Larry Niven

This article first appeared at in 2010. Editor’s update: James Van Allen was born in Iowa in 1914. His boyhood home housed a museum regarding his life and contributions to science. It was scheduled for demolition, however Lee Pennebaker purchased the house and saved it from destruction. His plan for the structure was to donate it to the Henry County Heritage Trust. Their plan for the old house is to move it next to Saunders School and in that location it will become the Henry County museum. Mount Pleasant, the city of his birth is the county seat of Henry County and is a small community in the southeast corner of the state. In 2010 there were 8,668 people living there.

Also on this day: Sticking to Business – In 1930, 3M marketed Scotch tape.
Love Bug – In 747: The London Lock Hospital opened as the first venereal disease clinic.
The Only One – In 1945, Eddie Slovik was executed.