Van Allen belt

American  

noun

Physics.

1. either of two regions of high-energy-charged particles surrounding the earth, the inner region centered at an altitude of 2,000 miles (3,200 km) and the outer region at an altitude between 9000 and 12,000 miles (14,500 and 19,000 km).

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Van Allen belt British  

noun

1. either of two regions of charged particles above the earth, the inner one extending from 2400 to 5600 kilometres above the earth and the outer one from 13 000 to 19 000 kilometres. The charged particles result from cosmic rays and are trapped by the earth's magnetic field

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Van Allen belt Scientific  

/ vănăl′ən /

1. Either of the two zones surrounding the Earth in which a thin distribution of atomic particles with very high energies are trapped by Earth's magnetic field. The inner belt lies between about 500 and 6,440 km (310 to 4,000 mi) above Earth's equator and consists mostly of a mix of protons and electrons. The upper belt lies between about 15,000 and 30,000 km (9,300 to 18,600 mi) and consists mostly of protons. Both belts are thickest at the equator and have irregular densities of particles. The outer radiation belt is much larger and the number of particles varies, increasing in the aftermath of solar flares. The polar auroras are caused when some of the charged particles from the outer Van Allen belt hit the upper atmosphere. The Van Allen belt is named after its discoverer, American astrophysicist James Van Allen (1914–2006).

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Van Allen belt Cultural  

1. Either of two layers of electrically charged (see electrical charge) particles held in orbits above the atmosphere by the magnetic field of the Earth. The belt is named after its discoverer, the twentieth-century American physicist James Van Allen.

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Etymology

Origin of Van Allen belt

First recorded in 1955–60; named after J. A. Van Allen

Example Sentences

This was impossible, he said, because the Van Allen belt was no natural phenomena.

From Slate • Jul. 17, 2019

The upper stage carrying the sports car now faces a foreboding six hours in the Van Allen belt, a swath of high-energy solar particles trapped by Earth's magnetic field.

From National Geographic • Feb. 6, 2018

He said the feasibility of mammalian reproduction in space beyond the Van Allen belt would depend on the creation of "radiation-hardened" facilities that could protect sperm, eggs and embryos from harm.

From BBC • May 22, 2017

This is just what we observe happening, but on a smaller scale, in the Van Allen belt around Earth.

From Textbooks • Oct. 13, 2016

Half a dozen ships; we could make a new Van Allen belt around Tanith of them, with what we have here.

From Space Viking by Piper, H. Beam