Earth Sciences

Van Allen belts

The Earth is surrounded by giant doughnut-shaped fringes or doughnuts that are composed of a large number of magnetically charged particles that are trapped and highly energetic. These radiation belts were discovered in 1958 by the first satellite in the United States, Explorer 1. The discovery was led by James Van Allen at the University of Iowa, which is why the belts were named after him. The Van Allen belts are a group of energy-charged particles that are gathered in place by the Earth's magnetic field. They can increase and decrease in response to the sun's incoming energy, sometimes swelling enough to expose satellites in low orbit to harmful radiation.

What are Van Allen belts?

Van Allen belts are two doughnut-shaped zones around the earth that are charged with energy, moving at about the same speed as the speed of light, these particles are mainly electrons and protons.

Discovery of Van Allen belts

Van Allen belts were discovered in 1958 by James Van Allen. The Van Allen experiment in Explorer 1, was launched on January 31, 1958, and consisted of a simple cosmic ray experiment consisting of a Geiger counter, which is a device that detects radiation and a recorder. The scientist had already been exploring the Earth’s upper atmosphere with balloons that could measure the levels of radiation in the atmosphere.

Follow-up experiments on three other missions with Explorer 3, Explorer 4 and Pioneer 3, established that there were two different types of radiation belts that were surrounding the Earth. During the flight, radiation levels increased and then suddenly fell to zero and then increased again, and then suddenly dropped to zero. What the team immediately noticed was that the regions that appeared as zero were really out of scale. These high radiation regions were mapped and are now known as Van Allen radiation belts.

Origin

At the beginning of the research on the Van Allen belts, it was thought that they had their origin in the radiation of the belts in space, but now it is known that, their origin can be due to the rays that are produced inside the electrical storms that happen inside the atmosphere of the earth.

Function of Van Allen belts

The data that have been collected to date through the sounds have succeeded in demonstrating that radiation belts are responsible for protecting the Earth from high-energy particles that could damage it, mainly the barrier for ultra-fast electrons. They trap charged particles from the sun and some from the interaction of the earth’s atmosphere with the sun’s radiation, thus acting as barriers against radiation.

Classification

There is an internal belt that is classified as the most intense and it extends from 1000 kilometers high to 6000 above our planet. This internal belt is formed mainly by energetic protons coming from the decomposition of other neutrons as a result of collisions between cosmic rays. The outer belt begins at an altitude of approximately 15,000 kilometers and reaches 25,000 kilometers. This external belt is mostly made up of electrons from solar windstorms that interact with the earth’s magnetic field.

Inside the external and internal belts, we can find a hole which has been catalogued as a safe zone caused as a result of low frequency radio waves. These radio waves also have their origin, according to studies, in thunderstorms. There is a third Van Allen belt known as the proton belt, which contains large amounts of energetic protons, which are thought to be the result of cosmic radiation from the solar wind.

Importance of Van Allen belts

Although at first glance it may not seem so, the importance of the Van Allen belts is very significant and lies in the fact that without them the Earth would not have a magnetic field and we would be exposed to great radiations. This means that cosmic ray particles could collide freely with the Earth’s atmosphere, causing there to be a higher background level of secondary neutrons in the air, which would lead to higher doses of background radiation on the surface. Belts do not directly impact human life, but if they did not exist, it would imply that other effects that occur in space affect life on earth.

Written by Gabriela Briceño V.
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