South Atlantic Anomaly

The South Atlantic Anomaly (SAA) is a special region on the earth’s surface. It is famous for its special characteristics.  In this region, the Earth’s radiation belt comes closest to the earth’s surface. So in this region, the radiation intensity is much higher than other places. This anomaly is caused because the magnetic field of earth is not perfectly aligned with it geographical position. It makes the magnetic field stronger in the north and it surrounds the geographic poles.  This makes the South Atlantic Anomaly closer to the Earth’s radiation belt.

South_Atlantic_AnomalyThis anomaly has a significant affect. Though, it is a good fortune that, the affect of it is not prominent upon humans living on the earth’s surface.  But unluckily, the affect is prominent on the satellites that are orbiting over this place. For its affect, the Hubble telescope stops its function when it passes through South Atlantic Anomaly. Another common consequence of this anomaly is satellite failure. Even, the International Space Station is also affected by it. Astronauts also face problems for this. The main reason behind this anomaly is the south Atlantic magnetic anomaly field. This magnetic field is always shifting. This anomaly is existing on the planet for more than billion years.

In a remote island inside the Atlantic Ocean, the Danish built an observatory with a view to knowing the suspicious anomaly of the earth’s radiation belt and magnetic field.  The name of the island is Tristan da Cunha. It is the most isolated island in the center of the South Atlantic Anomaly where the magnetic field of earth is lowest. Researchers are surprised to find that, at present, the earth’s magnetic field is decreasing by 5% in every hundred years. In the South Atlantic Anomaly, this decreasing rate is ten times faster.  The magnetic field of the earth protects it from radiation of outer space.  But for the earth’s radiation belt and its anomaly magnetic field in the South Atlantic Anomaly, this region is in high danger as it is poorly protected.

The earth’s radiation belt protects the earth from radioactive particles as well as from solar flares. It has two parts. They are the inner part and the outer part. The inner part of the belt traps protons and the outer part traps electrons. Generally the proton belt is about 1250 kilometers high from the earth surface.  But in the South Atlantic Anomaly region, the height of this belt lowers to about 200 kilometers. This makes the place highly intensive.


Normally all spacecrafts fly within the proton belt. But they cannot fly above the South Atlantic Anomaly for highly intense radiation. If a spacecraft fly above SSA, instruments in it often break down or become locked. This highly intense radiation made astronomers tense because they wondered if it could harm the astronauts. To find a solution, NASA created Fred, which was built up to measure the radiation to which the astronauts are uncovered. The Fred mission continued for four months on the International Space Station. At last the mission became successful and NASA acquired the result that is safe for astronauts to fly over South Atlantic Anomaly.

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