South Atlantic Anomaly (SAA)

South Atlantic Anomaly Latest News

A giant dent in Earth’s magnetic field, called the South Atlantic Anomaly, is continuing to expand, according to the latest data from a trio of satellites monitoring our world.

About South Atlantic Anomaly

• It is a unique location on Earth where the magnetic field is weaker than normal. 
• It is southeast of South America and southwest of Africa. In this area, the planet’s magnetic field dips down.
• It was first identified in the 19th century.
• Why does it occur?
  • Earth’s magnetic field acts like a protective shield around the planet, repelling and trapping charged particles from the Sun.
  • SAA exists because the Earth’s inner Van Allen radiation belt comes closest to the planet’s surface, causing an increased flux of energetic particles.
  • This leads to the penetration of solar energetic particles deep into Earth’s atmosphere, posing severe problems for airplanes and ships’ positioning systems as well as spacecraft electronic systems.

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What are the Van Allen Radiation Belts?

• The Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind. 
• The particles are captured by and held around a planet by that planet’s magnetic field.
• It surrounds Earth, containing a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.
• The outer belt is made up of billions of high-energy particles that originate from the Sun and become trapped in Earth’s magnetic field, an area known as the magnetosphere.
• The inner belt results from interactions of cosmic rays with Earth’s atmosphere.
• The Van Allen belts are most intense over the Equator and are effectively absent above the poles.

Source :SA