What is the South Atlantic Anomaly (SAA)?

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What is the South Atlantic Anomaly (SAA)? Blog Image


NASA is actively monitoring a strange anomaly in Earth's magnetic field called the South Atlantic Anomaly.

About South Atlantic Anomaly (SAA):

  • It is a region at the Earth’s surface where the intensity of the magnetic field is particularly low.
  • It stretches out between South America and southwest Africa.
  • Why it occurs?
    • 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.

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


Q1) What is magnetosphere?

A magnetosphere is the region around a planet dominated by the planet's magnetic field. Other planets in our solar system have magnetospheres, but Earth has the strongest one of all the rocky planets: Earth's magnetosphere is a vast, comet-shaped bubble, which has played a crucial role in our planet's habitability. 

Source: NASA Is Tracking a Huge, Growing Anomaly in Earth's Magnetic Field