south Atlantic anomaly

South Atlantic Anomaly

The Swarm constellation of satellites of the European Space Agency (ESA) has updated the development of South Atlantic Anomaly (SAA).

The magnetic field of the earth between Africa and South America is gradually weakening, causing problems for satellites and spacecraft.The phenomenon has been dubbed as the South Atlantic Anomaly.

The formation of South Atlantic Anomaly (SAA)

  • The Earth is surrounded by a pair of concentric donut-shaped clouds called the Van Allen radiation belts.

van allen belts

  • A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet’s magnetic field.
  • They are aligned with the magnetic axis of the earth, which is titled by 11 degrees from the rotation axis of the Earth.
  • Above South America, about 200-300 kilometers off the coast of Brazil, the nearby portion of the Van Allen Belt forms the South Atlantic Anomaly (SAA).
  • SAA is a region of reduced magnetic intensity where the inner radiation belt makes its closest approach to the Earth’s surface.


  • Satellites and other spacecraft passing through this region of space actually enter the Van Allen radiation belt and are bombarded by protons exceeding energies of 10 million electrons volts.
  • This can produced ‘glitches’ in astronomical data, problems with the operations of on-board electronic systems, and premature aging of computer, detector and other spacecraft components.
  • The weakening of magnetic field gives rise to speculations that Earth is heading for a pole reversal- a phenomenon in which north and south poles get reversed.
  • Magnetic reversals of the geomagnetic poles leave a record in rocks that are of value to paleomagnetists in calculating geomagnetic fields in the past.
  • Such information is helpful in studying the motions of continents and ocean floors in the process of plate tectonics.
  • This reversal last happened 7.8 lakh years ago. These reversals usually happen at an interval of 250, 000 years.

What the scientists have discovered?

  • South Atlantic anomaly is developing-The magnetic field has lost nearly 9% of its strength on a global average in the last 200 years.
  • This year, the “ minimum filed strength” in the South Atlantic Anomaly has  dropped tremendously.
  • Moreover, another centre of “minimum field strength” has emerged in the past five years, which cane possibly lead to the split up of the South Atlantic Anomaly.

Repercussions of Pole reversal

  • It will cause no harm on the surface level, which means that people will not feel the change even if the pole shift happens.
  • However, it could cause major issues for telecommunications and satellite systems.
  • Certain mobile phones and satellites may stop working.
  • The Earth’s magnetic field plays and important role in protecting the planet from solar winds and cosmic radiation that are harmful and a pole flip means Earth might be less protected from harmful space rays.
  • Animals that use Earth’s magnetic field for navigation-including birds, salmon and sea turtles-could not get lost during their routine journeys.


Important Topics Prelims

× How can I help you?
%d bloggers like this: