NASA has been closely tracking the developments of the South Atlantic Anomaly (SAA). What is the South Atlantic Anomaly? What causes it and what is its impact on the world? Read on to know more about the South Atlantic Anomaly, which comes under the geography section of the UPSC syllabus.
South Atlantic Anomaly
The National Aeronautics and Space Administration (NASA) has been observing an unusual anomaly in geomagnetism.
- A giant region of lower geomagnetic intensity is observed in the sky, covering an area between South America and Southwest Africa. This phenomenon is known as the South Atlantic Anomaly.
- It is observed that this phenomenon is drifting slowly in the north-westerly direction and is also in the process of splitting into 2 distinct cells of minimum magnetic intensity, within the greater anomaly.
- Some studies also show that this may be a recurrent phenomenon which might have affected earth for a long time (as far back as 11 million years ago).
Image source: www.sciencealert.com
What is causing the South Atlantic Anomaly?
- The African Large Low Shear Velocity Province, which is a large lump of heavy rock, located about 2900 km below the African continent, is disturbing the generation of geomagnetic fields. This is resulting in the weakening of the geomagnetic field, which is also aided by the tilt of the earth’s magnetic axis.
- The weakening dominance of the dipole field is also pointed out as a reason. Here a localised field with opposite polarity grows strongly in the SAA region and thus weakens the geomagnetic field intensity.
Geomagnetism
Earth’s magnetic field is produced by the continuously generating electrical currents, formed due to the movement of the earth’s molten iron outer core.
Significance of Geomagnetism:
- The behaviour of the Earth’s magnetic field can provide important information about the planet’s past, including the movements of continents and changes in the planet’s climate over geological time scales.
- As geomagnetism is generated by the planet’s molten outer core, the study of geomagnetism is essential for understanding the Earth’s structure and dynamics.
- It acts as a shield against harmful solar radiation and charged particles, and thus is important for life on the planet Earth.
- As compasses rely on the Earth’s magnetic field to determine direction, geomagnetism is very crucial for navigation.
South Atlantic Anomaly Impacts
- This phenomenon may not harm life on the surface of the earth, and hence there is no cause for alarm.
- As the satellites and spacecraft pass through this anomaly, they will be exposed to the charged particles from the Sun and this could short-circuit or lead to malfunctioning of the technological systems onboard satellites.
- It may also affect navigation systems and telecommunication systems.
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