Syllabus: 

GS1: Salient features of the World’s Physical Geography.

Context: 

Scientists have captured an audio representation of the Laschamps event, a dramatic geomagnetic excursion that took place 41,000 years ago.

More on the News

• In 2022, Scientists in Copenhagen have converted Earth’s magnetic signals from 32 locations into sound to highlight the planet’s magnetic field, the invisible shield against harmful cosmic radiation, and its fluctuations over the past 100,000 years.
• In 2024, they released another track based on a major event called Laschamps, which happened 41,000 years ago.
  During this event, Earth’s magnetic field became very weak (only 5% of today’s strength), and the north and south magnetic poles briefly flipped.
• The scientists are now working on a new track about the Brunhes-Matuyama reversal, a more extreme event that happened 780,000 years ago, when the magnetic poles reversed for a long time.
• Scientists also speculate that geomagnetic reversals and excursions may be linked to the South Atlantic Anomaly (SAA). 
• Unlike the geographic poles, Earth's magnetic poles are not fixed and tend to shift locations over time.

Magnetic Reversal and Magnetic Excursion 

• A magnetic reversal refers to a complete switch in the Earth's magnetic north and south poles, whereas a magnetic excursion denotes a temporary and partial deviation in the magnetic field's orientation. 
• While reversals are rare and global in nature, excursions occur more frequently and are typically confined to specific regions. 
• If the Earth retains the change in polarity for more than 100,000 years, scientists label them as reversals. 
• Earth’s magnetic field fluctuates over time due to the moving fluid in the outer core, which is powered by heat released from the inner core and the rotation of the planet. 
• Over the past 200 years, its strength has weakened by 10 percent. If this decline continues at the current rate, the magnetic field could drop to zero in about 1,500-1,600 years.
• Excursions occur about ten times more frequently than full reversals. 
• Since the Brunhes-Matuyama reversal, the most recent one, the Earth has witnessed three major excursions which are:
  Norwegian-Greenland Sea event (about 64,500 years ago)
  Laschamps event/Adams Event (between 42,000 and 41,000 years ago)
  Mono Lake event (about 34,500 years ago)