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Research on ancient rocks from South Africa and Brazil suggests weakening of Earth's magnetic field during the Ediacaran period (about 635 million to 541 million years ago).
- This weak field overlaps with Ediacaran oxygenation (rise in oxygen levels), believed to be responsible for emergence of early animals.
- Weakened magnetic field allowed hydrogen to escape into space, leaving fewer molecules for oxygen to bind with, translating into more free oxygen in the atmosphere and oceans.
Earth's magnetic field
- Earth is surrounded by an immense magnetic field forming a region called Magnetosphere.
- Earth’s magnetic field is generated in the Earth’s outer core by the geodynamo process.
- Here, the convective energy (which moves heat) from the slow-moving molten iron is converted to electrical and magnetic energy.
- The magnetic field forms two poles (a dipole) – North and South magnetic poles – having opposite polarities, like a bar magnet.
- Most dramatic changes impacting Earth’s magnetosphere are pole reversals.
Significance of Earth's magnetic field
- It prevents erosion of Earth’s atmosphere by harmful solar wind.
- It protects Earth from particle radiation emitted during Coronal Mass Ejection (CME) events and from cosmic rays.
- It guides particles from Sun towards poles where they create auroras.
Magnetic Pole reversal
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