Context:
Earth’s magnetic field underwent a major weakening 591 million years ago
Earth’s magnetic field:
- Magnetosphere – Region of immense magnetic field surrounding Earth
- Generated in – Earth’s outer core by the geodynamo process.
- Geodynamo process – Convective energy (which moves heat) from the slow-moving molten iron is converted to electrical and magnetic energy.
- Magnetic field forms 2 poles (a dipole) – North and South magnetic poles – having opposite polarities
- Magnetic Pole reversal – Forces that generate Earth’s magnetic field are constantly changing, causing changes in strength of magnetic field.
- Causes the location of Earth’s magnetic north and south poles to gradually shift, and to even completely flip locations around every 300,000 years.
- During a pole reversal, the magnetic field weakens but doesn’t completely disappear
- Significance of Earth’s magnetic field –
- Prevents erosion of Earth’s atmosphere by harmful solar wind.
- Protects Earth from particle radiation emitted during Coronal Mass Ejection (CME) events and from cosmic rays.
- Guides particles from Sun towards poles where they create auroras.
Source: The Washington Post
Previous Year Question
What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA) project?
[UPSC Civil Services Exam – 2017 Prelims]
(a) To detect neutrinos
(b) To detect gravitational waves
(c) To detect the effectiveness of missile defence system
(d) To study the effect of solar flares on our communication systems
Answer: (b)
