If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth ? GPS and navigation systems could fail. Tsunamis could occur at equatorial regions. Power grids could be damaged. Intense auroras could occur over much of the Earth. Forest fires could take place over much of the planet. Orbits of the satellites could be disturbed. Shortwave radio communication of the aircraft flying over polar regions could be interrupted. Select the correct answer using the code given below :

Physics : Astronomy And Space Science

Q 3 / 12

UPSC CSE Prelims 2022

If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth ?

GPS and navigation systems could fail.
Tsunamis could occur at equatorial regions.
Power grids could be damaged.
Intense auroras could occur over much of the Earth.
Forest fires could take place over much of the planet.
Orbits of the satellites could be disturbed.
Shortwave radio communication of the aircraft flying over polar regions could be interrupted.

Select the correct answer using the code given below :

EXPLANATION

Correct Option

The correct option is (c).

Explanation

Solar storms, often associated with Solar Flares and Coronal Mass Ejections (CMEs), release immense amounts of energy, electromagnetic radiation, and high-energy charged particles. When these interact with Earth's magnetic field (magnetosphere) and atmosphere, they cause a Geomagnetic Storm. The effects are primarily electromagnetic and atmospheric, impacting technology and high-altitude phenomena.

Statement-wise Analysis

Statement 1 is Correct: Solar storms disturb the Earth's ionosphere, through which GPS and navigation signals travel. Changes in electron density can cause signal scintillation or delay, leading to errors or complete failure of Global Positioning Systems (GPS) and other navigation systems.
Statement 2 is Incorrect: Tsunamis are generated by the displacement of large volumes of water, typically due to underwater earthquakes, volcanic eruptions, or landslides. Solar storms affect the magnetosphere and upper atmosphere; they do not possess the mechanical force to displace ocean water or trigger tectonic activity.
Statement 3 is Correct: Geomagnetic storms induce strong electric currents in the ground, known as Geomagnetically Induced Currents (GICs). These currents can flow through power grids, overheating transformers and causing widespread blackouts or permanent damage to electrical infrastructure.
Statement 4 is Correct: During a major solar storm, the influx of charged particles excites atoms in the upper atmosphere, creating auroras (Northern and Southern Lights). In severe storms, the auroral oval expands towards the equator, making intense auroras visible at much lower latitudes than usual.
Statement 5 is Incorrect: While solar flares emit intense radiation, the Earth's atmosphere absorbs the harmful X-rays and UV radiation. The energy reaching the surface is not sufficient to spontaneously ignite vegetation or cause forest fires globally.
Statement 6 is Correct: Solar activity heats the Earth's outer atmosphere, causing it to expand. This increases atmospheric drag on satellites in Low Earth Orbit (LEO). Increased drag decays their orbits, requiring course corrections or leading to premature re-entry.
Statement 7 is Correct: High-frequency (HF) and shortwave radio communications rely on reflecting signals off the ionosphere. Solar storms cause ionization irregularities (especially in polar regions), leading to radio blackouts. This disrupts communication for aircraft flying over polar routes.

Key Takeaway: Major solar storms primarily impact space weather, affecting satellite operations, radio communications, navigation systems, and power grids through electromagnetic induction and atmospheric heating. They do not cause direct physical disasters like tsunamis or forest fires on the Earth's surface.

SOURCENCERT Class 12 Biology Chapter 10: Microbes in Human Welfare