Aurora

GS-I Geography

Why in the news?

Recently, the northern lights, also known as the aurora borealis, were observed lighting up the night sky over Hanle village in Ladakh.
Similar sightings of the northern lights were reported in various parts of the world, including the US and the UK.
Additionally, countries like Australia and New Zealand witnessed the southern lights, also known as the aurora australis.

What are Auroras?

An aurora refers to a natural phenomenon where light displays occur in the Earth's sky, typically observed in regions near the North and South Poles.
These displays showcase vibrant patterns of light, presenting as curtains, rays, spirals, or flickering movements across the sky.
Commonly referred to as the northern lights (aurora borealis) in the North and the southern lights (aurora australis) in the South.

Auroras are composed of gases and particles such as oxygen and nitrogen.
When these particles collide with the Earth's atmosphere, they release energy, resulting in the emission of light.
The colors seen in auroras vary based on the type of gas involved in the collisions and the altitude at which the collisions occur.

Geomagnetic storms, caused by solar phenomena like coronal mass ejections (CMEs) and solar flares, intensify auroral events.
Coronal mass ejections involve the release of plasma and magnetic fields from the Sun, while solar flares are sudden bursts of energy.
Typically, coronal mass ejections and solar flares happen together, but they can also occur separately.

Intensity of Auroras and Solar Storm:

Intense solar storms cause heightened solar activity, resulting in more prominent auroral exhibitions.
During these storms, the influx of charged particles reaching the Earth's atmosphere enhances the intensity of the auroras.
The magnitude of the solar storm and the alignment of the Earth's magnetic field influence the visibility and vividness of the auroras.

Scientific and Cultural Significance of Auroras:

Auroras carry cultural and spiritual importance in diverse indigenous societies globally.
Scientific studies on auroras aid in comprehending the Earth's magnetosphere, interactions between the sun and Earth, and space weather phenomena.

What are Aurora Borealis?

The Aurora Borealis, commonly known as the Northern Lights, appears in the northern hemisphere, particularly in areas near the Arctic Circle.

Countries such as Norway, Sweden, Finland, Iceland, Canada, and Alaska often witness this phenomenon.
It occurs due to charged particles, mainly electrons and protons, emitted by the sun colliding with the Earth’s magnetosphere and interacting with gases in the atmosphere.
These collisions give rise to vibrant displays of light, with predominant colors being green, red, and purple.

What are Aurora Australis?

The Aurora Australis also referred to as the Southern Lights, manifests in the Southern Hemisphere, especially around the Antarctic Circle.
It can be observed in countries like Australia, New Zealand, Antarctica, and portions of southern South America.
Similar to the Northern Lights, the southern lights are caused by charged particles emitted by the sun interacting with the Earth’s magnetic field and atmosphere in the Southern Hemisphere, resulting in vibrant displays of colorful light.

What are geomagnetic storms:

About:

A geomagnetic storm refers to disturbances in the Earth's magnetic field caused by solar emission.

Causes:

The most significant storms stem from solar coronal mass ejections (CMEs), which occur when the Sun releases massive bursts of charged particles.
When a CME or high-speed solar stream interacts with Earth's magnetosphere, it disrupts its normal function.

Normally, Earth's magnetosphere shields us from solar particles, but during a geomagnetic storm, this protection weakens.

As a result, energetic solar wind particles penetrate Earth's atmosphere, particularly over the poles, creating phenomena like auroras.

Condition:

Geomagnetic storms are triggered by specific solar wind conditions, including extended periods of high-speed solar wind lasting for several hours or more.
These storms are intensified by a southward-directed solar wind magnetic field, opposing Earth's magnetic field, particularly on the dayside of the magnetosphere.

Impact

Solar weather events of this nature can amplify auroras, potentially making them visible in regions where they are not usually seen.
Additionally, they have the potential to disrupt navigation systems and induce harmful geomagnetic currents (GICs) in power grids and pipelines.

UPSC PYQ

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:

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