NORTHERN LIGHTS
- December 10, 2020
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Subject: Geography
Context: Northern Lights, also known as aurora borealis, are usually witnessed far up in the Polar Regions or the high latitude regions of Europe, like in Norway. But, recently, they could be visible in southern regions, such as in the Pennsylvania in the US.
Concept:
- This is happening due to a solar flare, which emerged from a Sunspot. The flare is accompanied by a Coronal Mass Ejection (CME) — a large bubble of radiation and particles emitted by the Sun that explodes into space at high speed.
- The US National Oceanic and Atmospheric Administration (NOAA) said the electromagnetic storm could be growing to major status, causing the Northern Lights to be visible in more number of areas than usual.
AURORA
- Auroras occur when charged particles ejected from the Sun’s surface — called the solar wind — enter the Earth’s atmosphere.
- While flowing toward Earth, the fast-moving solar wind carries with it the Sun’s magnetic field, which disrupts the magnetosphere — the region of space around Earth in which the magnetic field of our planet is dominant.
- When the Sun’s magnetic field approaches Earth, the protective magnetic field radiating from our planet’s poles deflects the former, thus shielding life on Earth.
- However, as this happens, the protective fields couple together to form funnels, through which charged solar wind particles are able to stream down to the poles.
- At the north and south poles, the charged particles interact with different gases in the atmosphere, causing a display of light in the sky. This display, known as an aurora, is seen from the Earth’s high latitude regions (called the auroral oval), and is active all year round.
- In the northern part of our globe, the polar lights are called aurora borealis or Northern Lights, and are seen from the US (Alaska), Canada, Iceland, Greenland, Norway, Sweden and Finland.
- In the south, they are called aurora australis or southern lights, and are visible from high latitudes in Antarctica, Chile, Argentina, New Zealand and Australia.
- Generally, the auroral oval is confined to the polar regions. But occasionally, the oval expands, and the lights become visible at lower latitudes. This happens during periods of high solar activity, such as the arrival of solar storms.