Alpenglow Phenomenon

Source-This post on Alpenglow Phenomenon has been created based on the article “NASA astronaut shares photos of ‘alpenglow’ from space: What is it?” published in “The Economic Times” on 29 January 2024.

Why in the news?

Recently, NASA astronaut Loral O’Hara of the International Space Station shared some amazing photos of “alpenglow” phenomenon observed near Hindu Kush mountain range.

About alpenglow phenomenon

1) About– Alpenglow is an optical phenomenon that appears as a horizontal reddish glow near the horizon opposite to the Sun. This happens when the solar disk is just below the horizon.
2) Duration– It can occur during the twilight hours before sunrise or after sunset.
3) Colour range – Between red, pink and orange.

When does it occur?

Alpenglow occurs when direct sunlight around sunrise or sunset is reflected off airborne precipitation, ice crystals or particulates in the lower atmosphere, as the sunlight has no direct path to reach a mountain.

Some important points about Hindukush Himalayan Region

Range-It stretches over 3500 kilometers across eight countries – Afghanistan, Bangladesh, Bhutan, China, India, Nepal, Myanmar and Pakistan.
Major river-It is the source of ten of Asia’s largest rivers – the Amu Darya, Indus, Ganges, Brahmaputra, Irrawaddy, Salween, Mekong, Yangtse (Jinsha), Yellow River, and Tarim (Dayan).
Why it is called third pole?- It has the largest concentration of frozen water on Earth after the North Pole and South Pole.
Glaciers-There are an estimated 54,000 glaciers in the Hindu Kush Himalayas. These glaciers cover 60,000 square kilometers and serve as a major source of the water in the region’s rivers.

UPSC Syllabus – Geography