What is Alpenglow?

Jan. 29, 2024

Astronaut Lora O'Hara, currently stationed aboard the International Space Station, recently shared images showcasing the Alpenglow phenomenon near the Hindu Kush mountain range.

About Alpenglow:

  • It is a natural phenomenon when mountain slopes are illuminated by the sun as it rises or sets.
  • The slopes turn a rosy, reddish, or orange hue depending on the angle of the sun and atmospheric conditions.
  • It occurs during the twilight hours before or after sunset. It can also occur in the first minutes after the sun rises or sets.
  • Alpenglow typically occurs in the range of colours between red, pink, and orange.
    • This is because these are the longest warm rays of electromagnetic waves (light) — they reach various surfaces, while cold rays are shorter and disappear faster in the atmosphere.
  • Its vibrancy and colour depend on the location of the sun, the angle of the light, and other atmospheric conditions like clouds, humidity, and particulates.
  • It can change quickly depending on how fast the sun sets on any given day.