What is it and how does a natural phenomenon arise?

During the Alps, peaks in the high mountains are illuminated with an impressive red light at sunset and sunrise.

Alpenglow is a special mood of light that occurs at sunset and at sunrise Alps And in others high mountains is happening. Alpenglow describes two distinct natural optical phenomena, referred to as first coloration and second coloration.

At sunset, the first hue appears first, then the second tint. On the other hand, at sunrise, the order of coloring is reversed. Thus the second color of the alpenglow occurs before the first color at sunrise.

Albengello’s first coloring

During the first coloring, the snow-covered areas of the peaks and rocky slopes are replaced by low slopes Son receipt. Red illumination ensures that the bright peaks of Berg In the foreground it stands out clearly from the background, which is still in the dark or again.

The second coloring of Albengello

During the second coloring, the sun is already below the horizon. It no longer illuminates mountain peaks, or only indirectly. The smallest particles in the atmosphere, such as fine dust and ice crystals, scatter sunlight, which weakens as it reaches the top. The snow-capped and lightly rocky peaks appear a dull red against the violet-hued sky.

How is Alpenglow formed?

The alpenglow at sunrise and sunset is caused by two effects.

  • The first effect of alpenglow occurs because a lot of light which strews wildly on its long way through Earth’s atmosphere when the sun is low in the sky. On the other hand, the orange to red band of sunlight is not scattered and gives the peaks their strong color during the alpenglow
  • The alpenglow’s second visual effect is triggered by the indirect lighting of the mountains above the shadow line. Sunlight hits the landscape behind the Alpenglow observer at a very low angle. From there it reflects, brightening the peaks over the shadows. With an increasing angle, the efficiency of this inversion drops sharply. This does not lead to a general brightening of the mountains, but to a clear bright strip.

Phosphorus causes alpenglow at night

Alpenglow mainly occurs at sunset and sunrise. However, in individual cases, phosphorus also causes a slight flushing of Alpengels at night. Phosphorescence is a property that ensures that a substance still glows or glows after strong illumination in absolute darkness.


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