Green Rim, Egypt

Last updated on September 16, 2023

Exploring the Enigmatic Green Rim Phenomenon in Egypt

Have you ever marveled at the mesmerizing colors that grace the sky during sunrise or sunset? The atmosphere plays a remarkable role in distorting the appearance of the sun, creating intriguing optical phenomena. One such phenomenon, known as the Green Rim, captivates observers with its elusive beauty. Today, we will delve into the depths of this atmospheric spectacle, specifically in the enchanting land of Egypt.

When sunlight passes through Earth's atmosphere, it undergoes a process called refraction, causing the sun's disk to appear slightly flattened and positioned higher in the sky. As we approach the horizon, this effect becomes even more pronounced, resulting in delayed sunsets and hastened sunrises. It is within this magical interplay of light that the Green Rim makes its appearance.

The Green Rim is formed due to the varying refraction of different colors of light. Green light refracts more strongly than red light, giving rise to the phenomenon of the "green sun." Consequently, the green portion of the sun's disk appears slightly higher, creating an upper green rim. Conversely, the blue rim is a rarity since the atmosphere scatters away a significant amount of blue light when the sun is low on the horizon.

It is worth noting that the Green Rim and the elusive Green Flash are distinct phenomena. While some sources erroneously attribute the green flash to the Green Rim, they are separate occurrences. The Green Rim is too narrow to be discerned by the naked eye alone, requiring additional magnification through mirages to be visible. On the other hand, the Green Flash manifests as a brief burst of green light that occurs just as the sun dips below or rises above the horizon.

Egypt, with its rich cultural heritage and breathtaking landscapes, provides a captivating backdrop for observing the Green Rim phenomenon. Imagine standing at the Plaza of the Bibliotheca Alexandrina, basking in the golden hour before sunset on a serene evening. The atmosphere is laden with a thick haze, which adds an ethereal quality to the scene. As the sun gradually descends, its green-tinged upper rim becomes apparent, casting a spellbinding glow upon the surroundings.

To fully appreciate the splendor of the Green Rim, it is essential to understand the scientific principles at play. The refraction of light through the atmosphere, particularly the differential refraction of green and red light, gives rise to this captivating optical illusion. As the sun's rays traverse the Earth's atmospheric layers, they undergo a bending effect, causing the green light to deviate more than its red counterpart. This divergence in refraction angles leads to the formation of the Green Rim.

While the Green Rim is undeniably a stunning sight to behold, it is not always easily visible. Factors such as atmospheric conditions, haze, and pollution can obscure its delicate appearance. However, when the conditions align perfectly, nature unveils its hidden beauty, leaving spectators in awe.

In conclusion, the Green Rim phenomenon in Egypt showcases the wondrous interplay of light and atmosphere. As sunlight refracts through Earth's atmospheric layers, the green portion of the sun's disk appears higher, giving rise to an upper green rim. While often mistaken for the Green Flash, the Green Rim is distinct and requires additional magnification through mirages to be observed. So, next time you find yourself gazing at a breathtaking sunset in Egypt, keep an eye out for the elusive Green Rim and let it transport you into a world of enchantment.

Green Rim imaged by Aymen Ibrahem (Night Sky over Egypt) from the Plaza of the Bibliotheca Alexandrina, about 20 minutes before sunset on March 12, 2008. Thick haze dimmed the sun. ©Aymen Ibrahem, shown with permission.

Our atmosphere refracts the sun’s rays causing its disk to appear slightly flattened and higher in the sky. Close to the horizon the effect increases dramatically causing sunset to be delayed and sunrise hastened.

Green light refracts more strongly than red and thus the ‘green sun’ appears slightly higher producing an upper green rim. We rarely see a blue rim because when the sun is low so much blue light is scattered away by the atmosphere.

Many websites and textbooks ascribe the green flash to this effect. No so, the green rim is far too narrow to see with the unaided eye. Green flashes require a mirage to vertically magnify the narrow rim.

Flattened sun Flattened moon

Sunset mirages

Green rim

Green flashes

Note: this article has been automatically converted from the old site and may not appear as intended. You can find the original article here.

Reference Atmospheric Optics

If you use any of the definitions, information, or data presented on Atmospheric Optics, please copy the link or reference below to properly credit us as the reference source. Thank you!