Green Flash.. ..Up Close - OPOD

Last updated on September 16, 2023

Green Flash Up Close: A Spectacular Atmospheric Phenomenon

The green flash, a breathtaking atmospheric phenomenon, is a rare and stunning sight that occurs during sunrise or sunset. As the sun hovers just above the horizon, a narrow cusped flash of green light can be observed for a brief moment. While this phenomenon may seem like a figment of imagination, it is indeed a real occurrence caused by the bending of light as it passes through the Earth's atmosphere. In this article, we will explore the green flash up close and delve into the intricate details that make this optical marvel so captivating.

A Glimpse of the Green Flash

Captured by Michiel de Boer, an avid photographer, this image offers a close-up view of the green flash as seen from near Ijmuiden in The Netherlands. The serene North Sea provides the backdrop for this awe-inspiring spectacle. The cusped green flash appears to hover momentarily above the horizon, its brilliance enhanced by patches of deep blues and yellows created by the turbulence caused by a passing ship. The mirage edge, characterized by the dark ragged sea 'horizon,' marks the boundary where the mirage occurs. After this fleeting moment, the green flash disappears, leaving behind a lasting impression.

Unraveling the Mirage

Before the green flash emerges, an earlier stage of the sunset reveals a classical Etruscan Vase or Omega sunset. This captivating scene is a result of warm air from the sea mingling with cooler air, creating a mirage with two distinct images. Normally, complete mirages consist of an odd number of images; however, in this case, only two images are visible as the mirage is slightly cut off below the horizon. As the sun descends, it is almost met by a second inverted sun rising from the waves, adding to the mystique of this atmospheric spectacle.

The Magnificent Merge

The meeting point of the two suns, known as the mirage 'fold line,' is where the magic of the green flash truly begins. At and near the fold line, there is a high vertical magnification and maximum color dispersion. Even at this stage, one can observe the enlarged red rims that will eventually merge into a vibrant red flash. As the slivers of the sun's uppermost limb slide together at the fold line, they form the distinct cusped shape of the green flash. The high vertical magnification elongates the green and sometimes blue rims of the sun, creating a vivid flash that is both mesmerizing and visible to the naked eye.

A Delicate Dance of Light

The green flash is a result of atmospheric refraction, which causes light to bend as it passes through the Earth's atmosphere. As sunlight travels through the atmosphere, it encounters layers of varying density and temperature. These variations in density and temperature cause the light to refract or bend at different angles. The shorter wavelengths of light, such as blue and green, are bent more than the longer wavelengths like red and orange. This differential bending of light is what creates the stunning display of colors during sunrise and sunset, culminating in the elusive green flash.

Exploring the Science Behind the Phenomenon

To fully comprehend the green flash, we must delve into the scientific principles that govern this captivating phenomenon. The green flash is a type of optical phenomenon known as a superior mirage. It occurs when the temperature gradient in the Earth's atmosphere causes light rays to curve, creating an image that appears above its actual position. The green flash specifically arises due to a combination of atmospheric dispersion, where different colors of light separate, and atmospheric refraction, where light bends as it passes through the atmosphere.

Observing the Green Flash

Witnessing a green flash requires specific conditions and precise timing. It is best viewed from a location with an unobstructed view of the horizon, such as a shoreline or open plain. The phenomenon is most likely to occur when the atmosphere is stable and free from significant turbulence. Additionally, a clear and pollution-free sky enhances the chances of witnessing this extraordinary event. Patience and attentiveness are key, as the green flash can be incredibly brief, lasting only a few seconds. Therefore, it is essential to keep a keen eye on the setting or rising sun and be prepared to capture the moment when it occurs.

The Green Flash in Cultural Lore

Throughout history, the green flash has captured the imagination of people from various cultures around the world. It has been the subject of countless legends and myths, often associated with spiritual or mystical significance. In some cultures, the green flash is believed to bring good fortune, while in others, it is considered a harbinger of impending disaster. These cultural interpretations reflect the awe-inspiring nature of the green flash and its ability to evoke wonder and fascination in those fortunate enough to witness it.

Capturing the Magic

Thanks to advancements in technology and the passion of photographers like Michiel de Boer, we are now able to capture and share the magic of the green flash with a wider audience. Through their lenses, we can explore the intricate details and nuances of this extraordinary phenomenon. These captivating images not only serve as a visual testament to the beauty of nature but also inspire us to marvel at the wonders that exist just beyond our everyday perception.

Conclusion

The green flash is a mesmerizing atmospheric phenomenon that showcases the captivating interplay between light and the Earth's atmosphere. As we have explored in this article, its appearance is a result of atmospheric refraction and dispersion, creating a momentary burst of vivid green light during sunrise or sunset. While witnessing the green flash requires specific conditions and keen observation, it is undoubtedly a sight worth waiting for. So, the next time you find yourself near a picturesque horizon during the golden hour, keep your eyes peeled for the elusive green flash and prepare to be amazed by the wonders of the natural world.

Green Flash.. ..up close

Another image from the sunset in the previous OPOD.

Taken by Michiel de Boer (images plus) looking across the North Sea from near Ijmuiden in The Netherlands.

Images ©Michiel de Boer

The narrow cusped green flash hangs for a second above the horizon. Some turbulence from the passing ship (at far right) creates patches of deep blues and yellows. The dark ragged sea ‘horizon’ marks the mirage edge. The flash gets no lower. It is the union of a rising sun sliver and a descending one. After this they are gone.

Below, an earlier stage of the sunset, a classical Etruscan Vase or Omega sunset. Air warmed by the sea topped by cooler air has created a mirage of two. images. .Complete mirages always have an odd number of images, here there are only two because the mirage is cut off slightly below the horizon. Back to the mirage below - The descending upper sun is almost met by a second inverted sun rising from the waves.

The suns eventually meet at the mirage ‘fold line’. At, and near, the fold is high vertical magnification and maximum colour dispersion. We see already the enlarged red rims that will eventually merge into a red flash.

At the end, the slivers of the sun’s uppermost limb slide together at the fold line into the final cusped green flash shape. The high vertical magnification stretches the suns' green, and sometimes blue, rims into a vivid flash bright and large enough to be seen by eye.

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