Omega, "Etruscan Vase" sunset

Last updated on September 16, 2023

Omega, "Etruscan Vase" Sunset: A Phenomenon of Atmospheric Optics

Sunsets have always captivated us with their stunning displays of color and beauty. One particular sunset phenomenon that has intrigued observers is the Omega or "Etruscan Vase" sunset. This captivating optical effect occurs when an inverted image of the sun's lower limb appears to rise out of the waves, creating a remarkable sight for those fortunate enough to witness it.

The distinctive feature of the Omega sunset is the noticeable reddening of the 'stem' where the two images of the sun's limb meet. This reddened stem is often referred to as a "red flash," similar to the I-Mir green flash that can occur later during these sunsets. The lower limb of the sun exhibits a red rim, and when the two images of this limb intersect, they are highly magnified in the vertical direction, resulting in the striking reddened stem or red flash.

The spikes visible on the apparent horizon during an Omega sunset are not waves but rather the fluttery edge of a mirage. Mirages are optical illusions caused by atmospheric conditions bending light rays, creating distorted images or false appearances. In this case, the mirage produces an intriguing visual effect, enhancing the overall enchantment of the Omega sunset.

The phenomenon of Omega sunsets is not limited to a specific location but can occur in various coastal areas around the world. Cape Hatteras, where Michael Myers captured a close-up image of an Omega sunset, is one such location renowned for its spectacular atmospheric optics displays. However, with the right atmospheric conditions and vantage point, this awe-inspiring event can be witnessed in other coastal regions as well.

To fully appreciate and understand the science behind Omega sunsets, it is essential to delve into the principles of atmospheric optics. These phenomena are a result of the interaction between light and the Earth's atmosphere, which can bend, scatter, and refract light rays in fascinating ways. Understanding the underlying physics of these phenomena adds depth to our appreciation of the natural world and the wonders it presents.

The reddening effect observed in the stem of an Omega sunset is due to the scattering of sunlight by particles in the atmosphere. As sunlight passes through the Earth's atmosphere, it interacts with molecules and tiny particles suspended in the air. These particles scatter shorter wavelengths of light, such as blue and green, more efficiently than longer wavelengths like red and orange. Consequently, when the sun is low on the horizon during a sunset, its light passes through a larger portion of the atmosphere, increasing the scattering of shorter wavelengths and resulting in a predominance of longer-wavelength colors, hence the reddish appearance.

The formation of mirages, including the fluttery edge seen in an Omega sunset, is a consequence of temperature gradients in the atmosphere. Temperature variations cause the density of air to change, which, in turn, affects the speed at which light travels through it. When light rays pass through air layers with different densities, they bend or refract, creating distorted images. In the case of mirages, these temperature gradients near the surface can cause light to bend upwards, giving the illusion of objects appearing above their actual position.

Observing an Omega sunset is a remarkable experience that reminds us of the extraordinary beauty and complexity of our atmosphere. The interplay between light, particles, and atmospheric conditions creates a mesmerizing display that leaves spectators in awe. Whether it be the reddened stem or the fluttery edge of a mirage, each element adds to the enchantment of this unique atmospheric optics phenomenon.

In conclusion, Omega sunsets are a captivating display of atmospheric optics, characterized by an inverted image of the sun's lower limb rising out of the waves. The reddened stem or red flash observed during these sunsets is a result of the magnification and scattering of longer-wavelength light. The spikes seen on the apparent horizon are not waves but rather the fluttery edge of a mirage, adding to the overall spectacle. Understanding the underlying physics of these phenomena enhances our appreciation of the natural world and the wonders it presents. So, keep an eye out for an Omega sunset and prepare to be amazed by the breathtaking beauty of our atmosphere.

A close up from Michael Myers' sunset sequence at Cape Hatteras.

An inverted image of the sun's lower limb is rising out of the waves.

The 'stem' where the two images meet is noticeable reddened.

This is sometimes called a red flash and is produces in the same way as the I-Mir green flash which sometimes occurs later in these sunsets. The lower limb of the sun has a red rim and the region where the two images of this limb meet is highly magnified in the vertical direction. The result - a reddened stem or red flash.

The spikes on the 'horizon' are the fluttery edge of the mirage rather than waves.

Image ©Michael Myers, shown with permission.

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!