View at EarthSky Community Photos. | Juned Patel captured this rare omega sunrise from Norfolk, UK, on June 5. Juned wrote: “This phenomenon is called an ‘omega sun’ because it resembles the Greek letter omega. The actual sun is the disk at the top. The bottom disk, which appears like an omega, is an inverted image of the sun due to refraction. The mirage occurs due to sunlight refracting through a layer of warmer, less dense air near the ocean’s surface.” Thank you, Juned! An omega sunset or sunrise explanation from Les Cowley, below.
What causes an omega sunset or sunrise?
Les Cowley at the great website Atmospheric Optics explains omega sunsets and sunrises this way:
As the sun descends a second sun rises from the water. Eventually the two join at a red hued vertically stretched ‘stem.’ Jules Verne likened this appearance to an Etruscan vase. The stem shortens and thickens until the two suns appear like a Greek letter omega …
The lower sun is not a reflection from the water. It is an ‘inferior mirage’, so named not from any poverty in appearance but because the miraged sun is below the ‘real’ one. The lower sun is an inverted image. It’s produced by refraction by a layer of warmer and less dense air close to the ocean surface. The discus shape is a combination of the upper limb of the erect sun and an inverted image of it beneath.
Omega sunset from 2015
Josh Blash caught this omega stage of an inferior mirage sunset on November 27, 2015 at Venice Beach, California. Josh also pointed out that Carl Sagan once said: “It does no harm to the romance of the sunset to know a little bit about it.” Visit Josh on Facebook.
Bottom line: Omega sunset seen over Venice Beach, California in November, 2015.
Click here for a more detailed explanation of Omega sunsets and sunrises
Deborah Byrd
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About the Author:
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.
