A man was walking along the British coast this week when he was surprised to see what in the distance looked like a large ship floating in the air. His remarkable photographs actually show an optical illusion caused by a rare ‘superior aerial image’.
52-year-old businessman David Morris was walking along the shores of the village of Gillan in Cornwall on Thursday when he noticed the strange face. He was able to pull out his smartphone and take a series of photos of the flying ship before the phenomenon passed.
“The images apparently show evidence of a phenomenon called fata morgana,” said a spokesman for the British Met Office. A rare and complex form of mirage in which horizontal and vertical deformation, inversion and elevation of objects in changing patterns occur.
“The phenomenon occurs on a water surface and is produced by the superposition of several layers of air with different refractive indices.”
If you put a straw in a glass of water, it can look broken because the light from the straw is bent by three different mediums (and refractive indices) of air, glass and water. The same principle happens in Morris’ photo with air layers that bend light differently.
“Superior mirage occurs due to the weather condition known as a temperature inversion, where cold air lies near the sea with warmer air above it,” says BBC meteorologist David Braine. BBC News. “Since cold air is denser than warm air, it bends light to the eyes of someone standing on the ground or on the shore, changing what an object looks like in the distance.”
You do not see it every day from Falmouth! 😲#mirage #valley#koringmuur pic.twitter.com/XvGr5s3rtz
– Colleague (@BBCSpotlight) March 4, 2021
This type of mirage can make ships appear in the distance as if they were hovering above where they actually are, but they can also make ships visible below the horizon as they usually would not be. Braine also notes that superior mirage is more common in the Arctic regions of the planet, but that it is “very rare” to be detected in the south, such as in the United Kingdom, in winter.
“I was just admiring the image in such a lovely part of the country,” Morris says.
Image credits: Headline of photo cut by David Morris / Apex