A walker in Cornwall has captured a rare optical illusion showing a tanker apparently hovering above the sea. David Morris spotted the mirage while strolling near Falmouth and described himself as “stunned” by the sight.
The phenomenon, known as a superior mirage, occurs when a temperature inversion causes cold air to lie close to the sea with warmer air above. Since cold air is denser, it bends light rays downwards, making distant objects appear higher than they are.
BBC meteorologist David Braine explained that superior mirages are more common in the Arctic but can occur in UK winters under the right conditions. “Here a distant ship appears to float high above its actual position,” he said.
The effect can also make objects below the horizon visible, a phenomenon sailors call “looming”. In some cases, the image may be distorted, creating “towering” or “stooping” mirages.
Superior mirages differ from the more familiar inferior mirages, which create the illusion of water on hot roads or in deserts.
