The sky holds many wonders. The old familiar ones like the stars and Milky Way and the moon, or puffy clouds that look like dragons and rainbows and sunbeams…well, most everyone are familiar with those sights.
Rarer are such optical wonders of light and shadow like "sun dogs"—ice crystals in the upper atmosphere that make it appear like two or more suns are in the sky. Layered atmospheric refractions also cause wonder and sometimes confusion: land masses can be seen floating above the horizon, ominous shadows appear to be descending upon the countryside, or bright planets like Venus and Jupiter can appear to sparkle, change color, and skip erratically across the sky—leading many to frantically report a UFO sighting.
Yet of all the illusions that the world can create to fool and tantalize the human eye, few are as spectacular as the rarest of the rare: the Brocken spectre phenomenon.
During the Middle Ages sightings on Brocken—the highest peak of Germany's Harz Mountains-led surprised witnesses of the bizarre illusion to name it after the mountain. Later, German scientist Johann Silberschlag observed and officially recorded the meteorological phenomenon during 1780.
This spectacular optical illusion occurs when thick fog or mist is back lit by bright sunlight, the light is beneath the observer, and the sun rays are refracted upwards past an object or a person. The observer, when positioned at the correct angle to the back light, sees the refracted and diffracted, ghostly image through fog.
A Brocken spectre often occurs on mountainsides, against clouds and sometimes can be observed from aircraft.
The shapes can be lenticular, oval or round and sometimes triangular depending on the refraction and how much the light rays are being bent. Objects, even people, take on a weird, ghostly appearance. The entire episode seems otherworldly.
Adding to the confusion and consternation of an unsuspecting witness, the top of an object or head of a figure usually surrounded by concentric rings of rainbow colored light. The light is being scattered by diffraction. It looks like a rainbow because it is. The same principle can occur when watering a lawn with a garden hose nozzle set to spray and the sunlight passes through the water droplets at the correct angle.
For many years, superstitious villagers near the Harz Mountain range claimed that a climber seeing a Brocken spectre would die in a fall the following day.
As far as is known, the photographers that captured the spectacular photos linked to at the end of the article all lived to tell the tale.
Eerie Brocken spectre photos
Brocken spectre 1
Brocken spectre 2
Brocken spectre 3