The Spectre of the Brocken (or Broken) is sometimes seen in just the right combination of fog, sun, and position. It looks like the outline of a human being, shadowy in the mist, with a pale rainbow as a halo. It's not supernatural, though — it's just physics. Find out how this happens below.

The Spectre of the Brocken is often seen at the top of mountains, late or early in the day, in high mist. You generally need altitude to see it, because it requires space for both a strong, directed sun on one side of you and an alley of clear space on the other. Sometimes the spectres are confined to the space of an empty patch of woods. Sometimes larger ones hang in the air to the side of a ridge. Some spectres look like giants walking over the tops of faraway mountains.

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These figures aren't anything more supernatural than a shadow. Most of the time we can't see the shadows that a low sun makes when we're on the peak of mountains. The sun casts our shadows outwards across a valley, and at such a distance scattered sunlight obliterates the shadow before it can be projected against the landscape. A mist, though, provides a portable screen. We see the light reflected back by the mist around us and we see the place where our shadow blocks out that light. Sometimes it looks like an ordinary shadow, but when the sun is low enough to project the shadow onto the mist above us it can be incredibly dramatic to look at.

The halo of rainbow light is also created by the mist droplets. Light is reflected off the back wall of the drop of mist. When white light travels through a prism, like a water droplet, it bends. Each wavelength of light bends to a different degree. Our eyes can only take in the light that is sent back to our pinhole of a pupil. The red light that hits our eyes will only come from one particular angle to our pupils. The orange will come from another angle, the yellow light from another, and so on. Since our pupils are placed in our heads, the rainbow that we see will encircle our focus on the head, and look like a halo.

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Brocken Spectres aren't only caused by people. There are pictures of the 'spectres' of animals, rock outcropping, and even airplanes. Take a look around the next time you're on a mountain peak in the mist.

Image: E64

Second Image: Modern Hiker

Via: AT Optics.

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