The effect is created by the reflection of light from tiny ice crystals that are suspended in the atmosphere or that comprise high-altitude clouds (e.g. The photos can be seen on the official website of Hessdalen lights at . A light pillar is an atmospheric optical phenomenon in which a vertical beam of light appears to extend above and/or below a light source. Numerous photographers have taken pictures of the Hessdalen lights and posted on several online websites. Cole, a tour guide with Alaska Photo Treks, was setting up a. Many lights and other objects in the sky go unrecognised, or at least are little understood by those observing them. The automated station discovered that the Hessdalen lights generally appears in the sky at night amid 9 pm and 1 am, especially during winters. Ripples on the surface of the water reflect the light source in many directions, and those that happen to be aimed at the viewer, combine to form a bright line pointing toward the light source. At first, Ronnie Cole thought the bright light in the sky over southern Alaska was an airplane. In the Northern Hemisphere, the phenomenon is called the northern lights (aurora borealis), while in the. This is similar to viewing a light source on a body of water. When that wind slams into Earth's ionosphere, or upper atmosphere, the aurora is born. Its appearance as a vertical line is an optical illusion, resulting from the collective reflection off the ice crystals but only those that are in the common vertical plane, direct the light rays towards the observer (See drawing). Unlike a light beam, a light pillar is not physically located above or below the light source. A Sun halo seen from Lofoten Islands, Norway. In very cold weather, the ice crystals can be suspended near the ground, in which case they are referred to as diamond dust. Sundogs, light pillars, and other kinds of halos seen in the sky are atmospheric phenomena that occur when light is reflected or refracted by ice crystals in the atmosphere. More rarely, column-shaped crystals can cause light pillars as well. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. As light pollution continues to reduce the number of stars and other celestial objects that we can see, delicate dark-sky-only phenomena such as airglow. The larger and more numerous the crystals, the more pronounced this effect becomes. A halo (from Ancient Greek (hls) 'threshing floor, disk') is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in the atmosphere. Each flake acts as a tiny mirror which reflects light sources that are appropriately positioned below it (see drawing), and the presence of flakes at a spread of altitudes causes the reflection to be elongated vertically into a column. The crystals responsible for light pillars usually consist of flat, hexagonal plates, which tend to orient themselves more or less horizontally as they fall through the air. Since they are caused by the interaction of light with ice crystals, light pillars belong to the family of halos.
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