10 phenomena observed with light

BY:SUBHI SHARMA

LOYOLA SCHOOL, JAMSHEDPUR

Polar Stratospheric Clouds exist at very high altitudes within Earth’s stratosphere (around 70,000 ft). Clouds normally do not form in stratosphere because of its extreme dryness. During winters however in high latitudes temperature falls low enough to permit formation of clouds in stratosphere. These clouds appear colorful when sunlight is refracted off ice crystals. They are only noted during sunrise and sunset.

POLAR STRATOSPHERIC CLOUDS

Halos are optical phenomenon produced by ice crystals creating colored or white arcs in the sky. Mostly they are visible near the sun or moon, but sometimes they can be seen even in the opposite part of the sky. In extreme cold weather they can also form around artificial lights.

HALOS

MAMMATUS CLOUDS

Mammatus clouds are cellular pattern of pouches hanging underneath the base of a cloud. They are formed in sinking air contrary to any other form of clouds that are formed in rising air. There are various hypotheses offered behind the mechanism of its formation.

MOONBOW

A moonbow is a rainbow produced by moonlight rather than from direct sunlight. Moonbows are usually faint. Because of the faint light usually it becomes difficult for the human eye to discern colors in a moonbow and as a result they often appear to be white. However, all colors of a moonbow do appear in long exposure photographs.

LIGHT PILLARA light pillar is a visual phenomenon created when light is reflected off by ice crystals giving out roughly horizontal parallel light beams. The light can come from the sun, moon or from terrestrial sources such as streetlights. The pillars are not physically over the lights or anywhere else in space. They are purely collected beams of light reflected from all the millions of crystals, which just reflect light towards the observer’s eyes.

Aurora Borealis

Aurora or polar light are mesmerizing natural light display in the skies of high latitude regions. They are caused when energetic electrically charged particles from solar wind accelerate along the magnetic field lines into the upper atmosphere, where they collide with gas atoms, causing the atoms to give off light. The auroral zone is typically 10° to 20° from the magnetic poles.

VIRGA

Virga is an observable wisp of precipitation that falls from a cloud, but evaporates before reaching the ground. It is very common in the desert and in temperate climates. In North America, it is commonly seen in the Western United States and Canadian Prairies.

Triple Rainbows

Rainbows are formed when sunlight is refracted off water droplets suspended in air. Sometimes when sun breaks through dark thunderclouds during a heavy downpour, more than one rainbow is created that is only visible against a dark backdrop.

Green Flashes of SunGreen flashes and green rays are optical phenomena that occur shortly after sunset or before sunrise. A bright green spot is visible no more than a couple of seconds on top of the sun. They can be observed from any altitude (even from an aircraft). They are usually seen at an unobstructed horizon l ike an ocean, but are even possible over cloud tops and mountain tops.

Anticrepuscular RaysAnticrepuscular rays are near-parallel light beams that appear to converge to a point towards the sun. Anticrepuscular rays are most frequently visible during sunrise or sunset. Although they appear to converge, it is merely an illusion. They in fact run almost parallel and the apparent convergence is to the vanishing point at infinity.