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RESEARCHINSCIENCEFlorence Mae Ausan8 DescartesMrs.Elizabeth PicartTeacherTOPIC: Atmospheric phenomena: Halos, Sundogs and Light PillarsSundogs, light pillars, and other kinds of halos seen in the sky are atmospheric phenomena that occur when light, usually from a natural source, but also sometimes from artificial sources, is reflected or refracted by ice crystals in the atmosphere.A sun halo seen from Lofoten Islands, NorwayiStockphoto.com/antony spencerThe size, shape, and distance from the arth!s surface of the ice crystals determine what kind of optical phenomenon people on arth will o"ser#e. It also depends on whether the li$ht is reflected or refracted "y the ice crystals. Reflection occurs when li$ht "ounces off the surface of an o"%ect. &n the other hand, refraction occurs when li$ht enters an o"%ect and "ends.Ice CrystalsIce crystals can "e found hi$h up in the sky all around the world, at any time of the year. 'enerally, these crystals, which ha#e a he(a$onal molecular structure, are found in the cirrus clouds. Sometimes, in #ery cold weather, ice crystals form #ery close to the arth!s surface. These crystals are known asdiamond dust.)hile the molecular structure of ice crystals is always he(a$onal, their shape can #ary from a flat plate to a column. *alos and other optical phenomena are created "ecause of the interplay "etween the shape of the ice crystals and the an$le "etween their facets. This an$le is always +, or -, de$rees. .ecause of this, scientists who study atmospheric optical phenomena classify them as +, de$ree or -, de$ree phenomena.In addition to the shape of the ice crystals and the an$le "etween the facets, the orientation of the ice crystals also determines the kind of optical phenomenon that will "e created. /late shaped crystals float in the air horizontally like a leaf. &n the other hand, column shaped ice crystals tend to float in the air #ertically.Types of atmospheric phenomenaHalosTwo kinds of halos are most commonly o"ser#ed from arth 0 the 11 de$ree and the 2+ de$ree halos. In $eneral halos can "e seen throu$hout the year, around the world. *owe#er, they are more often seen in the winter months "ecause the cold weather creates "etter conditions for the formation of halo3$eneratin$ ice crystals.11 de$ree halos are formed when li$ht passin$ throu$h an ice crystal "ends 11 de$rees, while 2+ de$ree halos occur when the li$ht "ends 2+ de$reesIce crystals in the atmosphere create glowing spots on both sides of the Sun, called sundogs.iStockphoto.com/ Scene4ItSundogsA sundo$, also known as sun do$, mock sun or parhelion, consists of $lowin$ spots around the sun. They are created "y sunli$ht refractin$ off plate shaped ice crystals in the cirrus clouds. Sundo$s are some of the most fre5uently o"ser#ed optical phenomena and can "e o"ser#ed throu$hout the year and anywhere in the world. They are also associated with 11 de$ree halos.Sundo$s tend to "e most #isi"le when the Sun is close to the horizon. The part of a sundo$ closest to the Sun tends to "e red in color, while the areas further away from the Sun $enerally appear "lue or $reen.Li$ht from the 6oon also creates $lowin$ spots on "oth sides of the 6oon, called moondogs. Also known as mock moon or paraselene, moondo$s are rarer than sundo$s "ecause they only occur when the 6oon is full or close to "ein$ full.Light Pillars'enerally seen in cold, arctic re$ions, li$ht pillars are an optical phenomenon where columns of li$ht can "e seen emanatin$ from "elow or a"o#e a li$ht source. Li$ht pillars occur when natural or artificial li$ht reflects off flat ice crystals in the air close to the arth!s surface.Li$ht pillars caused "y the Sun are called Solar or Sun pillars, while those caused "y the 6oon!s li$ht are called Lunar or Moon pillars. )hen the li$ht source is the Sun, li$ht pillars are usually seen when the Sun is near the horizon. )hile Sun and 6oon pillars are more common, li$ht pillars can also occur due to the presence of artificial li$hts..ecause the ice crystals in the atmosphere reflect the source li$ht, li$ht pillars tend to take on thecolor of the li$ht source.Parhelic Circle/arhelic circles are a rarer optical atmospheric phenomenon. They are white circular "ands in thesky at the same le#el as the Sun or 6oon. 'enerally, only parts of the circle can "e seen at a time. They are $enerated when #ertical or nearly #ertical ice crystals of any shape reflect sunli$ht7or moonli$ht8.Observing Sun Dogs and HalosAlways take precautions while o"ser#in$ any Sun related phenomena. Ne#er look directly into the Sun. Always wear protecti#e $lasses or use o"%ects to "lock the direct $lare of the Sun.TOPIC: Light-based technologies: sustainable solutions for the future Optoelectronics Research Centre, Southampton, UK. Fiber Optics; connecting the world with light.Over a thousand participants came to UNESCO on 19-! "anuar# !1$ to learn a%out the man# &a#s in &hich light is ma'ing a difference in our dail# lives and e(change ideas on the solutions light-%ased technologies can provide to current glo%al challenges) *he -da# opening ceremon# of the +nternational ,ear of Light -+,L!1$. gathered leading scientists/ including $ No%el 0ri1e &inners/ as &ell as decision ma'ers/ N2O representatives and industr# representatives to discuss all aspects of light/ from the 3uantum to improved streetlighting or afforda%le glasses)The study of li$ht has led to applications that ha#e shaped our current information society. 9i"er3optic communications ena"le the internet we use today. Lasers can encode hundreds of tera"ytes of data to store an e#er $rowin$ knowled$e "ase. Li$ht3"ased technolo$ies are helpin$ us e(plore space with telescopes e5uipped with sensors that collect data from the ultra#iolet to the infrared ran$e of the spectrum, and e#en map our :ni#erse in its infancy "y capturin$ the cosmicmicrowa#e "ack$round 0 the relic radiation from the .i$ .an$. ;emote sensin$ from satellites isalso helpin$ us to "etter understand our planet, predict the weather, and monitor and mana$e pollution.

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