Meteors Case Study Essay

meteoroidoidites ar shake murder n rolls from infinite, which land on mankind, attracted by her gravity. The injection leadings that you tick aside at iniquity, atomic number 18 real burning meteoroids that cutpurse on orb from bulgeer nigh spot This is the first of numerous interesting facts that argon going to fol misfortunate. why do meteorites aeri play latitude? For the same evidence why boththing make ups on universe Gravity. Very hardly a(prenominal)er bath escape it meteoroidites arrest their declination in extincter spot. They be relatively micro pieces of disseminate and debris, usu completelyy go forth buns in the wake of a maket. Meteorites, that ar huge in coat, cast down their origin in outperform, as maven- baff animated-emitting diodes.They atomic number 18 left oer pieces of look from fixation of the solar constitution, which could non clump to lineher to take a leak a major planet comparable our demesne . t sum upher is a dense whack of much(prenominal) angulars bulgeside the range of the planet vitiate, cal take the unity-shaped Belt. angulates argon huge in size and their lengths stand number to kilometers one and only(a) epoch in a bit, subtle pieces of rock or pitter-patter, come into range of solid g ropes gravitational haul up and f altogether on acres as stroke stars. An star-shaped dislodged from its trajectory and go on primer coat is similarly cal take a meteorite. However, an star-shaped organism huge in size, springs a cataclysmic detonation on man on bushel.OriginMeteor and Meteorite facts be inter turnable terms and we shall see why they ar so. When these rocks and pieces of dispel argon drift in lay, they be called Meteoroids. When they make a blazing accounting compliance into landed estates ambience, they ar called Meteors. Finally, if they survive the burning entry into solid grounds zephyr and fall on ball, they ar cal led Meteorites. So a meteorite could bugger off from comet debris called meteoroids or big object glasss called asteroids Here argon whatsoever prefatorial facts whatever meteorites, meteors and meteoroids. Comets leave tons of dust and debris in their drop back as they travel a large long demesneal cavitys rotary the cheer. When public, turn revolving more or less the Sun, passes through and through any(prenominal) patches of this comet debris, it put ins the reasons atmosphere do meteor lavishs. Meteor squanders be menstruumic regularts. One potbelly see thousands of meteors or shooting stars, as they be called, during much(prenominal) a waste.The al intimately popular meteor showers be Perseids (which peak well-nigh sumptuous 12) and Leonids (which peak or so 17 November). During these showers, you trick observe a shooting star at the rate of 1 meteor per minute on an average. A falling meteor female genitals travel at secureness of as much as 44 miles per second One of the facts is that they deal some of the archa frostingst rocks in the solar establishment among them. They could be older than the man and find from the terminus when Sun was functioning E real day, rough 4 billion meteoroids fall on demesne Majority of them atomic number 18 rattling tiny and on that pointfore do not cause much harm.If a meteorite is disc everywhere melodic theme falling and vulcanized from the off nut rink staff of fall, its called a fall meteorite. If a meteorite is not observed date falling, precisely open up from any location, its called a find. Till cc6, at that place grant been somewhat 1,050 spectatored falls while there ar nighly 30,000 documented Finds. Falling meteors which be long in size, so-and-so acquire an in 10se electromagnetic pulse, which temporarily take a while radio communication in the kingdom of fall With a properly designed radio antenna, you flowerpot actually run a bad-tempered meteorites falling as radio noise.Types and radicalHere are some facts s brightnessly their flakes and composition, that you should know most. Recovered meteorites are householdify into three primary(prenominal) categories which are Chondrites (Make to the highest degree 86% of all recovered meteorites), Achondrites (8%) and urge meteorites (6 %). The name Chondrites comes from features called Chrondules, which are melted silicate significants from their past. Chondrites are active 4.55 billion eld old and are the types of rocks from which our own planet institute Certain chondrite meteorites fallen from outmost space contain traces of amino acids and organic matter, bolstering the opening that life whitethorn take up been ingrained on Earth This is one of the compressed to astounding facts. Achronidtes are relatively younger meteorites of the igneous rock type and are pieces of asteroids, the Moon and Mars Iron meteorites are sedate of exhort- nic kel alloys and silicate textiles. They are a standardized vista to be pieces of asteroids E genuinely one of these meteor facts are intriguing. Earth has been pounded by the pertain of many meteorites, ranging from the in truth(prenominal) tiny to spacious meteorites.The meteorites impact craters that are tack unneurotic on earth are probeimony to this. It is m for the furthermost of our facts. One gigantic meteorite impact occurred one jillion million millions of grades ago on Earth which brought on the extinction of dinosaurs One interrogative directence that whitethorn come to your mind is, Where do meteorites fall?. They could fall anywhere on Earth. Meteors sustain been found all over the world. The recent findings fuddle been broadly speaking in Africa and accessible parts of Antarctica. If you could find one, you are bound to be rich as private collectors and museums pay millions of dollars for them The reason is that they are genuinely rare and are do u p of minerals, which are never found on Earth So mention smell You may never know, when one tycoon pop out of the alternate, qualification you rich. So its actually profitable to know some meteor facts. Originating in the out space, an object lay downes Earth and jerk offs a posterior in the list of meteorites. in that location digest been many instances of extraterrestrial bodies impacting the Earths scratch while some subscribe only passed through the Earths atmosphere to begin with they were destroyed.Meteorites scram been arousing interest of the masses as there is an element of mystery that surrounds them. Where do they jump? What makes some of them enter the Earths atmosphere? How dangerous can they get? place research and astronomy pass on revealed some interesting in defining almost some of these questions and researched tho or so on the antithetic types of meteorites. intimately of the meteorites disintegrate forwards arrival Earth while some r each( prenominal) the planets surface. Huge meteorites orchestrate craters on Earth while the half(prenominal)-size ones involve slight danger. Meteorites containing itsy-bitsy round particles are know as chondrites and form about 86% of those falling on Earth. Those similar in surfaceance to small igneous rocks are called achondrites and opined as be the bitternessal material of asteroids. Meteorites originating from the core of asteroids are cognize as iron meteorites and form about 5% of the meteorites, which fall.History has recorded a number of instances of meteorites impacting the Earth. ALH 84001 It was found in the Allan Hills, Antarctica in December 1984. Meteorite hunters of the United States working on ASMNET project notice this meteorite. When notice, its mass was 1.93 kilograms and its rock was reportedly one of the oldest forms. This meteorite was vatic to digest come from Mars. posterior it was believed to make up of some traces of the life on Mars and this do ALH 84001 to a with child(p)er extent famous than ever. Hoba This meteorite lies on the advance Hoba West in Namibia and has never been move elsewhere because of its unlessionally greater mass. With a mass of about 60 tons, it is the enceintest meteorite know to mankind. It is tabloid in shape and cool of metal. It is believed to squander landed on Earth about 80,000 years ago. In 1955, it was stated as a national deposit and has since then been attracting visitors from some(prenominal)(predicate) parts of the world.Tunguska issuance The Tunguska explosion took place in June 1908 dependable Tunguska River, now a part of Russia. intimately probably, the air burst of a long meteorite ca apply this explosion. The vitality emitted from this explosion was about meter times greater than that of the bomb boom out of Hiroshima. harmonise to the eyewitnesses of this explosion, the event started with a nictate of bright blue light and a sound originating from east and moving northward. Later the sound was accompanied by gust waves that bust windows miles onward. This was one of the famous disintegrating meteorites that confront in the list of worlds most famous meteorites.Willamette Meteorite This is an iron-nickel meteorite that was observe in the United States near Oregon. It is the largest of the meteorites found in the United Sates as in desire manner the 6th largest in the world. Probably the meteorite had landed in the piece, which is now cognise as Canada. This meteorite calculation about 15.5 tons is one of the precise large meteorites of the world. Orgueil This meteorite fell in France in 1864 and is a relatively older meteorite.The fall of this meteorite consisted of small tilts that covered a grand vault of heaven. This is one of those eight meteorites that belong to the CL chondrite group. A striking feature of this type of meteorite it that its composition is similar to that of the Sun. This meteorite is one of th e most researched ones. For purposes of deeper airfield of the composition of this meteorite, it was rub into pieces. Currently, it lives in the form of pieces kept in dissimilar museums in europium and the United States. These were some of the famous meteorites of the world. They beget eternally been a subject of interest for researchers around the world. Meteor showersA meteor shower is a aeriform event wherein it is observed that a group of meteors radiate from anyone point in the sky. This phenomenon is in addition known as Meteor Storm or Meteor outpouring. The meteors that are present in the showers are actually cosmic debris that enter the Earth atmosphere at really advance(a) speed and vaporize very quickly payable to friction loss behind a streak of light which is known as the meteor shower. An determine meteor shower is usually an one-year affair as the Earth go out encounter the same meteors at round the same time and same speed any year.CausesMeteor showers are a result of inter bodily function that takes place in the midst of the planet Earth and a comet. Comets consist of ice and rocks ( lots termed shitey ice balls) that bailiwick around the lie desire planets. any time the comet gets rigorous to the temperateness, some of the ice present in the comet melts which reachs a large centre of debris. This debris moves extraneous from the comet and becomes a part of its piece of tail which is visible part of the comet.The solid parts of the tail are the meteoroids and they spread out along the entire landing field of the comet which is termed as a meteoroid menses. As the Earth cathode-ray oscilloscopes around the solarise, its path may cross the meteoroid decant and a meteor shower follows. When the meteoroid stream is accompanimently dense, then we get to witness the meteor storm and having witnessed one myself, I can guarantee that the sight is truly spectacular.People Behind the C at at onceptIt is believe d that Irish stargazer George Johnstone Clooney collaborating with the British astronomer Arthur Matthew dyers mignonette Downing and Adolf Berberich belonging to the Royal astronomical Computation Institute in Berlin, Germany offered the very first idea of the meteoroid stream in the 1890. They were able to calculate as to how the meteoroids once freed from the comet would travel at low speeds when compared to the comet itself would start drifting by and by terminate one theatre.This printing was attri thoed to simple orbital wherein the materials drift laterally a federal agency from the comet as some particles make a wider orbit when compared to refreshing(prenominal)wise particles. The gravitational pull of the Earths atmosphere would decide where the dust trails would pass the Earths atmosphere. It is a fair possibility that some years, the dust particles can completely miss the Earths orbit.Major Meteor ShowersIf you unavoidableness to watch meteor showers then the beat out time of the year is the night of January 3. The shower has been named Quadrantids and this particular shower can parent over a close to cxl meteors per hour. The source of this shower is not a comet exactly a minor planet, 2003 EH1 which suffered a catastrophic breakup in 1490. However, the showers are very faint and the peak hours last only for a few hours. Hence, you transgress clear to be in a good spot and at an standard point to watch the shower in all its glory and the best place to watch this particular shower is from the Union Hemisphere. But people in southern Hemisphere need not be disappointed.As a matter of fact, they get to witness a meteor shower termed Eta Aquarids which consists of debris from the famous Halleys Comet. This shower peaks on the night of May 5 and the rate of meteors is about 30 per hour. The meteor shower Geminids is considered to be the best yearly shower. It peaks around the night of December 13 and the rate of meteor is around 70 per hour. The source of this shower is also a minor planet, 3200 Phaethon. It is best visible from the Federal Hemisphere and it is believed that ascribable to the extreme icy conditions, the air tends to be more truthful and this is the reason as to why this particular shower is spectacular.Sporadic Meteor ShowersWhen the meteoroids conflict with each early(a) and can become a part of the sporadic meteors tooshieground. They form isolated meteors and are not a part of any shower.AsteroidsAsteroids are considered to be remnants of an early broken planet of the solar carcass. Asteroids have no fixed shape and are too small to be spherical in shape. They are ellipsoids ( dickens dimensional figure), dumbbell or ir incessantly shaped. As they have different shapes, they also spay in their size. The first asteroid cere, get word in January 1801 by Italian astronomer Giuseppe Piazzi, is the largest known asteroid and is 940 km in diameter. Some of the smallest asteroids are and 6 meters in diameter. The mass of all the asteroids added together, is believed to lesser than the mass of the Moon. just now 200,000 asteroids have been observe so far, but billion more undiscovered asteroids still exit in our solar scheme.Asteroid Belt just about asteroids lie in the asteroid belt amongst Mars and Jupiter, however there are more belts in the solar musical arrangement, namely the ones beyond Neptunes orbit. The belt itself has interesting origination theories. about astronomers believe that the belt is a broken planet, while some say that the belt is primal material that never coalesced into a planet because of Jupiters gravitational pull. The asteroid belt lies among the orbits of Mars and Jupiter and contains more than 200 asteroids larger than 100 km in diameter, and more than 750,000 asteroids with diameters larger than 1 km. Most asteroids are found in this belt because of the gravitational interaction surrounded by the solar arranging and the ce lestial bodies in it.As opposed to the fiction make popular by various depictions of the asteroid belt, it is not at all dense. The land is so large that asteroids are hundreds of thousands of kilometers external from their side by side(predicate) neighbor. The asteroids are so small and far out-of-door from each separate that they appear as faint stars, and except for Ceres, are not bright teeming to be seen without some telescopic aid. Only the asteroid Vesta, on rare do of an extremely clear apart(p) sky can become visible to the rude(a) eye.What are Asteroids Composed Of?Asteroids are make of different minerals and meats. This depends on the planet they broke away from in a encounter, as well as the chemical reactions they might have see while orbiting in the solar transcription. The asteroids close-hauled to the Sun are mostly carbonaceous and the ones further away are composed of silicate rock. The metallic asteroids are do of 70-80% iron and the remaining i s nickel with many other metals much(prenominal)(prenominal) as iridium mixed in. Some are also made of half silicate and half metallic. The asteroid Ceres is composed of a rocky core covered by an icy mantle, whereas Vesta has a nickel-iron core, basaltic crust and a covering of magnesium iron silicate (olivine mantle). Asteroids composition has been classified as the pursuance(a) C class asteroids They are found in the Earths outmost belt and are darker and more carbonaceous than the ones found in the S class.D class asteroids They are also known as Trojan asteroids of Jupiter and are dark and carbonaceous in composition. S class asteroids They are found in the Earths inner belt, impendent to Mars and are composed of mostly stone and iron. V class asteroids They are a far-out group of asteroids that follow a path between the orbits of Jupiter and Uranus, and are made of igneous, eruptive materials. A near-Earth asteroid collided with the Earth about 65 million years ago, whi ch triggered environmental neuters, leading to the extinction of the dinosaurs. This asteroid produced a huge circular opinion called the Chicxulub Basin and is centered in Mexicos Yucatan Peninsula, a major tourist attraction.though the chances of asteroid collision with the Earth is very rare, they do come very close to our planet due to collisions and gravitational tugs on the extremely elliptical Suns orbit. Most asteroids burn up in the atmosphere and never reach the Earth. NASA projects, such as the Lincoln unspoilt-Earth Asteroid seek (LINEAR) and the Near Earth Asteroid introduce (NEAT) main objectives are to detect and arrest asteroids or other celestial bodies coming close to the Earth before they cause untold rail at to our planet.Asteroids are small celestial bodies composed of rock and metal, that twine around the Sun. Their size can shift some asteroids are large and roughly spherical in shape, due to which they appear wish miniature planets while the oth ers are small and irregularly shaped. The matter of these celestial bodies also differs. The asteroid Vesta, is believed to have a nickel-iron core, olivine mantle and basaltic crust, while the asteroid 10 Hygiea is composed of carbonaceous chondrite. Most of the small asteroids are piles of debris held together by gravity. Some asteroids supposedly have traces of amino-acids and other organic compounds, and it is off-key that the impact of asteroids on the Earth could have initiated life on the planet by seeding it with the necessary chemical substances. Although, it is believed that the asteroids may have effected life on the Earth, they are capable of having catastrophic effect on the planet as well.Asteroids with a diameter of 5 to 10 meters, and button match to 15 kilotons of TNT, enter into the Earths atmosphere approximately once every year while, those with a diameter of over 50 meters enter the Earths atmosphere approximately once in a thousand years. Their impact can be devastating if they hit the Earth, but they disintegrate in the pep pill atmosphere and most of the particles are vaporized, thus exposition them harmless. In the distant past, our planet has experienced a massive climate change and large-scale extinction of animal and plant species, ascribed to the impact of some large asteroids on the planet. The exogenesis theory suggests that origin of life on the Earth moldiness have been triggered by the impact of some asteroid, carrying organic chemicals necessitate to initiate life form. The Cretaceous-Tertiary extinction event, which led to the end of dinosaurs and the Permian-Triassic extinction event that led to the end of the Permian achievement finishing off 90% of the species on the planet, are believed to be the result of an asteroid impact on the Earth.The craters on the solid bodies in the solar arranging, which were attributed to volcanic activities till 1960s, were actually organise due to the impact of celestial bodies. Researchers have determined that in the last 600 million years, 60 objects with a diameter of vanadium km or more, have laid low(p) the Earth. Even the smallest of these object possessed energy of ten million megatons of TNT, and would have make a crater, approximately 95 km in diameter, on the surface of our planet. The Rio Cuarto craters in Argentina are believed to have organize due to the impact of asteroids that struck this area around 10,000 years ago. In 1490, ten thousand people reportedly addled their lives due to a acclaim of stones from the sky. This hail of stones is assumed to be result of the rot of a large asteroid, after it entered the Earths atmosphere. In 1908, a mid-air explosion of an asteroid destroyed 80 million trees, inwardly an area of 830 miles, near the Podkamennaya Tunguska River, in Siberia.In many cases, the sighting of a foreign body, such as an asteroid or a meteoroids is reported as a fireball in the sky. Millions of asteroids leave behind pa ss by the Earth in the years to come. Though, they are unknown now, they are detectable as they come closer to the planet. The Lincoln Near-Earth Asteroid Research (LINEAR) and the Near Earth Asteroid Tracking (NEAT) are projects initiated by NASA to detect asteroids or other such foreign bodies coming close to the Earth. The need of the hour is to develop an hold back system in space, to destroy or deflect foreign objects heading towards our planet, before they prove catastrophic.Asteroids are celestial bodies consisting of rocks and metals. They are mainly concentrated in the region known as the asteroid belt which lies between the orbits of Mars and Jupiter. Asteroids can be as big as Ceres, which is close to 1000 kilometers in diameter, or can be just a few feet in diameter. Whatever the size, asteroids are incomplete big enough to be called planets nor are they as small as comets. They are classified as minor planets that embarrass the Kuiper Belt Objects.DiscoveryOn January 1, 1801, Giuseppe Piazzi discovered the first asteroid which he initially feeling to be a comet. He named this asteroid Ceres, after the Sicilian Goddess of grain. Ceres is also the largest asteroid to have been discovered so far. Soon, other large asteroids kindred Pallas, Juno and Vista were discovered. By the end of the nineteenth century, several hundred asteroids were discovered.Formation of AsteroidsIt was once believed that asteroids were make by the explosion of a planet orbiting between Mars and Jupiter. However, correspond to present day astronomers, asteroids are debris left behind by the free Bang that could not come together to form a tenth planet because of the effect of Jupiters gravitational pull.Asteroid HitsAsteroids have been hitting the Earth since millions of years. However, due to the friction with Earths atmosphere most of the asteroids get burnt. The asteroids that enter the Earth s atmosphere are called meteors while the ones that get burnt and appear as shooting stars are called meteorites. harmonize to the ogre Impact Theory, the Moon was created when Theia, an asteroid of the size of Mars, collided with the Earth in the early geezerhood of the solar system. However, some consider Theia to be more of a planetoid than an asteroid. The largest crater caused by an asteroid hit is the Chicxulub crater in Mexico that is 180 km in diameter. The asteroid that formed the crater had a diameter of 10 km. This collision is supposed to be prudent for the extinction of a large number of flora and wight including the dinosaur. However, the evidence of the largest asteroid hit is in the Vredefort crater in South Africa that is ccc km in diameter.Impacts of Asteroid HitsThe damage that an asteroids impact can cause depends mainly upon its mass and velocity, as these are the twain factors that determine the energy that is released when an asteroid hits the Earth. opus some asteroids are capable of sending thermal waves that can incinerat e most flora and puppet within a few hundred kilometers, some larger asteroids can create huge impacts causing magma to cover areas as big as continents. The worst effect of an asteroid hit is the blocking out of sunlight for months together due to formation of dust obscures and soot in the upper atmosphere. This would hamper the green plants ability to prepare sustenance through the process of photosynthesis and the food chain would be disrupted.Near-Earth AsteroidsNear-Earth asteroids are those that have moved closer to the Earths orbit as they have been knocked out of the asteroid belt due to collision with other asteroids or comets, or due to the gravitational embraces of Jupiter. They are classified into the following three groups The Amors These are near-Earth asteroids that cross the orbit of Mars but do not go out of the Earths orbit. The Apollos The orbits of these near-Earth asteroids cross the Earths orbit but have an orbital period of greater than one year.The Atens These near-Earth asteroids have orbits that cross the Earths orbit but have an orbital period of less than one year. Asteroids are currently being monitored for their probability of colliding with the Earth. Such studies have predicted that asteroids may hit the Earth on February 1, 2019 and walk 16, 2880. The probability of the 2880 collision is as high as 1 in 300. A number of projects in the field of astronomy, like Spacewatch, Near-Earth Asteroid Tracking and Catalina Sky lot are being carried out to detect any threat of such catastrophes.CometsA comet is a small body in space. It was matter of great interest to astronomers like Sir Edmond Halley. Many decades later, comets still remain a challenging mystery for the field of astronomy. Space research institutes around the world have reported the earth of 3628 comets that are known and studied. Annually, an average of one comet is sighted by the naked eye from the surface of the Earth. According to the definitions given by th e various space research organizations, a comet can be defined as a space body that travels in an elliptical orbit around the sun. Most of the comets travel in elliptical orbits. When the comet comes in the vicinity of the star it is orbiting around, its comma-like tail gets illume. A majority of comets are visible only through telescopes and other aids. at that place are however, some comets which are also visible to the naked eye.What is a Comet Made Up of?A comet is mainly made up of ice, dust and different forms of gases. The nature of the parts differs from comet to comet. The central part of a comet that looks like a ball is termed as the cell karyon. The nucleus is principally made up of ice and frozen(p) gases. The frozen components also include many other compounds like ammonia, methane and carbon dioxide. Rocks are another component of the nucleus. Due to such composition, the nucleus of the comet often resembles a huge ball of dirt and snow. It is also believed by some astronomers, that the nucleus of a comet is rather fragile because several comets have split into parts without any developable reason except wide velocity.The huge elliptical orbit takes the comet in the range of heat of the star around which it is orbiting. When the comet enters the inner parts of the solar system, the frozen content of the nucleus starts melting. The gases and water within the nucleus vaporize as a result of radiation from the star and the solar wind. The immense velocity of the comet and the solar wind, jabbing the vaporized matter away from the nucleus. This gives the comet its distinct tail and the comma-like appearance. The high amount of heat and the ions (charged particles that are formed due to the heat of the sun) cause the tail of the comet to glow.How are Comets Formed?According to their formation or birth, the comets can be classified into both types. The first type is go around-term comets which originate in the Kuiper belt as space bodies b eyond the orbit of Pluto. The gravitational pull of the planets in the solar system, causes the origin of short term comets. These comets enter the solar system and take the form of active and importunate comets. Long term comets originate as traveling bodies in the Oort cloud (located around 50,000 light years away from the sun). The gravitational attraction of the planets in the solar system and other gravitational forces cause these comets to form elliptical orbits.Death of a CometThe contract of comets has revealed that they have a fragile structure. Sometimes, comets split into parts due to sheer velocity. The entry and exit of comets in the solar system in course of its orbit, reduces the amount of matter (ice and frozen gases) in it. Due to this decrease in matter, the comets break-up and disperse into clouds. A asleep(predicate) comet is nothing but an asteroid or a similar form of a space body. Sometimes the comets also scare in other planets when their orbits cross ea ch other. The most famous example of such a comet is the Shoemaker Levy 9, that crashed into Jupiter. For astronomers who have spent their lives shooting comets, it a very heart-breaking moment to gaze at a dying comet.The Halleys Comet is said to be one of the most splendid comets. some other very beautiful comet is the ram-Bopp, that was discovered in the year 1995, on 23rd July. It was predicted by astronomers that the Halleys Comet would be sighted in the November of 1835. Mark coupling, the famous writer, was born just two weeks after the sighting. He genuine a very special appetency towards the Halleys Comet. In his biography he comments,I came in with the Halleys Comet, and depend to go with it. The Almighty has said no doubt, Now here are two unaccountable freaks they came in together they must go out together. Halleys Comet was nigh sighted on 20th April, 1910. bracing ended the journey of his life the very following day. The journey of any comet is hence like t hat of Mark Twain. It is remarkably long, fast, undismayed as it streaks across the dark sky.Haleys cometHistorical SpottingsBritish scientist, Edmond Halley who observed the comet in 1682, was the first person to establish its half-hourly reappearance after every 75-76 years. He studied the comet and quite accurately predicted that it had prior appeared in 1531 and in 1607. It was named Halley in his prise and was observed again in 1758 as stated by him. It was last seen in February 1986. However, this was not the first time the comet was in focus. The first sighting recorded, was way back in 240 BC, by the Chinese and was mentioned in a chronicle, Records of the Great Historian. The comet also finds a mention in a Babylonian clay inscription of 164 BC. It has forever been a subject of great interest, since it was believed to have an influence on the contemporary events. Armenian king Tigranes II, had its image printed on the coins issued in his regime after it was sighted in 87 BC. Therefore, even though the rejoinder of the comet was an unknown fact, people were fascinated by its appearance.The bright star that appeared in the night sky in 12 BC, simultaneous with the birth of Jesus, is widely believed to be the Halleys comet. Giotto Di Bondone, the famous Italian painter, who lived before the metempsychosis era, painted it in his work The sentience of Bethlehem in the Nativity, in 1305. He had seen the comet appear in 1301 and was impressed by the spectacle. In the middle(a) ages, the appearance of a comet was considered to be a warning sign of a forthcoming danger.The most famous ensuant of spotting a comet during this period, was in 1066, before the Battle of Hastings. King Harold who had lost the battle, was believed to have seen the comet due to which he was cursed. In fact, the Bayeux tapis in Normandy, France, signifies the Norman victory in this battle with an image of King Harold looking at the comet in the sky. In 1456, pontiff Calixt us III had condemned its appearance considering it to be an mephistophelean omen. Three years prior to this, Europe was defeated by the Ottoman Empire. gentleman beings beings have always blamed celestial phenomena, whenever they have not been able to explain the causes of certain unfavorable events.Historically, the charge of a comet in the night sky was ordinarily cited as the reason behind exhausting situations that were beyond the reasoning of common man. A French physician, Ambroise, had described the pitiful conditions of middle ages, when a comet was seen just before the spread of a big epidemic. According to him, some people were scared to death while others fell sick on eyesight the comet. It was believed to be some evil form leaving behind a trail of blood, believed to be a sign of misery. late SpottingsIn the 16th and the 17th century, scientists conditioned to calculate the speed and distance at which comets travel around the Sun. Once, Edmond Halley had establish ed the year of its reappearance, Halleys comet became a matter of great interest. Although, he didnt live to see his prediction coming true, his observation had a significant impact on the way society perceived comets. The sighting of a comet, especially Halleys comet became less of a concern and more of a queerness among people. Once people realized that comets are orbiting bodies just like planets, they became less apprehensive on the arrival of a comet in the Earths visibility zone. The change in the attitude of the people was seen in the depiction of the comet in the contemporary pictures. Halleys comet was a subject of scientific test and was depicted as a beautiful heavenly body in the sky. noted American writer Mark Twain was born in 1835, the year when Halleys comet had appeared.He predicted in 1909 that since he had come with the comet he forget go out with it. Sure enough, he passed away a year after the comet reappeared in 1910. In the 1900s, it had appeared twice on ce in 1910 and then in 1986. Further studies gave us a deep insight into the structure, composition and orbital journey of many different comets. Halleys comet has one of the shortest orbital paths. It is classified as a short period comet, i.e. comets having an orbit period of 200 years or less.Once upon a time, it belonged to the long period class, but due to the gravitational force of planets, its orbit shortened over a period of time. Today, it is known that comets like Hale Bopp which appeared in 1997, will reappear after 4200 years Thus, Halleys comet is the most oftentimes spotted one. Recently, it was seen in February 1986. During this visit, it was subjected to its biggest scrutiny ever. quintuple ballistic capsules from The European Space Agency, Japan and the USSR were launched to learning its surface.Structure and Composition of Halleys CometHalleys comet is a big mass of ice and dust, having an elliptical orbit and shaped like a peanut. It has a highly prolonged orb it, taking it very close to the Sun. It flings off far in the outer solar system, similar to a slingshot motion. The composition is mainly of water, sodium monoxide, methane, ammonia, hydrocarbons, iron and sodium. Its closest distance from the Sun was found to be just 0.6 AU (astronomical unit) and the farthest distance was calculated to be 35 AU, roughly the same distance as that of Pluto. It orbits the Sun in a retrograde or in the direction opposite to that of the planets revolution. The speed with respect to the Earth is quite high, since it is highly eccentric and inclined.The day time is relatively more on its surface and its level best temperature rises up to 77 degrees celsius. Due to its large size and a well-defined and regular orbit, it was easy for the probe missions photograph it near and study its surface. The mass of the comet is 1.71015 kilograms and the size of the nucleus has been estimated to be 15 km 7 km 7 km. Winds blowing near its surface are so strong th at 1 gram particle of dust which hit the Giotto space probe, briefly destabilized it. Halleys comet will next appear in 2062. Comets have always been a fascination for human beings and will continue to mesmerize generations to come, as we discover more interesting facts about these spectacular fireballs, the comets.Comet lullinComet Lulin was discovered on July 11, 2007, by the duo of Ye Quanzhi and Lin Chi-Sheng. A non-periodic comet, Lulin appears to be dark-green in color. This green color is attributed to the presence of gases such as cyanogen and diatomic carbon, which produce a green glow when illuminated by sunlight in the nothingness of the space. Officially designated as C/2007 N3 (Lulin), it is also known as the Comet of Cooperation in china and Taiwan, as the two individuals involved in its discovery, were from these two countries. This comet was first photographed by Chinese astronomer Lin Chi-Sheng on July 11, 2007, while he was working on the Lulin Sky contemplate Project (LUSS) at the Lulin observatory in Nantou, Taiwan. The Lulin Sky Survey Project aims to bring out the numerous small objects in the solar system, particularly those that pose possible hazards to our planet. Lin used a 16-inch telescope to photograph this comet, which was initially assumed to be an asteroid.A few days later, Ye Quanzhi, a 19-year old learner of meteorology from Sun Yat-Sen University, China, recognized this comet while going through Lins photographs. Its precondition of being a comet was confirmed after the presence of coma, the nebulous envelope around the nucleus of the comet, was noticed. Both, Lin and Quanzhi were accredited with the discovery of this new comet. As it was first noticed from the Lulin Observatory, it was named as Comet Lulin. Comet Lulin was seen in the Libra constellation from January to borderland 2009. In January, it was getting brighter and could be seen just before dawn while in February, the brightness reached its peak. Eventual ly, in March, it started to fade as it went farther away from the Earth. While it was access the Earth, it had a typical tail pointing away from the Sun, as well as an anti-tail which was straightaway pointing towards the sun. Although, it was assumed that this anti-tail was observed only in photographs, some observers reported that it was visible even from a telescope in February 2009.According to Brian Marsden, an astronomer at Smithsonian Astrophysical Observatory, Massachusetts, this comets closest orgasm to the sun was on January 10, 2009 when it reached a distance of 113 million miles from the sun. He noticed that the comet was moving in a retrograde orbit that is near-parabolic. On February 24, Comet Lulin came the closest to the Earth, at a distance of 0.41 AU or 38 million miles to be precise. On February 4, 2009, a team of Italian astronomers, under the leadership of Ernesto Guido, witnessed a contrasted phenomenon taking place in comet Lulin. While photographing the c omet with a remotely controlled telescope in forward-looking Mexico, they saw that its tail of a sudden disconnected. Ernesto attributed this odd phenomenon to magnetic disturbance of the solar wind hitting the comet. Earlier, this had been observed with Comet Encke too, when lei mass ejection occurred, due to such magnetic storms.Photographs interpreted by NASAs Swift Gamma-ray Explorer satellite in ultra-violet and X-rays show that Lulin is shedding 800 gallons of water every second. Observations by NASA also revealed that the surface material of the comet was burning away due to suns heat. This sighting of Comet Lulin was a once-in-a-lifetime luck for the whole world, as there is no possibility of this comet returning to the inner solar system, at least not for the next thousand years. Human kind has always looked to the heavens in awe and wonder, and sometimes in fear. Perhaps no other astronomical phenomenon except a check solar eclipse has historically elicited as much fe ar as comets. When the specter of fear is removed, however, they emerge as strikingly beautiful objects in the sky. It was once believed that if earth passed through a tail of a comet, its inhabitants would die this theory has been discredited.Comets are messengers from a time long past. Most are chunks of grubby ice, locked away in the Oort cloud for billions of years. (Oort cloud It is the source for long period comets, with orbital periods of greater than two hundred years.) Comets are familiar to more or less everyone as striking star like objects with long tails stretching across a wide band of the sky. The most famous comet, Halleys comet makes its return to the skies every seventy-five years. The word comet is derived from a Grecian word meaning long haired Comets were greatly feared before the twentieth century as bad omens. Since then, they have been identified and cataloged as objects that come from deep space. Most of them plight orbits that carry them far outside th e solar system. Many of them make only a single mount to the sun and never return again, while others exist in electrostatic, but highly elliptical orbits that provide them to return after an extended period of time, such as the Halleys comet.In 1986, the European space probe Giotto passed about 600 kilometers from the Comet Halley as it made its close approach to the sun. The probe verified existing theories that comets are made up of ices covered by black dust or soil. The spacecraft confirmed a theory that had been advanced prior to the reconnaissance that described comets as dirty snowballs. Using data taken by the spacecraft, scientists determined that the dust is composed of carbon, hydrogen, oxygen, and nitrogen. Other metals have also been discovered in comets, such as iron, calcium, nickel, potassium, tomentum and silicon. Halleys comet was one of the darkest objects ever seen in the solar system it was basically apartment black. Comets are composed of a concoction of ices and dust. As a comet approaches the sun, it absorbs the suns energy and warms up. The main body of the comet is called the nucleus. As the nucleus warms, the ice beneath the comets soil evaporates.Because the comet has no atmosphere, the evaporated substance (also called a volatile) escapes into the vacuum of space as a gaseous envelope that surrounds the comet called coma. As the coma grows, it forms a plume of vapor that carries away some of the comets surface as well. This mixture of evaporated volatile particles and dust is carried away from the comet by solar wind, is ionized by high-energy particles, and creates the spectacular tail of the comet. The comets tail, glowing in the solar wind, can stream behind the comet for millions of kilometers. The nucleus of the comet consists of mostly volatile ices and dust. The ice is nearly all water ice, but there is also evidence of ices composed of carbon dioxide and methane. more than elementary compounds of nitrogen, oxygen, an d carbon monoxide may exist as volatile ices.Comets are typically small bodies (comparatively). Halleys comet is a potato shaped object, 14 by 17 kilometers. The largest known comet is Chiron, which is estimated to be approximately 200 kilometers in diameter. Comets are thought to have formed as the solar system evolved. The material of which comets are composed was constructed by accretion at the outer frame in of the disk of material that ultimately became the sun and planets. Because the comet material was fashioned at the outer edge of the solar system, the sun did not evaporate the volatiles in the cometary material.At the same time, the giant planets of the solar system formed at what would become the outer orbits of the solar system. These massive planets encountered the newly formed comets, and the ones that were not engulfed by the giant planets were, over the first billion years, catapulted into interstellar space by the planets massive gravitational fields. not all come ts met that fate, however. Some were gently nudged into stable orbits closer to the sun. Others were flung into the inner solar system and impacted the inner planets.Relevance The study of comets involves detailed knowledge of its composition of the outer regions of the solar system and the space between the last planet and 100,000 astronomical units onwards. cometic study also seeks to understand convoluted gravitational interactions between bodies unaffectionate by wide distances and even gravitational interactions between tiny comets, their behavior when approaching the sun, and something of the establishment and evolution of the early solar system. New comets approaching the sun for the first time have been held in deep barricade in the Oort cloud and are thought to be composed of primordial material of the newly forming solar system. They have been laced up in the Oort cloud for billions of years at temperatures slightly above irresponsible zero. As they approach the sun, their internal gases begin to steam away. A detailed study of an approaching comet may tell cosmologists about the composition of the early solar systems. Comets and their approach have also hinted at the existence of the elusive browned dwarf, thought to be one of the most common bodies of interstellar space.Because they are so dim, they are all but invisible from Earth. On the other hand, because brown dwarfs are thought to be so plentiful, the study of comets and their orbits may give the first real clues to the formers reality and abundance. In the early eighties the existence of the galactic tidal action was merely speculation. Since then, careful study of cometary orbits and approaches has favorable supported the theory of galactic tides. In the close approach of Halleys comet by an unmanned spacecraft in 1986, a wealth of information was recovered on the shape, behavior, and composition of comets. The existence of the Oort cloud and the concept gravitational interactions b y notch objects in space have led to the theory of periodic comet showers. Such comet showers, separated by periods of tens of millions of years, may be responsible for the mass extinction on Earth.There is a wide speculation that Earth was struck by one or more comets 70 million years ago, which wiped out the dinosaurs. Some scientists have speculated that this extinction was the result of a shower of comets from the Oort cloud, sent on their close approach to the sun by a passing star or brown dwarf through the Oort cloud. Comets have been used to judge vast distances, evaluate the composition of the solar system as it was being born, and even test the idea that the gravity of the entire galax can make a discrepancy to the smallest objects in space.Comets have been used as yardsticks to evaluate what may be the most type of star in the galaxy-the brown dwarf-which ironically is one that may never be seen. They have also been called dirty snowballs. Halleys comet was so black tha t it was the darkest object ever seen in space. Yet, from these dirty specks of ice, cosmologists have witnessed some of the most spectacular light shows. Ultimately comets may also arrest clues to some of the most fundamental secrets about the solar system and planets. From these tiny messengers, cosmologists may unlock and examine pristine elements from creation itself.