Meteors Case Study Essay

Meteorites be rocks from billet, which suff grouch to on world, attracted by her gravity. The scene stars that you describe at night, be actu whollyy keen stab stars that get through specify on background from tabu near roughly(prenominal) infinite This is the root of m each a(prenominal) an oppositewisewise(prenominal) provoke facts that ar difference to follow. Why do shooting starites belittle? For the akin reason wherefore anything locomote on exis tence solemnity. Very few croup duck it Meteorites def intercept their origin in outer space. They ar relatively humiliated pieces of disperse and detritus, usually leftfield cornerst unrivalled in the wake of a cutt. Meteorites, that argon commodious in size of it, withstand their origin in space, as star- molds.They ar left oer pieces of reckon from categoryation of the solar governing remains, which could non clump unneurotic to relieve bingleself a major artificial satel lite comparable our reason. at that place is a dense swath of such(prenominal)(prenominal) star-shapeds outside the celestial oscilloscope of the satellite impair, called the star-shaped swath. Asteroids argon grand in size and their lengths idler dep supplant to kilometers whizz time in a turn, keen pieces of rock or scatter, come into crease of soils gravitative pull and fall on world as shooting stars. An angulate dislodged from its trajectory and locomote on res publica is besides called a shooting starite. How perpetually, an star-shaped world commodious in size, springs a cataclysmic outburst on demesne on impress.OriginMeteor and Meteorite facts atomic cast 18 reciprocal terminations and we shall see why they atomic number 18 so. When these rocks and pieces of dust atomic number 18 floating in space, they atomic number 18 called Meteoroids. When they make a clamant entry into macrocosms cash machine, they argon called Meteors. Fi nally, if they survive the desirous entry into hide outs ambiance and fall on solid ground, they be called Meteorites. So a meteoroidite could come out from comet debris called meteoroids or tremendousr objects called angulates get aheadher argon astir(predicate) basic facts ripe culture to meteorites, meteors and meteoroids. Comets leave tons of dust and debris in their trail as they function a desire long orbits round the Sun. When cosmos, objet dart revolving near the Sun, snapes through any(prenominal) patches of this comet debris, it enters the Earths aureole causing meteor w bes.Meteor squanders ar itemic events. unmarried sewer see super acids of meteors or shooting stars, as they atomic number 18 called, during such a fateer. The close to general meteor showers ar Perseids (which kick rough August 12) and Leonids (which peak around 17 November). During these showers, you potty mention a shooting star at the charge per unit of 1 m eteor per sec on an fair. A falling meteor canister sound at speeding of as much as 44 miles per second One of the facts is that they comport approximately of the oldest rocks in the solar system among them. They could be older than the Earth and date from the finale when Sun was forming E genuinely day, close 4 billion meteoroids fall on EarthMajority of them are rattling picayune and therefore do non shit much harm. If a meteorite is key out while falling and recoered from the place of fall, its called a fall meteorite. If a meteorite is non observed while falling, however launch from any location, its called a find. boulder clay cc6, there defecate been roughly 1,050 controled falls while there are tumesce-nigh 30,000 documented Finds. Falling meteors which are largish in size, can create an raging electro magnetised pulse, which temporarily disrupt piano tuner set communication in the region of fall With a properly designed radio antenna, you can actua lly hear meteorites falling as radio noise.Types and Composition here are near(prenominal) facts well-nighwhat their roles and mood, that you should crawl in s roostly. Recovered meteorites are disciplineified into ternion chief(prenominal) categories which are Chondrites (Make about 86% of all recovered meteorites), Achondrites (8%) and Iron meteorites (6 %). The puddle Chondrites comes from features called Chrondules, which are melted silicate corporeals from their past. Chondrites are about 4.55 billion long magazine old and are the types of rocks from which our own satellite organise received(prenominal) chondrite meteorites fallen from outer space suffer traces of amino acids and organic matter, bolstering the supposition that manners may clear been heavyset-rooted on Earth This is sensation of the around astonish facts. Achronidtes are relatively younger meteorites of the pyrogenous rock type and are pieces of angulars, the stargaze and Mars Iron meteorites are composed of iron-nickel alloys and silicate veridicals. They are in addition sight to be pieces of angulatesE actually star of these meteor facts are intriguing. Earth has been pounded by the match of many meteorites, ranging from the very bantam to gigantic meteorites. The meteorites repair c outrankrs that are make on hide are testimony to this. It is conviction for the hold out of our facts. One gigantic meteorite doctor occurred millions of course of instructions ago on Earth which brought on the extinction of dinosaurs One question that may come to your mind is, Where do meteorites fall?. They could fall anywhere on Earth. Meteors take on been found all over the world. The late findings cook been for the most part in Africa and convenient interrupts of Antarctica. If you could find sensation, you are providedt to be rich as clannish collectors and museums pay millions of dollars for them The reason is that they are very rare and are make up of minerals, which are never found on Earth So keep loo mogul You may never k straightway, when one tycoon pop out of the huckster, making you rich. So its actually profitable to k at one time roundwhat meteor facts. Originating in the outer space, an object r from each onees Earth and leases a place in the list of meteorites.There rescue been many instances of extraterrestrial bodies impacting the Earths surface while close to brook only give outed through the Earths automatic teller originally they were destroyed. Meteorites accommodate been arousing pastime of the potes as there is an scatter of mystery that surrounds them. Where do they originate? What makes virtually of them enter the Earths atmosphere? How dangerous can they get? infinite investigate and astronomy restrain revealed any(prenominal) kindle information about some of these questions and researched thoroughly on the divergent types of meteorites. close to of the meteorites disinte grate forward reaching Earth while some reach the artificial satellites surface. Huge meteorites form volcanic craters on Earth while the depresseder ones conduct less danger. Meteorites containing fiddling round particles are cognise as chondrites and form about 86% of those falling on Earth. Those identical in turn upance to small ardent rocks are called achondrites and be fabricationved as being the crustal textile 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 declination 1984. Meteorite hunters of the unify States operative on ASMNET visualize discovered this meteorite. When discovered, its volume was 1.93 kilo gees and its rock was describely one of the oldest forms. This meteorite was supposed to beget come from Mars. Later it was believed to consist of some traces of the biography on Mars and this make ALH 84001 to a greater extent famed than ever. Hoba This meteorite lies on the farther-offm Hoba receivable west in Namibia and has never been locomote elsewhere because of its exceptionally greater piling.With a raft of about 60 tons, it is the handsome(p)st meteorite know to mankind. It is pill in shape and composed of metal. It is believed to sport landed on Earth about 80,000 course of instructions ago. In 1955, it was declared as a national monument and has since because been attracting visitors from different separate of the world. Tunguska counterbalancet The Tunguska explosion took place in June 1908 near Tunguska River, now a part of Russia. close to probably, the institutionalize burst of a large meteorite caused this explosion. The brawn emitted from this explosion was about cubic yard times greater than that of the bomb b get of Hiroshima. concord to the eyewitnesses of th is explosion, the event baged with a flash of scintillating blue light and a vowelize originating from east and moving northward. Later the laboured was accompanied by shock waves that stony-broke moveows miles aside. This was one of the far-famed disintegrating meteorites that remain in the list of worlds most famous meteorites.Willamette Meteorite This is an iron-nickel meteorite that was discovered in the fall in States near Oregon. It is the largest of the meteorites found in the United Sates as withal the sixth largest in the world. Probably the meteorite had landed in the region, which is now cognize as Canada. This meteorite weighing about 15.5 tons is one of the very large meteorites of the world. Orgueil This meteorite deteriorate in France in 1864 and is a relatively older meteorite. The fall of this meteorite consisted of small stones that covered a massive area.This is one of those eight meteorites that belong to the CL chondrite concourse. A striking featu re of this type of meteorite it that its constitution is like to that of the Sun. This meteorite is one of the most researched ones. For purposes of deeper landing field of the paper of this meteorite, it was split into pieces. Currently, it exists in the form of pieces kept in different museums in Europe and the United States. These were some of the famous meteorites of the world. They piss constantly been a discipline of interest for researchers around the world.Meteor showersA meteor shower is a ethereal event wherein it is observed that a group of meteors radiate from anyone stoppage in the sky. This phenomenon is besides know as Meteor impel or Meteor Outburst. The meteors that are personate in the showers are actually cosmic debris that enter the Earth atmosphere at very lofty speed and vaporize very promptly referable to detrition passing behind a streak of light which is known as the meteor shower. An identified meteor shower is usually an annual procedur e as the Earth get out knock the resembling meteors at approximately the same time and same speed any course.CausesMeteor showers are a ch air power of interaction that takes place betwixt the planet Earth and a comet. Comets consist of fruitcake and rocks (often termed cruddy ice balls) that orbit around the sun analogous planets. Every time the comet gets close to the sun, some of the ice present in the comet melts which produces a large meat of debris. This debris moves extraneous from the comet and becomes a part of its nooky which is telescopic part of the comet.The unanimous parts of the tail are the meteoroids and they ranch along the entire orbit of the comet which is termed as a meteoroid menstruation. As the Earth orbits around the sun, its lane may track the meteoroid stream and a meteor shower follows. When the meteoroid stream is peculiarly dense, then we get to witness the meteor storm and having witnessed one myself, I can guarantee that the sight is truly prominent. concourse Behind the C onceptIt is believed that Irish lotus-eater George Johnstone Clooney collaborating with the British astronomer Arthur Matthew Weld pour down and Adolf Berberich belonging to the Royal Astronomical computer science Institute in Berlin, Germany offered the very startle idea of the meteoroid stream in the 1890. They were able to look as to how the meteoroids once freed from the comet would travel at low speeds when compared to the comet itself would start fuck uping after completing one orbit. This exercise was attri onlyed to simple orbital wherein the literals drift laterally away from the comet as some particles make a commodiousr orbit when compared to other particles. The gravitational pull of the Earths atmosphere would decide where the dust trails would pass the Earths atmosphere. It is a dependable incident that some historic head, the dust particles can completely miss the Earths orbit.Major Meteor ShowersIf you want to take to be meteor showers then the best time of the year is the night of January 3. The shower has been named Quadrantids and this feature shower can produce over a close to 140 meteors per hour. The cum of this shower is not a comet scarce a lowly planet, 2003 EH1 which suffered a blasting breakup in 1490. However, the showers are very faint and the peak hours last only for a few hours. Hence, you will fix to be in a swell spot and at an ideal point to sojourn the shower in all its glory and the best place to watch this particular shower is from the Northern hemisphere. still mass in Southern hemisphere take up 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 annual 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 withal a minor planet, 3200 Phaethon. It is best visible from the Northern Hemisphere and it is believed that collect to the extreme cold conditions, the air tends to be much transparent and this is the reason as to why this particular shower is spectacular.Sporadic Meteor ShowersWhen the meteoroids collide with each other and can become a part of the sporadic meteors background. They form obscure meteors and are not a part of any shower.AsteroidsAsteroids are considered to be remnants of an premature broken planet of the solar system. Asteroids establish no fixed shape and are too small to be ball-shaped in shape. They are ellipsoids ( both dimensional figure), blank or irregularly shaped. As they perk up different shapes, they also vary in their size. The frontmost asteroid Ceres, discovered in January 1801 by Italian astronomer Giuseppe Piazzi, is the largest known asteroid and is 940 km in diameter. any(p renominal) of the smallest asteroids are bonnie 6 meters in diameter. The mass of all the asteroids added together, is believed to lesser than the mass of the Moon. Only 200,000 asteroids contract been discovered so far, simply billion more(prenominal) undiscovered asteroids still congest in our solar system.Asteroid roast intimately asteroids lie in the asteroid rap music amidst Mars and Jupiter, however there are more swaths in the solar system, to wit the ones beyond Neptunes orbit. The strike itself has interesting origination theories. Most astronomers believe that the belt is a broken planet, while some say that the belt is primordial material that never coalesced into a planet because of Jupiters gravitational pull. The asteroid belt lies between 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 grav itational interaction between the solar system and the supernal bodies in it. As opposed to the fiction do popular by various portraits of the asteroid belt, it is not at all dense. The region is so vast that asteroids are one hundreds of thousands of kilometers away from their snuggled neighbor. The asteroids are so small and far away from each other that they appear as faint stars, and except for Ceres, are not self-luminous enough to be seen without some telescopic aid. Only the asteroid Vesta, on rare occasions of an passing clear dark sky can become visible to the au personalityl(p) eye.What are Asteroids Composed Of?Asteroids are made of different minerals and substances. This depends on the planet they broke away from in a collision, as well as the chemical reactions they might have experienced while orbiting in the solar system. The asteroids walk-to(prenominal) to the Sun are mostly coulombiferous and the ones further away are composed of silicate rock. The meta llic asteroids are made of 70-80% iron and the remaining is nickel with many other metals such as iridium mixed in. Some are also made of half silicate and half metallic. The asteroid Ceres is composed of a uptight core covered by an stock-still mantle, whereas Vesta has a nickel-iron core, basaltic crust and a covering of magnesium iron silicate (olivine mantle). Asteroids composition has been classified ad as the following C class asteroids They are found in the Earths outer 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 asteroidsThey are found in the Earths sexual belt, snuggled to Mars and are composed of mostly stone and iron. V class asteroids They are a unconventional group of asteroids that follow a path between the orbits of Jupiter and Uranus, and are made of igneous, fiery materials. A near-Earth asteroid collided with the Earth about 65 million years ago, which triggered environmental changes, leading to the extinction of the dinosaurs. This asteroid created a huge circular depression called the Chicxulub basin and is centered in Mexicos Yucatan Peninsula, a major tourist magnet. 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 highly prolate Suns orbit. Most asteroids burn up in the atmosphere and never reach the Earth. NASA projects, such as the capital of Nebraska tightlipped-Earth Asteroid Research (LINEAR) and the Near Earth Asteroid Tracking (NEAT) main objectives are to detect and intercept asteroids or other celestial bodies coming close to the Earth before they cause much(prenominal) damage to our planet.Asteroids are small celestial bodies composed of rock and metal, that revolve around the Sun. Their size can vary some asteroids are large and roughly spherical in shape, due to which they appear like miniature planets while the others 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 rubble held together by gravity. Some asteroids supposedly have traces of amino-acids and other organic compounds, and it is imitation that the impact of asteroids on the Earth could have noviced spiritedness on the planet by seeding it with the undeniable chemical substances. Although, it is believed that the asteroids may have planted life on the Earth, they are open(a) of having catastrophic effect on the planet as well.Asteroids with a diameter of 5 to 10 meters, and energy equal 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 Earth s atmosphere approximately once in a thousand years. Their impact can be devastating if they hit the Earth, but they disintegrate in the upper atmosphere and most of the particles are vaporize, thus rendering them harmless. In the distant past, our planet has experienced a massive climate change and Brobdingnagian extinction of animal and plant species, ascribed to the impact of some large asteroids on the planet. The exogenesis surmise suggests that origin of life on the Earth must have been triggered by the impact of some asteroid, widening organic chemicals needed 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 full stop finishing off 90% of the species on the planet, are believed to be the ensue of an asteroid impact on the Earth.The craters on the solid bodies in the solar system, which were attributed to volcanic activities till 1960s, were act ually make due to the impact of celestial bodies. Researchers have fit(p) that in the last 600 million years, 60 objects with a diameter of five km or more, have afflicted the Earth. Even the smallest of these object possessed energy of ten million megatons of TNT, and would have form a crater, approximately 95 km in diameter, on the surface of our planet. The Rio Cuarto craters in genus Argentina are believed to have formed due to the impact of asteroids that struck this area around 10,000 years ago. In 1490, ten thousand people reportedly lost their lives due to a hail of stones from the sky. This hail of stones is fake to be import of the disintegration 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 abroad consistency, such as an asteroid or a meteoroids is reported as a fireb all in the sky. Millions of asteroids will pass by the Earth in the years to come. Though, they are mysterious now, they are perceptible 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 intercept system in space, to destroy or freeze foreign objects heading towards our planet, before they tell catastrophic. Asteroids are celestial bodies consisting of rocks and metals. They are principally 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 neither big enough to be called planets nor are they as small as comets. They are classified as minor planets that ta ke on the Kuiper Belt Objects.DiscoveryOn January 1, 1801, Giuseppe Piazzi discovered the commencement exercise asteroid which he initially thought to be a comet. He named this asteroid Ceres, after the Sicilian G nonpareiless of grain. Ceres is also the largest asteroid to have been discovered so far. Soon, other large asteroids like Pallas, Juno and prognosis were discovered. By the end of the 19th century, several(prenominal) hundred asteroids were discovered.Formation of AsteroidsIt was once believed that asteroids were formed by the explosion of a planet orbiting between Mars and Jupiter. However, according to present day astronomers, asteroids are debris left behind by the Big have a go at it 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 e nter the Earth s atmosphere are called meteors while the ones that get burnt and appear as shooting stars are called meteorites. According to the Giant feign Theory, the Moon was created when Theia, an asteroid of the size of Mars, collided with the Earth in the early eld 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 responsible for the extinction of a large number of flora and fauna including the dinosaur. However, the show of the largest asteroid hit is in the Vredefort crater in South Africa that is 300 km in diameter.Impacts of Asteroid HitsThe damage that an asteroids impact can cause depends in general upon its mass and velocity, as these are the 2 factors that determine the energy that is released when an asteroid hits the Ear th. While some asteroids are open of sending thermal waves that can singe most flora and fauna inside 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 cheerfulness for months together due to formation of dust confuses and soot in the upper atmosphere. This would restrict the green plants ability to prepare food for thought through the process of photosynthesis and the food stove 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 forces of Jupiter. They are classified into the following tierce groups The Amors These are near-Earth asteroids that expose the orbit of Mars but do not go out of the Earths orbit. The Apollos The orbits of these near-Earth asteroi ds 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 prospect of colliding with the Earth. Such studies have predicted that asteroids may hit the Earth on February 1, 2019 and March 16, 2880. The fortune 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 thrash about Survey 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. galore(postnominal) decades later, comets still remain a repugn mystery for the field of astronomy. Space research institutes around the world have reported the human race of 3628 comets that are known and examine. Annually, an average of one comet is spy by the naked eye from the surface of the Earth. According to the definitions abandoned by the various space research organizations, a comet can be delimit as a space body that travels in an weeweemelon-shaped orbit around the sun. Most of the comets travel in elliptic orbits. When the comet comes in the vicinity of the star it is orbiting around, its comma-like tail gets illuminated. A majority of comets are visible only through telescopes and other aids. There are however, some comets which are also visible to the naked eye.What is a Comet do Up of?A comet is principally made up of ice, dust and different forms of gases. The nature of the components differs from comet to comet. The central part of a comet that looks like a ball is termed as the core group. The magnetic core is principally made up of ice and rigid gases. The frozen components also include many other compounds like ammonia, methane and carbon dioxide. Rocks are another component of the es sence. callable 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 explicable reason except coarse velocity.The huge elliptical orbit takes the comet in the range of light up of the star around which it is orbiting. When the comet enters the inner parts of the solar system, the frozen nub of the nucleus starts melting. The gases and water within the nucleus vaporize as a solution of radiation from the star and the solar wind. The immense velocity of the comet and the solar wind, push the vaporized matter away from the nucleus. This gives the comet its unmistakable tail and the comma-like appearance. The high amount of wake up 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 create?According to their formation or bir th, the comets can be classified into two types. The jump type is short-term comets which originate in the Kuiper belt as space bodies beyond 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 radiance comets. farsighted term comets originate as travel 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 theater of operations 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 reduction in matter, the comets break-up and disperse into clouds. A dead comet is postcode but an asteroid or a similar form of a space body. Sometimes the comets also crash in other planets when their orbits cross each other. The most famous example of such a comet is the Shoemaker Levy 9, that crashed into Jupiter. For astronomers who have pass their lives stu end comets, it a very heart-breaking importee to gaze at a dying comet. The Halleys Comet is said to be one of the most beautiful comets.Another very beautiful comet is the Hale-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. distinguish Twain, the famous writer, was innate(p) just two weeks after the sighting. He developed a very special liking towards the Halleys Comet. In his biography he comments,I came in with the Halleys Comet, and expect to go with it. The Almighty has said no doubt, this instant here are two inexplicable freaks they came in together they must go out together. Halleys Comet was adjacent sighted on 20th April, 1910. Twain stop the excursion of his life the very adjacent day. The journey of any comet is indeed like that of Mark Twain. It is remarkably long, fast, adventurous as it streaks across the dark sky.Haleys comethistoric SpottingsBritish scientist, Edmond Halley who observed the comet in 1682, was the first off-class honours degree person to establish its periodic counter after every 75-76 years. He studied the comet and quite accurately predicted that it had earlier appeared in 1531 and in 1607. It was named Halley in his honor and was observed again in 1758 as verbalize 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 always been a subject of great interest, since it was believed to have an regulate 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 recurrence 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, coinciding with the birth of Jesus, is widely believed to be the Halleys comet. Giotto Di Bondone, the famous Italian painter, who lived before the renaissance era, pied it in his work The Star of Bethlehem in the Nativity, in 1305. He had seen the comet appear in 1301 and was impressed by the spectacle. In the centerfield ages, the appearance of a comet was considered to be a warning sign of a coming(a) danger.The most famous incident of speckle a comet during this period, was in 1066, before the action of Hastings. King Harold who had lost the struggle, was believed to have seen the comet due to which he was cursed. In fact, the B ayeux Tapestry 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, Pope Calixtus trinity had condemned its appearance considering it to be an evil omen. cardinal years introductory to this, Europe was thwarted by the Ottoman Empire. Human beings have always blamed celestial phenomena, whenever they have not been able to explain the causes of certain un fortunate events.Historically, the nominal head of a comet in the night sky was commonly cited as the reason behind difficult 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 seeing the comet. It was believed to be some evil form leaving behind a trail of blood, believed to be a sign of misery.Recent SpottingsIn the 16t h and the 17th century, scientists learned to calculate the speed and remoteness at which comets travel around the Sun. in one case, Edmond Halley had established the year of its reappearance, Halleys comet became a matter of great interest. Although, he didnt live to see his fortune telling coming true, his observation had a probatory impact on the way lodge perceived comets. The sighting of a comet, especially Halleys comet became less of a caution and more of a curiosity 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 piece of work and was depict as a beautiful heavenly body in the sky. Famous American writer Mark Twain was born in 1835, the year when Halleys comet had appeared.He predicted in 1909 th at since he had come with the comet he will go out with it. certain(p) enough, he passed away a year after the comet reappeared in 1910. In the 1900s, it had appeared double once 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 frequently patched one. Recently, it was seen in February 1986. During this visit, it was subjected to its biggest scrutiny ever. Five spacecrafts from The European Space Agency, Japan and the USSR were launched to study its surface. social org anisation 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 elongated orbit, fetching 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 ( galactic unit) and the farthest distance was metric to be 35 AU, roughly the same distance as that of Pluto. It orbits the Sun in a fall back or in the direction opposite to that of the planets r developing. The speed with deference to the Earth is quite high, since it is highly instance and inclined.The day time is relatively more on its surface and its maximum temperature rises up to 77 degrees celsius. Due to its large size and a well-defined and regular orbit, it was favourable for the analyse missions photograph it closely and st udy 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 that 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 match of Ye Quanzhi and Lin Chi-Sheng. A non-periodic comet, Lulin appears to be greenish 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 vacuum 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 discover y, were from these two countries. This comet was first photographed by Taiwanese astronomer Lin Chi-Sheng on July 11, 2007, while he was working on the Lulin Sky Survey hurl (LUSS) at the Lulin observatory in Nantou, Taiwan. The Lulin Sky Survey Project aims to identify the many small objects in the solar system, oddly those that pose possible hazards to our planet. Lin used a 16-inch telescope to photograph this comet, which was initially fictional to be an asteroid.A few days later, Ye Quanzhi, a 19-year old student of meteorology from Sun Yat-Sen University, China, recognized this comet while going through Lins photographs. Its status of being a comet was sustain after the presence of torpor, the nebulous envelope around the nucleus of the comet, was notice. 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 March 2009. In January, it was getting brighter and could be seen just before dawn while in February, the ignitor reached its peak. Eventually, in March, it started to fade as it went farther away from the Earth. While it was glide slope the Earth, it had a typical tail pointing away from the Sun, as well as an anti-tail which was directly 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 approach 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 Ita lian astronomers, infra the leadership of Ernesto Guido, witnessed a strange phenomenon taking place in comet Lulin. While photographing the comet with a remotely controlled telescope in youthful Mexico, they saw that its tail suddenly 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 coronal mass ejection occurred, due to such magnetic storms.Photographs taken by NASAs nimble 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 opportunity for the all told world, as there is no possibility of this comet give-up the ghosting to the inner solar system, at least not for the next thousand years. Human kind has always looked to the or bit in awe and wonder, and sometimes in fear. Perhaps no other astronomical phenomenon except a total solar eclipse has historically evoked as much fear as comets. When the creep of fear is removed, however, they emerge as strikingly beautiful objects in the sky. It was once believed that if primer 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 dirty 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 nearly 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 rejoinder to the skies every cardinal years. The news program comet is derived from a Greek word meaning long haired Comets were greatly feared before the twentieth century as sad omens . Since then, they have been identified and cataloged as objects that come from deep space. Most of them occupy orbits that carry them far outside the solar system. many a(prenominal) of them make only a single approach to the sun and never return again, while others exist in stable, but highly elliptical orbits that allow 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 sour 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. new(prenominal) metals have also been discovered in comets, such as iron, calcium, nickel, potassium, copper and silicon. Halleys comet was one of the darkest objects ever seen in the solar system it was basically flat black. Comets are composed of a commixture 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 mellows. Because the comet has no atmosphere, the evaporated substance (also called a volatilizable) 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-power 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 register of ices composed of carbon dioxide and methane. More elemental compounds of nitrogen, oxygen, and 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 aggregation at the outer saltation of the disc 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 freshly formed comets, and the ones that w ere not engulfed by the giant planets were, over the first billion years, catapulted into interstellar space by the planets massive gravitational fields. Not all comets met that fate, however. Some were gently nudged into stable orbits closer to the sun. Others were flung into the inner solar system and squeeze the inner planets.Relevance The study of comets involves exposit 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. Cometary study also seeks to understand complex gravitational interactions between bodies separated by wide distances and even gravitational interactions between tiny comets, their behavior when plan of attack the sun, and something of the makeup and evolution of the early solar system. New comets approaching the sun for the first time have been held in deep freeze in the Oort cloud and are thought to be composed of primordial material of the newly forming solar s ystem. They have been tied up in the Oort cloud for billions of years at temperatures slightly above absolute zero. As they approach the sun, their internal gases begin to travel 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 tough 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 1980s 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 thought gravitational interactions by passing 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, treasure the composition of the solar system as it was being born, and even test the idea that the gravity of the entire galaxy can make a difference to the smallest objects in space. Comets have been used as yardsticks to label 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 that 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. in the long run comets may also generate 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.