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The 1783 Great Meteor was an unusually bright bolide observed on August 18, 1783, from the British Isles at a time when such phenomena were not well understood. The meteor was the subject of much discussion in the ''Philosophical Transactions of the Royal Society'' and was the subject of a detailed study by Charles Blagden. ==Observations== The event occurred between 21:15 and 21:30 on August 18, 1783, a clear, dry night. Analysis of observations has indicated that the meteor entered the Earth's atmosphere over the North Sea, before passing over the east coast of Scotland and England and the English Channel; it finally broke up, after a passage within the atmosphere of around a thousand miles (1610 km), over south-western France or northern Italy. There were many witnesses. Perhaps the most prominent was Tiberius Cavallo, an Italian natural philosopher who had happened to be amongst a group of people on the terrace at Windsor Castle at the time the meteor appeared. Cavallo published his account of the phenomenon in v. 74 of the ''Philosophical Transactions'' : Some flashes of lambent light, much like the ''aurora borealis'', were first observed on the northern part of the heavens, which were soon perceived to proceed from a roundish luminous body, whose apparent diameter equaled half that of the moon, and almost stationary in the same point of the heavens () This ball at first appeared of a faint bluish light, perhaps from appearing just kindled, or from its appearing through the haziness; but it gradually increased its light, and soon began to move, at first ascending above the horizon in an oblique direction towards the east. Its course in this direction was very short, perhaps of five or six degrees; after which it directed its course towards the east () Its light was prodigious. Every object appeared very distinct; the whole face of the country, in that beautiful prospect before the terrace, being instantly illuminated.〔See 〕 Cavallo noted both that the meteor, which was visible for around thirty seconds in total, appeared to split into several smaller bodies immediately following the main mass and that a rumbling noise, "as it were of thunder at a great distance", was heard around ten minutes after the meteor appeared, which he speculated "was the report of the meteor's explosion". Other accounts, such as those of Alexander Aubert and Richard Lovell Edgeworth, noted red and blue colour tints in the fireball. Some accounts appeared rather more fanciful; the ''London Magazine'' mentioned a letter by a lieutenant on a British warship which had been positioned north of Ireland "who relates he saw the same meteor moving along the north-east quarter () but he adds something singular enough, namely, that a little time afterwards, he saw it moving back again, the contrary way to which it came".〔"Account of the Late Meteors...", ''The London Magazine'', v.52, 495〕 The author added that "several other observations of this meteor have come into my hands, but they are so inconsistent with these already related, as well as with one another, that I forebear to mention them".〔"Account of the Late Meteors", 496〕 Gilbert White, writing in 1787, was to remember the "amazing and portentous" summer of 1783 as "full of horrible phaenomena () alarming meteors and tremendous thunder-storms that affrighted and distressed the different counties of this kingdom".〔White, G. ''The Natural History of Selborne'', Letter CIX (to the Hon. Daines Barrington)〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1783 Great Meteor」の詳細全文を読む スポンサード リンク
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