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The year 1990 in science and technology involved some significant events. ==Astronomy and space exploration== * February 14 – The Pale Blue Dot photograph of Earth is sent back from the ''Voyager 1'' probe after completing its primary mission, from around 3.5 billion miles away. * April 23 – Gamma ray burst GRB 090423 is detected, coming from the most distant known astronomical object of any kind at this time. * April 24 – The Space Shuttle ''Discovery'' places the Hubble Space Telescope into orbit. * October 13 – Earth-grazing meteoroid of 13 October 1990: A 44 kilogram, 41.5 km/s meteoroid passes above Czechoslovakia and Poland at 97.9 km. It is the first time calculations of the orbit of such a body based on photographic records from two distant places is made.〔 Aphelion of its orbit changed from 2.80 AU to 1.80 AU.〕 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「1990 in science」の詳細全文を読む スポンサード リンク
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