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A transit of Earth across the Sun as seen from Jupiter takes place when the planet Earth passes directly between the Sun and Jupiter, obscuring a small part of the Sun's disc for an observer on Jupiter. This can only happen when Jupiter is at or near opposition, and near one of its nodes. During a transit, Earth can be seen from Jupiter as a small black disc moving across the face of the Sun. The event is particularly interesting because both the Earth and the Moon can usually be seen together in transit. In rare cases one of them transits and the other does not, such as on December 21, 2060, when there is a grazing transit for the Moon and a near-miss for the Earth. In other cases, the two may be so close together that they are hard to tell apart, such as on June 24, 2055, when the Earth and Moon are less than 20" apart as seen from Jupiter. Naturally, no one has ever seen a transit of Earth from Jupiter, nor is this likely to happen in the foreseeable future. The last one took place on January 5, 2014;〔 ((end of transit) )〕 the next will occur on January 10, 2026. A transit could be observed from the surface of one of Jupiter's moons rather than from Jupiter itself. The times and circumstances of the transits would naturally be slightly different. The Earth–Jupiter synodic period is 398.883 days. It can be calculated using the formula 1/(1/P-1/Q), where P is the sidereal orbital period of Earth (365.25636 days, not the same as a tropical year) and Q is the orbital period of Jupiter (4332.71 days). The transits belong to series of four or five transits separated by 12 years. The transits also belong to 83-year series; consecutive ones are almost identical. Eight series are active and have 24 to 28 members. ==References== * Albert Marth, ''Note on the Transit of the Planet Mars and its Satellites across the Sun’s disc, which will occur for the Planet Jupiter and its Satellites on April 13, 1886'', Monthly Notices of the Royal Astronomical Society, 46 (1886), 161–164. () * Andrew Crommelin, ''Ephemeris for physical observations of Jupiter, 1901'', Monthly Notices of the Royal Astronomical Society, 61 (1900), 117–118 () (full article: ()) * ( SOLEX ) * 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「Transit of Earth from Jupiter」の詳細全文を読む スポンサード リンク
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