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天文学

310 件の記事

Valhalla Basin on Jupiter's moon Callisto, taken by Voyager 1

多環盆地巨大衝突が刻む天体の同心円状構造

多環盆地インパクト盆地クレーター天文学
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Albedo change in Greenland: The map shows the difference between the amount of sunlight Greenland reflected in the summer of 2011 versus the amount it reflected between 2000 and 2006. Some areas reflect close to 20 percent less light than a decade ago.[1]

アルベド（反射能）が地球の気候と宇宙の天体に与える影響

アルベド反射能地球温暖化気候変動
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A comet was mentioned in the Anglo-Saxon Chronicle and by the Venerable Bede in the year 729 CE.[13][14]

彗星の正体と宇宙の旅氷と塵が織りなす天体現象

彗星ハレー彗星オールトの雲エディントン
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Comparison of the Arecibo (top), FAST (middle) and RATAN-600 (bottom) radio telescopes at the same scale

アレシボ天文台宇宙の深淵を覗いた巨大電波望遠鏡の軌跡

アレシボ天文台電波望遠鏡プエルトリコSETI
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The flash from the LCROSS Centaur impact.

LCROSSミッション月面への意図的な衝突が明かした水の存在

LCROSSNASA月探査水氷
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An elliptic, parabolic, and hyperbolic Kepler orbit: Elliptic (eccentricity = 0.7) Parabolic (eccentricity = 1) Hyperbolic orbit (eccentricity = 1.3)

軌道離心率天体の軌道形状を決定するメカニズム

軌道離心率ケプラー軌道天体力学楕円軌道
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The semi-major (a) and semi-minor (b) axes of an ellipse

軌道要素の基礎軌道長半径と軌道短半径の幾何学と天文学的意味

軌道長半径軌道短半径離心率ケプラーの法則
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The yellow shell indicating one light-day distance from the Sun compares in size with the positions of Voyager 1 and Pioneer 10 as of 2008 (red and green arrows respectively). It is larger than the heliosphere's termination shock (blue shell) but smaller than Comet Hale-Bopp's orbit (faint orange ellipse below). Click on the image for a larger view and links to other scales.

光秒（Light-second）とは？宇宙と通信の距離を測る究極の単位

光秒光速天文学通信遅延
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Diagram of the Moon's phases shown in the outer perimeter as seen from the northern hemisphere. The Earth is at the center of the diagram and the Moon is shown orbiting.

月の満ち欠け月相の仕組みと観測のポイント

月の満ち欠け月相新月満月
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Derivative of −Δt. The axis on the right shows the length of the solar day.

会合日（太陽日）の仕組みと天体ごとの周期的な違い

会合日太陽日恒星日自転周期
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The celestial equator is currently inclined by about 23.44° to the ecliptic plane. The image shows the relations between Earth's axial tilt (or obliquity), rotation axis, and orbital plane.

天球赤道とは？地球の傾きと星空の座標系を解説

天球赤道天球黄道地軸
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Location of the northern lunistices from 2006 to 2025

月面停止（ルナスティス）のメカニズムと18.6年周期の天文学的影響

月面停止ルナスティス赤緯主要月面停止
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