Astronomical unit
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The astronomical unit is a unit of length defined as 149597870700 m. Historically, the astronomical unit was conceived as the average Earth-Sun distance, before its modern redefinition in 2012.
Transits of Venus across the face of the Sun were, for a long time, the best method of measuring the astronomical unit, despite the difficulties (here, the so-called "black drop effect") and the rarity of observations.
Voyager 1
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Voyager 1 is a space probe launched by NASA on September 5, 1977, as part of the Voyager program, to study the outer Solar System and the interstellar space beyond the Sun's heliosphere. It was launch
Astronomical unit
…au Neptune 30.1 — Average distance from the Sun — Eris 67.8 — Average distance from the Sun — Voyager 2 141 — Distance from the Sun in September 2025 Voyager 1 168 — Distance from the Sun in September 2025 Light-day 173 — Distance light travels in one day — Sedna (aphelion) 937 — Distance to the farthest point…
Locations of Voyager's scientific instruments
Voyager 1 lifted off atop a Titan IIIE.
Jupiter's Great Red Spot as seen from Voyager 1
Voyager 1 image of Valhalla, a multi-ring impact structure 3,800 km in diameter on Callisto.