Jupiter
Videos
Jupiter is the fifth planet from the Sun and the largest in the Solar System. A gas giant, Jupiter's mass is more than two and a half times that of all the other planets in the Solar System combined and slightly less than one one-thousandth the mass of the Sun. Jupiter orbits the Sun at a distance of 5.20 AU (778.5 Gm) with an orbital period of 11.86 years. It is the third brightest natural object in the Earth's night sky after the Moon and Venus and has been observed since prehistoric times. Its name derives from Jupiter, the chief deity of ancient Roman religion.
Jupiter captured by New Horizons space probe. The small spot on top of Jupiter is the shadow cast by its moon Ganymede.
Size of Earth compared to Jupiter in true colours
Enhanced colour view of Jupiter's southern storms
Close-up of the Great Red Spot imaged by the Juno spacecraft in true colour. Due to the way Juno takes photographs, stitched image has extreme barrel distortion.
Astronomical unit
Videos
The astronomical unit is a unit of length defined to be exactly equal to 149,597,870,700 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.