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Curated category

Moons with a prograde orbit

  • Polydeuces (moon)Polydeuces is a moon of Saturn so small that its discovery came down to counting pixels. On the 21st of October 2004, the Cassini spacecraft captured four…
  • Calypso (moon)Calypso is a moon of Saturn so small and so bright that it almost defies easy description. Its surface reflects more light than almost any other object in…
  • Adrastea (moon)Adrastea, the tiny moon also catalogued as Jupiter XV, holds a distinction that sets it apart from every moon discovered before it. When David C.
  • Dione (moon)Dione is a moon of Saturn, and for most of human history it was nothing more than a pinprick of light glimpsed through a large telescope pointed at the night…
  • Telesto (moon)Ground-based observations in 1980 revealed a faint point of light near Saturn. Smith, Reitsema, Larson and Fountain identified this object as a new moon…
  • Ariel (moon)Ariel is a moon of Uranus, discovered on the 24th of October 1851 by the astronomer William Lassell. It was found alongside a slightly larger neighbor…
  • Tethys (moon)Tethys, the fifth-largest moon of Saturn, sits about 295,000 kilometers from the planet's center. Its surface is almost pure water ice, bright enough to rank…
  • Ganymede (moon)Ganymede, the largest moon in the entire Solar System, holds a magnetic field that no other moon anywhere is known to possess.
  • Io (moon)Io has over 400 active volcanoes, more than any other object in the Solar System. Several of them fire plumes of sulfur and sulfur dioxide as high as 500 km…
  • Titan (moon)Titan, Saturn's largest moon, holds a distinction that no other moon in the Solar System can claim: a dense atmosphere thicker than Earth's own, wrapped…
  • Galilean moonsThe Galilean moons are four worlds circling Jupiter, each one large enough to rank among the biggest objects in the Solar System.
  • Helene (moon)Pierre Laques and Jean Lecacheux spotted the moon from Pic du Midi Observatory in 1980. Ground-based observations revealed a faint object orbiting Saturn…
  • Europa (moon)Europa, the smallest of Jupiter's four Galilean moons, holds a secret beneath its frozen skin that has captivated scientists for decades.
  • Miranda (moon)Miranda, the smallest and innermost of Uranus's five round moons, holds a surface so fractured and layered that scientists who first saw its images in…
  • MimasMimas, the seventh-largest moon of Saturn, holds a record that sounds almost impossible: it is the smallest body in the solar system known to have pulled…
  • Titania (moon)Titania is the largest moon of Uranus and the eighth-largest moon in the entire Solar System, measuring 1,578 kilometres across.
  • UmbrielUmbriel is the third-largest moon of Uranus, and it holds a reputation as one of the darkest, most enigmatic objects in the outer Solar System.
  • Proteus (moon)Proteus, Neptune's largest inner satellite, was hidden in plain sight for decades. Not because it is small - at about 420 km across, it outpaces Neptune's…
  • Callisto (moon)Callisto hangs in the darkness beyond Jupiter's main radiation belt, orbiting at a distance of roughly 1.883 million kilometers from the planet it…
  • Hyperion (moon)Hyperion is a moon of Saturn unlike any other body in our solar system. It tumbles through space without any predictable orientation.
  • Styx (moon)On the 11th of July 2012, astronomers announced the existence of a tiny moon orbiting Pluto. Mark R. Showalter led the team that found this object using…
  • Oberon (moon)Oberon, the outermost major moon of Uranus, has a name borrowed from the fairy king of Shakespeare's A Midsummer Night's Dream.
  • Rhea (moon)Rhea hangs in the darkness beyond Saturn, a world of ice roughly the size of Australia, and almost nobody has heard of it.
  • Metis (moon)Metis, the innermost known moon of Jupiter, appeared in history as nothing more than a tiny dot. On the 4th of March 1979, astronomer Stephen P.
  • Nix (moon)On the 15th of May 2005, astronomers using the Hubble Space Telescope captured images that would change our understanding of Pluto.
  • Phobos (moon)Phobos is a tiny, lumpy rock orbiting Mars so close to the planet's surface that it travels faster than Mars itself spins.
  • EnceladusEnceladus, a moon of Saturn barely 500 km across, is shooting water into space right now. More than 100 geysers blast from its south pole at speeds reaching…
  • Deimos (moon)Deimos is the smaller and outer of the two moons of Mars, and it carries the name of dread itself. In Greek mythology, Deimos personified terror, a companion…
  • Iapetus (moon)Iapetus, one of Saturn's moons, puzzled the astronomer Giovanni Domenico Cassini for more than three decades. In October 1671, Cassini spotted it on the…
  • Hydra (moon)On the 15th of May 2005, astronomers using the Hubble Space Telescope spotted faint points of light near Pluto. These images captured two new moons that had…
  • Thebe (moon)Stephen P. Synnott found Thebe in images from the Voyager 1 space probe taken on the 5th of March 1979. This discovery happened while the spacecraft was…
  • Charon (moon)Charon is the largest moon of the dwarf planet Pluto, and it is strange in almost every way a moon can be. Its mean radius is 606 km, which makes it more…
  • MoonThe Moon is the only natural satellite of Earth, and it orbits at an average distance of 384,399 km. That gap is roughly thirty times the width of Earth.
  • Amalthea (moon)Edward Emerson Barnard stood at the eyepiece of a 36 inch refractor telescope on the 9th of September 1892. He was working at Lick Observatory when he…