Inner moon Reference Libraries

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Planetary Ring
2004-10-19 04:45:42

Planetary Ring -- A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. The most spectacular and famous planetary rings are those around Saturn, but all four of the solar system's gas giant planets (Jupiter, Saturn, Uranus, Neptune) possess ring systems of their own. The origin of planetary rings is not precisely known, but...

Neptunes Moon Larissa
2004-10-19 04:45:41

Planet Larissa -- Larissa is the fifth of Neptune's known moons. It was discovered by Harold Reitsema based on ground-based stellar occultation observations, and was photographed by Voyager 2 in 1989. Larissa is irregular (non-spherical) in shape and appears to be heavily cratered, with no sign of any geological modification. Little else is known about it. Since its orbit is below...

Uranus Moon Portia
2004-10-19 04:45:41

Uranus' moon Portia -- Portia is a moon of Uranus, named after the 2 two heroines in plays by William Shakespeare. It was discovered in 1986 by Voyager 2. Very little is known about it. Since it is below Uranus' synchronous orbit radius, Portia's orbit is slowly decaying due to tidal forces and it will one day break up into a planetary ring or impact on Uranus' surface. -----...

Saturns Moon Janus
2004-10-19 04:45:41

Saturn's moon Janus -- Janus is a moon of Saturn discovered by the French astronomer Audouin Dollfus in 1966. Dollfus is credited with the discovery of Janus but it's not really certain whether the object he saw was Janus or Epimetheus and his observations led to a spurious orbit (Walker discovered it independently but his telegram arrived a few hours after Dollfus'). Larson and...

Saturns Moon Epimetheus
2004-10-19 04:45:41

Saturn's moon Epimetheus -- Epimetheus is a moon of Saturn that was probably first observed by Walker and Audouin Dollfus in 1966 when they discovered Janus, but the situation was confused since Janus is in a very similar orbit and so Walker officially shares the discovery of Epimetheus with Fountain and Larson who showed in 1978 that there were two satellites involved. The situation was...

Saturns Moon Prometheus
2004-10-19 04:45:41

Saturn's moon Prometheus -- Prometheus [pra-MEE-thee-us] is the third of Saturn's known satellites. It was discovered from photographs taken by Voyager during its encounter with Saturn by S. Collins and others. Prometheus acts as a shepherd satellite for the inner edge of Saturn's F Ring. The moon is extremely elongated about 145 by 85 by 62 kilometers (90 by 53 by 39 miles) in...

Saturns Moon Atlas
2004-10-19 04:45:41

Saturn's moon Atlas -- Atlas, the second of Saturn's known satellites, orbits near the outer edge of the A-ring and is about 40 by 20 kilometers (25 by 15 miles) in size. It is probably a shepherd satellite for Saturn's A-ring. Atlas was discovered by R. Terrile in 1980 from photographs taken by Voyager during its encounter with Saturn. ----- Discovered by: R. Terrile/Voyager 1...

Jupiters Moon Metis
2004-10-19 04:45:40

Jupiter's moon Metis -- Metis [MEE-tis] is the innermost known satellite of Jupiter. It was named after a Titaness who was a consort of Zeus (Jupiter). Metis and Adrastea lie within Jupiter's main ring and may be the source of material for the ring. Very little is known about Metis. 40 kilometers (25 miles) in diameter, orbiting 128,000 kilometers (79,500 miles) from Jupiter....

Word of the Day
  • Small missiles, especially grape, canister, fragments of iron, and the like, when fired, as upon an enemy at close quarters.
  • To fire mitraille at.
The word 'mitraille' comes from the Old French 'mitaille', meaning 'small coins', sometimes used to mean 'scrap iron'.