The Discovery of the Galilean Satellites . ... Probably the most significent contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. ... Galileo's Observations of Jupiter's Moons . ... Jupiter . ...

... Neptune is smaller in diameter but larger in mass than Uranus . ... N eptune has been visited by only one spacecraft, Voyager 2 on Aug 25 1989. ... A t the time of the Voyager encounter, Neptune's most prominent feature was the Great Dark Spot (left) in the southern hemisphere. ... Neptune's winds blew the Great Dark Spot westward at 300 meters/second (700 mph). ... L ike Uranus and Jupiter, Neptune's rings are very dark but their composition is unknown. ... Neptune's Ring System . ... Uranus .. ...

... HR 8799: Discovery of a Multi planet Star System . ... NRC Canada Explanation: How common are planetary systems like our own Solar System? In the twelve years previous to 2008, over 300 candidate planetary systems have been found orbiting nearby stars. ... Although the HR 8799 planetary system has significant differences with our Solar System, it is a clear demonstration that complex planetary systems exists, systems that could conceivable contain an Earth-like planet . ... Planets Ahoy . ...

Giant Jupiter. Jupiter . ... Jupiter has no solid surface that is why speaking about its dimensious point the radius of the upper border line of the clouds, where the presseru is about 10 KPa; radius of Jupiter on the equator is 71400 km. ... The Jupiter satellites. ... Nowadays 16 satellites of the Jupiter are known: Adrastea, Mitis, Amaltea , Phina,then 4 Galilei satellites: Io , Europe , Hanimed , Callisto , Leda, Aimalia, Zicitea, Elara, Ananke, Carme, Pasipe and Sinope. ... Jupiter's ring. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Our Galaxy . ... Weird and Fun . ... It came from another galaxy: This artistтАЩs impression shows HIP 13044 b, an exoplanet orbiting a star that entered our galaxy from beyond. ... HIP 13044 is one of tens of millions of stars in the тАЬHelmi streamтАЭ, stars that belonged to a dwarf galaxy consumed by our own Milky Way galaxy, some six to nine billion years ago. ... Tweets that mention ESO finds weird doomed planet from another galaxy | ...

Discover the cosmos! ... 2002 June 14 . 55 Cancri: Familiar Planet Discovered . ... The discovery of a Jupiter -like planet in a Jupiter-like orbit around nearby Sun -like star 55 Cancri , announced yesterday, gives a new indication that planetary systems similar to our Solar System likely exist elsewhere. The planet, discovered by G. Marcy ( UC Berkeley ) and collaborators, is one of two new planets found around 55 Cancri -- in 1997 a Jupiter-massed planet was found orbiting very close in. ...

... More on 51 Peg: . The discovery of a Jupiter--mass planet in orbit around the solar--type star 51Peg has been reported by Michel Mayor and Didier Queloz (Geneva Observatory) on October 6th at the 9th Cambridge workshop on "cool stars, stellar systems, and the sun" held at Florence (Italy). ... Recall that the measurements of radial velocity only yield v sin i which in turn gives us M sin i. For most values of i, sin i will be greater than 0.5 and this gives a mass estimate of 0.5 Jupiter masses. ...

Armagh Observatory, 24 July 2000: . The Minor Planet Center at the Smithsonian Astrophysical Observatory, Cambridge, Massachusetts, USA, has announced the discovery of a new moon of Jupiter, bringing to 17 the number of known satellites orbiting the giant planet. ... At that time, Jupiter was about 370 million miles from Earth, just about as close as it ever gets, and therefore a good time to search for any faint satellites. ... Last Revised: 10th August 2000 . ...