[DOC] [TLE] Galilean moons - Wikipedia [PAR]  [DOC] [TLE] Galilean moons - Wikipedia [PAR] From top to bottom: Io, Europa, Ganymede, Callisto. The Galilean moons are the four largest moons of JupiterIo, Europa, Ganymede, and Callisto. They were discovered by Galileo Galilei around January 1610 and were the first group of objects found to orbit another planet. [DOC] [TLE] Moons of Jupiter - Wikipedia [PAR] Naming. The Galilean moons of Jupiter (Io, Europa, Ganymede, and Callisto) were named by Simon Marius soon after their discovery in 1610. [DOC] [TLE] The Discovery of the Galilean Satellites - Views of the Solar System [PAR] Galileo first observed the moons of Jupiter on January 7, 1610 through a ... and 
publish to the world the occasion of discovering and observing four Planets,... [DOC] [TLE] Jupiter's Moons: Facts About the Largest Jovian Moons - Space.com [PAR] Jul 5, 2012 ... Not only is Jupiter the largest planet in the solar system, it is also the most ... after 
discovering four moons orbiting Jupiter in January 1610. [DOC] [TLE] Galilean Moons of Jupiter - JPL - NASA [PAR] The planet Jupiter's four largest moons, or satellites, are called ... observed them 
in 1610. ... 1610  Galileo Galilei and Simon Marius independently discover. [DOC] [TLE] JUPITER'S FOUR MOONS - souledout.org monad [PAR] These four largest and brightest moons of Jupiter, first discovered by Galileo 
Galilei in 1610, are known as the Galilean satellites. Starting from left to right the
... [DOC] [TLE] The Galilean Moons of Jupiter [PAR] Summary: Jupiter has more than 60 known moons, but understanding the 
geology of its four largest will hopefully lead to some groundbreaking discoveries
. [DOC] [TLE] Galileo's Discovery of Jupiter's Moons [PAR] Just over four hundred years ago - on January 7th, 1610 - the Italian astronomer 
... 1610, he identified all four of what we now refer to as the "Galilean Moons": Io, 
... In it he referred to Jupiter's newly discovered moons as the "Medicean Stars",... [DOC] [TLE] The Galileo Project | Science | Satellites of Jupiter [PAR] On 7 January 1610 he observed the planet and saw what he thought were three 
fixed stars near ... The Earth was, in fact, not the only planet to have a moon, 
Jupiter had four. ... In 1655 Huygens discovered the first and largest; then in 1671
-72... [DOC] [TLE] Galileo Discovers Jupiter's Four Largest Moons - Awesome Stories [PAR] On the 7th of January, 1610, Galileo turned his telescope to the sky and 
discovered that Jupiter had three moons. The following night, he realized the 
planet had... [DOC] [TLE] What are the Galilean Moons? - Universe Today [PAR] Apr 26, 2016 ... Jupiter's largest moons are known as the Galileans, all of which were ... 
astronomer who discovered them between January 7th and 13th, 1610. ... By 
January 13th, he had discovered a fourth moon, and named them the... [DOC] [TLE] When Did Galileo Discover Jupiter? - Biography - YourDictionary [PAR] He was also the first astronomer to discover the four largest moons that orbit the 
... On January 10, 1610 Galileo discovered another one of Jupiter's moons. [DOC] [TLE] The moons of Jupiter - Phys.org [PAR] Sep 15, 2015 ... In 1610, he made the first recorded discovery of moons orbiting Jupiter ... With a 
diameter of 3,642 kilometers, it is the fourth-largest moon in the... [DOC] [TLE] JUPITER'S Moons - EnchantedLearning.com [PAR] Galileo first discovered the four largest moons of Jupiter, Io, Europa, ... in 1610, 
using a 20-power telescope; these moons are known as the Galilean moons. ... 
He noticed that the observed period of Io's orbit differed by about 20 minutes; he
... [DOC] [TLE] Jupiter - Sen.com [PAR] He realised that these points of light were bodies orbiting Jupiter. His discovery 
was of the four largest moons of Jupiter - Io, Europa, Ganymede and Callisto. Io ... 
Discovered in 1610 by Galileo, Ganymede circles Jupiter once every 7 days at a
... [DOC] [TLE] Jupiter's Moons: a list of all of its moons - Bob the Alien's Tour of

Question: He discovered the four largest moons of Jupiter in 1610
Answer: Galileo