Galileo discovered Saturn in 1610, it is unknown who discovered Venus. I found these things in about 30 seconds using google. You need to search by individual planet, not as a group.

Here's some nicely put together sites to help out. Good luck! http://www.windows.ucar.edu/tour/link=/our_solar_system/solar_system.html http://curious.astro.cornell.edu/question.php?number=82

Mercury: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/mercury_discovery.shtml Venus: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/venus_discovery.shtml Earth: Mars: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/mars_discovery.shtml Jupiter: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/jupiter_discovery.shtml Saturn: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/saturn_discovery.shtml For those planets (Except Earth) the reply is: There is no single person who is credited with the discovery of _____(Insert planet Name). ------------- (Insert planet name) is one of the five planets that can be seen in the night sky without using a telescope or binoculars. Uranus: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/uranus_discovery.shtml The planet Uranus was discovered by William Herschel on March 13, 1781. He discoverd Uranus while surveying stars in the night sky using a telescope that he had built himself. Herschel noticed that one of these "stars" seemed different, and after observing it many more times, noticed that it orbited the sun. He calculated that Uranus had an orbit that was about 18 times farther from the sun than Earth. Herschel also discovered two of the moons of Uranus (Titania and Oberon). Neptune: http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/neptune_discovery.shtml Neptune was the first planet to be discovered by using mathematics. After the discovery of Uranus in 1781, astronomers noticed that the planet was being pulled slightly out of its normal orbit. John Couch Adams of Britain and Urbain Jean Joseph Leverrier of France, used mathematics to predict that the gravity from another planet beyond Uranus was affecting the orbit of Uranus. They figured out not only where the planet was, but also how much mass it had. A young astronomer, Johann Gottfried Galle, decided to search for the predicted planet and observed Neptune for the first time in 1846. Pluto (No more a real planet): http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/tombaugh.shtml Pluto was discovered in 1930 by Clyde Tombaugh. Astronomers noticed that the orbits of Neptune and Uranus were being affected by the gravity of an unknown object in ths solar system. Clyde Tombaugh carefully studied images of the night sky and after a lot of hard work he finally discovered Pluto. Clyde Tombaugh was only 24 years old when he made this discovery.

The eight known planets (excluding Earth): "Timocharis made the first recorded observation of Mercury in 265 BC." http://www.windows.ucar.edu/tour/link=/mercury/News_and_Discovery/news_disc_overview.html "Pythagoras is usually credited with recognizing in the sixth century BC that the morning and evening stars were a single body, though he thought that Venus orbited the Earth." http://en.wikipedia.org/wiki/Venus "Aristotle was among the first known writers to describe observations of Mars, noting that, as it passed behind the moon, it was farther away than was originally believed." http://en.wikipedia.org/wiki/Mars#Viewing "No one knows for sure who discovered Jupiter, but we know the ancient Greeks named him after the god, Zeus." http://www.windows.ucar.edu/tour/link=/jupiter/discovery.html "In ancient Roman mythology, the god Saturnus, from which the planet takes its name, was the god of the agricultural and harvest sector." http://en.wikipedia.org/wiki/Saturn#History_and_exploration "The earliest recorded sighting was in 1690 when John Flamsteed catalogued Uranus as 34 Tauri." http://en.wikipedia.org/wiki/Uranus#Discovery "Galileo's drawings show that he first observed Neptune on December 28, 1612" http://en.wikipedia.org/wiki/Neptune#Discovery The three Dwarf Planets: "It was discovered on January 1, 1801, by Giuseppe Piazzi." http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29 "In 1930 Clyde Tombaugh was searching for a ninth planet...Pluto would later be found on photographs dating back to March 19, 1915." http://en.wikipedia.org/wiki/Pluto#Discovery "Eris was discovered by the team of Mike Brown, Chad Trujillo, and David Rabinowitz[6] on January 5, 2005" http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29#Discovery