Solar System Inner planets Outer planets

Solar Nebular Theory How did the solar system begin? The solar system began as a huge cloud of dust and gas called a ________________. Nebula Gravity _________________ caused the cloud to condense and form the sun and its nine planets. Hydrogen Helium Primary gases were ______________ and ______________. 5 The solar system began to form about ____ billion years ago when a star exploded in a huge supernova. Particles form its explosion “rained down” on a nearby nebula, “seeding” it with chemicals that would become ___________ and its __________. The sun planets

The nebula had been slowly rotating, but began to collapse to its center. The nebula’s rotational speed increased which flattened the nebula into a more disk-like shape. As the cloud continued to collapse in on itself, a large massive ___________ formed in the center. protosun Smaller clumps of matter formed around the central protosun forming the _____________. planets _____ ________were so close to the sun’s heat that the lighter elements like H and He boiled away. All that was left were the heavier, rocky, metallic elements. They are called _________ Planets. They include __________, Venus, Earth and ________. Inner planets Terrestrial Mercury Mars

The ______ planets farther from the sun were not so affected by the sun’s heat. They retained their lighter gases and grew to enormous sizes. These were called the Gas Giants or ______ planets. outer Jovian They are Jupiter, _________, Uranus, and _________. Saturn Neptune Smaller clumps of matter formed around the planets. These became ____________ or moons. satellites _________ is believed to be an escaped moon of Neptune. __________ exist between Mars and Jupiter. Pluto Asteroids

Mercury Closest planet to the Sun Shortest period of revolution During day, planet is hot, but at night, it is freezing cold. Almost no atmosphere (no weather) no moons or rings First explored by Mariner 10 in 1975 Lots of impact craters (like our moon)

Venus Earth’s twin because it’s similar in diameter, mass, size Atmosphere is mostly carbon dioxide and about 3% nitrogen. The yellow clouds are concentrated sulfuric acid thick clouds cause this to be the hottest planet because of the Greenhouse Effect Has phases like our moon First radar mapped by Magellan in 1991 Brightest planet

Mars Called the Red Planet 1 Martian year = about 2 Earth years Atmosphere – 95% Carbon Dioxide and 5% Nitrogen. Very thin with clouds of ice appears to have season – polar ice caps Has 2 moons – Phoebus and Deimos Explored by Mariner 4 (1965), Viking (1976), Pathfinder (1997) and Rovers – Spirit and Opportunity (2004) evidence of liquid water on its surface has largest known mountain in the solar system (Olympus Mons)

Jupiter Largest planet Rotates once every 10 hours Atmosphere – 90% Hydrogen, 10% Helium, methane, and ammonia Great Red Spot – possibly a calm area in a very turbulent atmosphere (high winds from internal heat). Radiates more energy than it receives from sun Has 63 moons (as of February 2004) - 4 largest visible with binoculars – Io, Europa, Ganymede, Callisto Io – most geologically active volcano Has faint rings (dark colored) Visited by Pioneer 10 (1973) & 11 and Voyagers I & II in late 70s Liquid metallic Hydrogen (high pressure)

Saturn Second largest planet Atmosphere – 75% Hydrogen, 25% Helium Has colored bands of gases (like Jupiter) Has 34 moons – Titan is well known Has 7 rings and 1000s of ringlets Visited by Pioneer 11 (1979), Voyager I & II, and Cassini in 2004 Such a low density, could float on water

Uranus Rotation 17.2 hours (slowest of Jovians) 1 Uraniun year – 84 Earth years Atmosphere is 83% Hydrogen, 15% Helium, and 2% methane. Planet appears blue because the red is absorbed by the methane in the atmosphere Has 21 named moons and 6 unnamed; only moons named after Shakespeare and Pope 11 rings Visited by Voyager 2 (1986) Rotates almost on its side with South Pole facing the Sun

Neptune Smallest gas planet 1 Neptunian year = 16.5 Earth years Atmosphere is 15% Hydrogen, little Helium, and methane (blue appearance) Great Dark Spot; fastest winds in solar system 2000 km/hour Gives off 2.7 times more energy than it receives from the Sun Has 13 known moons and 4 rings Triton is Neptune’s largest moon and the coldest known place in solar system Discovered in 1846 Visited by Voyager 2 (1989)

PLUTO NOT a Jovian planet, but it is an outer planet 1 Plutonian year – 248 Earth Years Discovered in 1930 Atmosphere is mostly frozen methane and helium Has 1 moon – Charon Has not been visited yet, but Its orbit is so elliptical that it was actually nearer to the Sun than Neptune until March 1999.