Our SUN At the Center of our Solar System Made of 74% Hydrogen and 25% Helium Keeps planets in orbit around it with it’s large gravitational pull. Has a mass of 1.989 x 1030 kg

Mercury Closest Planet ~ 0.37 A.U. “The Morning Star” Fastest traveling planet (108, 000 mph) Shortest year of all the planets (88 days) Named after the Roman messenger of the gods. Greatest extremes in temperatures (Day: 800°F Night: -300°F) Very cratered surface because it has no atmosphere & is close to the sun. Lifeless & waterless Sometimes called “The Morning Star” Encountered by Mariner X (1974-75) Caloris Basin is the largest crater (930 miles across) Closest Planet ~ 0.37 A.U. “The Morning Star”

Venus 2nd Planet ~ 0.72 A.U. “Earth’s Sister Planet” Very dense atmosphere of sulfuric acid droplets (pale yellow) & carbon dioxide (poisonous gas) Very hot (avg. temp. 900°F) due to greenhouse effect Longest day of any planet (day is longer than its year). Retrograde rotation (clockwise) “The Evening Star” seen in phases like our moon. Easiest planet to spot, 3rd brightest object in the sky. Magellan orbitter sent back satellite images in 1990 (crushed by atmosphere) Pioneer-Venus used radar to map surface through the dense atmosphere Topography similar to Earth “Earth’s Sister Planet”

Earth 3rd Planet -- 1 A.U. “Venus’ Sister Planet” Constantly changing (evolving) due to wind, water, gravity, & glaciers tectonic plate movement (continental drift) is about 2.5 cm. per year Seven continents were once one large continent called Pangaea (200 million years ago) Only known planet to support life. Only planet with liquid water (70% of the surface) Largest terrestrial (solid) planet Atmosphere is composed of nitrogen (78%), oxygen (21%), argon, & carbon dioxide. Composed in layers (crust, mantle, & core)              “Venus’ Sister Planet”

Mars 4th Planet ~ 1.52 A.U. “The Red Planet” Surface is riddled with canals (appear as lines) possibly carved by running water? VERY thin atmosphere that seems to be disappearing (95% carbon dioxide) Cold, dry, & lifeless planet with polar ice caps composed of frozen CO2 2nd closest planet to Earth (Venus is brighter because its closer & larger) Two Viking spacecraft (1976) & Pathfinder (1997) landed on its surface. Asteroid belt located between orbits of Mars & Jupiter Two moons :Phobos & Deimos “The Red Planet”

Jupiter The Great Red Spot 5th Planet ~ 5.20 A.U. Larger than all of the planets combined. (1/1000 the size of the sun) Re-radiates heat into space Gets hotter & hotter as you go inward. Great Red Spot (over 200 years old & larger than Earth) is a cyclonic storm that orbits the planet every 6 days. Ringed planet that shines brighter than any other planet except Venus Shortest day of any planet (~10 hours). Like a miniature solar system. Voyager I & II (1979-80) and Pioneer X & XI (1973-4) encountered Jupiter Galileo (1995-2003) studied Jupiter’s moons close-up. “Emperor of the Solar System”

Saturn 6th Planet ~ 9.54 A.U. “The Ringed Planet” Second largest planet that contains the hottest gases in the solar system (over 1billion°F) Rings are composed of ice, rock, & debris Jupiter’s “sister planet” similar in all aspects. Many irregular moons (56+) Most distant planet that can be seen without a telescope. Least dense of all planets (would float) Encountered by Pioneer (1979), Voyager I (1980) & Voyager II (1981) Was encountered by Cassini (2005) “The Ringed Planet”

Uranus 7th Planet ~ 19.22 A.U. Titania “The Green Planet” First planet to be discovered using a telescope. (William Herschel, 1781) Ring system similar to the other gas planets. Lateral rotation (east & west poles) Only planet larger than the Earth that has less gravity (low density) Neptune’s “sister planet”. Studied close-up by Voyager II (1986) May have once been the “Star of Bethlehem”, but probably too faint. Moons named after Shakespearian characters (Titania, Miranda, Ariel, & Umbriel) “The Green Planet”

Neptune 8th Planet ~ 30.06 A.U. Triton The Great Dark Spot Furthest planet from the sun about 12 out of every 248 years. Very faint, cannot be seen without a telescope. Ring system similar to other gas planets More methane (blue-colored gas) than its slightly larger “sister planet”, Uranus. Also encountered by Voyager II (1989). Its moon, Triton, is the coldest place in the solar system. (-391ºF) “The Blue Planet”

Pluto Dwarf Planet ~ 39.5 A.U. “The Dark Planet” Discovered in 1930; thought to have been Earth-sized at one time. 1/1600 of the sunlight that Earth receives. Crosses orbits with Neptune twice every 248 years. Made of frozen methane or rock. Some believe that it is actually a moon of Neptune. Its moon, Charon, is close to the same size. Two recently discovered moons: Nix & Hydra (2005) Since 2006 considered to be a “Dwarf Planet” or Kuiper Belt object.            “The Dark Planet”