Our Solar System

The Sun The sun is the biggest, brightest, and hottest object in the solar system. The sun is made of about 70% hydrogen and 28% helium.

Mercury Length of day: 58.7 Earth days Length of year: 88 Earth days Distance from Sun: 58 million km Diameter: 5 thousand km Mercury has little atmosphere due to proximity of the Sun

Mercury (con.) Mercury is the closest planet to the Sun and smallest. It is named after the Roman messenger to the gods because of its quick rotation around the Sun First recorded observation by Timocharus in 265 BC.

Mercury (con.) Mercury has a molten iron core and is covered with craters. NASA sent Messenger satellite to orbit planet in 2004 Biggest temperature switch among all planets (-183 Celsius to 427 degrees Celsius)

Venus Length of day: 243 Earth days Length of year: 225 Earth days Distance from the Sun: 108 million km Diameter: 12,100 km Atmosphere is 97% carbon dioxide

Venus (con.) Named after the Roman goddess of love and beauty. Hottest planet in the solar system (up to 465 degrees Celsius) Due to its atmosphere Venus is the brightest object in the sky after the Sun and the Moon

Earth Length of day: 24 hours Length of year: 365.25 days Distance from the Sun: 150 million km Diameter: 12,900 km Only planet not named after Greek/Roman god

Earth (con.) Earth is the fifth largest planet and the third from the sun. Liquid covers 71 percent of the Earth’s surface. First satellite sent into space October 4, 1957 to orbit Earth (Sputnik)

Moon

Mars Length of day: 1.03 Earth days Length of year: 1.88 Earth years (687 days) Distance from the Sun: 227 million km Diameter: 6,800 km “Ice caps” on poles made of carbon dioxide and H20.

Mars (con.) Mars has a thin atmosphere that contains mostly carbon dioxide. Mariner 1 and 2 landers were the first to reach Mars in 1976. Currently Opportunity and Curiosity are roaming the surface of Mars.

Moons of Mars Discovered in 1877 by Asaph Hall of the US Naval Observatory Named for the sons of Mars Phobos- Greek for “panic/fear” Deimos- Greek for “terror/dread”

Asteroid Belt Circumstellar disk that orbits the Sun between the planetary orbits of Mars and Jupiter composed of leftover planetary debris/dust from the already formed planets Composed of partially rocky/icy material Notable asteroids: Ceres, considered a dwarf planet (945 km in diameter)

Jupiter Length of Day: 0.42 Earth days Length of Year: 12 Earth years Distance from the Sun: 778 million km Diameter: 140,000 km Named for the head of Roman god pantheon due to its size

Jupiter (con.) The Great Red Spot, a huge storm of swirling gas that has lasted for hundreds of years. Jupiter is the first of the “gas giants”, planets with rocky cores and massive gaseous atmospheres. 11 times the diameter and 1000 times the volume of Earth

Moons of Jupiter Jupiter has four large Galilean moons, twelve smaller named moons and twenty-three more recently discovered but not named moons. The following four large Galilean moons which were first observed by Galileo in 1610.

Ganymede Largest of Jupiter’s moons. Ganymede has extensive cratering and an icy crust. Pictures from the Hubble ST detected a thin oxygen atmosphere.

Callisto Callisto is the second largest. Callisto has the oldest, most cratered surface of any body yet observed in the solar system.

Io It’s the third largest of Jupiter’s moons. Io has hundreds of volcanic calderas. Some of the volcanoes are active.

Europa It is slightly smaller than the Earth’s moon. The surface strongly resembles images of sea ice on Earth. There may be a liquid water sea under the crust. (Galileo) Europa is one of the five known moons in the solar system to have an atmosphere.

Saturn Length of Day: 10.7 hours Length of Year: 29 Earth years Distance from the Sun: 143 billion km Diameter of planet: Oldest written observations of Saturn are from 700 BC by the Assyrians

Saturn (con.) Named for the Roman god of agriculture and wealth Saturn rotates so fast that it flattens out at the poles. Saturn is 96.3% hydrogen, 3.25% helium, and small amounts of methane and ammonia.

Rings of Saturn Saturn’s rings are not solid; they are composed of small countless particles. The rings are very thin. Though they’re 250,000km or more in diameter, they’re less than one kilometer thick.

Uranus Length of day: 17.2 hr Length of year: 84 Earth years Uranus is named for the Greek lord of the gods. Uranus is blue-green because of the methane in its atmosphere. Rotates similar to Venus

Uranus (con.) Uranus is notable because of its appearance of sideways rotation due to being at a 90 degree tilt. Along with Neptune it is considered one of the “ice giants” due to cold temperatures (-224 Celsius)

Miranda Closest of Uranus’s five major moons Known for its deformed, icy surface and miles deep canyons Recent research shows the deformities may come from gravitational pull of Uranus

Neptune Named after the Roman god of the sea. Takes 165 Earth years to complete a rotation (2011 was first). Like Uranus, the methane gives Neptune its color.

Neptune (con.) Has 6 rings circling it Has 13 moons, the most notable of which is Triton Triton is notable because of its nitrogen atmosphere, opposite rotation, and discovery of it having seasons

Pluto Pluto, formerly considered the last planet in the solar system is the farthest from planetary body the sun in the solar system. Discovered by Clyde Tombaugh in 1930.

Pluto (con.) Pluto was recently visited by New Horizons (image right) Reclassified as a dwarf planet in 2006 after emergence of similarly sized objects in Kuiper belt and asteroid belt Surrounded by five moons (biggest is Charon)