Notes: Our Solar System

Distances from the Sun: Measured in astronomical units (AU) 1 AU = 150 million kilometers (93 million mi.) Average for Earth = 1 AU

Terrestrial Planets: 4 planets closest to Sun Rocky crusts and dense mantles and cores Crusts shaped by Tectonics, Volcanism, Weathering and Erosion, & Impact Cratering Smaller than outer planets

Mercury: Surface covered by craters (oldest surface) No atmosphere

Venus: (Earth) Volcanoes and lava plains cover surface Dense atmosphere causes high temps (470*C) (Earth)

Mars: Thin atmosphere Temperatures range from 20*C to -90*C

The Gas Giants (Jovian Planets): 4 largest planets, farthest from Sun Made of hydrogen, helium, and other gases Extremely dense atmospheres Have rings and many moons

Jupiter: Largest planet Fast winds and stormy weather The Great Red Spot - storm larger than Earth, 100 years

Saturn: Large rings made of chunks of water ice Outer ring is 3 times as wide as the planet

Uranus: Axis of rotation is almost in the plane of its orbit

Neptune: Appears a deep blue due to methane gas

Smaller Objects in the Solar System: Bodies formed near the center are mostly rock and metal (asteroids, meteors) Bodies formed far from the center are mostly ice with some rock and metal (comets, dwarf planets)

Solar System Formation Began as a rotating ball of dust and gasses Gravity caused the ball to flatten into a disk shape Dust and gasses within the disk were merged through gravitational force to become planets and other objects

Stars A large sphere of hydrogen gas hot enough for nuclear reactions to occur in its core A star and the planets that orbit it make up a solar system