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Chapter 12 Study Guide!!

(Thanks for your help Nick Dawson)

Solar System: Made up of eight planets, including Earth, and many other objects that orbit the Sun.

Our SOLAR SYSTEM FORMED more than 4.6 billion years ago. Scientists think there was a HUGE cloud of gas, ice, and dust. Gradually, this cloud packed together (contracted) into a HUGE spinning disk. The disk’s center was so hot and dense that nuclear fusion reactions began to occur and the SUN was born from this. EVENTUALLY, the rest of the material in the disk cooled enough to clump into scattered solids. FINALLY, these clumps collided and combined to become the 8 planets that make up our solar system.

Besides the planets and SUN, there are many other structures in our solar system.

The FIRST 4 'INNER' planets are rocky planets.  The next 4 'OUTER' planets are made of gas.

A phrase that might help you remember the order of the planets: My Very Educated Mother Just Served Us Noodles....  Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.  


Mercury: Closest planet to the Sun and has no atmosphere. Temperatures and reach 425 degrees Fahrenheit and can drop to –274 degrees Fahrenheit.
Mariner 10: 1st American spacecraft mission to Mercury in 1974-1975.

Venus: 2nd planet from the Sun and is called Earth’s twin. Hottest planet in the solar system. Temperatures can rise between 842 and 887 degrees Fahrenheit.
Mariner 2: Flew past Venus in 1962 to observe Venus’s atmosphere and rotation.
Note: Mercury and Venus have NO moons. 

Earth: 3rd planet from the Sun. Has abundant liquid water and supports life.

Mars: 4th planet from the Sun and its nickname is “The Red Planet”. Iron oxide on its surface gives the planet a red-orange like color. Temperatures range from –125 and 95 degrees Fahrenheit.
Olympus Mons: The largest volcano in the solar system (inactive and is located on Mars).
Mariner 9: 1st U.S. spacecraft to orbit Mars (occurred 1971 and 1972). 
Phobos: Moon of Mars and is about 25 km in length. It takes about 7 hrs. to revolve around Mars once. It is the inner most moon.
Deimos: Moon of Mars and is about 13 km in length. It takes about 31 hrs. to revolve around Mars once and is the outer most moon.

Jupiter: 5th planet from the Sun. It’s mainly composed of hydrogen and helium.  Has about 63 moons orbiting it. Largest planet in the solar system.
Great Red Spot: A continuous storm of swirling, high-pressure gas.
Io: One of the 4 largest moons of Jupiter. It is the closest of the 4 largest moons to Jupiter. It’s also the most volcanically active object in the solar system.
Europa: Mostly composed of rock with a thick, smooth crust of ice. Under the ice might be an ocean as deep as 50 km.
Ganymede: Largest moon in the solar system and has a thin oxygen atmosphere similar to Europa’s.
Callisto: Mostly composed of ice and rock. Has a heavily cratered crust with a thin carbon dioxide atmosphere.

Saturn: 6th planet from the Sun and is the 2nd largest planet in the solar system. Mainly composed of hydrogen and helium. About 47 moons orbit Saturn.
Titan: Largest moon of Saturn and has a thick atmosphere of nitrogen, argon, and methane.

Uranus: 7th planet from the Sun and about 27 moons orbit it. Its atmosphere gives the planet a bluish-green color. It’s tilted on its side and its atmosphere is primarily composed of hydrogen, helium, and some methane.
Titania: Uranus’s largest moon has many craters and valleys.

Neptune: The 8th planet from the Sun and its atmosphere is also made up of hydrogen, helium, and some methane just like Uranus’s atmosphere. Has about 13 moons.
Great Dark Spot: Similar to the Great Red Spot on Jupiter, it is about the same size as Earth and has the highest wind speeds in the solar system. In 1994, it disappeared and reappeared according to the Hubble Space Telescope.
Triton: Neptune’s largest moon and its atmosphere is mainly composed of nitrogen.
Ceres: Discovered in 1801 and is the largest asteroid in the asteroid belt.

Pluto: Has a diameter of about 2,300 km and takes about 248 Earth-years to complete its orbit. PLUTO IS NO LONGER CONSIDERED A PLANET! :-(
Eris: Discovered in 2005 and has a diameter of about 2,400 km making it a little larger than Pluto. Takes 557 Earth-years to complete its orbit.

Comet: composed of dust and rock particles mixed with frozen water, methane, and ammonia.
Oort Cloud: cloud of comets located beyond the orbit of Pluto.
Comet Hale-Bopp: On July 23, 1995, it headed toward the Sun making it the brightest comet visible from Earth in 20 years.

Meteoroid: piece of dust and rock, along with those derived from other sources.

a meteoroid that burns up in Earth’s atmosphere.

Meteorite: a meteoroid that strikes Earth’s surface.

Asteroids: a piece of rock similar to the material that formed into the planets.

If you study all these terms, you will have a more likely chance of getting an A. So PLEASE study!!!!!!! :)