Section 2: Inner Planets

Classifying Planets• Terrestrial vs. Jovian: • Terrestrial-like Earth: Mercury, Venus, Earth and Mars.• Jovian-huge gas planets: Jupiter, Saturn, Uranus, and

Neptune.• Inner vs. Outer:

• Inner-found before the asteroid belt: Mercury, Venus, Earth, and Mars.

• Outer-found after the asteroid belt: Jupiter, Saturn, Uranus, and Neptune.

• Inferior vs. Superior:• Inferior-between the Sun and Earth: Mercury and Venus.• Superior-after Earth: Mars, Jupiter, Saturn, Uranus, and

Neptune.

Mercury • Named after the Roman Fleet

Footed God • The smallest planet• Closest to the Sun• Heavily cratered• Large iron core (70% of

Mercury’s volume)• No atmosphere• 427 (800F) to -127 ºC (-197F)• The year is only 88 days• Spins the slowest on its axis, but it

revolves the fastest around the sun

Venus

• 2nd from Sun• Thick atmosphere of Carbon

Dioxide- runaway greenhouse effect• Shines the brightest in our night sky• Most volcanoes in solar system of

the planets• Spins backwards• Up to 900 ºF• Named after the Roman goddess of

beauty and love- often called Earth’s twin

• Clouds of sulfuric acid• Magellan, Cassini Huygens and

MESSENGER have all flown by

Earth

• Earth: 3rd from Sun• Temperatures

perfect for water in solid, liquid, and gas states.

• Has ozone to protect from the Sun’s harmful radiation.

• 70% water, 30% land

Mars

• 4th from Sun• ½ the size of Earth• Red planet- from rusted iron in crust.• Has frozen water under ice caps• Largest volcano- Olympus Mons• Largest Canyon- Valles Marineris• 2 moons: Phobos (fear) and Deimos

(flight)• Cold: -100 ºC night, just above

freezing during day (-148 F)• Named after Roman God of War• 24.5 hour day• Has seasons like Earth

NASA on Mars

• The Mariner 9• Viking 1 and Viking 2• Global Surveyor• Mars Odyssey• Spirit and Opportunity Land Rovers• Mars Pathfinder

Section 3: Outer Planets

Jupiter• 5th from the Sun• Largest planet (1,323 Earths)• Named after Roman God of all Gods• Mostly hydrogen and helium• The Great Red Spot- a approx. 400

year old hurricane big enough to hold 2-3 Earths.

• Spins fastest on its axis• Has lightning in clouds• Has 50 named moons and 14 other

moons not named• Has 3 rings of dust• Studied by Galileo space probe

• 4 huge “Galilean Moons”:• Io: most volcanically active body in solar

system.• Europa: mostly rock with a thick, cracked but

smooth crust of ice; deep, warm ocean that holds twice as much water as Earth’s oceans.

• Ganymede: Larger than Mercury, most likely had a volcanic past. Likely to have an ocean.

• Callisto: Cratered and most likely covered in a salty ocean.

Jupiter’s 4 Big Moons

Saturn• 6th from Sun• Second largest planet (752 Earths)• Named after Roman Lord of the

Rings• Mostly hydrogen and helium• It’s low density would allow it to

float in water• Known as the ringed planet- has

largest and most complex ring system• Made of ice and rock• 7 Rings A-G: Cassini division is

the gap between rings

Saturn’s Moons• Saturn has over 30 moons.• The largest moon is Titan:

• Larger than Mercury• Has areas of water ice• Has areas composed of hydrocarbons-

organic compounds that contain hydrogen and carbon.• All living things are made of carbon.

• Scientists are interested in the possibility of life here.

Uranus

• 7th from the Sun• 3rd largest (Fits only 64 Earths)• 27 moons• Mostly hydrogen, helium & 2% methane• Looks bluish-green in color• Tilted 98º- rotates on its side• 11 rings- dark and narrow• Father of Neptune and Jupiter• May have slushy water • 5 large moons- Miranda• This planet was discovered using math-

nobody was even looking for it.

Neptune

• 8th from Sun• 4th largest (58 Earths)• Has rings• Has at least 13 moons: Triton, the largest, has

geysers that erupt methane and nitrogen• Has a Great Dark Spot “Wizard’s Eye”• Named after Roman God of the Sea• Similar atmosphere to Uranus, but more

methane, so it looks even bluer.

Pluto

• Farthest from the sun• It takes 248 years to orbit the sun• Now considered a dwarf planet• Named after the Roman God of the

Underworld• Has 5 moons: the biggest one is named

Charon which is about ½ the size of Pluto• Solid ice-rock surface

Comets , Asteroids, and Meteoroids• A comet, is composed of ice, dust and rock

particles mixed with methane and ammonia.• Halley’s comet appears every 76 years.• It will appear again in 2061.

• An asteroid is a rocky object formed from material similar to the planets- found in asteroid belts

• A meteoroid is a rocky object formed from asteroids or comets.• If it burns up in our atmosphere it is a shooting

star• When it hits Earth it is called a meteorite

• Sedna has been labeled a distant planetoid

• It is smaller than Pluto, but bigger than a comet.

• It is three times farther away from Earth than Pluto