A Family of PlanetsChapter 21

Section 1 The Nine Planets

Log: Oct.8

• What is our solar system?

• What is it made of?

Planet- means “wanderers” ancient astronomers knew they were physical bodies and could predict movement

Measuring Distances

• Astronomical Unit: (AU) the average distance between the sun and earth

• 150,000,000 km= 8.3 light minutes

Light from sun take about 8mins to travel to planet earth

Measuring Distances

• Speed of Light: 18,000,000km per minute

• light minute or Light hour

Inner Planets

• (Mercury, Venus, Earth, and Mars)

• More closely spaced

• Terrestrial- Means rocky

Outer Planets

• Known as Gas giants

• Pluto is dwarf planet and exception to the rule

Log: Oct 9

• Name some differences between inner and outer planets

Log: Oct.13th

• Why are the outer planets called the Gas Giants?

Section 2The Inner Planets

Pages 648-653

Key Words

• Revolution- the motion of a planet orbiting another

• Period of revolution- The time it takes the planet to orbit the sun (year)

• Orbit

• Period of Rotation- the time it takes a planet to rotate on its axis (day)

Log: Oct. 14

• What does the period of revolution and period of rotation tell me about a planet

Mercury

Mercury : Closest to sun

Facts

• The smallest planet in our solar system.

• Lacks Atmosphere so temperatures are extreme

• 430 degrees Celsius • -170 degrees Celsius

• No known Moons• Spacecrafts

– Mariner 10 – MESSENGER

Name and speed

• Greek God Mercury do to the speed of its revolution

• Mercurian 1 Year= 88 Earth days

• Mercurian 1 day = 59 Earth Days

• Mercury is the closest planet to our Sun. It is named for the ancient Roman god of trade and profit. Legend says Mercury's winged sandals gave him super speed. Mercury the planet is super fast, too. It zips around the Sun every 88 days - faster than any other planet. No wonder it got its name from the quickest of the ancient gods.

• http://www.nasa.gov/multimedia/videogallery/index.html?media_id=18133414

New Key Words

• Prograde-spins on axis counterclockwise

• Retrograde- spins on axis clockwise

Venus

• Earths Twin Similar– size– mass – composition– distance from the Sun

Venus Facts

• 2nd planet from our Sun • Named for the Roman

goddess of love and beauty. – brightest planet in the night

sky. • Surface is hidden beneath hot,

poisonous air – made up mostly of carbon dioxide– clouds of sulfuric acid,

– hurricane-force winds and

lightning.

• Venus has no moon and no rings.

• 1Venus Day=243 Earth days

• 1Venus Year= 224 Earth Days

Earth :An Oasis

• 3rd Planet from Sun• Water• known to harbor life•

Mars: Our Intriguing Neighbor

Two mars moons

Mars

• 4th Planet from Sun• Spacecrafts

– Viking 1 &2– Mars Pathfinder

• Moons• Very low pressure so

no liquids present • Evidence mars had

water in past

• Temperature• Frozen Ice Caps of

water and CO2• 'Red Planet' because

of its red soil

How Mars Got it’s Name

• The planet is named for the Roman God of War.

• It has two moons, Phobos (fear) and Deimos (panic).

• The moons get their scary names from the horses that pulled the chariot of the Greek god Ares.

Olympus Mons on Mars: The Largest Volcano

The largest volcano in the Solar System is on Mars. Olympus Mons rises 24 kilometers high and measures 550 km across. By comparison, Earth's largest volcano, Mauna Loa in Hawaii, rises 9 km high and measures 120 km across.