chapter 24 section 2 notes

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Chapter 24Section 2: The Inner PlanetsMinersville Area School District8th Grade General ScienceMr. Motuk

TRANSCRIPT

  • 1. Chapter 24:Section 2 The Inner Planets

2. II.The Inner Planets

  • A.CalledTerrestrial Planets
    • 1.First four planets:Mercury ,Venus ,Earth ,Mars
    • 2.All have a solid crust surface
    • 3.Most have an atmosphere of some kind
    • 4.Most have at least one moon

Pgs. 646 - 650 3.

  • B.Mercury
    • Closest planet to the Sun
      • Revolution time: 88 days
      • Rotation time: 59 days
    • Third smallest planet
    • Probed byMariner 10 (1974-1975)
      • Imaged 45% of surface
      • Surface crater riddled (similar to our Moon)
      • Has large cliff lined valleys
      • Has a weak magnetic field (indicates iron core)

4.

  • B.Mercury
    • Probed byMariner 10 (1974-1975)
      • Very thin atmosphere:
        • 1.Hydrogen, Helium, Sodium & Potassium
      • Surface Temperature:
        • 1.Daytime: 842o F
        • 2.Night: -274o F

5.

  • C.Venus
    • Second planet from the sun
      • Revolution: 255 days
      • Rotation: Retrograde = spins backwards
      • Probed by Venera (Russian) in 1970
      • Probed by Magellan (US) in 1990 to 1994
    • Earths Twin Sister
      • Size, Mass, Gravity similar to Earth

6.

  • Venus
    • 3 .Atmosphere: Thick & toxic
      • Air Pressure = 90 times that of Earth
      • Mostly carbon dioxide
      • Clouds: Rain sulfuric acid
      • Only allow 2% of sunlight through to surface
        • Solar energy trapped = extreme Greenhouse Effect

7. Chapter 23:Section 2

  • C.Venus (continued)
    • Surface temperature =878o F
      • Surface covered by craters, fault lines, & Volcanoes
      • Winds = 300 km / hr.

8. Earth:

  • D.Earth
    • Third Rock from the Sun
    • Average distance from the sun = 93,000,000 miles
    • Only planet water exists as 3 states of matter
      • Solid, Liquid, & Gas
    • Atmosphere protects the planet
      • From meteor strikes (most burn up)
      • Intense Solar Radiation (UV, X-Rays, Gamma Rays, etc.)

9. Ch 23:Section 2

  • E.Mars
    • Fourth Planet from the Sun
    • The Red Planet
    • Surface mainly iron oxide dust (Rust)
    • Revolution time: 687 days
    • Has polar ice caps
      • a.Northern: frozen Water (H 2 O)
      • Southern: frozen Carbon Dioxide (CO 2 )

10.

  • F.Discoveries on Mars
    • Mariner 9(19711972)
      • Discovered dried riverbeds
      • Olympus Mons:Largest know volcano in the Solar System
      • Rift Zones: Deep crustal tears
    • Viking 1 & 2 (1976)
      • Each consisted of Orbiter & Lander
      • Photographed entire Martian surface (Orbiters )

11.

  • F.Discoveries on Mars (continued)
    • Marss Atmosphere
      • Studied meteorological, chemical, & biological aspects
        • Discovered barren, rocky, windswept surface
        • Atmosphere: very thin; Carbon Dioxide, Nitrogen & Argon
        • Surface Temperatures: 95 o F (day) to -274o F (night)
        • Temperature changes create intense winds & dust storms
        • NO evidence of life (past or present)

12. 13.

  • Martian Seasons
    • Marss axis of rotation is tilted 25 degrees, which is close to Earths tilt of 23.5 degrees.
    • Because of this Mars goes through seasons as it orbits the Sun.
      • As one ice cap grows smaller, the other grows larger.
    • The color of the ice caps and other areas of Mars also changes with the seasons.
      • This is caused by the movement of dust and sand during dust storms.

14.

  • Martian Moons
    • Mars has small, crater riddled moons
      • Phobos:25 km in diameter
        • Slowly spiraling toward Mars
        • Expected impact of surface in 50 million years
      • Deimos:13 km in diameter
    • Both are irregularly shaped
    • Both orbit Mars several times a day

15. 16. Mission to Mars ?

  • How should Mars be explored?
    • Travel time to Mars is a consideration
      • Orbits at their closest = 1.5 years travel time
      • Orbits at their farthest = over 5 years travel time
    • Length of travel time invites great risks to humans
  • Should humans explore Mars?
    • Humans do more meticulous & detailed work than probes
    • Zero gravity travel weakens muscles & bones
    • Body fluids move upward (increase kidney function)
    • Radiation exposure drastically increased
  • Should robots explore Mars?
    • Robots arent affected by 0 Gs; travel time not a factor
    • Robots using videotronics can be controlled from Earth
      • Signals can have up to 20 min. delay
      • Robots cannot improvise & adapt to changing situations