1. Ch. 28 – minor bodies of the solar system

2. Ch. 28.1 – earth’s moon Vocabulary:
Satellite - A smaller celestial body that orbits a larger body; can be artificial or natural
The moon - the natural satellite of the Earth
Luna - Latin for moon
Lunar - pertaining to the moon

3. Apollo Space Program - Between 1969 and 1972, six US spacecraft landed astronauts on the moon 
Moon’s gravity - only 1/6 of Earth’s because it has less mass
No atmosphere - moon does not have enough gravity to hold gases
Temperature - varies a lot between day and night because there is no atmosphere to absorb and transport thermal energy

4. The lunar surface Areas of dark and light patches on the moon
Dark: impact craters filled with lava
Light: highlands composed of rock
Impact craters: left from impacts with other objects in space
Surface is invisible from Earth without a telescope
There are no volcanoes

5. The interior of the moon
Has core, mantle and crust
Density of the moon is 3/5th that of Earth.
Rotation period: days (one turn on its axis)
Orbit around Earth: 27.3 days (one orbit around the Earth)
Because rotation and orbit periods are the same, we always see the same side of the moon.
The side we see: near side
The side we don’t see: far side (only can see it from space)

6. The formation of the moon
Giant Impact Hypothesis: 4 billion years ago, a mars-sized object struck the Earth and sent debris into orbit around the Earth. This debris eventually clumped together to form the moon.
Is not a theory because of lack of data to support it.

7. Group activity
Imagine your group is setting up a moon base. Make a list of the supplies and materials you would need to build a base for 100 people. You may wish to organize their group in a way to allow one person to be in charge of identifying resources needed to supply each major need. (10 minutes)

8. Light and dark side of the moon

9. Ch. 28.2 - Movements of the Moon
The Earth Moon System
The Moon has an elliptical orbit around the Earth; the distance is not always the same.
average distance 384,000km (=240,000 miles)

10. Eclipses – when one celestial body passes through the shadow of another.
Solar Eclipses
When the moon is directly in between the sun and the Earth, the shadow of the moon falls on Earth’s surface
Umbra – when the sunlight is completely blocked
Penumbra – when the sunlight is partially blocked
Can only occur during a New Moon
Next solar eclipse in the US: 2017
Happens every 18 months somewhere on Earth
Lasts less than 3 minutes

11. Lunar eclipse – when the Earth is between the sun and the moon
Total lunar eclipse: moon must pass entirely into Earths umbra, otherwise it is a partial lunar eclipse
Can only occur during a Full Moon
Happens 1-3 times a year
Lasts for several hours
Moon appears reddish during a total lunar eclipse because Earth’s atmosphere filters out blue light of indirect sun light

12. See when the next eclipse will occur:

13. Phases of the moon

14. A. Waxing Phases of the Moon
The size of the lighted side of the moon appears to increase
B. Waning Phases of the moon
The lighted side appears to be decreasing
Earthshine – sunlight reflected off the Earth back onto the moon.
C. Time from new moon to new moon: 29.5 days

15. Tides on Earth
Because of the gravitational pull between Earth and the moon, the Earth’s liquid is pulled toward the center of the moon, causing the tides.
The sun also has an effect on the tides and when the sun and the moon are on the same side of the Earth, there are especially high tides.
Sequence of high and low tides lasts 12 hrs. 25 min.
Drawing of Fig 10, p. 798

16. Ch. 28.3 – Satellites of Other Planets
Mercury and Venus have no moons
Mars – 2 tiny moons
Jupiter – 4 large moons
Io – very hot, has volcanoes
Europa – covered with a crust of ice 100 km (63 miles) thick
May have ocean of liquid water below ice – scientists want to study it for signs of life
Also has many small moons

17. Saturn – dozens of moons
Titan – only moon in solar system known to have an atmosphere
Uranus – 5 large and at least two dozen small moons
Neptune – at least 13 moons

18. Ch. 28.4 – Asteroids, Comets and Meteoroids
The largest minor bodies in the solar system
Small, rocky irregular-shaped object that orbits the sun
A dwarf planet is an asteroid that has become large enough so that gravity has caused it to become round
Drawing of an asteroid: (p 805, Figure 1)

19. e. Location of asteroids in the solar system:
In the asteroid belt located between Mars and Jupiter
Inside the orbit of Mars
Trojan asteroids near Jupiter
Some beyond Jupiter’s orbit
f. Near-Earth asteroids could be dangerous to Earth because they could inflict great damage.

20. Comets
Small bodies made of ice, rock and cosmic dust that follow elliptical orbits around the sun.
Head of the comet is made of a core (or nucleus) and a coma (spherical cloud of gas and dust)

21. c. Human spacecraft have taken samples of comet heads d
c. Human spacecraft have taken samples of comet heads d. One tail of the comet is made of ice that has turned to gas because of heating from the sun. A second tail is made of dust. e. Most are located in the Oort cloud. f. Drawing of a comet: (p 807, Figure 3)

22. The Kuiper Belt
A ring of icy bodies located just outside Neptune’s orbit

23. The Oort Cloud
spherical cloud of dust and ice far beyond Neptune’s orbit; where most comets come from
might be matter left over from the formation of the solar system
bodies in the Oort cloud take a few million years to complete one orbit around the sun.

24. Meteoroids Very small bits of rock or metal
Range in size from 1 mm up to 100m (33 ft). Larger than that is considered an asteroid.
Meteors – Bright streak of light produced from a meteoroid burning up in the Earth’s atmosphere.
Commonly called shooting stars
Meteorite – Left over pieces of meteoroid that have struck Earth’s surface.
Almost all meteoroids result from collisions between asteroids