The Moon is Earth's only natural satellite and orbits our planet about every 27 days. It has no atmosphere and experiences extreme temperature ranges. The lunar surface features highlands, craters, and low-lying maria plains filled with hardened lava. The side facing Earth always appears the same while the far side has more craters and few maria. Phases and eclipses occur due to the relative positions of the Moon, Earth, and Sun. Twelve American astronauts walked on the Moon between 1969-1972, with future lunar bases potentially allowing long-term human habitation.

1. A look at our nearest
neighbor
The Moon

2. What is the Moon?
• A natural satellite
• One of more than 96 moons in
our Solar System
• The only moon of the planet
Earth

3. • The moon is a “natural satellite”.
• A satellite is anything the orbits a planet.
• Artificial satellites, ones made by humans,
have four main uses:
– Communications
– Monitoring the weather
– Observing the Earth
– Exploring the solar system

4. Where is the moon?
• About 384,000 km
(240,000 miles)
from Earth
• 3,468 km (2,155
miles) in diameter
(about ¼ the size of
Earth)

5. How does the moon move?
• It revolves or orbits the Earth about
every 27 days
• It rotates on its axis once every 27 days
• Since the moon rotates and revolves at
the same rate, the same side of Moon
always faces Earth

6. What’s up there?
• No atmosphere
• No liquid water
• Extreme temperatures
– Daytime = 130C
(265°F)
– Nighttime = -190C (-
310 F)
• 1/6 Earth’s gravity
– (Take your weight and
divide it by six)

7. What does the
land look like on
the moon?

8. Highlands
• Mountains up to 7500 m
(25,000 ft) tall
• Rilles (trench-like
valleys)

9. Craters
• Up to 2500 km (1,553 miles) across
• Most formed by meteorite impacts on the Moon
• Some formed by volcanic action inside the Moon

10. Maria
• Originally thought to be
“seas” by early
astronomers
• Darkest parts of lunar
landscape
• Filled by lava after crash
of huge meteorites on
lunar surface 3-4 billion
years ago
• Mostly basalt rock

11. Maria
Craters

12. How about the side we can’t see?
• First seen by Luna 3
Russian space probe in
1959
• Surface features
different from near
side
– More craters
– Very few maria

13. • Moonlight is reflected sunlight
• Half the moon’s surface is
always lit
• From Earth we see different
amounts of the Moon’s lit
surface
• The amount we see is called a
“phase”
Why does it seem to
change shape?

14. FULL
QUARTER
CRESCENT
GIBBOUS
FOUR MAIN SHAPES

16. Lunar Eclipses
• Moon moves into
Earth’s shadow – this
shadow darkens the
Moon
• About 2-3 per year
• Can last up to 4 hours

17. Solar Eclipses
• Moon moves between
Earth and Sun
• Moon casts a shadow
on part of the Earth
• Total eclipses rare –
only once every 360
years from one
location!

18. The Tides
• Tides caused by pull of Moon’s gravity on Earth
– High tide
• Side facing the Moon and side facing away from the Moon
• About every 12 ½ hours
– Low tide –
• In between high tides

19. Exploring the
Moon
• Neil Armstrong - first
human on the Moon
– July 20, 1969
• Six Apollo missions
– 1969-1972
– 382 kg (842 lbs) rocks
• 12 Americans have
walked on the moon

22. When will we return?

23. Moon base of the future?
• What would you need to live there?

24. Photo resources
• http://www.nasm.si.edu/apollo/AS15/a15images.htm
• http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-
moon.html#apollo
• http://clementine.cnes.fr/index.en.html
• http://cass.jsc.nasa.gov/pub/research/clemen/clemen.html
• http://spaceflightnow.com/news/n0108/15mooncreate/
• http://seds.lpl.arizona.edu/nineplanets/nineplanets/pxmoon.html
• http://www.nrl.navy.mil/clementine/clemovies/clemovies_index.html
• http://www.solarviews.com/eng/moon.htm
• http://news.bbc.co.uk/1/hi/sci/tech/620649.stm
• http://skyandtelescope.com/observing/objects/eclipses/article_99_1.asp
• http://lunar.arc.nasa.gov/results/ice/eureka.htm
• http://www.space.com/scienceastronomy/solarsystem/moon_nss_0206
04.html