1 of 40

MOONS THE IN SOLAR SYSTEM

Unit 3: Our Solar System

2 of 40

TERRESTRIAL MOONS

Earth and Mars

3 of 40

EARTH’S MOON

4 of 40

The Earth and moon viewed from Mercury

5 of 40

The Earth viewed from Saturn

6 of 40

If you zoom in….

7 of 40

EARTH’S MOON BASIC FACTS:

  • It’s the only place beyond Earth where humans have set foot (so far!)
  • 24 people have visited the moon, 12 of them walked on it
  • The mass of the moon is about 1/100th that of Earth
  • It’s surface is cratered and pitted from comet and asteroid impacts
    • it has very little atmosphere to protect it

8 of 40

The moon and Earth, from Mars Express

9 of 40

If the Earth and moon were instead side by side…

10 of 40

11 of 40

HOW DID THE MOON FORM?

12 of 40

HOW DID THE MOON FORM?

  • Giant-Impact Theory
    • The Moon formed during a collision between the Earth and another small planet, about the size of Mars
    • The debris from this impact collected in an orbit around Earth to form the Moon

13 of 40

14 of 40

15 of 40

MARS’ MOONS

16 of 40

MARS’ MOONS

  • They look very similar to asteroids
  • Many people think that they once lived in the asteroid belt and were captured by the gravitational pull of Mars
  • Phobos orbits close to Mars, while Deimos is smaller and orbits much farther away

17 of 40

18 of 40

MOONS OF THE OUTER PLANETS

19 of 40

THE “TOP 7” MOONS IN THE SOLAR SYSTEM

Satellite

Planet

Diameter

(km)

Mass

(relative to the Moon)

Ganymede

Jupiter

5262

2.03

Titan

Saturn

5150

1.83

Callisto

Jupiter

4820

1.46

Io

Jupiter

3640

1.21

Moon

Earth

3476

1.00

Europa

Jupiter

3122

0.66

Triton

Neptune

2700

0.29

20 of 40

THE GALILEAN SATELLITES OF JUPITER

21 of 40

VIRTUALLY NOTHING WAS KNOWN ABOUT THE MOONS OF JUPITER PRIOR TO THE ARRIVAL OF SPACECRAFT IN THE 1970S

  • Galilean Moons:
    • Io
    • Europa
    • Ganymede
    • Callisto
  • A total of 95 moons now known (mostly tiny)

22 of 40

THE GALILEAN SATELLITES OF JUPITER

23 of 40

CALLISTO: MOST DISTANT OF GALILEAN SATELLITES

  • Among the most heavily cratered objects that orbit the sun
  • Very little geologic activity

24 of 40

GANYMEDE: LARGEST MOON IN SOLAR SYSTEM

  • Only moon known to create its own magnetic field
  • Evidence of an underground ocean

25 of 40

EUROPA: THE BEST PLACE TO LOOK FOR PRESENT-DAY ENVIRONMENTS SUITABLE FOR LIFE

  • Thought to have an ocean of salty water below its frozen outer shell of ice

26 of 40

CRACKS IN THE ICE CRUST OF EUROPA

  • Evidence of water flows from the interior

27 of 40

VIEWS OF THE CRACKS

28 of 40

SPECULATIONS ON INTERIOR STRUCTURE OF EUROPA

29 of 40

A FUTURE EUROPA LANDER COULD TELL US MUCH ABOUT THE POSSIBLE SUBSURFACE OCEAN OF EUROPA

30 of 40

IO: THE MOST VOLCANICALLY ACTIVE WORLD IN THE SOLAR SYSTEM

  • Hundreds of active volcanoes
  • Some lava eruptions are dozens of miles high

31 of 40

CHANGES ON IO: 1979-1999

32 of 40

33 of 40

SATURN’S MOONS

34 of 40

146 TOTAL MOONS

  • 66 are confirmed and named
  • Range in size from as small as a sports arena to bigger than Mercury

35 of 40

ENCELADUS: MOST REFLECTIVE MOON

  • Enceladus sprays its ocean out into space where a spacecraft can sample it
  • Scientists have determined that Enceladus has most of the chemical ingredients needed for life, and likely has hydrothermal vents spewing out hot, mineral-rich water into its ocean

36 of 40

TITAN: THE MOON WITH AN ATMOSPHERE

  • Larger than Mercury
  • The only other world with liquids on its surface

37 of 40

38 of 40

URANUS’ LITERARY MOONS

  • 27 moons
  • Named mostly using characters from Shakespeare

39 of 40

NEPTUNE’S MOONS

  • 14 moons
  • Named for Greek sea gods

40 of 40

TRITON: ICY VOLCANOES

  • Neptune’s largest moon
  • Ice volcanoes that spout nitrogen, methane, and dust that instantly freezes
  • The only large moon in the solar system with a retrograde orbit

​