1. Earth and Other Planets
3 November 2015
Chapter 16
Great Idea:
Earth, one of the planets that orbit the Sun, formed 4.5 billion years ago from a great cloud of dust.

2. Chapter Outline The Formation of the Solar System
Exploring the Solar System
The Earth

3. The Formation of the Solar System

4. Clues to the Origin of the Solar System
Objects gravitationally bound to Sun
Deduction of origin
Observations
Earth
Space

5. Clue #1: Planetary Orbits
Features of solar system
All planets orbit in same direction
Orbits in same plane
Most rotate in direction of orbit

6. Clue #2: Distribution of Mass
Most material within Sun
Two types of planets
Terrestrial planets
Jovian planets
Other objects
Moons, asteroids, comets

7. The Nebular Hypothesis
Cloud of dust and gas
99% H and He
Collapse of nebula
Planetary orbits
Clumping of matter
Planetesimals
Temperature

8. Basic Planet Categories
Terrestrial planets
Mercury
Venus
Earth
Mars
Jovian planets
Jupiter
Saturn
Uranus
Neptune

9. Some Conclusions Planets formed at same time as Sun
Planetary and satellite/ring systems are similar to remnants of dusty disks such as that seen about stars being born
Planet composition dependent upon where it formed in solar system

10. Nebular Condensation (protoplanet) Model
Most remnant heat from collapse retained near center
After sun ignites, remaining dust reaches an equilibrium temperature
Different densities of the planets are explained by condensation temperatures
Nebular dust temperature increases to center of nebula

11. Nebular Condensation Physics
Energy absorbed per unit area from Sun = energy emitted as thermal radiator
Solar Flux = Lum (Sun) / 4 x distance2
Flux emitted = constant x T4 [Stefan-Boltzmann]
Concluding from above yields
T = constant / distance0.5

12. Nebular Condensation Chemistry

13. Nebular Condensation Summary
Solid Particles collide, stick together, sink toward center
Terrestrials -> rocky
Jovians -> rocky core + ices + light gases
Coolest, most massive collect H and He
More collisions -> heating and differentiating of interior
Remnants flushed by solar wind
Evolution of atmospheres

14. iClicker Question
The most abundant chemical element in the solar nebula
A Uranium
B Iron
C Hydrogen
D Helium
E Lithium

15. Pictorial View of Origins

16. Pictorial View Continued

17. HST Pictorial Evidence

18. HST Pictorial Evidence

19. iClicker Question
As a planetary system and its star forms the temperature in the core of the nebula
A Decreases in time
B Increases in time
C Remains the same over time
D Cannot be determined

20. iClicker Question
As a planetary system and its star forms the rate of rotation of the nebula
A Decreases in time
B Increases in time
C Remains the same over time
D Cannot be determined

21. The Formation of Earth Planetesimals Great bombardment
Combined (accretion) to form earth
Great bombardment
Meteors
Growth of planet
20 metric tons per day

22. Differentiation Differentiation Structure Heat from collisions
Dense material sank to center
Lighter material rose to surface
Structure
Core
Mantle
Crust

23. Crust and Us

24. Earth’s Interior - How We Know It

25. iClicker Question
Which of the diagram represents the mantle of the Earth? A B C D
E None of the above.

26. iClicker Question
Which of the diagram represents the outer core of the Earth? A B C D
E None of the above.

27. iClicker Question
Energy transport from one region to another by the movement of material as in the mantle of the Earth is known as
A chaos.
B radiance.
C conduction.
D differentiation.
E convection.

28. iClicker Question
The existence of earthquake shadow zones indicates that there is an abrupt change between the properties of the mantle and those of the core. Specifically, the transverse wave shadow zone shows that the outer core must be
A solid.
B liquid or semi-liquid.
C gaseous.
D similar to crustal material.
E impossible to determine.

29. The Formation of the Moon
Large object (asteroid close to size of Mars) impacted earth
Parts of mantle blown into orbit
Moon formed from this material

30. Planetary Idiosyncracies
Cratering
Mercury, Mars, Moon
Few on Earth
weathering
Rotation
Venus
Earth’s axis
Uranus

31. The Evolution of Planetary Atmospheres
Earth’s atmosphere
Early
Outgassing
Atmosphere was N2, CO2, H2, & H2O
Gravitational escape
Living organisms

32. iClicker Question
All our observations of the Sun and planets have been made from the surface of the Earth.
A True
B False

33. iClicker Question
All planets and most of their moons orbit in the same direction around the Sun
A True
B False

34. iClicker Question
Almost all planets and moons rotate on their axes in the same direction as the planets orbit the Sun.
A True
B False

35. iClicker Question What is the shape of our solar system?
A spherical (like a ball)
B flat (like a dish)
C tubular (like a hot dog)

36. iClicker Question The mass in our solar system is evenly distributed.
A True
B False

37. Exploring the Solar System

38. The Inner Solar System Mercury, Venus, Mars Mars Exploration
Mercury and Venus too hot for life
Mars Exploration
Multiple missions
Found evidence of water

39. The Outer Solar System Jupiter, Saturn, Uranus, Neptune Jupiter Saturn
Layered structure
No solid surface
Jupiter
Comet Shoemaker-Levy 9
Galileo spacecraft
Saturn
Cassini spacecraft

40. The Outer Solar System II

41. Moons and Rings Jupiter’s Moons Saturn’s Moons Rings
Io, Europa, Ganymede, Callisto and 63 others known
Saturn’s Moons
Titan, Mimas, Hyperion and about 59 (61?) others
Rings
Ice and rock - more ice in Saturn’s rings
Moons and Rings

42. Dwarf Planet Pluto Surprises
It has moons
Original moon discovered 1978
Charon (KAIR’ en)
Now more
2005 discovery of 2 additional moons
Named Nix and Hydra
2011 #4 is P4 (Kerberos)
July 7, 2012 #5 is P5 (Styx)

43. Pluto’s Interior to Surface Old -> New Model
partially hydrated rock core
water ice layer II
predominant water ice layer I
Model 2
organics layer
predominantly water ice layer

44. The Launch of New Horizons Pluto Mission 17 Jan 2006

45. Io’s Volcanoes from New Horizons

47. Pluto

48. Pluto’s Methane (frozen)

49. Charon

50. Pluto

51. Pluto Atmosphere Detection

52. Pluto and Charon

53. Carbon Monoxide (Frozen)

54. Solar Wind at Pluto

55. Pluto “Heart” Region

56. Pluto Mountain Range

57. Nix and Hydra

58. Pluto, True Color

63. Asteroids, Comets, and Meteors
Small rocky bodies
Orbit sun
Most in belt between Mars and Jupiter
Comets
Dirty snowballs
Orbit outside Pluto
Oort cloud
Kuiper belt
Halley’s Comet
Stardust and Deep Impact missions
Meteoroids, Meteors, and Meteorites
Meteor showers
Original solar system material

64. Planetary Summary

65. iClicker Question Mercury, Venus, Earth, and Mars are called:
A galaxial objects
B standard planetoids
C Jovian planets
D terrestrial planets
E dwarf planets

66. iClicker Question Jupiter, Saturn, Uranus, and Neptune are called:
A galactic objects
B standard planetoids
C Jovian planets
D terrestrial planets
E dwarf planets

67. iClicker Question The asteroid belt is located:
A between the Sun and Mercury
B between Mercury and Venus
C between Mars and Jupiter
D outside of our solar system

68. iClicker Question
Distinctive features of the solar system such as the rotation of the Sun, orbits of the planets, and the distribution of mass into one large central object and lots of much smaller orbiting bodies is explained by:
A the Hubble theory
B the nebular hypothesis
C the Trefil and Hazen gambit
D the relativity theory

69. iClicker Question What are the Jovian planets primarily composed of?
A rocky substances
B element 119 (Jo)
C hydrogen and helium
D iron (Fe)
E silicon (Si)

70. iClicker Question
Outgassing and gravitational escape are processes by which
A planets form an atmosphere
B space travel may become possible
C solar systems form planets
D string theory can be applied

71. iClicker Poll Question
Have you ever seen a meteor or meteorite?
A yes
B no
C don’t know what these are

72. iClicker Poll Question
Should future missions to the planets carry people or robots?
A People only
B Robots only
C People and robots
D Neither, missions to planets are a waste of money