The Solar System

1
Chapter 8

• The Solar System

2
How was it formed

• The Nebular Theory
• Started as nebula about 5 billion years ago
• Composed of hydrogen and helium
• Nearby supernova sent shock waves through galaxy
• caused gases to be pulled inward
• supplied new elements
• Shrank to a spinning disk 10 billion kilometers
  across
• Gravity heated center to protostar - the sun

3
How was it formed

• Other matter spun around the new sun
• gathered into clumps- protoplanets
• Near the sun the light weight gases boiled away
• Mercury, Venus, Earth, Mars
• In those far away the gases did not boil away
• Jupiter, Saturn, Uranus, Neptune
• the gas giants

4
How was it formed

• Around the protoplanets smaller clumps formed
  moons or satellites.
• Pluto is thought to be a moon of Neptune that
  broke away.
• Asteroid belt- clumps of rocks between Mars and
  Jupiter
• Jupiters gravity stopped a planet from forming
• Oort Cloud- Near the edge clumps of matter- home
  of comets.

5
The Origin of the Moon Giant Impact Hypothesis

• A very large body crashed into the Earth. Debris
  from the impact made a moon.

6

• 4.6 byr ago -- Moon formed, possibly due to
  collision of Earth and a large, Mars-sized
  object.
• If Earth already differentiated, most material
  expelled would be mantle material, not iron core

7

• Rock at impact heated, losing volatile elements
• Some debris falls back to Earth, some forms Moon.
• Earth and Moon each pulled back into spherical
  shape by gravity.

8
Why Do We Think This?

• The moon has no iron
• Earths iron had already concentrated in the core
  by the time of the impact
• The iron core of the impactor melded with that of
  the Earth, leaving the moon with no iron of its
  own
• The moon and Earth share isotopes of oxygen that
  are not found on other planets or objects far
  from Earth

9
Surface Features on the Moon

• Two types of Surfaces
• Highlands
• More heavily cratered ? surface is older.
• Maria (Seas)
• Less heavily cratered ? surface is younger.

10
What causes tides?
2 Bulges from Gravitational Attraction
Centrifugal Force
11
Gravitational Attraction

• All masses are drawn to each other.
• The moon because of its closeness to the Earth
  exerts a greater gravitational effect on the
  Earth than the Sun, despite the fact that the Sun
  is much more massive than the Moon.

12
Centrifugal Force

• unequal masses of Earth and Moon
• center of rotation lies beneath the Earths
  surface.
• second tidal bulge
• ocean shifts away from center of rotation

13
Special Features of the Planets

• Mercury
• Many Craters
• no atmosphere
• no erosion
• Slow rotation makes it hot and cold

14
Venus

• Thick atmosphere of carbon dioxide
• Sulfuric acid clouds
• Greenhouse effect
• carbon dioxide traps heat.
• Makes Venus hotter than Mercury
• Retrograde rotation - rotates backward

15
Mars

• Red planet- covered by iron oxide (rust)
• Mons Olympus -
• Largest volcano in the solar system
• Two ice caps
• north - water -never melts
• south -carbon dioxide melts in summer

16
Two moons of Mars
Phobos
Deimos
17
Jupiter
18
Jupiter

• Largest of the gas giants
• Huge storms - red spot
• Small solid core
• Liquid metal layer makes a huge magnetic field
• Magnetosphere
• Gives off more heat than it receives from the sun
• Thin ring

19
16 moons

• 4 seen by Galileo helped change science

20
Saturn

• Similar to Jupiter
• Clouds, magnetosphere, gives off heat
• Rotates in 10 hours - makes it bulge in the
  middle and flat at the poles
• Low density- would float in water

21
Saturn

• Many rings
• complex system
• made of water
• weave in and out

22
Saturn

• Many moons -
• Titan- the largest is like the early Earth.

23
Uranus

• Twice as far from the sun as Saturn.
• Covered with ocean of superheated water
• Tilted on axis
• Rings of methane ice
• Many moons

24
Neptune

• Like Uranus
• Hydrogen and helium atmosphere
• Surface of water and methane
• Rings made of dust
• Eight moons

25
Triton

• Large moon
• Thought to be captured
• Retrograde revolution
• out of plane of Neptunes rotation

26
Pluto

• Moon sized
• Made of methane
• Pink atmosphere on the sunny side
• Moon Charon 1/2 the size of Pluto
• Scientists think it is a moon broken away from
  Neptune
• Orbit crosses Neptune
• Orbit not in plane with other planets

27
The Sun

• An average star
• Over 1 million earths would fit inside
• 1/4 the density of the Earth
• made of 4 layers

28

• Corona- Outermost layer
• Temp-1,700,000ºC
• Few particles

• Chromosphere-
• middle of atmosphere
• Temp-27,800ºC
• 1000s of km thick

29

• Photosphere-
• Temp-6000ºC
• 550 km thick
• Surface of the sun

Core-
1,000,000ºC
15,000,000ºC
30
Activity on the Sun

• Storms on the sun
• Prominences- Loops or arches of gas that rise
  from the chromosphere
• Solar Flares- Bright bursts of light, huge
  amounts of energy released
• Sunspots- Dark areas on the suns surface
• in the lower atmosphere
• Motion shows the rotation of the sun
• Interferes with radio

31
Meteorites

• Leave a crater where they hit the ground
• Meteorite Crater in Arizona
• Evidence of meteorites from the moon and from Mars

32
Comets

• Chunks of dust and gas from the Oort Cloud that
  orbit the sun
• When it gets close to the sun it gets hotter
• Some of the gas and dust form a cloud around the
  head called the coma
• Solar wind pushes the gases away from the sun and
  make the tail
• Tail is pushed by the solar wind
• Tail always points way from the sun

33
Coma
Tail
Nucleus
34
(No Transcript)