The Earthlike Planets

1
The Earthlike Planets

• Planets of the Inner Solar System

2
Earth

• Molten interior
• Magnetic field
• Active crust
• 75 ocean 3km deep
• O2 rich atmosphere

3
Earths Formation

• Differentiation
• Cratering
• Flooding
• Surface evolution

4
Earths Interior

• Dense (5 ? water)
• Seismic studies
• Metallic core
• Rocky mantle
• Thin crust
• Dynamo

5
Plate Tectonics

• Moving plates
• Convection in mantle
• Rifts
• Subduction
• Mountains
• Pangaea 200 Myr ago

6
Earths Atmosphere

• Primaeval atmosphere
• Natural greenhouse
• Oceans remove CO2
• Humans release CO2
• Plants produced O2
• Ozone (O3) layer

7
The Moon

• Small airless
• Rocks record history
• Visited by humans

8
Lunar Geology

• Craters impacts
• Maria ancient lava
• Dark dusty surface
• No plate tectonics

9
History of Earths Moon

• Differentiation
• Cratering
• Flooding
• Surface evolution

10
Origin of Earths Moon

• Large impact hypothesis
• Mars-sized body
• Collides with Earth
• Debris formed Moon

11
Mercury

• Small moonlike world
• Hot (4300C) surface
• Massive iron core
• Caloris impact basin
• Lobate scarps

12
History of Mercury

• Differentiation
• Major collision
• Heavy cratering
• Lava filled lowlands
• Iron core contracted
• Crust cracked

13
Venus

• Hellish 4700C surface
• Pressure 100? ours
• Air of CO2, some acid
• Greenhouse effect

14
Surface of Venus

• Radar lander views
• Plains, uplands mountains
• Volcanoes, channels coronae
• Craters indicate age of surface 300-500Myr

15
History of Venus

• CO2 not removed
• Runaway greenhouse
• Dry, strong crust
• No plate tectonics
• Resurfacing by major volcanism

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Mars

• Half size of Earth
• Cold thin air, seasons
• Craters volcanoes

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The Atmosphere of Mars

• Mostly CO2
• 1 Earth pressure
• ?1400C to 200C
• Dry/water ice poles
• No liquid water
• Atmosphere escaped

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Geology of Mars

• Rusty red deserts
• South older than north
• 25km high volcano
• 4000km long valley

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Water on Mars

• Flood erosion features
• Meandering drainage
• Polar cap layering
• Martian meteorites

20
History of Mars

• Differentiation into crust, mantle core
• Cratering triggered lava flows
• Volcanic activity but no tectonics
• Slow decline in activity to the present

21
The Moons of Mars

• Phobos
• Deimos
• Captured asteroids?