Inner PlanetsChapter 2.3Pages 62-69

• Terrestrial planets• Small, solid planets

– Mercury– Venus– Earth– Mars

Inner Planets

• 1st Planet, 58,000,000km• Rotation 59 Earth days• Revolution 88 Earth Days• Extremely thin atmosphere

– Fast moving, very hot, molecules escaped Mercury’s weak gravitational pull.

Mercury

• Solid surface, many flat planes and many craters

• Greatest temperature range of all planets (430°C to - 170°C)

• No moons

Mercury

• 2nd Planet 108,000,000km

• “Evening Star”• Similar in size and

density to Earth (“Earth’s twin”)

• A solid, rocky, cratered surface with volcanoes.

Venus

• Rotates so slowly (8 months) that its day is longer than its year (7.5 months)

• Rotates east to west (retrograde rotation)

• No moons

Venus

• Never has a sunny day.• Atmosphere so thick, the

pressure is 90 times that on Earth.

• Atmosphere is mostly CO2 and sulfuric acid– Clouds trap heat and

surface is 460°C. (Greenhouse Effect)

Venus’ Atmosphere

• 3rd Planet 150,000,000 km– Rotation 24 Earth

hours– Revolution 365.25

Earth Days• 70% covered in water

– Supports life.

Earth

• As an atmosphere – mostly 78% nitrogen and 21% oxygen

• 3 main layers – crust, mantle and core

• Dynamic planet (constantly changing)

• One natural satellite called Moon.

Earth

• 4th Planet 228,000,000km• “Red planet” – solid, rocky

planet.– Rotation 1.03 Earth Days– Revolution- 687 Earth

Days• Two moons – Phobos and

Deimos

Mars

• Mars has seasons because it has a tilted axis– Winds stir up soil, causing

dust storms– Frozen ice caps of carbon

dioxide at south pole and frozen ice at north pole during the winter season.

• Very thin atmosphere, mostly carbon dioxide

Mars