THE INNER

PLANETS

4 INNER PLANETS Small, have rocky surfaces

Terrestrial Planets: meaning earth

MERCURY

EXPLORING MERCURY closest to the Sun Interior is made up of iron and nickel metals

So close to the sun that people can’t get a good view of it.

Only half of Mercury has been photographed

Many flat plains and craters

MERCURY’S ATMOSPHERE Thin/No atmosphere Gases where once heated so much they moved so fast they escaped Mercury’s atmosphere

Greatest range of temperature of all planets

FOLDABLE Nearest planet to sun Our moon and Mercury’s surface

look alike (craters) No atmosphere No moons Revolves around sun with same

side always facing sun Greatest range of temperature

(662°F=day, -274°F=night)

VENUS

Earth’s twin (similar in size) If you see a bright object in the

west after sunset it is most likely Venus

Venus’s RotationTakes 7.5 Earth months to revolve around sun

8 months to rotate on axis Day is longer than Year Rotates east to west (clockwise)

unlike most planets Retrograde rotation: moving

backward

VENUS’S ATMOSPHERE Atmosphere so thick it is always

cloudyNo sunny days

If you stood on Venus you would be crushed. Atmosphere is so strong

Greenhouse Effect: trapping of heat by atmosphere

EXPLORING VENUS

19 spacecraft have visited 1st only last 23 minutes before it was destroyed

Rocky areas, volcanoes with lava flows, craters, strange domes

FOLDABLE Second planet from sun Spins slowly backwards as it

orbits Atmosphere made mostly of

carbon dioxide Hottest planet (860°F) Surface: craters, mountains,

volcanic lava flows. No moons Day is longer than year

EARTH

FOLDABLE 3rd planet from the sun 70% water, 30% land 1 moon Conditions necessary for life Has volcanoes and earthquakes Three layers

Crust: solid rocky surfaceMantle: hot molten rockCore: inner solid, outer liquid

MARS

Red planet: looks slightly red in the sky

You could walk on Mars but would need airtight suit and oxygen tank

Frozen ice at each pole Has season’s just like Earth

EXPLORING MARS Giant volcanoes but probably not

active Red rock from rusty dust No oceans or water now Was water millions of years ago

MARS’S MOONS Has two moon’sPhobos: 27 km in diameter (distance car travels on highway in 15 minutes

Deimos: 15 kmCovered with craters

FOLDABLE 4th planet from sun Rust causes surface to have a red glow Polar ice caps at each pole Two small moons (covered in craters) Thin atmosphere Huge dust storms cover surface at times Has seasons Volcanoes No water now Day=25 hours Year=686 days