Objectives

Essential Question What would life be like on another

planet?

Objectives Describe conditions on other planets

in our solar system Explain why the planets have

different conditions (Inner vs. Outer)

Retrograde Motion Retrograde motion

A planet’s apparent backward motion in the sky

Similar to passing a slower car

Measuring Distance in Space Astronomical Unit (AU)

A planets average distance to the Sun Sun to Earth = 1 AU = 1.496x108 km

Kepler’s First Law

Perihelion – When a planet is closest to the sun in its orbit

Aphelion – When a planet is farthest away from the sun in its orbit

Eccentricity – The shape of a planets elliptical orbit

Terrestrial Planets

Inner Planets

Mercury

No Moons 1/3 size of

Earth Mercury has

essentially NO atmosphere

Mercury

Temp ranges from 700 K to 100 K Due to slow rotation and proximity to the sun

Surface covered with craters and plains

Nickel Iron core Molten Zone in the interior

Venus

•No Moons

•Average temp: 737 K (Runaway Greenhouse Effect)

•Almost 90 times greater pressure

•Retrograde Rotation

Venus

Atmosphere has Carbon Dioxide and Nitrogen

Surface smoothed by volcanic lava flows, few impact craters

Interior similar to Earths

Earth

• One Moon

• Water on Surface

• Atmosphere 78% N and 21% O

Mars

• Two Moons

• Thin Atmosphere with constant wind

Mars

Southern Mars is heavily cratered and high lands

Northern Mars dominated by plains with few craters

4 Shield Volcanoes – Olympus Mons Large because there are no moving

tectonic plates Polar Ice caps – dry ice over water ice Interior – Solid Nickel Iron Core

Gas Giant Planets

Outer Planets

Jupiter• Eleven times larger

than Earth

• Atmosphere contains H and He

• Great Red Spot – Atmospheric Storm that has been rotating for more than 300 years.

Jupiter

Four Galilean (Satellites)Moons: Io, Europa, Ganymede, Callisto

Moons are composed of Ice and Rock mixtures

Jupiter has a Ring

Saturn

• Atmosphere composed of Hydrogen, Helium and Ammonia Ice near top of clouds

Saturn

Rings composed of pieces of rock and ice (Range in size from microscopic to the size of a house)

Seven Major rings made up of narrower rings

Gravity of Saturn keeps the rings from coming together to form a moon

18 Satellites, largest is Titan

Uranus

• Atmosphere contains Hydrogen, Helium and Methane Gas

• Methane gives planet its bluish color

Uranus

Rotational Axis is tipped Possibly caused by a collision

18 Moon and 10 rings Rings are dark in color and hard to see

Temperature avg. -215 C

Neptune

• Atmosphere contains Hydrogen, Helium and Methane

• Has clouds

• Great Dark Spot – Storm disappeared in 1994

Neptune

Eight moons – Largest Triton Triton has a retrograde orbit

Neptune has 6 rings composed of microscopic dust particles

Pluto Has a solid Surface Not a Terrestrial Planet or a Gas

Giant Planet Half Ice and Half Rock Pluto has a Moon – Charon Past Kuiper Belt

Status recently changed – No longer a planet : (