Outer PlanetsAstronomy Chapter 2.4

Pages 70-77

• The gas giants– Jupiter

– Saturn

– Uranus

– Neptune

Outer Planets

• Structure:– Do not have solid

surfaces

– Huge spheres of gas, no well-defined surface

– All have rings.

Outer Planets

• Structure:– Large masses =

large gravitational pulls

– Gravitational pull keeps gases from escaping

– Thick Atmosphere’s contain mostly hydrogen and helium

Outer Planets

• Solid Core– Each gas giant has a partly solid core– These cores have much more mass than

Earth.– Not much is known because they are buried

deep in the planets.

Outer Planets

• The most massive planet. (300 times more massive than Earth.)

• Thick atmosphere, colorful bands of gases

• The Great Red Spot – giant area of swirling clouds (many times bigger than Earth)

Jupiter

• 4 of Jupiter’s moons – Galilean moons (Io, Europa, Ganymede, Callisto) discovered by Galileo

• Scientists have found 62 moons so far.

Jupiter

• Io – active volcanoes

• Europa – icy crust, may have liquid water under it

Jupiter

• Ganymede – largest moon, twice the mass of Earth, icy, cratered surface with huge grooves

• Callisto – icy surface, no part of surface is free of craters

Jupiter

• Second largest planet

• Thick atmosphere

• Atmosphere also contains clouds and storms.

Saturn

• Less dense than water. Would float in huge body of water.

• Known for its hundreds of beautiful rings.

• Rings made of ice and rock.

Saturn

• Titan is the largest moon.

• Titan has such a thick atmosphere light can not pass through it.

• Scientists have found 61 moons so far.

Saturn

• Twice as far from the sun as Saturn.

• Looks blue because of methane in atmosphere.

• Axis is tilted on its side at a 90° angle.

Uranus

• Rings go around the North and South poles.

• Moons show volcanic eruptions and crater hits.

• Scientists have found 27 moons so far.

Uranus

• 30 times farther from the sun than Earth.

• Atmosphere contains clouds, surface is not as smooth as Uranus.

Neptune

• Discovered as a result of a mathematical prediction

• Great Dark Spot lasted 5 years

• Scientists have found 13 moons so far.

Neptune

Based on the characteristics of both innerand outer planets, should Pluto be a planet?

Why or why not?

Pluto

• Pluto has one moon, Charon– Charon is ½ the size of

Pluto• Pluto is 1/3 the size of

Earth’s moon– Classified as a “dwarf

planet”• Pluto is the largest of many

rocky, ice objects revolving around the sun beyond Neptune’s orbit.

Pluto

What to Work On• Complete Inner and Outer Planet packets