The Planets

IN: What objects make up our solar system?

20-1 pgs. 538-548

The SunThe Sun The sun is the The sun is the

biggest, brightest, biggest, brightest, and hottest object and hottest object in the solar system.in the solar system.

The sun is an The sun is an ordinary star.ordinary star.

The sun is made of The sun is made of about 70% about 70% hydrogen and 28% hydrogen and 28% helium.helium.

Small Rocky WorldsSmall Rocky Worlds Terrestrial Planets – the small, dense,

rocky planets of the inner solar system. Mercury Venus Earth Mars

Terrestrial PlanetsTerrestrial Planets

MercuryMercury

Mercury is solid Mercury is solid and is covered with and is covered with craters.craters.

Mercury has almost Mercury has almost no atmosphere.no atmosphere.

Has no moon.Has no moon.

VenusVenus Venus is the sixth Venus is the sixth

largest planet. It’s largest planet. It’s about three-fourths about three-fourths the size of earth.the size of earth.

The surface is rocky The surface is rocky and very hot. The and very hot. The atmosphere atmosphere completely hides the completely hides the surface and traps surface and traps the heat.the heat.

Also, has no moon.Also, has no moon.

EarthEarth Earth is the fifth largest planet and the third Earth is the fifth largest planet and the third

from the sun.from the sun. Liquid covers 71 percent of the Earth’s Liquid covers 71 percent of the Earth’s

surface.surface. The Earth has one moon.The Earth has one moon.

MoonMoon

MarsMars Mars is the fourth Mars is the fourth

planet from the planet from the sun.sun.

Mars has a thin Mars has a thin atmosphere that atmosphere that contains mostly contains mostly carbon dioxide.carbon dioxide.

Mars has two small Mars has two small moons.moons.

Moons of MarsMoons of MarsPhobosPhobos

DeimosDeimos

Asteroid BeltAsteroid Belt

Big Gaseous WorldsBig Gaseous Worlds

Gas Giants – the large, gaseous planets of the outer solar system.

Jupiter Saturn Uranus Neptune

– All gas giants have rings!

Gas GiantsGas Giants

JupiterJupiter

Jupiter’s Red SpotJupiter’s Red Spot The Great Red Spot, a huge storm of The Great Red Spot, a huge storm of

swirling gas that has lasted for hundreds swirling gas that has lasted for hundreds of years.of years.

Jupiter does not have a solid surface. The Jupiter does not have a solid surface. The planet is a ball of liquid surrounded by planet is a ball of liquid surrounded by gas.gas.

Moons of JupiterMoons of Jupiter

Jupiter has four large Galilean Jupiter has four large Galilean moons, twelve smaller named moons moons, twelve smaller named moons and twenty-three more recently and twenty-three more recently discovered but not named moons.discovered but not named moons.

We’ll take a look at the four large We’ll take a look at the four large Galilean moons which were first Galilean moons which were first observed by Galileo in 1610.observed by Galileo in 1610.

IoIo

– Io is the fifth moon Io is the fifth moon of Jupiter. It’s the of Jupiter. It’s the third largest of third largest of Jupiter’s moons.Jupiter’s moons.

– Io has hundreds of Io has hundreds of volcanic calderas. volcanic calderas. Some of the Some of the volcanoes are volcanoes are active.active.

EuropaEuropa

Europa is the sixth of Europa is the sixth of Jupiter’s moons and is Jupiter’s moons and is the fourth largest.the fourth largest.

It is slightly smaller It is slightly smaller than the Earth’s moon.than the Earth’s moon.

The surface strongly The surface strongly resembles images of resembles images of sea ice on Earth. There sea ice on Earth. There may be a liquid water may be a liquid water sea under the crust.sea under the crust.

Europa is one of the Europa is one of the five known moons in five known moons in the solar system to the solar system to have an atmosphere.have an atmosphere.

GanymedeGanymede

Ganymede is the Ganymede is the seventh and seventh and largest of Jupiter’s largest of Jupiter’s known satellites.known satellites.

Ganymede has Ganymede has extensive cratering extensive cratering and an icy crust.and an icy crust.

CallistoCallisto

Callisto is the eighth of Jupiter’s known Callisto is the eighth of Jupiter’s known satellites and the second largest.satellites and the second largest.

Callisto has the oldest, most cratered Callisto has the oldest, most cratered surface of any body yet observed in the surface of any body yet observed in the solar system.solar system.

SaturnSaturn

Saturn is the second largest planet and the Saturn is the second largest planet and the sixth from the sun.sixth from the sun.

In 2004 we got images of the rings.In 2004 we got images of the rings.

Rings of SaturnRings of Saturn

Saturn’s rings are not Saturn’s rings are not solid; they consist of icy solid; they consist of icy particles that range in particles that range in size from a few size from a few centimeters to several centimeters to several meters across.meters across.

The rings are very thin. The rings are very thin. Though they’re Though they’re 250,000km or more in 250,000km or more in diameter, they’re less diameter, they’re less than one kilometer thick.than one kilometer thick.

UranusUranus

Uranus is blue-Uranus is blue-green because of green because of the methane in its the methane in its atmosphere.atmosphere.

Its axis is tilted 90Its axis is tilted 90oo..

NeptuneNeptune Neptune is the Neptune is the

fourth largest fourth largest planet and the planet and the eight from the sun.eight from the sun.

Like Uranus, the Like Uranus, the methane gives methane gives Neptune its color.Neptune its color.

PlutoPluto Pluto – doesn’t fit either category. Pluto is

a small icy world clearly different from either the Terrestrial and Gas Giant worlds.

Dwarf PlanetsDwarf Planets Ceres – discovered on January 1, 1801, 45 years Ceres – discovered on January 1, 1801, 45 years

before before Neptune. Neptune. Considered a planet for half a Considered a planet for half a century before reclassification as an asteroid. century before reclassification as an asteroid. Accepted as a dwarf planet by the IAU on September Accepted as a dwarf planet by the IAU on September 13, 2006. 13, 2006.

Pluto – discovered on February 18, 1930. Classified Pluto – discovered on February 18, 1930. Classified as a planet for 76 years. Reclassified as a dwarf as a planet for 76 years. Reclassified as a dwarf planet by the IAU on August 24, 2006. Haumea – planet by the IAU on August 24, 2006. Haumea – discovered on December 28, 2004. Accepted by the discovered on December 28, 2004. Accepted by the IAU as a dwarf planet on September 17, 2008. IAU as a dwarf planet on September 17, 2008.

Makemake – discovered on March 31, 2005. Accepted Makemake – discovered on March 31, 2005. Accepted by the IAU as a dwarf planet on July 11, 2008. by the IAU as a dwarf planet on July 11, 2008.

Eris – discovered on January 5, 2005. Called the Eris – discovered on January 5, 2005. Called the "tenth planet" in media reports. Accepted by the IAU "tenth planet" in media reports. Accepted by the IAU as a dwarf planet on September 13, 2006. as a dwarf planet on September 13, 2006.

Kuiper BeltKuiper Belt

OUT: Summarize the differences between terrestrial planets and gas giants.