• Beyond Mars stretches the Beyond Mars stretches the outer solar system where the outer solar system where the four largest planets slowly orbit four largest planets slowly orbit the sun.the sun.

• We call these planets, We call these planets, Jupiter, Saturn, Uranus, and Jupiter, Saturn, Uranus, and Neptune, the gas giants.Neptune, the gas giants.

• The gas The gas giants are giants are made mainly made mainly of hydrogen, of hydrogen, helium, and helium, and other gases.other gases.

• When you think of gases, you When you think of gases, you probably think of Earth’s air, probably think of Earth’s air, which is not very dense.which is not very dense.

• However, the giant planets are However, the giant planets are so large and have such huge so large and have such huge amounts of these gases that amounts of these gases that they have a LOT of mass.they have a LOT of mass.

• The The HUGE gravitational forceHUGE gravitational force from such a large mass is from such a large mass is enough to pull the gas enough to pull the gas particles close together and particles close together and make the atmosphere very make the atmosphere very dense.dense.

• Inside, the gases become Inside, the gases become more dense than water.more dense than water.

• The outermost parts are less The outermost parts are less dense and more like Earth’s dense and more like Earth’s atmosphere.atmosphere.

JupiterJupiter

Imagine traveling into one…Imagine traveling into one…• The atmosphere is thin and The atmosphere is thin and

very cold. There may be a haze very cold. There may be a haze of gases.of gases.

SaturnSaturnSaturnSaturn

• A little lower is a layer of A little lower is a layer of clouds that reflect sunlight, clouds that reflect sunlight, just like on Earth.just like on Earth. There are There are strong winds and other strong winds and other weather patterns.weather patterns.

NeptuneNeptune

• Lower down, it Lower down, it

is warmer and is warmer and

there are layers there are layers

of clouds of of clouds of

different different

materials.materials. UranusUranus

• As you go farther,As you go farther, the the atmosphere gradually atmosphere gradually becomes dense enough to be becomes dense enough to be called a liquid. It also gets called a liquid. It also gets thousands of degrees hotter thousands of degrees hotter as you get closer to the as you get closer to the center of the planet!center of the planet!

• The materials The materials

become more become more

and more dense and more dense

until they are until they are

solid.solid.NeptuneNeptune

• Read (734 or 94E) to find out Read (734 or 94E) to find out more about the gas giants.more about the gas giants.

• Complete the pages in your Complete the pages in your Planet BookPlanet Book..