Science3.3

The gas giants have very deep atmospheres

The gas giants – Jupiter, Saturn, Uranus, Neptune – are made mainly of hydrogen, helium, and other gases.

The giants planet are so large and have such large amounts of these gases that they have a lot of mass. The huge gravitational force from such a large mass is enough to pull the gas particles close together and make the atmosphere very dense.

At first, the atmosphere of a giant planet is thin and cold with haze of gases. A little lower is a layer of clouds that reflect sunlight which causes strong winds and other weather patterns.
Lower down, it is warmer and there are layers of clouds of different materials. As you go farther, it becomes dense enough to call a liquid.
Scientists think that each of the four gas giants has a solid core, larger than Earth, deep in its center.


Jupiter is a world of storms and clouds.
*Jupiter is the largest planet in the solar system.
*It is more that 10 times larger than Earth in diameter and more than 1200 times larger in volume.
*If you could weigh the planet, all the other planets put together would weigh less than half as much as Jupiter.
*Even though it is big, Jupiter takes less than 10 hours to turn once on its axis. This fast rotation produces fast winds and stormy weather.
*Jupiter has many more bands than Earth does. Stripes of cold clouds form along the bands. The clouds look white because they are made of crystals that reflect sunlight. The lower clouds are brown or red and made of different chemicals. Sometimes there are clear patches of bluish clouds.
*long lasting storms can form between bands of winds that blow in opposite directions. Scientist are trying to find out which chemicals produce the spot’s reddish color.


Saturn has large rings
Saturn is the sixth planet from the Sun.
It is only a little smaller than Jupiter, but its mass is less than one-third that of Jupiter. As a result, Saturn has a much lower density than Jupiter.

Saturn was the first planet known to have rings. A planetary ring is a wide, flat zone of small particles that orbit a planet. Saturn’s rings are made of chunks of water ice. Saturn’s rings have bright and dark stripes that change over time.

Just like Earth, Saturn ‘s axis is tilted and you can look at Saturn’s rings to tell the seasons. A typical season will last more than seven Earth year.

Saturn is almost ten times farther from the Sun than Earth is, so it takes almost 30 Earth years to go around the Sun once.
Uranus and Neptune are extremely cold.
Uranus and Neptune are only about 15 percent hydrogen and helium. Most of the mass of each planet is made up of heavier gases, such as methane, ammonia, and water. So, Uranus and Neptune are more dense than Jupiter.

Uranus looks blue-green, and Neptune appears deep blue. Each planet has methane gas above a layer of white clouds. Methane gas absorbs red, orange, and yellow parts of sunlight, so each planet’s bluish color comes from the remaining green, blue and violet light that passes back out of the atmosphere.