Page 39 - Curriculum Visions Dynamic Book

Saturn is not a precise sphere but is flattened on both poles. Its pole-to-pole diametre is 10% less than its diametre at the equator. This is the result of centrifugal force throwing the gases of the planet outward against gravity more strongly at the equator than at the poles.
The atmosphere
Saturn’s atmosphere is 91% hydrogen, more in percentage terms than any other planet in the solar system. Helium makes up just 6%, with smaller amounts of methane and ammonia.
In the inner regions of the atmosphere the pressure is equal to millions of Earth’s atmospheres, and hydrogen turns into a liquid. On the other hand, the pressure also causes the temperature of the inner atmosphere to be several thousand degrees.
atmosphere The envelope of gases that surrounds the Earth and other bodies in the universe.
centrifugal force A force that acts on an orbiting or spinning body, tending to oppose gravity and move away from the centre of rotation.
equator The ring drawn around a body midway between the poles.
false colour The colours used to make the appearance of some property more obvious.
gravity The force of attraction between bodies.
latitude Angular distance north or south of the equator, measured through 90°.
mass The amount of matter in an object.
pole The geographic pole is the place where a line drawn along the axis of rotation exits from a body’s surface.
pressure The force per unit area.
 This false-colour image of Saturn provides detailed information on the clouds and hazes in Saturn’s atmosphere.
The blue colours indicate a clear atmosphere down to a main cloud layer.
Different shadings of blue indicate variations in the cloud particles in size or chemical composition. The cloud particles are believed to be ammonia-ice crystals. The dark region around the south pole at the bottom indicates a big hole in the main cloud layer.
The green and yellow colours indicate a haze above the main cloud layer.
The haze is thin where the colours are green but thick where they are yellow. Most of the southern hemisphere (the lower part of Saturn) is quite hazy. These layers are aligned with latitude lines due to Saturn’s east-west winds.
The red and orange colours indicate clouds reaching up high into the atmosphere.
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