14.4 The Solar System Outer Planets (page 562)

Planets There are 8 planets: Mercury Venus Earth Mars Jupiter Saturn Uranus (YOOR uh nus) Neptune Pluto --- dwarf Terrestrial Planets Gas Giants **You are responsible for knowing the planets in order!!!! A good way to remember the order is through a pneumonic. (My Very Energetic Mom Just Sent Us Nine Pizzas)

The Gas Giants The last four outer planets are much larger and more massive than Earth, and they do not have solid surfaces. For these reasons they are called the “Gas Giants” They have many moons. They are also surrounded by a set of rings.

Jupiter The largest planet: 318x Earth Jupiter is the fourth brightest object in the sky (after the Sun, Moon and Venus) Galileo discovered four of Jupiter’s moons in 1610 Jupiter has 63+ moons (Ganymede is the largest with a mass 2x that of Earth’s moon)

Jupiter Thick atmosphere of hydrogen and helium The atmosphere has many colorful bands of swirling clouds The Great Red Spot: a giant area of swirling clouds many times bigger than Earth (a storm similar to a hurricane) Jupiter is a gas planet and does not have a solid surface (though it most likely has a solid core 10-15x the mass of Earth)

Jupiter Jupiter radiates more energy into space than it receives from the Sun!!!!! It’s interior is hot, due to gravitational compression. It has a huge magnetic field. It has rings, but much fainter and smaller than Saturn’s.

Saturn Saturn is the 2nd largest planet It is easily visible in the night sky It is the least dense of all the planets. It is less dense than water. Its atmosphere is about 75% hydrogen; 25% helium It probably has a rocky core

Saturn There are 100s of rings that are made up of ice and rock, each traveling in its own orbit The rings are very thin (less than 1 km) Saturn has 30 moons: Titan (the largest), Tethys, Iapetus, Dione, and Rhea.

Uranus 4x the diameter of Earth It is a bluish color due to traces of methane (CH4) in its atmosphere. Twice as far away from the Sun as Saturn (next to it). Discovered in 1781by William Herschel Uranus’s axis of rotation is tilted at an angle of about 90 degrees from vertical

Uranus Uranus is the coldest of all the planets It is also the second-least dense planet after Saturn Its atmosphere is about 83% hydrogen, 15% helium, 2% methane Like other gas planets, Uranus has rings Uranus has 27 moons (21 named, 6 unnamed)

Neptune Neptune is the fourth largest planet It is often called the “cold, blue planet” It also has rings. It is possibly shrinking and growing warmer Neptune possibly has a rocky core

Neptune Neptune's most prominent feature was the Great Dark Spot (left) in the southern hemisphere. It was about half the size as Jupiter's Great Red Spot (about the same diameter as Earth). Neptune has 13 known moons. Neptune was discovered in 1846 due to a mathematical prediction involving Uranus

Pluto Only has 1 moon: Charon Pluto has a solid surface (probably rock and ice) is less than 2/3 the size of Earth’s moon. Pluto is not considered a planet Orbit very elliptical Not like gas giants Just rock and ice

Assignment Do the review questions for 14.4 on page 569