3.  Mercury Venus  Earth Mars Small in size Made of rock and metal. Few satellites. Slow rotation.

4.  Mariner 10 probe visits mercury in 1974.  Surface is very much like our moon, full of craters.  Very little gravity, almost no atmosphere.  Greatest temperature changes in solar system: 430ºC ~ -170ºC

5.  Venus is covered by a thick layer of clouds.  Most of the atmosphere is composed of CO2.  Greenhouse effect has raised temperature to 462°C. Rotates opposite of other planets.  Day is longer than year!!!

6.  Earth is located in the “Goldilocks Zone”  Not too hot, not too cold, just right (for liquid water).  Lots of water, and a thick atmosphere of oxygen.

7.  Mars has an atmosphere of CO2, but the atmosphere is very thin.  Temperatures range from 20°C ~ - 140°C.  Evidence of features and erosion caused by water is everywhere.  Some water is in the polar ice caps, atmosphere, and frozen in the ground.

8.  Mars is full of extinct volcanoes.  Mars’ tilted axis gives rise to seasonal changes.  NASA’s Spirit & Opportunity

9.  Jupiter Saturn  Uranus Neptune Large in size. Made of Gas(Hydrogen, Helium). Rotate rapidly. Many satellites. Rings.

10.  Jupiter is a massive ball of hydrogen and helium gas.  The Great Red Spot is a hurricane 3x’s the size of Earth and at least 400 years old!

11. Io Callisto Ganymede Europa

12.  Saturn, like Jupiter, is made of hydrogen and helium and is actually lighter than water.  It’s rings are formed of concentric circles of chunks of rock and ice orbiting the planet.  Titan

13.  Discovered in 1781 by William Herschel.  Uranus is tilted on its side.  Has very faint rings.  Atmosphere contains methane.

14.  Neptune was discovered mathematically in 1846 after it became known that the orbit of Uranus was abnormal.  Has a large perpetual storm called the Great Dark Spot. Triton Atmosphere of Hydrogen, Helium, Methane, and Ammonia

15.  Small rocky planets located beyond Neptune.  Most are small and very far away and so weren’t discovered until recently.

16.  Chunks of rock out in space.  Can be several meters or kilometers across.  May be left over planet.

17.  Large chunks of rock and ice which orbit the sun.  The ice evaporates as it approaches the sun, leaving a tail behind.