Our Solar System

One sun8 planets

5 dwarf planets170 moons

Photo Credit: STSci

The Main Planets are…

Terrestrial Planets: Gas Giants:

Mercury Venus Earth Mars

Jupiter Saturn Uranus Neptune

Terrestrial Planets

These are the 4 planets closest to the sun They are small and have dense, hard

rocky surfaces These planets are similar to each other in

composition, but not in their specific characteristics.

Because of their different distances from the sun- they have different surfaces.

Terrestrial Planets

MERCURY: The smallest terrestrial planet, with many craters on it’s surface and almost no atmosphere.

VENUS: Has a similar density and internal structure to Earth. Venus rotates in the opposite direction of all of the other planets. It’s surface is almost entirely covered with clouds and are made almost entirely of sulfuric acid.

Terrestrial Planets

EARTH: Earth is unique due water on the surface (appx 70% of the surface is covered!)

MARS: Covered with rust, causing it to look red. 95% of it’s atmosphere is CO2 and with little cloud coverage. Mars has two polar ice caps where some frozen H2Oand frozen CO2 exists. Mars has a tilted axis similar to Earth, giving it seasons.

The Gas Giants

They are the 4 farthest from the sun They have very thick atmospheres made

mostly of hydrogen and helium They are much, much larger compared to

the terrestrial planets Because of their size, they have a much

greater mass and stronger gravity

The Gas Giants

Each Gas Giant has many moons as well as rings surrounding it.

The Gas Giants are covered with gases and below the clouds of gasses lies a sea of liquid hydrogen and helium (caused by the great pressure on the planet)

Astronomers believe they have a dense core hidden deep within the planet made of rock and iron.

The Gas Giants JUPITER: Largest planet, Jupiter’s

atmosphere has a giant red spot on the surface that is larger than Earth. This spot is a giant storm. Jupiter has 4 beautiful large moons (Galileo discovered) that are visible with a telescope. (pic on p. 565)

SATURN: Second largest, the most spectacular and visible rings of all the gas giants. The largest moon Titan is larger than Mercury!

The Gas Giants URANUS: a very cold planet (compared to

the others) and is twice as far from the sun as Saturn. Not discovered until late 1700’s. It’s the only planet with an axis at a 90° angle to the orbital plane. 27 total moons, 5 of the largest moons have lava flowing on their surfaces!

NEPTUNE: Neptune is very similar to Uranus in terms of color and size, and is covered in blue clouds. Discovered in mid 1800’s. At least 13 moons (may be more).

The bench warmers are…

Dwarf Planets: Moons:

Ceres Pluto Haumea Makemake Eris

Mercury - 0 Venus - 0 Earth -1 Mars – 2 Jupiter – 63 Saturn – 61 Uranus – 27 Neptune – 13 (Pluto has 3)

Dwarf Planets and Pluto

Dwarf planets are any planet who has not completely cleared it’s path yet (the path that it takes during it’s revolution).

Astronomers recently discovered the other dwarf planets in our solar system and with the new information collected, they reclassified Pluto.

Pluto (not demoted, just found his real family!)

Pluto is smaller than Earth’s Moon! Pluto has three moons of it’s own. Pluto's orbit is much more elliptical than the other planets, at times it is closer to the sun than Neptune.