The Solar System

Kayli White & Anne Riley

The inner planets vs. the outer planets

• The inner planets: Mercury, Venus, Earth, and Mars. They are relatively small, composed mostly of rock, and have few or no moons.

• The outer planets: Jupiter, Saturn, Uranus, Neptune, and Pluto.They are huge, mostly gaseous, ringed, and have many moons The exception is Pluto, the dwarf planet, which is small, rocky, and has one large moon plus two tiny ones.

Temperatures of the Planets

• Generally, the farther from the Sun, the cooler the planet. Differences occur when the greenhouse effect warms a planet (like Venus) surrounded by a thick atmosphere.

Density of the Planets

• The outer, gaseous planets are much less dense than the inner, rocky planets.

• The Earth is the densest planet.

• Saturn is the least dense planet; it would float on water.

A day on the Planets Compared to Earth

• A day is the length of time that it takes a planet to rotate on its axis (360°). A day on Earth takes almost 24 hours.

The planet with the longest day is Venus. A day on Venus takes 243 Earth days. (A day on Venus is longer than its year; a year on Venus takes only 224.7 Earth days)

The planet with the shortest day is Jupiter. A day on Jupiter only takes 9.8 Earth hours.

Mercury• Planet closest to the

Sun• Has no moons• Dry, nearly airless,

and full of craters• Much like our moon• Mercury's core is 75%

of Mercury by volume and 80% of it by mass

Venus• Second planet closest to

the Sun• Has no moons• Atmosphere is 97%

carbon dioxide• It’s surface temperature

is 480 °C (896 °F)

Earth• Third planet from the Sun• Has one moon• Only planet capable of

sustaining life• Three distinct layers. The

core is the central part made up of molten nickel and iron.

• The next layer is the mantle consisting of solid, hot rock.

• The crust upon which we walk and live is the upper-most layer, consisting of soil, clay, and fine rock.

Mars• Fourth planet from the

Sun• Has 2 moons• Has a reddish color due

to the iron oxide (rust) that is in the soil

• Has the largest volcano• Most Earth-like planet

and may one day habitat humans

Jupiter• Fifth planet from the

Sun• Has 18 large moons and

many small ones• About 1,320 Earths

could fit inside of it• Has faint ring system• Great Red Spot: gigantic

storm on Jupiter’s surface

Saturn• Sixth planet from the

Sun• Has 18 large moons and

many small ones• Gas giant composed of

hydrogen, with small proportions of helium.

• Has rings consisting mostly of ice particles

• Least dense planet

Uranus• Seventh planet from the

Sun• Has 15 moons• First planet to be

discovered• Has a system of about

11 rings• Atmosphere composed

of hydrogen, helium, methane, and ammonia

Neptune• Eighth planet from the sun• Has 2 moons• Atmosphere composed of

hydrogen, helium, methane, and ammonia

• Uranus’ twin• Great Dark Spot: (left)

a depression in the atmosphere surrounded by high cirrus clouds

Pluto• Farthest planet from

the Sun• Has 1 large and 2 small

moons• Considered a dwarf

planet• Small, rocky

Space Probes• A space vehicle carrying

sophisticated instrumentation but no crew

• Goes around planets collecting information and pictures to help scientist understand the weather and changes that planets go through

• Unlike an artificial satellite, which is placed in a permanent orbit around the earth, a space probe is launched with enough energy to escape the gravitational field of the earth and navigate among the planets.

• Many do not return back to Earth