The Planets

The Solar System The solar system is made up of the Sun and all the objects that travel around it Planets and their moons, asteroids and comets all revolve around the Sun Planets also rotate

Orbital Period When an object revolves around a much larger object, it is said to be in orbit The time taken for a planet to complete one full revolution around the Sun is its orbital period The Earth’s orbital period is days

Rotational Period Planets also rotate (spin) The time taken for a planet to complete one full rotation is its rotational period The Earth’s rotational period is 23h 56 min

Comparing Planets The rotational period, orbital period, mass and diameter of the other planets are always compared to that of Earth Distances are given using the astronomical unit (AU) –equal to the average distance from Earth to the Sun

The Planets Planets are split into three groups: 1.Inner Planets (Terrestrial Planets) 2. Outer Planets (Gas Giants) Mercury, Venus, Earth and Mars Jupiter, Saturn, Uranus and Neptune 3. Dwarf Planets Pluto, Ceres, Eris, Haumea, Makemake

Mercury The Roman name for Hermes (the messenger)

Distance from Sun0.39 AU Diameter0.38 Mass 0.06 Rotational Period59 days Orbital Period88 days = 0.24 years Average Surface Temperature 350ºC Surface:Covered with craters Number of moons0 Fun Fact:Not visible at night

Venus The Roman name for Venus (goddess of love)

Distance from Sun0.72 Au Diameter0.95 Mass 0.88 Rotational Period243 days Orbital Period225 days = 0.62 years Average Surface Temperature 470ºC (hottest) Surface:Many volcanoes Number of moons0 Fun Fact:Rotates east to west

Earth Also known as “home”

Distance from Sun1 Au Diameter1 Mass 1 Rotational Period1 day Orbital Period1 year Average Surface Temperature 22ºC Surface:70% water Number of moons1 Fun Fact:Only planet known to sustain life

Mars Roman name for Ares (God of War)

Distance from Sun1.52 Au Diameter0.53 Mass 0.11 Rotational Period25 days Orbital Period687 days = 1.88 years Average Surface Temperature -23ºC Surface:Reddish coloured soil Number of moons2 (Phobos & Deimos) Fun Fact:Atmosphere is mostly carbon dioxide

Jupiter Roman name for Zeus (chief of the 12 Olympians)

Distance from Sun5.27 Au Diameter11.25 Mass 318 Rotational Period10 hours Orbital Period12 years Average Surface Temperature –150ºC Number of moons63 Fun Fact:Largest planet

Saturn Latin name for Cronus (Father of Zeus)

Distance from Sun9.54 Au Diameter9.45 Mass95 Rotational Period11 hours Orbital Period30 years Average Surface Temperature –180ºC Number of moons60 Fun Fact:- Rings are composed of ice-covered rock & dust - Less dense than water

Uranus Named after the Greek god of the sky (Zeus’s grandfather)

Distance from Sun19.19 Au Diameter4.01 Mass15 Rotational Period17 hours Orbital Period84 years Average Surface Temperature –210ºC Number of moons27 Fun Fact:Rotates on an axis tilted 90° to the solar plane

Neptune Roman name for Poseidon (Ruler of the Sea)

Distance from Sun30.06 AU Diameter3.96 Mass17 Rotational Period16 hours Orbital Period165 years Average Surface Temperature –220ºC Number of moons13 Fun Fact:Appears blue because of methane gas

Pluto Roman name for Hades (Ruler of the dead)

Distance from Sun39.5 AU Diameter0.19 Mass0.002 Rotational Period8 days Orbital Period248 years Average Surface Temperature –220ºC Number of moons1 Fun Fact:Was classified as a planet until mid-2008

MVEMJSUNP Remember: My Very Excellent Mother Just Served Us Nine Pizzas

The Other Dwarfs Ceres –Located in the asteroid belt –Largest object in the asteroid belt Haumea –Orbits the Sun beyond Neptune –Has two moons

The Other Dwarfs Makemake –Orbits the Sun beyond Neptune –The brightest object in the Kuiper Belt, other than Pluto Eris –Orbits the Sun beyond Neptune –The largest of the dwarf planets –Has one moon (Dysnomia)