The Solar System

Our Solar System

• Is a group of planets orbiting a central star that we call the Sun

• The solar system contains the Sun, 8 planets, 3 dwarf planets, and various moons, asteroids, meteors, and space debris

• In 2006 the International Astronomical Union decided to remove Pluto as a planet and create a new category after the discovery of an object bigger then Pluto

The Sun

• The Sun is the largest thing in our solar system

• It is 109x the size of the Earth and 330 000x heavier!!

• You could fit over a MILLION Earths in the Sun!

• All the planets are bound to the Sun by gravity

Rotation vs. Revolution

rotation = term used to describe a planet spinning on itself (its axis)

• it takes the Earth 1 day (24 hrs) to rotate once• the Earth doesn’t rotate on its true axis but tilted on a 23.5

angle

revolution = the movement of a planet or body around another object

• the Earth revolves around the Sun• it take the Earth 365.24 days to revolve around the Sun

once

Revolution & Rotation of the Planets

• All the planets in the solar system revolve around the Sun in a counterclockwise direction in slightly elliptical (oval) orbits

• All planets also rotate in a counterclockwise direction (well, almost all)

The Solar System

Terrestrial / inner planets------------------ Gas giants ------------------

Mercury• Closest planet to the Sun• A rocky ball only slightly

bigger than the Earth’s moon

• Made of rock, covered in craters

• Takes only 88 Earth days to orbit the Sun

• Has virtually no atmosphere• Temperature -180 to 426C• Extreme temperatures cause

huge cracks to form on the planet’s surface

Venus

• Size and composition are similar to Earth

• Rocky surface with a thick atmosphere of CO2

• Rain is sulfuric acid on this planet, not water!

• Takes 244 Earth days to spin on its axis… sloooow

• Very hot (470C) due to its thick atmosphere

Earth

• Only planet to support life that we know of

• Called the blue planet since it’s mostly covered with water

• Temperature -85 to 58C• Rocky core • Atmosphere composed

mainly of N2, O2

• Only planet to have water in all 3 states

• One moon

Mars

• Called the red planet due to iron oxide in its surface

• Half the size of Earth• Temperature -120 to 30C• Rocky surface with a thin

atmosphere of mainly CO2

• Massive volcano named Olympus Mons is almost 3x bigger than Mt. Everest!

• Canyon 8 km deep• Winds can exceed 900 km/h• Dust storms can last for weeks• 2 moons, Phobos & Deimos

Jupiter• Largest planet• It’s 2.5x heavier than all

the planets combined!• Has a Great Red Spot, as

big as 3 Earths, that’s a giant storm

• Solid core, but mostly made of H2, He, and CH4 (methane) gases

• Takes only 10 hrs to rotate on its axis but 11.9 yrs to revolve around the Sun

• Has very thin rings made of ice particles

• Temp -150C• More than 60 moons!!

Saturn• 2nd biggest planet• Most elaborate ring

system, made of dust and ice particles (some are as big as a house!)

• Made mostly of H2 and He gases

• Could float in a bath tub if you could find one big enough!

• Temp -170C• Many, many moons

Uranus• 3rd biggest planet in the

solar system

• Blue-green colour from methane in its atmosphere

• Tilted on its side, so it looks like it’s rolling through its orbit

• Rotation is opposite to other planets

• Also has a ring system

• Takes 84 Earth years to orbit the Sun

• Temperature -215C

Ok, we all know the joke, but it’s YUR-ah-nus

Neptune• Gas giant

• Similar in composition and atmosphere to Uranus

• Darker blue colour

• Thin rings made of ice particles

• Takes almost 165 Earth years to orbit the Sun

• Temp is -235C, yikes!

• 13 known moons

• Named after the Roman god of the sea

Dwarf Planets

• Adopted in 2006

• Dwarf planets are objects that: – orbit the sun– have enough mass to become round– are not large enough to have an impact on their

area

• There are currently 3 dwarf planets in our solar system: Pluto, Eris, & Ceres