The Solar System

Introduction

• A solar system consists of a star and objects that revolve around it.

• Our Solar System consists of the Sun and nine known planets and the moons that orbit those planets.

• The force of gravity keeps planets in orbit around the sun.

The Sun

• It is over one million times larger than Earth.

• It is eight light minutes away from Earth or 92,957,000 miles.

• The temperature is 15 million degrees K. One K = 13-25 million degrees!

The Nine Known Planets

The Inner Planets The Outer Planets

• Mercury

• Venus• Earth• Mars

• Jupiter• Saturn• Uranus• Neptune• Pluto

Mercury

• Closest planet to the sun

• Approximately half the size of Earth

• Rocky surface covered by craters

• No water or air results in unchanged appearance

• Surface temperatures are hot enough to melt lead

Uranus

• Seventh planet from the Sun

• Four times larger in diameter than the Earth

• Blue-green in color• The tilt of the axis

causes sunlight for 42 years at a time

Venus

• Second planet from the Sun

• Approximately the same size as the Earth

• Atmosphere consists of poisonous gases

Earth

• Third planet from the Sun

• Largest of the four inner planets

• Only planet where life is known to exist

• 70% of the surface is covered by water

Mars

• Fourth planet from the Sun

• Approximately half the size of Earth

• Known as the Red Planet

• Has four seasons similar to Earth

• Resembles Earth more than any other planet

Jupiter

• Fifth planet form the Sun

• Largest planet in our Solar System

• 1300 Earths could fit inside Jupiter

• Doesn’t have a surface; made of gases

Saturn

• Sixth planet from the Sun

• Second largest planet

• 800 Earths could fit inside Saturn

• Thousands of rings are made up of ice and rock fragments

Neptune

• Eighth planet form the Sun

• Four times larger in diameter than the Earth

• Blue in color

Pluto

• Ninth planet from the Sun

• Smallest of the planets

• Coldest planet• Unusual orbit

caused it to be the 8th planet from 1979 - 1999!

Let’s compare the planets to

Earth

A day on :

Mercury = 3 Earth monthsVenus = 117 Earth daysMars = 41 minutes longer than

an Earth dayJupiter = 10 Earth hoursSaturn = 10 ½ Earth hoursUranus = 13 ½ Earth hoursNeptune = 18 Earth hoursPluto = 7 Earth days

If you weigh 85 lbs. On Earth, you weigh:

• 32 lbs on Mercury• 77 lbs on Venus• 32 lbs on Mars• 244 lbs on Jupiter• 112 lbs on Saturn• 79 lbs on Uranus• 105 lbs on Neptune• 2.5 lbs on Pluto

The Orbital Speed of the Planets

• Mercury = 30 miles per second• Venus = 22 miles per second• Earth = 19 miles per second• Mars = 15 miles per second• Jupiter = 8 miles per second• Saturn = 6 miles per second• Uranus = 4.2 miles per second• Neptune = 3.3 miles per second• Pluto = 2.9 miles per second

Therefore, the further away from the Sun, the slower the orbital speed.

The Earth has one Moon. How many moons do the other planets

have?• Mercury - 0• Venus - 0• Mars - 2• Jupiter - 17• Saturn - 22• Uranus - 15• Neptune - 2• Pluto - 1• The Moon

It takes 365 days for Earth to revolve around the Sun.

How long does it take the other planets?

• Mercury - 88 Earth days• Venus - 225 Earth days• Mars - about 2 Earth years• Jupiter - 11.8 Earth years• Saturn - 30 Earth years• Uranus - 84 Earth years• Neptune - 165 Earth years• Pluto - 248 Earth years