The Planets

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus,

Neptune, (Pluto?)

How far away are the planets?

Astronomical Unit

We use AU’s to measure the distance between planets.

1AU is the distance from the Sun to the Earth.

1AU = 150 million kilometers or 93 million miles

Mercury is .5 AU from the Sun and Pluto is 50 AU from the sun

Mercury

Mercury is the closest planet to the sun.

It is very hot = 800°F It is very cold = -280°F It has many craters and

very rocky It has the longest day and

night cycle – 3 months of daylight and 3 months of darkness

No Moons

Venus

Venus is called Earth’s sister planet as it is similar in size.

Venus is 850° F in the day and at night.

Its surface is covered with lava

It is covered by thick white clouds made of carbon dioxide

No Moons

Mars

Mars has a very rocky surface Temperature: -80◦ F to

70 ◦ F These are actual photos from

Mars! What do you think the face is? We have found evidence of

water It is about ½ the diameter of

Earth 2 moons

Jupiter Jupiter is the largest planet. It is 10X the size of Earth. It is a “gas giant.”

Temperature: -234◦F It spins very fast on its

axis: once every 10 hours. The fast rotation causes

many storms and high winds.

It is known for its “great red spot” which is thought to be a large storm.

62 moons

Saturn

Saturn is known for its thick rings.

The rings are made of chunks of water and ice.

Temperature: -288◦F It is just slightly smaller

than Jupiter Also known as one of the

“gas giants.” 47 moons

Uranus

Also a gas giant It turns on its side and in the

opposite direction as Earth and the other planets.This is called retrograde rotation.

It is made up of “heavy” gases: methane, ammonia and water.

It takes 84 Earth years to travel around the Sun once!

Temperature: -274◦F 27 Moons

Neptune

Very similar in size to Uranus

Temperature: -346◦F Neptune is very cold Methane ice crystals are

visible in the atmosphere. It also has a dark spot

like Jupiter which is also a storm.

13 Moons

Pluto: “Dwarf Planet”

Made of ice and rock It is smaller than our

moon. It has 3 moons. Since they orbit each

other, they are known as a double planet.

It takes 248 Earth years to orbit the Sun once!

Two Classifications of Planets

The terrestrial planets are those closest to the Sun, they have layers and are rocky: Mercury Venus Earth Mars

The four gas giants are:

Jupiter Saturn Uranus Neptune

They are made of mostly helium and hydrogen

What is the difference between a comet, asteroid and meteor?

Comet Asteroid Meteor

Made of rock and ice

Made of rock Made of bits of ice and rock from either Comets or Asteroids

Small objects with gas tail

Irregular shape Many different shapes

Orbits the Sun Orbits the Sun and has hit Earth

Has hit Earth

When it hits Earth it is called a Meteorite