The SunThe Sun The Sun is the center of The Sun is the center of

the solar system.the solar system. It is a star ( a hot ball of It is a star ( a hot ball of

glowing gases.) It is our glowing gases.) It is our closest star.closest star.

The sun is big enough to The sun is big enough to hold over one million hold over one million Earths. Even so, the sun Earths. Even so, the sun is an average-sized star.is an average-sized star.

The Sun is 870,000 The Sun is 870,000 miles across.miles across.

The Sun ‘s gravity helps The Sun ‘s gravity helps hold the objects in the hold the objects in the solar system in place.solar system in place. Click on the SUN

to learn more.

MercuryMercury If you were to step onto the surface of Mercury you would If you were to step onto the surface of Mercury you would

think that you were on the moon.think that you were on the moon. Meteorites continually bombard the surface of Mercury.Meteorites continually bombard the surface of Mercury. The sky is always black because there is no atmosphere to The sky is always black because there is no atmosphere to

cause light from scattering.cause light from scattering.

VenusVenus Venus is sometimes Venus is sometimes

called called Earth'sEarth's sister sister planet. In some ways planet. In some ways they are very similar.they are very similar.

  Venus is only slightly Venus is only slightly smaller than Earth and smaller than Earth and both have few craters both have few craters indicating relatively indicating relatively youngyoung surfaces. surfaces.

      This dense atmosphere This dense atmosphere produces a run-away produces a run-away greenhouse effectgreenhouse effect that that raises Venus' surface raises Venus' surface temperature by about 400 temperature by about 400 degrees.   degrees.   

EarthEarth•Earth is our home.  Earth is the third planet from the Sun and the fifth largest:

• Seventy-one percent of the Earth's surface is covered with water. Earth is the only planet on which water can exist in liquid form on the surface .

MarsMarsMars is the fourth planet from the Sun and the seventh largest.  Though Mars is much smaller than Earth, its surface area is about the same as the land surface area of Earth.

MarsMars

  The first spacecraft to The first spacecraft to visit Mars was visit Mars was Mariner 4Mariner 4 in 1965. Several others in 1965. Several others followed including followed including Mars 2Mars 2, , the first spacecraft to land the first spacecraft to land on Mars and the two on Mars and the two VikingViking Landers in 1976. Landers in 1976. Mars PathfinderMars Pathfinder landed landed successfully on Mars on successfully on Mars on July 4,1997 .July 4,1997 .

JupiterJupiter

Jupiter Jupiter is the fifth planet from the Sun and by far the largest.Jupiter is more than twice as massive as all the other planets combined (318 times Earth).

The Great Red Spot on JupiterThe Great Red Spot on Jupiter

The Great Red Spot The Great Red Spot is a hurricane like is a hurricane like storm that was first storm that was first observed more than observed more than 300 years ago. The 300 years ago. The Spot is an oval about Spot is an oval about 12,000 by 25,000 km, 12,000 by 25,000 km, big enough to hold big enough to hold two Earths. two Earths.

SaturnSaturn

Saturn is the sixth planet from the Sun and the second largest. Two prominent rings (A and B) and one faint ring (C) can be seen from the Earth. The rings are made of small ice and rock particles. They range in size from a centimeter to several meters.

UranusUranus

Uranus is the seventh Uranus is the seventh planet from the planet from the SunSun and the third largest.and the third largest.

Like the other gas Like the other gas planets, Uranus has planets, Uranus has bands of clouds that bands of clouds that blow around rapidly. blow around rapidly.

NeptuneNeptune

Neptune is the eighth Neptune is the eighth planet from the planet from the SunSun and the fourth largest and the fourth largest (by diameter). (by diameter).

The surface is made The surface is made of frozen gases.of frozen gases.

PlutoPluto

Pluto is made of ice. Pluto is made of ice. It has a moon almost It has a moon almost

as big as it is.as big as it is. Pluto is the farthest Pluto is the farthest

planet from the Sun planet from the Sun (usually) and by far (usually) and by far the smallest the smallest

OrbitOrbit

The orbit is the path The orbit is the path an object takes an object takes around another object around another object in space.in space.

The The orbitorbit is the path an object is the path an object

takes around another object in takes around another object in space.space.

Orbit

RevolutionRevolution

Revolution is the movement of one object Revolution is the movement of one object around another object. Earth makes one around another object. Earth makes one revolution around the sun every 365 ¼ days. revolution around the sun every 365 ¼ days. One revolution takes one year.One revolution takes one year.

RotationRotation

Rotation is the Rotation is the spinning of an object spinning of an object on its axis.on its axis.

AxisAxis

The imaginary line The imaginary line that goes through the that goes through the North Pole and the North Pole and the South Pole.South Pole.

Solar EclipseSolar Eclipse

A solar eclipse A solar eclipse happens when the happens when the moon’s shadow falls moon’s shadow falls on Earth. This on Earth. This happens when the happens when the moon moves between moon moves between the Earth and the the Earth and the Sun. During a total Sun. During a total solar eclipse, the solar eclipse, the moon blocks out the moon blocks out the sun.sun.

Lunar EclipseLunar Eclipse

This is called a lunar This is called a lunar eclipse. A lunar eclipse. A lunar eclipse happens eclipse happens when Earth’s shadow when Earth’s shadow falls on the moon. A falls on the moon. A total lunar eclipse total lunar eclipse causes all of the causes all of the moon’s face to look moon’s face to look dark red.dark red.