Which planet is closest to the sun?

• Mars
• Venus
• Mercury
• Earth

One Astronomical Unit (AU) is...

• The distance from the Earth to the Sun
• 100,000 Kilometers
• The radius of the solar system
• The diameter of the Earth to the Sun

Why are Astronomical Units (AU) used to measure distances in space?

• Because objects in space are too small.
• Because objects in space are really far apart.
• Astronauts don't know how to use a meter stick.
• It is a unit smaller than a millimeter.

Which of the following planets have rings?

• Mercury
• Mars
• Venus
• Uranus

Which of the following planets DOES NOT have any moons?

• Mercury
• Jupiter
• Earth
• Mars

Which are the two gases that make up the composition of the Sun and the outer planets?

• Hydrogen and Nitrogen
• Helium and Nitrogen
• Hydrogen and Oxygen
• Hydrogen and Helium

Which of the following terms would NOT describe an inner planet?

• Small
• Gaseous
• Rocky
• Dense

Which of the following terms would NOT describe an outer planet?

• Rocky
• Gaseous 
• Large
• Has rings

How does Mercury's mass compare to Earth?

• It is 333,000 times Earth's mass.
• It is 0.82 of Earth's mass.
• It is 0.11 of Earth's mass.
• It is 0.06 of Earth's mass.

How many Earth days does it take Neptune to rotate on its axis?

• 0.67
• 243.02
• 43
• 0.72