Solar system

The four inner planets are...

• Rocky and small
• Very large and made of ice
• Small and made of ice
• Very large and made of gases

The outer planets are...

• Rocky and small
• Very large and made of ice
• Small and made of ice
• Very large and made of gases

Which two planets are out of order in this list of our solar system?
Mercury-Earth-Venus-Mars-Jupiter-Saturn-Uranus-Neptune-Pluto.

• Mercury and Earth
• Earth and Venus
• Saturn and Jupiter
• Uranus and Neptune

How does a telescope help us understand the moon?

• It tells us how it was formed
• It tells us how hot it is there
• It helps us see surface features
• It can tell us what the moon is made of

A probe landed on Mars and did a soil test. What information did it discover?

• There are no living organisms in Martian soil.
• Mars is slightly oval in shape.
• Mars is about one-fourth the size of Earth.
• The gravity on Mars is much less than on Earth.

Why is space travel difficult for people?

• We cannot take the air or food we need into space
• the distance are very great; it is dangerous and expensive.
• It is impossible to escape the sun's or Earth's gravity.
• We do not have a destination to visit that we know will support life.

What holds the planets in their orbits around the sun?

• gravity
• speed
• string
• air currents

Which object has the most gravity?

• Earth
• moon
• Jupiter
• sun

Without gravity, what would be the shape of the solar system?

• Planets would revolve in perfect circles
• Much different than it is now.
• Planets' orbits would cross
• All planets would be in the same orbit

Does this graph show relative size or distance from the sun of the planets?

• It shows both size and distance.
• It does not show size or distance.
• It shows distance from the sun
• It shows relative size.