Chapter 28 Our Solar System

All of the outer planets--

• have many moons
• are small
• have a short orbit around the Sun
• are rocky

How does the distance between two objects affect the force of gravity?

• The closer the two objects are the more gravitational force they have.
• The farther apart the two objects are the more gravitational force they have.
• The closer the two objects are the less gravitational force they have.

The Sun is at the center of our solar system. All the planets in the solar system orbit around the Sun. Which of the following planets has the longest orbit?

• Mercury

• Earth

• Pluto

• Neptune

What keeps a planet moving on its path around the sun

• gravity & inertia
• heat & pressure
• inertia & pressure
• gravity & heat

All of the following characteristics of Jupiter's moon, Europa, are conditions that make it suitable for supporting life EXCEPT-

• water on the surface

• oxygen in the atmosphere

• gravity on the surface

• surface temperature of -260F

What pulled the matter towards the center of the nebula as the solar system was forming?

• inertia
• heat
• pressure
• gravity

Earth's atmosphere contains water vapor and carbon dioxide. These greenhouse gases are important because-

• they are substances animals need to breathe

• they trap thermal energy in the atmosphere

• protect against magnetic particles

• create Earth's gravitational field

The closer a planet is to the sun...

• the faster it travels
• the slower it travels

Which statement best describes a galaxy?

• a cluster of millions of stars held together by gravity
• a star, with planets, moons and other small space bodies revolving around it
• all known objects
• all of the above

Which movement creates day/night?

• rotation
• revolution