What is the lighter part of a shadow where light is partially blocked called?

• the umbra
• the penumbra

What is the central, darker part of a shadow called?

• the umbra
• the penumbra

In thinking about a solar eclipse, what does the light source in the diagram represent?

• the Sun
• the Moon
• the Earth

In thinking about a solar eclipse, what does the ball in the diagram represent?

• the Sun
• the Moon
• the Earth

What is the center of gravity in our solar system?

• Earth
• Moon
• Sun

Which characteristic of the Sun primarily determines the orbits of planets in our solar system?

• large volume
• mostly made of hydrogen
• strong gravitational field
• high surface temperatures

The further away objects are

• the stronger the gravitational pull.
• the weaker the gravitational pull.
• the gravitational pull does not change.

The more mass either object has

• the stronger the gravitational pull.
• the weaker the gravitational pull.
• the gravitational pull does not change.

Which objects would have the least gravity between them? (Assume all objects have the same mass.)

• A
• B
• C

The Sun releases huge amounts of energy due to

• nuclear fusion
• nuclear fission