Gravity in our Solar System

What force is responsible for the formation of the solar system?

• Magnetism

• Electricity

• Gravity

• Nuclear force

Approximately how many years ago did the solar system begin to form?

• 2.5 billion years ago

• 3.6 billion years ago

• 4.6 billion years ago

• 5.6 billion years ago

What happens to the planets if the sun's gravitational pull suddenly stops?

• They will move closer to the sun.

• They will shoot off in the direction they were moving.

• They will stop moving entirely.

• They will collide with each other.

The sun's gravity and the planets' ___ keep them in orbit.

What is the massive object at the center of the Milky Way galaxy?

• A giant star

• A supernova

• A black hole

• A nebula

How did the initial cloud of dust and gases in space begin to form the solar system?

• It expanded rapidly.

• It collapsed in on itself.

• It was hit by a meteor.

• It was pulled by another galaxy.

The solar system is part of a giant collection of stars known as the ___ galaxy.