The totality (all) of existence. This includes planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy. EVERYTHING!

• Universe
• Solar System
• Galaxy
• None of These

The force that attracts a body toward the center of the earth, or toward any other physical body having mass.

• Gravity
• Orbit
• Universe
• All of These

Consists of the Sun and the objects that orbit it, whether they orbit it directly or by orbiting other objects that orbit it directly.

• Solar System
• Universe
• Galaxy
• All of These

Unmanned spacecraft that leaves Earth’s orbit and explores space

• Space Probe
• International Space Station
• The Space Shuttle
• None of These

Habitable artificial satellite in low Earth orbit.

• Space Station
• Satellite
• Probe
• None of These

A missile, spacecraft, aircraft or other vehicle that obtains thrust from a rocket engine.

• Probe
• Space Station
• Rocket
• None of These

An artificial object which has been intentionally placed into orbit.

• Universe
• Rocket
• Satellite
• Gravity

A rocket-launched spacecraft, able to land like an unpowered aircraft, used to make repeated journeys between the earth and earth orbit.

• Space Shuttle
• Rocket
• Probe
• Satellite

The action of traveling in or through an unfamiliar area in order to learn about it.

• Exploration
• Orbit
• Rover
• All of These

The gravitationally curved path of an object around a point in space.

• Orbit
• Rover
• Rocket
• None of These