For what reason can we see the moon at different places in the sky?

• Moon always produces light
• Moon's distance from Earth changes
• Moon's axis is tilted
• Moon revolves around Earth

What is a comet?

• Composed of iron and stone
• It orbits the Earth
• Larger than the moon
• It has a tail of gas and dust

Where does fusion normally occur?

• In Earth's core
• The Sun
• Comet's tail
• The Moon

Which two factors determine the gravitational force between two objects?

• Time and temperature
• Color and Hardness
• Mass and Distance apart
• Shape and orbital speed

Why does a comet's tail point away from the Sun?

• The comet is heading towards Earth
• Solar winds are blowing it away from the Sun
• Black hole is pulling it closer
• Heading to Mars

Why are meteoroids usually harmless to Earth?

• They burn up in the atmosphere
• They hit Earth
• They are always hitting other planets
• They are made up of soft material

When astronauts are in space for long periods of time, what happens to their bones?

• They become stronger
• They become more dense
• They expand
• They become harder

If scientists wanted to study an unknown planet, what type of equipment would they need?

• Space shuttle
• Satellite
• Probe with instruments
• Spacecraft

What best explains Earth's motion?

• Earth moves in an elliptical motion around the Sun
• No unbalanced force acting on the planet
• The sun moves in orbit around Earth
• The gravitational forces are equal between Earth and the Sun

What is a risk for living in space for long periods of time?

• Eating space food
• Sleeping against a wall
• Microgravity
• High radiation levels