The Solar System Formation

How old is our solar system?

• 4.6 billion years
• 13.8 billion years
• 6,000 years
• 15,000 years

A celestial cloud of dust and gas is called . . .

• nebula
• supernova
• accretion disc
• bombardment

A massive explosion of a star is called . . .

• supernova
• nebula
• pulsar
• black hole

What caused the solar nebula to contract and spin?

• a supernova
• an asteroid impact
• radiation
• random motion

What celestial body eventually evolved into our modern solar system?

• a nebula
• a supernova
• a quasar
• a galaxy

When the solar nebula spun out into a disc-shape, what direction did it start spinning?

• clockwise
• counter-clockwise

Smaller particles collecting together into larger and larger objects is called . . .

• accretion
• contraction
• explosion
• rotation

Does the gravity of planets cause them to migrate slowly over time?

• Yes, the planets have changed positions
• No, the planets stayed where they formed
• Yes, and they are STILL moving!
• No, planets are too big to move

When the inner planets (and moons) were bombarded by asteroids, what did the asteroids leave behind?

• craters
• calderas
• mountains
• valleys

Why is Mercury covered with craters, but Earth is not?

• Earth's atmosphere protects and weathers
• Earth's moon blocks asteroids
• asteroids just missed Earth
• most asteroids land in Earth's oceans