What ginormous object creates stars?

• Big bang

• Frost line

• Nebula

• Oort cloud

What is a nebula made of?

• light

• gas

• rocks

• gas and dust

What could make a nebula begin to form stars?

• An exploding star

• Planets colliding

• A passing asteroid

• Nuclear fusion

What force causes the nebula to collapse?

• Nuclear fusion

• Gravity

• Black hole

• Electromagnetism

What happens once the nebula begins to spin?

• a completely flat disk forms

• all the material collects in the middle

• the newborn sun blows out all the material into space

• a planetary disk forms with a bulge in the center.

What are the inner planets made of (primarily)?

• hydrogen and helium

• rock

• ice

• gas

Why are the inner planets smaller?

• they are more dense

• they are the same size as the outer planets

• less material to make them -- (the nebula had lots of gases)

• rock is more compact

What formed between the outer planets and the inner planets?

• the comet belt

• the asteroid belt

• Kuiper belt

• Oort cloud

What are the outer planets made of?

• rock

• Carbon dioxide

• gas and ice

• oxygen

why are the outer planets so large?

• there's less gravity

• they are the same size as the inner planets

• gas spreads out more

• there's more material to make them