Chapter 28 Our Solar System

About 99% of all matter contained in the solar nebula now exists in

• Nebula
• sun
• Moon
• planets

Who proposed a heliocentric model of the universe, in which the planets revolve at different speeds around the sun?

• Galileo
• Kepler
• Copernicus
• Newton

The law that describes how a planet orbits the sun is called the

• law of ellipses.
• law of equals
• law of orbital periods
• law of periods

A region of the solar system just beyond Neptune’s orbit, which contains small bodies made mostly of ice, is called

• the Kuiper belt.
• an asteroid belt.
• Quasar.
• the outer atmosphere.

Neptune’s Great Dark Spot is a(n)

• area that never faces the sun.
• ocean
• desert
• storm

The least dense planet in the solar system is

• saturn
• uranus
• pluto
• jupiter

Which planet has volcanic regions that may still be active?

• Mars
• Venus
• jupiter
• moon

Which of the following separates the outer planets from the inner planets?

• Van Allen Belt
• the asteroid belt
• the Great Red Spot
• a large magnetic field

A rotating cloud of gas and dust from which Earth’s solar system formed is called a(n) 

• astronomical explosion.
• solar nebula
• supernova.
• solar eclipse

When the solar system formed, smaller bodies joined together through collision and the force of gravity to form larger bodies called 

• moons
• planetesimals
• planets
• protoplanets