Formation of the universe
What two things did the Big Bang create?
Matter and energy.
What is the shape of our solar system?
Answer: A disk.
What is a galaxy?
Answer: A huge collection of stars, dust, and gas.
Define "condensed".
Answer: Compressed or made smaller.
What are asteroids?
Answer: Small rocky objects that never formed into planets.
What event describes the beginning of the universe?
The Big Bang.
How old is our solar system?
Answer: 4.6 billion years
How many galaxies are estimated to be in the universe?
Answer: Hundreds of billions.
Define "molecule".
Answer: Bonded groups of atoms
How do we know about the formation of the solar system?
Answer: Through analysis of comets and asteroids.
What is the first element formed after the Big Bang?
Hydrogen.
What is a nebula?
Answer: Dense clouds of gas.
What force pulls nebulas together?
Answer: Gravity.
Define "nuclei".
Answer: The center of an atom.
What are planetesimals?
Answer: Small objects formed from gas and dust that combined to form planets.
Why were there no whole atoms in the early universe?
It was too hot.
Why are the inner planets rocky?
Answer: Stellar winds blew away gases from the inner planets.
What happens during nuclear fusion?
Answer: Nuclei combine to form larger atoms and release energy.
Define "Big Bang".
Answer: The event when the universe expanded from a tiny point.
Why is Pluto no longer considered a planet?
Answer: It is now classified as a Kuiper Belt Object.
Who provided evidence for the Big Bang in 1929?
Edwin Hubble.
What are Kuiper Belt Objects?
Answer: Icy planetesimals beyond Neptune.
What are the differences between terrestrial and gas planets?
Answer: Terrestrial planets are rocky; gas planets are gaseous with small rocky cores.
Define "asteroid".
Answer: Small rocky objects orbiting the Sun.
Describe the evidence for the Big Bang in your own words.
Answer: Explanation should include that the universe is expanding, indicating it was once closer together.