Teacher’s Questions for The Dark Side of the Universe



Before Reading:

  1. What is our universe made up of?
  2. Do you know what dark matter or dark energy are? Can you make some guesses about what they might be?
  3. What is gravity?


During Reading:

  1. What is “star stuff”? Name a few examples of star stuff.
  2. What does the “dark” in dark matter and dark energy refer to?
  3. What is the majority of our universe made up of: dark energy, dark matter, or star stuff? How much of our universe is made up of star stuff?
  4. Did Fritz Zwicky discover that dark matter increased or decreased a galaxy cluster’s total mass?
  5. Do scientists think dark matter particles are very small or very large?
  6. Name two differences between star stuff and dark matter particles.
  7. Name one kind of particle that is a strong candidate for dark matter.
  8. Name one big way in which dark matter and dark energy are different from each other.
  9. What kind of cosmic event helped scientists discover dark energy?
  10. Is our universe expanding or shrinking? Is the universe expanding at a rate that is accelerating or decreasing?


After Reading:

  1. What force of nature led scientists to discover dark matter? (Hint: It’s the same force of nature that keeps you on the ground.)
  2. How do scientists know that dark matter and dark energy exist? What kinds of clues to the existence of dark matter and dark energy have researchers found?
  3. In what ways are scientists “looking” for dark matter? How are scientists “looking” for dark energy?



  1. Can you think of other things that humans can’t see but know exist?
  2. Is it important to study things that are invisible? What can invisible things tell us about our world and ourselves?