CMB-S4

CMB-S4 Next Generation CMB Experiment

high school course

The Cosmic Microwave Background

Welcome to the CMB-S4 course for high school students. This course consists of a series of talks presented by CMB-S4 scientists from across the collaboration. Dr. Kasey Wagoner presents the second talk of the series with a deeper dive into the comic microwave background. 

To start, keep this google form open on another tab and answer the questions after you watch each video. Once you have completed all the sections, submit the form so your answers may be recorded. Your name and email will be collected at the start of the quiz; this will allow us to send each student an electronic certificate of participation.

Course Objectives

II. The Cosmic Microwave Background (CMB)

  1. Overview of CMB
    • Define the Cosmic Microwave Background and its significance in the context of the Big Bang theory.
    • Discuss the role of observatories and satellites in measuring the CMB, such as the Planck satellite and WMAP.
  2. Patterns in the CMB
    • Understand what the different colors and patterns observed in the CMB indicate about the early universe.
    • Explore the implications of angular size vs. temperature fluctuations on the universe’s geometry.
  3. Cosmic Structure and Homogeneity
    • Discuss the homogeneity and isotropy of the universe at large scales.
    • Explore the implications of the cosmological principle for our understanding of the universe.

1 – What is Cosmology?

  1. What is cosmology?
  2. Who coined the term, “The Big Bang”?
    • Albert Einstein
    • Edwin Hubble
    • Fred Hoyle
    • Georges Lemaître
  3. The CMB stands for _____________

2 – The Afterglow of the Big Bang

  1. What was the state of the early universe?
    • A collection of fully formed stars and galaxies.
    • A cold, gaseous cloud of hydrogen and helium.
    • A solid mass with no movement or energy.
    • A hot, dense plasma consisting of quarks and photons
  2. How did the behavior of photons change as the universe cooled down?
    • Photons were able to travel freely through space as the universe cooled, allowing them to decouple from matter.
    • Photons began to interact more frequently with matter, causing them to gain energy.
    • Photons became trapped in a dense fog of particles, unable to travel freely.
    • Photons stopped existing as the universe cooled, leading to a dark and cold universe.
  3. What does the CMB depict?
    • The current temperature of interstellar space
    • The earliest observation of the universe
    • The distribution of galaxies in the universe
    • The gravitational waves emitted from black holes
    • The afterglow of the Big Bang
  4. Where can the CMB be observed?
    • From the South Pole
    • In our solar system
    • Areas where there are high concentrations of dark matter
    • Across the entire sky in every direction
  5. How long after the Big Bang was the CMB emitted?
    • Immediately after the Big Bang
    • Approximately 38,000 years after the Big Bang
    • Approximately 380,000 years after the Big Bang
    • Approximately 38,000,000 years after the Big Bang

3 – The Color of the CMB

  1. A perfect emitter and absorber of all wavelengths of radiation is known as a _______
  2. What kind of blackbody does the CMB resemble?
    • Blackbody at 0.27 K
    • Blackbody at 2.7 K
    • Blackbody at 27 K
    • Blackbody at 270 K
  3. How is the CMB best described at small angular resolutions?
    • Each point on the CMB has a spectrum the shape of a blackbody.
    • Each point on the CMB emits all colors equally
    • Each point on the CMB is monochromatic, emitting only one color.
    • Each point on the CMB emits colors that change randomly over time.
  4. Of the satellites and telescopes that have measured the CMB, which one had the smallest angular resolution?
    • FIRAS (Far-Infrared Absolute Spectrophotometer)
    • COBE (Cosmic Background Explorer)
    • WMAP (Wilkinson Microwave Anisotropy Probe)
    • Planck satellite (Max Planck)
    • Hubble Space Telescople (Edwin Hubble)
  5. What does the red line across the WMAP measurement of the CMB mean?
    • A high-temperature region of the early universe
    • The trajectory of the Andromeda Galaxy
    • The disk of the Milky Way Galaxy
    • The edge of the observable universe

4 – Patterns in the CMB

  1. What does the angular size vs temperature fluctuations plot tell us about the universe?
    • The overall geometry of the universe
    • The number of galaxies in the universe
    • The composition of the universe 
    • The age and expansion rate of the universe
  2. Approximately what angular size creates the largest temperature fluctuations?
    • 0.2॰
    • 0.5॰
    • 1॰
    • 2॰
  3. Navigate to the CMB simulator Kasey used in his talk: https://chrisnorth.github.io/planckapps/Simulator/. What configuration of baryonic matter, dark matter, and dark energy creates the parameters of our universe?

5 – Telescopes 

  1. Why do ground-based telescopes have better resolution than satellite telescopes?
    • Ground-based telescopes avoid the glare of the Sun
    • Ground-based telescopes can be larger
    • Ground-based telescopes are enhanced by Earth’s atmosphere.
    • Ground-based telescopes use more advanced technology 
  2. Which color diagram exhibits a B-mode polarization pattern?
  4. What are the future goals of studying the CMB?
    • Mapping the surface of nearby exoplanets
    • Finding the B-mode pattern to provide evidence for inflation
    • Predicting new light particle species 
    • Measuring the magnetic fields of distant galaxies
    • Learning how galaxy clusters evolved as the universe expanded