Cosmic microwave background

High school (ages 12+)
Space & Astronomy

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/cosmic-microwave-background

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. Who discovered Cosmic microwave background?1965
2. What is the discoverers?Arno Penzias and Robert Wilson
3. What is the key feature?Nearly uniform microwave radiation filling all of space, with tiny temperature anisotropies
4. Why did the CMB become visible only after about 380,000 years?Before that, the universe was a hot, foggy mix of photons, protons, and electrons that scattered light. When it cooled, protons and electrons joined to form hydrogen, letting photons travel freely.
5. How did scientists discover the CMB?In 1965, Arno Penzias and Robert Wilson found a steady microwave signal while trying to reduce noise in a receiver. The signal matched predictions of the Big Bang and earned them a Nobel Prize.

Cosmic Microwave Background (CMB): The relic radiation from the early universe, a faint afterglow of the Big Bang observable today.
Big Bang Theory: The standard cosmological model describing the universe's origin and evolution from an extremely hot, dense state.
Recombination Epoch: The period when the universe cooled enough for electrons and protons to form neutral atoms, making the universe transparent.
Surface of Last Scattering: The conceptual boundary from which the CMB photons we observe were last interacting with matter.