The evidence for the Big Bang

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Spectrum strip with lines shifted far toward red; pie chart of its gas, nearly all hydrogen and helium. A newly measured galaxy has a large redshift, and the gas around it is almost pure hydrogen and helium. Which conclusions fit, by Esme's reading?

   • It is moving toward us, so it is young
   • It is nearby, and its gas was made in supernovas long ago
   • It is red in color and made of iron
   • It is very far away, and its gas is close to Big Bang gas

2. Read this first

   Table, Evidence for the Big Bang (NASA, ESA), with columns Observation, What it shows

   Galaxy redshifts grow with distance, space is expanding; microwave background at about 2.7 K, a hot, dense early universe; mostly hydrogen and helium, a little lithium, early element-making.

3. 2.

   Which list of evidence supports the Big Bang model without relying on any one method, by Jun's reading?

   • The Sun's age, Earth's age and the Moon's age
   • Redshifts of one galaxy measured three times by one telescope
   • Starlight, sunlight and moonlight
   • Redshifts, the microwave background and light-element amounts
4. 3.

   Light from very distant galaxies left them billions of years ago. Why does that let astronomers test the Big Bang model, by Kira's reading?

   • Distant galaxies are where the explosion was
   • Old light is the microwave background itself
   • Far away means long ago, so early times can be seen
   • Distant light shows what the universe looks like today
5. 4.

   Luz's friend says the Big Bang was an explosion at one spot in empty space. Which response is best?

   • Disagree: space itself expanded everywhere from a hot, dense state
   • Disagree: the universe has stayed the same
   • Agree: debris flew out from one center
   • Agree: the Milky Way is near the blast site
6. 5.

   Noah's friend says the microwave background is just the glow of all the stars. Which response is best (NASA)?

   • Agree: it comes from the stars of the Milky Way galaxy
   • Agree: starlight adds up to it
   • Disagree: it comes from Earth's atmosphere
   • Disagree: it was released before any stars existed
7. 6.

   The background light set off about 380,000 years after the start. What fraction of the universe's 13.8 billion years is that, by Pia's math?

   • About 3%
   • About 30%
   • About 0.3%
   • About 0.003%
8. 7.

   If the universe were much older than 13.8 billion years, what would the background's temperature be today, by Ren's reading?

   • Colder than 2.7 K
   • Exactly 2.7 K
   • About 3,000 K
   • Hotter than 2.7 K
9. 8.

   The Planck mission gives about 13.8 billion years, and the oldest stars measured are a little younger. Why does that fit, by Tala's reading?

   • Stars formed after the universe began, so they must be younger
   • It shows the stars made the background
   • Stars should be older than the universe
   • It shows the universe's age is just a rough guess with no support
10. 9.

    Four prediction cards, labeled A to D. Which prediction does the Big Bang model make about very distant, early galaxies, by Zee's reading?

    • They should hold fewer heavy elements
    • They should sit at the center of the universe
    • They should show blueshifts
    • They should hold more iron than the Sun

11. Background temperature (NASA, ESA)

    Time	Temperature
    at release	about 3,000 K
    today	about 2.7 K

12. 10.

    The background was about 3,000 K at release and is 2.7 K now. Its wavelengths have stretched by about what factor, by Ari's math?

    • About 1,100 times longer
    • About 3 times longer
    • Unchanged, since light keeps its wavelength
    • About 1,100 times shorter