The evidence for the Big Bang

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 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.

2. 1.

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

   • Redshifts, the microwave background and light-element amounts
   • The Sun's age, Earth's age and the Moon's age
   • Starlight, sunlight and moonlight
   • Redshifts of one galaxy measured three times by one telescope
3. 2.

   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?

   • Far away means long ago, so early times can be seen
   • Distant light shows what the universe looks like today
   • Distant galaxies are where the explosion was
   • Old light is the microwave background itself
4. 3.

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

   • Agree: debris flew out from one center
   • Disagree: space itself expanded everywhere from a hot, dense state
   • Agree: the Milky Way is near the blast site
   • Disagree: the universe has stayed the same
5. 4.

   Three evidence lines pointing to one explanation. Milo's cousin says the Big Bang is just a theory, meaning nobody really knows. Which response is best?

   • Agree: it has not been tested
   • Disagree: a scientific theory is backed by many tested observations
   • Disagree: theories do not change
   • Agree: theories are guesses that scientists make before they test anything
6. 5.

   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 0.003%
   • About 0.3%
   • About 3%
   • About 30%
7. 6.

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

   • About 3,000 K
   • Hotter than 2.7 K
   • Colder than 2.7 K
   • Exactly 2.7 K
8. 7.

   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 should be older than the universe
   • It shows the universe's age is just a rough guess with no support
   • It shows the stars made the background
   • Stars formed after the universe began, so they must be younger
9. 8.

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

10. Background temperature (NASA, ESA)

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

11. 9.

    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 shorter
    • Unchanged, since light keeps its wavelength
    • About 1,100 times longer
    • About 3 times longer
12. 10.

    Four cards, labeled A to D. Which observation would scientists need before changing the Big Bang model, by Bo's reading?

    • A galaxy with a redshift
    • Someone's opinion that it seems strange
    • Strong, repeated evidence that disagrees with its predictions
    • A single unchecked measurement