The evidence for the Big Bang

Grade 9 Science Worksheet

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.

   Match each observation to what it supports. Which pairing is right, by Bo's reading?

   • Redshifts: hot start; background: expansion
   • Background: starlight; redshifts: galaxy color
   • Redshifts: expansion; background: hot start; elements: early element-making
   • Elements: expansion; redshifts: element-making
3. 2.

   Timeline with galaxies drawn closer together further back in time. If galaxies are moving apart today, what was the universe like long ago, by Esme's reading?

   • Farther apart and colder
   • Exactly the same as today
   • Packed into one spot in empty space
   • Closer together, hotter and denser

4. Background temperature (NASA, ESA)

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

5. 3.

   The background light was about 3,000 K when released and is about 2.7 K now. By about what factor has space stretched, by Jun's math?

   • About 1,100
   • About 0.0009
   • About 11
   • About 3,003
6. 4.

   Peak = 2,898,000 nm·K ÷ temperature; 2.7 K. Using peak = 2,898,000 nm·K ÷ temperature, where does 2.7 K background light peak, by Kira's math?

   • About 500 nm, in visible light
   • About 1 nm, in X-rays
   • About 1 mm, in the microwaves
   • About 1 km, in radio
7. 5.

   The background was found in 1965 by Penzias and Wilson (NASA). Why was it strong evidence, by Luz's reading?

   • It was starlight from our galaxy
   • The model predicted a leftover glow, and it was found
   • It showed the universe has stopped expanding and is now shrinking
   • It showed galaxies are moving apart
8. 6.

   As the universe expands, what happens to the background's temperature over time, by Noah's reading?

   • It keeps falling
   • It jumps up and down each year
   • It keeps rising
   • It stays at 3,000 K
9. 7.

   Four cards, labeled A to D. Which of these would most weaken the Big Bang model if it were found, by Pia's reading?

   • A scientist calling the model just a theory
   • A microwave glow in each direction
   • A star clearly older than 13.8 billion years
   • A galaxy with a large redshift
10. 8.

    Hydrogen and helium make up nearly all the atoms in the oldest stars, which have very little iron. What does this support, by Tala's reading?

    • Old stars have used up their iron
    • The first stars formed from Big Bang gas, before much iron existed
    • The oldest stars formed first, from galaxy collisions
    • The Big Bang made mostly iron
11. 9.

    If the universe's 13.8 billion years were one 24-hour day, about how many hours ago did the Sun form (4.6 billion years ago), by Zee's math?

    • About 16 hours ago
    • About 4.6 hours ago
    • A few seconds ago
    • About 8 hours ago
12. 10.

    Three evidence lines pointing to one explanation. Three independent lines of evidence all point to the same model. Why does that matter, by Ari's reading?

    • Independent agreement makes the explanation much stronger
    • It means the model is just a guess that has not been tested yet
    • One line would be enough
    • It shows the evidence pieces are the same