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: expansion; background: hot start; elements: early element-making
   • Redshifts: hot start; background: expansion
   • Background: starlight; redshifts: galaxy color
   • 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?

   • Exactly the same as today
   • Closer together, hotter and denser
   • Farther apart and colder
   • Packed into one spot in empty space
4. 3.

   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 1 mm, in the microwaves
   • About 1 nm, in X-rays
   • About 1 km, in radio
   • About 500 nm, in visible light
5. 4.

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

   • The model predicted a leftover glow, and it was found
   • It showed galaxies are moving apart
   • It was starlight from our galaxy
   • It showed the universe has stopped expanding and is now shrinking
6. 5.

   All-sky map of the background with tiny temperature differences. The background is nearly the same temperature in every direction, with only tiny differences (NASA). What does this suggest, by Milo's reading?

   • It shows galaxies' colors
   • The early universe was hot and smooth everywhere
   • It comes from one nearby star
   • The universe began as a blast at one spot in space
7. 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
8. 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 star clearly older than 13.8 billion years
   • A microwave glow in each direction
   • A scientist calling the model just a theory
   • A galaxy with a large redshift
9. 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 oldest stars formed first, from galaxy collisions
   • The first stars formed from Big Bang gas, before much iron existed
   • The Big Bang made mostly iron
10. 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?

    • A few seconds ago
    • About 4.6 hours ago
    • About 8 hours ago
    • About 16 hours ago
11. 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
    • One line would be enough
    • It means the model is just a guess that has not been tested yet
    • It shows the evidence pieces are the same