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?

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

   • Packed into one spot in empty space
   • Exactly the same as today
   • Closer together, hotter and denser
   • Farther apart and colder
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 km, in radio
   • About 1 nm, in X-rays
   • 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?

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

   • The early universe was hot and smooth everywhere
   • It shows galaxies' colors
   • The universe began as a blast at one spot in space
   • It comes from one nearby star
7. 6.

   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 microwave glow in each direction
   • A star clearly older than 13.8 billion years
   • A galaxy with a large redshift
   • A scientist calling the model just a theory
8. 7.

   All-sky map of the background with tiny temperature differences. Why do the tiny temperature differences in the background matter, by Ren's reading (NASA)?

   • They show where the explosion happened
   • They are nearby stars
   • They were seeds that grew into galaxies
   • They are errors made while drawing the map
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?

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

    • About 8 hours ago
    • About 16 hours ago
    • A few seconds ago
    • About 4.6 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?

    • It shows the evidence pieces are the same
    • 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