Red-Shift and the Expanding Universe · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Galaxies rushing away

Science · Space Systems & Earth's History · ages 15-16
Name ______________________   Date ____________

  1. What pattern links distance and red-shift?

    • Farther galaxies show bigger shifts
    • Nearer galaxies show bigger shifts
    • Distance makes no difference

  2. What does red-shift mean for a galaxy's light?

    • Its lines shift toward longer redder wavelengths
    • Its light turns off
    • Its lines shift toward shorter bluer wavelengths

  3. What does the distance pattern imply?

    • Galaxies are shrinking
    • Space itself is expanding
    • Light is slowing down

  4. Why did proving other galaxies matter?

    • It gave red-shift its stage with real distances
    • It showed stars are cold
    • It ended all telescopes

  5. Why does the siren analogy help?

    • Sirens prove sound is light
    • Sirens are red
    • A dropping pitch matches stretching waves from a leaving source

  6. What is the microwave afterglow?

    • Heat from the Sun
    • Faint microwaves from every direction left by the hot start
    • Signals from phones

  7. Why do two independent lines of evidence harden the case?

    • Two teams share funding
    • A fluke is unlikely to strike twice in matching ways
    • Longer textbooks sell better

  8. One shifted galaxy alone would settle the expanding universe.

    Circle one:   True   False

LightMySky · lightmysky.comW1-mt_JeAfpxw49W-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Galaxies rushing away W1-mt_JeAfpxw49W-s1

  1. Farther galaxies show bigger shifts · Hubble found shift growing with distance.
  2. Its lines shift toward longer redder wavelengths · The whole barcode slides toward the red end.
  3. Space itself is expanding · Everything rushing apart means an expanding universe.
  4. It gave red-shift its stage with real distances · Without far distances, shifted light meant little.
  5. A dropping pitch matches stretching waves from a leaving source · Both are waves stretched by a rushing source.
  6. Faint microwaves from every direction left by the hot start · It is a second witness that never met Hubble.
  7. A fluke is unlikely to strike twice in matching ways · Independent agreement is far harder to dismiss.
  8. False · A single result could be dust or odd motion.
Worksheet · LightMySky