Finding Exoplanets · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Finding Exoplanets

Science · Space Exploration · ages 11-13
Name ______________________   Date ____________

  1. What is the habitable zone around a star?

    • A distance range where every planet already has living things
    • A distance range where surface liquid water could exist
    • A distance range where all planets have the same temperature

  2. What does the transit method look for to find a planet around another star?

    • Small brightness dips that return at regular intervals
    • Large brightness rises that return at regular intervals
    • Whole-star colour changes that return at regular intervals

  3. Finding oxygen by itself in a planet's atmosphere proves that life exists there.

    Circle one:   True   False

  4. During a transit, a star's brightness reading drops from 1000 units to 990 units. How many units did it dip by?

    Answer: ______________

  5. Continuous monitoring finds matching dips beginning on days 9, 18 and 27, with no matching dips between them. If one planet causes these transits, which explanation fits?

    • A possible transit every 18 days, needing further checks
    • A possible transit every 3 days, needing further checks
    • A possible transit every 9 days, needing further checks

  6. A star's spectral lines repeatedly shift toward shorter wavelengths, then longer wavelengths. What possible planet-related cause does the radial velocity method test?

    • An orbiting planet may pull the star toward and away from us
    • An orbiting planet may hide the star for the whole of its orbit
    • An orbiting planet may turn the star's entire surface red and blue

  7. Astronomers find substantial amounts of oxygen and methane, plus water vapour, in a planet's atmosphere. Why investigate this combination as a possible clue to life?

    • The gases prove life, without checking the planet or its star
    • The gases prove surface oceans, without measuring temperatures
    • The gases may need fresh sources, which could include life

  8. Mia says, 'One dip in a star's brightness proves that a planet orbits it.' Which response explains why she needs more evidence?

    • One dip gives the planet's complete orbit and proves it exists
    • One dip has other possible causes and needs follow-up
    • One dip proves an orbit, even if every later reading is steady
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Answer key

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

Finding Exoplanets W1-mt_UjuriPLVgT-s1

  1. A distance range where surface liquid water could exist · The zone concerns possible surface liquid water with suitable conditions. It does not guarantee water, equal temperatures or life.
  2. Small brightness dips that return at regular intervals · A transiting planet blocks some starlight. Recurring brightness dips are a clue that astronomers investigate further.
  3. False · Non-living processes can produce oxygen. Other observations and checks are needed to investigate possible life.
  4. 10 · Subtract the during-transit reading from the usual reading: 1000 - 990 = 10 units.
  5. A possible transit every 9 days, needing further checks · Both gaps are 9 days: 18 - 9 = 9 and 27 - 18 = 9. A 9-day orbit fits the stated one-planet explanation.
  6. An orbiting planet may pull the star toward and away from us · Motion toward and away from us shifts spectral lines in opposite directions. A planet's gravitational pull can produce that motion.
  7. The gases may need fresh sources, which could include life · Chemical reactions can remove oxygen and methane. Substantial amounts together may need continuing sources, but living and non-living explanations must be tested.
  8. One dip has other possible causes and needs follow-up · Dust or a measurement error could cause a single dip. Follow-up observations can look for recurrence and test other explanations.
Worksheet · LightMySky