A SCIENCE EXPEDITION / 3 CHAPTERS / 8 STOPS
A Planet Hidden in Starlight
When does a dip in a star’s light become evidence for a planet?
Start with a recurring dip, work with real Kepler observations, and follow the additional measurements that turn an attractive explanation into a stronger scientific case.
90–150 minutes, across several visits. No deadline; each chapter is a natural place to pause.
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EXPEDITION COMPLETE
You followed the evidence.
What extra evidence would you ask for before moving from a recurring dip, or a chemical clue, to a confident planet claim?
Your completion marks record your journey, not a qualification or a test score. Revisit any stop below, or choose another expedition.
Choose another expedition →Chapter 1 · Catch the recurring dip
- 01
Science mystery
Make your first explanation
Ready to exploreFollow the three clues and compare your initial explanation with the discussion. What observation makes a transit plausible?
- 02
Interactive lab
Measure real Kepler starlight
Ready to exploreInspect a dip, compare successive times and stack the observations. Use the optional worksheet, then distinguish your rough estimates from independent confirmation.
Chapter 2 · Ask light a second question
- 03
Interactive lab
Read a spectral fingerprint
Ready to exploreExplore how spectral lines carry information. These line profiles are teaching models, so do not treat them as new observations of TrES-2.
- 04
Interactive lab
Measure motion in shifted light
Ready to exploreExplore wavelength shifts and consider how stellar motion can support a planet interpretation. A single shift alone does not establish an orbit.
- 05
Investigation
Question the habitable-zone shortcut
Ready to exploreFind what a habitable-zone estimate includes and what it leaves out. Does being in the zone establish surface water or life?
Chapter 3 · Separate discovery from possibility
- 06
Investigation
Follow the planet’s history
Ready to exploreCompare water, atmosphere and planetary history. Which additional evidence would change a claim about habitability?
- 07
Evidence File
Examine a possible planet’s evidence
Ready to exploreTrace the chemical evidence at HS 0209+0832. Which observations are established, and where does the possible planet interpretation enter?
- 08
Investigation
Make a careful final judgment
Ready to exploreWeigh the possible second-generation planet interpretation and its alternatives. Contrast this inference with the confirmed TrES-2b system you explored earlier.
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