Bell ringer: start here (while attendance happens)
Phenomenon hook · 5 min

Side-by-side images: Earth, Mars, Venus, and a recently discovered exoplanet (TRAPPIST-1e) all rendered as round planets. No labels.
Task: Which of these could support life? How would you decide? What do you need to know that you don't?
Open Four Planets, No Labels; that page IS this bell ringer.

Answer in your Field Notebook, dated.

Today we are learning

I can list at least 5 factors that might affect whether a planet supports life.

I can: tick as you go (for you, not for marks)
full course map →
AI Partners available for today's work
Remember: every AI use gets documented. → AI Documentation Template

What today is about

The question that drives the whole unit: What does a planet need to support life?

Today we open Unit 1 by zooming all the way out. Before we define habitability, before we name conditions, before we touch any vocabulary, we look. Four planets, no labels. You decide which could support life and how you'd know.

Carry-forward from Unit 0: remember Lovelock (1965) from Unit 0 Blocks 2 + 3, the paper that proposed detecting life by reading a planet's atmosphere for chemical disequilibrium? Meeting it again here isn't a coincidence. "How would we recognize life elsewhere?" is the same question as "what makes a planet habitable?", asked from the other side. The modern follow-up you previewed, Thompson et al. (2022), is literally about TRAPPIST-1e, one of the planets in today's image set. Today's launch isn't a new framework; it's the same OPVL muscle you built in U0, applied to a new question. You'll work with new sources this unit (NASA archive entries, peer-reviewed astronomy papers, AI explanations of habitability), and Lovelock + Thompson return when you build your habitability framework. Every U1 source gets OPVL'd the same way you OPVL'd Lovelock in U0.

The point of today isn't to be right. It's to surface what you already believe, and the gaps in what you know. Whatever five factors you list at the end of class become the seed of the framework you'll build, test, and defend over the next ten blocks.

By Block 10 you'll deliver the Goldilocks Report: a structured comparison of Earth, Mars, and a chosen exoplanet against your own habitability criteria, defended to peers playing a NASA evaluation committee. That's where this question goes. Today is where it starts.

Before you start the work

Start with the Four Planets gallery: it is today's phenomenon. The Read is the assessment you are building toward, and the carry-forward is the Unit 0 paper this connects to. Notes go in your Class Notebook as a Power outline.

Taking notes? Power 1 seeds for today
four planets, four image types · what habitability needs · the format
Video preview: The Known Universe (AMNH)
Watch (6:32)
One continuous zoom (Himalayas to the afterglow of the Big Bang and back) rendered from real survey data (the Digital Universe Atlas), not artist's imagination. That distinction matters today.
Read
Goldilocks Report: the destination for this unit. Read just Sections 1 and 2 today: what it is, and the eight exoplanets you'll choose from.
Four Planets, No Labels
The launch gallery: four unlabeled disks, flip-to-reveal after question 3.
Read: Where Your Atoms Came From
Read before class. Bring your three answers.
Extension: the factor nobody lists
When your list of habitability factors is on the board, go and see the one that almost never makes it up there.
Carry-forward from U0
Lovelock (1965) + Thompson et al. (2022) from U0 Block 2: the biosignature lineage behind this whole unit (atmospheric disequilibrium as the signature of life). Your U0 OPVL doesn't expire; both papers return when you build your habitability framework in Block 7.

Today's work: looking before naming

Whole-class activity. No choice board today; we work this together so everyone's first list of factors is shared evidence we can build on in Block 2.

Learning Intention: I can list at least 5 factors that might affect whether a planet supports life.
1
What can you see?
Project the four round, unlabeled planets: Earth, Mars, Venus, TRAPPIST-1e. Students name what they observe (color, size apparent, surface features) before any inference. Observation only.
2
What can you guess?
Same four planets, now with the question: which of these could support life, and how would you decide? Whole-class discussion. Capture every reason offered on the board; no judging right or wrong yet.
3
What would you need to know?
Final move: what data is missing? What would you need to measure or look up before answering with confidence? This gap list becomes the unit's question bank; we'll return to it in Block 10.

Open your Class Notebook and type today's entry header as Heading 2:

A: Sep 3 | U1 B1 | What Makes a Planet HabitableB: Sep 2 | U1 B1 | What Makes a Planet Habitable

What you're submitting today

Exit ticket: formative. Not graded against the rubric today; this is the K/U vocabulary we'll keep building all unit.

Exit ticket (submit by end of class)

Name at least 5 factors that might affect whether a planet supports life, and one thing you want to learn in this unit. Bullet list is fine.

Submit via Google Classroom (link posted in August)

Rubric link: Today is formative: no scored band. We're seeding the K/U vocabulary that the rubric will use once we're scoring (starting at the Goldilocks Report).

One question before you leave

Three to five minutes. Your answer is saved to your reflection journal, where you can read back everything you have written this year.

No grade. Save it; we'll come back to your "now I think…" sentence in Block 10 and see how it changed.

Today's reflection is in Google Classroom, under Reflection Journal.

Link posted in August

Sign in with your school account. Your teacher can see what you write here.