Home  › Units  › Unit 1: Earth and Universe

Unit 1: Earth and Universe (Habitability and Systems)

Is Earth special, or is it one of many habitable planets we just haven't found yet?

Runs Thu Sep 3 – Fri Oct 23

Five weeks. We zoom out. Earth as one planet among many. Mars as the failed-habitable case. A student-chosen exoplanet as the unknown. You build a habitability framework, apply it to all three, and defend your verdict to a NASA evaluation committee.

Reference Unit 1 calendar: when each block runs
Meeting dates for each block in Unit 1, by rotation
Block A rotation B rotation
Block 1 Thu Sep 3 Fri Sep 4
Block 2 Mon Sep 7 Tue Sep 8
Block 2b Wed Sep 9 Thu Sep 10
Block 3 Fri Sep 11 Tue Sep 15
Block 4 Wed Sep 16 Thu Sep 17
Block 5 Fri Sep 18 Tue Oct 6
Block 6 Mon Oct 5 Thu Oct 8
Block 7 Wed Oct 7 Mon Oct 12
Block 8 Fri Oct 9 Wed Oct 14
Block 9 Tue Oct 13 Fri Oct 16
Block 10 Thu Oct 15 Fri Oct 23

Your section follows one rotation, A or B. Check which one you are in and read that column.

Words for this unit

Learning in English? Start with the key words. Unit 1 key words, with sentence starters · the same words in Tamil, Hindi, French, Korean and Japanese

What you should be able to say by the end

Habitability emerges from interactions among a world's systems rather than from any single condition.

Questions that get you there

Unit 1 launches Thread 2: Systems thinking formally, with the first student-built systems diagram of Earth's subsystems. It also extends Thread 1: OPVL and AI Documentation from Unit 0 to planetary data sources: NASA exoplanet archive entries, peer-reviewed astronomy summaries, AI explanations of habitability.

The unit anchors on three cases: Earth (the baseline), Mars (the failed-habitable case that shows how easily habitability can be lost), and one exoplanet of the student's choosing (the unknown). The summative, the Goldilocks Report, is the structured comparative analysis. The Stakeholder Q&A in Block 10 introduces the audience-defense format students will use in every subsequent unit summative.

The A and B rotations meet the Discover India Week break at different points in this unit, so check the calendar rather than assuming your neighbour's dates.

Scale is genuinely beyond intuition for most learners. Every cosmic claim in this unit is anchored to a comparison students can grasp: Chennai-to-Mumbai, an A4 page, a school year.

The ten blocks

Block 1: Phenomenon Launch
What makes a planet habitable? Side-by-side images of Earth, Mars, Venus, and TRAPPIST-1e. Students list factors before the unit teaches them anything.
A: Thu Sep 3 · B: Fri Sep 4
Block 2: Earth as Baseline
Systems thinking launches. Students name Earth's four subsystems and draw a first systems diagram with at least one interaction.
A: Mon Sep 7 · B: Tue Sep 8
Block 2b: Earth Systems, Second Pass
Same target as Block 2, one path, nine steps with a "done when" line on each. No AI partner, no readings. Added after Block 2 asked for too much at once.
A: Wed Sep 9 · B: Thu Sep 10
Block 3: Mars as Calibration
Compare Earth and Mars. What Mars had, what it lost, why. Apply the early habitability framework to Mars and identify where it fails.
A: Fri Sep 11 · B: Tue Sep 15
Block 4: Scale of the Cosmos
AU, light-year, habitable zone. Students place 5+ objects at correct relative scale. Goldilocks Report assigned today.
A: Wed Sep 16 · B: Thu Sep 17
Block 5: Exoplanet Detection
Transit method. What a light curve tells us (size, period) and what it doesn't (composition, life). Read a real transit dip.
A: Fri Sep 18 · B: Tue Oct 6
Block 6: Choose Your Exoplanet
Work through the 8 exoplanet data cards. Pick one for the Goldilocks Report. Identify two questions you'll need to answer.
A: Mon Oct 5 · B: Thu Oct 8
Block 7: Habitability Framework
Complete the Habitability Framework Template for all three planets. Color-code each criterion MEETS / PARTIAL / FAILS with reasoning.
A: Wed Oct 7 · B: Mon Oct 12
Block 8: Drafting Day
First full draft of the Goldilocks Report. ≥4 sources cited (incl. NASA Exoplanet Archive). AI Documentation section completed.
A: Fri Oct 9 · B: Wed Oct 14
Block 9: Stakeholder Q&A Prep
Rehearse against the Q&A bank in pairs. Identify the strongest objection to your verdict and prepare your response.
A: Tue Oct 13 · B: Fri Oct 16
Block 10: NASA Committee Defense
Defend the Goldilocks Report to peers playing the NASA evaluation committee. Unit reflection.
A: Thu Oct 15 · B: Fri Oct 23

Assessment

Goldilocks Report
Build a habitability framework. Apply it to Earth, Mars, and a chosen exoplanet. Defend the verdict to a peer NASA evaluation committee. Report due Block 9. Defense Block 10.

AI partners for this unit

The Planet Hunter
Socratic reasoning about specific exoplanets. Pushes you to define what habitability means before evaluating any planet.
The Systems Diagrammer
Systems-thinking coach. Helps you build and refine systems diagrams with explicit feedback-loop sign-and-direction work.
The Source Evaluator
OPVL on any planetary data source: NASA archive entries, pop-sci articles, AI explanations of astronomy.
The Skeptic
Stress-test your Goldilocks Report verdict before the Stakeholder Q&A.

Resources for this unit

Earth as a Planet
The shared baseline: what Earth is made of, where its air came from, and how we know. Three carousels adapted from OpenStax. Decks 1 and 2 are assigned in Blocks 2 and 3; deck 3 is an extension.
Readings
Text alternatives to the four Watch videos, same content and depth: How Far Is Far · Four Spheres, One System · How Mars Lost Its Air · Watching for Shadows
Background readings
Homework, read before the block, worked in class. Each one ends with three questions to bring with you: Where Your Atoms Came From (Block 1) · Life Needs Matter to Move (Block 2) · How We Know How Old Everything Is (Block 4)
Systems Gallery
Twelve real interactions between Earth's spheres, six in Chennai, each with its first arrow written and a source to cite. Where to go once you have one loop from Block 2b. The nine steps themselves are pictured in Build Your First Systems Diagram.
Goldilocks Report: Lock-Point Exemplars
Four worked examples for the four places a band most often gets lost. Off-assessment content on purpose. One flaw is planted; find it.
Habitability Zone Calculator
A multi-criteria simulator for the Goldilocks Report. 12 preset planets, Compare mode, and an Export that feeds the AI Documentation Template.
Foundational Papers: Lovelock 1965 + Thompson 2022
The biosignature lineage behind the Goldilocks framework: atmospheric disequilibrium as the signature of life. First OPVL'd in U0 Block 2; Thompson's TRAPPIST-1e methane work returns in Blocks 5 + 7. PDFs in Google Classroom.
OPVL Framework
Returning from Unit 0: now applied to planetary data sources.
AI Documentation Protocol
Required for every AI conversation that feeds into the Goldilocks Report.
The Rubric
K/U / T/T / C across all four bands. C strand carries the Stakeholder Q&A weight.
U1 EAL Pre-Teach
15-term vocabulary handout: habitability, habitable zone, exoplanet, magnetic field, systems thinking. Multilingual reference linked.