Lesson 3: Moons, Asteroids, and Comets

How do moons, asteroids, and comets form, and what distinguishes them from planets?

What patterns exist in their distribution and composition throughout the solar system?

How do these smaller bodies help us understand the early conditions of the solar system?

How do collisions and gravitational interactions affect their orbits and evolution?

What observational evidence supports models of small-body formation?

Moon / Satellite

Asteroid

Comet

Kuiper Belt

Oort Cloud

Impact cratering

Differentiation (for larger moons)

Orbital resonance

Meteoroid

Planetary debris

HS-ESS1-2 – Use models and observational evidence to explain the formation, distribution, and characteristics of moons, asteroids, and comets within the solar system.

NGSS Crosscutting Concepts

Cause and Effect

Systems and System Models

Patterns

Stability and Change

Students will interpret orbital diagrams and impact data to support evidence-based explanations.

Students will analyze patterns in the distribution of asteroids, comets, and moons to make predictions about solar system formation.

Students will develop reasoning skills by connecting observational evidence to theoretical models of small-body evolution.

Students will explore the formation and characteristics of moons, asteroids, and comets, examining how they differ from planets and what they reveal about the early solar system. Students will study their orbits, collisions, and interactions, using observational data and models.

Activities may include:

Mapping the location of asteroids (main belt, Trojan asteroids) and comets (Kuiper Belt, Oort Cloud)

Comparing sizes, composition, and orbital patterns of moons and small bodies

Investigating craters and impact history to infer past collisions

Purpose: Reinforce understanding of cause-and-effect relationships in small-body formation, distribution, and evolution, while connecting observations to theoretical models.
DOK Level: 3 – Strategic Thinking / Reasoning (analyzing data and constructing evidence-based explanations)

Connects to NASA and ESA missions such as OSIRIS-REx (asteroid sampling) and Rosetta (comet exploration).

Understanding small bodies helps explain Earth’s impact history, potential asteroid threats, and origins of water and organic materials.

Highlights the role of international collaboration in planetary science and space missions.

Students may think all moons form the same way as planets.

Students may believe comets or asteroids are rare or unimportant to understanding the solar system.

Students may assume craters are only on planets, not realizing small bodies also record impact history.

Students may confuse asteroids and comets or their locations within the solar system.

Scaffolded instruction for interpreting orbital diagrams and small-body data.

Graphic organizers to track characteristics, orbits, and formation mechanisms.

Technology integration: simulations of asteroid and comet orbits, impact events.

Peer collaboration for mapping and analyzing small-body data.

Step-by-step guidance for connecting observations to formation models.

Support for interpreting both visual and numerical data on small bodies.

• Checkpoints during mapping and simulation exercises.

• Quizzes on key vocabulary and small-body concepts.

• Evaluation of student-created diagrams showing moons, asteroids, and comets in the solar system.

• Constructed-response assignments explaining how small bodies provide evidence for early solar system processes.

• Astronomy slides and worksheets on moons, asteroids, and comets

• Orbital diagrams and data tables of small bodies

• Simulations of asteroid and comet orbits and collisions

• Images of moons, asteroids, and comets from Hubble, Rosetta, and OSIRIS-REx

• Articles or case studies on small-body missions and discoveries