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Discovering the Universe

Have you ever wondered why stars rise and set, or why the sky changes from season to season? It all comes down to how Earth spins and orbits the Sun. Because of Earth’s tilt, different parts of the planet get more or less sunlight at different times of year—that’s what gives us seasons. (Most people think it’s because the Earth gets closer or farther from the Sun, but that’s actually a common misconception.)

As we orbit, our view of the night sky shifts too, so the stars you see in summer are totally different from the ones in winter. The Moon’s changing shape? That’s just sunlight hitting it from different angles as it moves around Earth. And depending on your location on the planet, the stars may appear to move in arcs, rise and set at different angles, or never set at all. As you explore these ideas, you’ll begin to uncover the patterns behind the sky’s motion—and why it’s been such a mystery for thousands of years.

Watch the Science Lesson

RECORDING WILL BE POSTED 09/17/2025

In-Class Activity: Retrograde Motion

Planets normally drift eastward against the stars, but when Earth “overtakes” a slower outer planet (or an inner planet passes between us and the Sun), that planet appears to loop backward briefly—a bit like a faster car passing a slower one on a highway.

Do the Assignments

Homework

Each week, you'll be assigned a set of discussion questions, quantitative problems, and quiz questions. Refer to the Student Handout for the assignment for this week.

Space Podcast

Each week, students choose a space-related podcast episode to listen to and write a short summary in their journal. These reflections help students stay connected to current science news while developing their ability to explain scientific concepts in their own words. 

Astronomer Spotlight - Due this week!

Students will research and present a 5-minute talk and poster about a notable astronomer (past or present), highlighting their discoveries, impact on science, and personal journey. This project includes both a visual component (printed or hand-written poster) and a brief presentation.  

Astronomy Lab: Telescope Resolution

Telescope resolution is simply how sharp your scope’s image can be—how close two stars can sit before they blur into one—and it matters because knowing your resolution helps you pick the right targets and understand exactly what details you can expect to see.

Supplemental Videos

The videos below are short explanations of topics discussed in class.