Galaxies & the Universe
📋 What it is
A galaxy is a huge gravity-bound collection of stars, gas and dust; the universe holds billions of them.
🗣️ Coach says
Zoom way out and stars gather into galaxies — vast pinwheels or blobs of billions of stars bound by gravity, often around a giant black hole. Our Milky Way is one galaxy among hundreds of billions in the observable universe.
🧠 Memory hook
Stars → galaxies → the universe. We live in one galaxy (the Milky Way) among billions.
😂 Giggle
What's an astronomer's favorite key on the keyboard?
The space bar!
😲 Whoa!
There are more stars in the observable universe than grains of sand on every beach on Earth — by a huge margin.
✅ Quick check: What is a galaxy, and what galaxy do we live in?
Say your answer out loud first — then reveal.
A galaxy is a gravity-bound collection of billions of stars, gas and dust; we live in the Milky Way.
Galaxies are the large-scale "cities" of stars; ours is the Milky Way.
🧪 Try it! (2 minutes)
Sprinkle salt/sugar in a loose spiral on dark paper — a mini galaxy. Each grain = billions of stars.