The Life of Stars
What a star is, how fusion powers it, how to read the HR diagram, what star colors mean, how we measure distance with parallax, and how stars die as white dwarfs, neutron stars or black holes. Ends with a quiz.
High School · Science
Astronomy
Every point of light is a message that left home long ago.
Astronomy is the science of everything beyond Earth's atmosphere: planets, stars, galaxies and the universe as a whole. It is also one of the oldest sciences. People tracked the stars for calendars and navigation long before telescopes existed.
What makes astronomy strange is that we almost never get to touch what we study. Nearly everything we know comes from light: how bright it is, what color it is and how it shifts over time. These lessons show you how to read that light.
Units
How do astronomers know anything?
A star is far too distant to visit. So astronomers measure its light. Brightness, combined with distance, tells you how much energy a star really gives off. Color tells you its surface temperature. Tiny shifts in position over a year tell you how far away it is.
Put those clues together for many stars and patterns appear. Those patterns let us work out how stars are born, how long they live and how they end. The first unit walks you through each clue.
About these lessons
These free lessons are written for high school students and anyone curious about the sky. Facts are checked against NASA and ESA sources, which are listed at the end of each unit. All drawings are original SVG art made for Jugami.