Choose a course designed around topics commonly taught at an approximate age or learning level. This is not school placement or equivalency; start where you feel comfortable and choose another course at any time.
2levels
Freealways
A
Choose a level
Each level builds on the one before. Start wherever feels comfortable.
Orbits and gravity, light and telescopes, the solar system, the Sun and the stars, how stars live, die and make the elements, galaxies and the Big Bang, and the search for life, measured with the numbers astronomers use.