← Back to Astronomy
Astronomy: The universe from your backyard
Astronomy lets you read the universe with nothing but light, patience and honest measurement.
Light as the messenger
Every wavelength carries physics: a spectrum reveals composition, temperature and motion of objects we will never touch. Telescopes are time machines; distance is lookback time.
Gravity builds structure
Kepler’s laws and Newtonian gravity link orbits to mass. The same law that drops an apple also shapes galaxies, which is the whole magic of the theory.
F = G·m₁m₂/r²What this course teaches
Nine units: the sky and its motions, orbits and gravity, light and telescopes, the solar system, stars, stellar evolution, the Milky Way, galaxies, and cosmology.
Flashcard
v = H₀d
Hubble’s law of expansion
Recession velocity grows with distance; the constant itself is the expansion rate and the age of the universe’s fingerprint.
Check your understanding
A star’s spectrum shows the same lines, redshifted. That indicates: