Why do stars shine in different colors, from deep reds to brilliant blues?

A star's color is a direct reflection of its surface temperature, determined by the physics of blackbody radiation. Hotter stars emit more energy and peak at shorter, bluer wavelengths, while cooler stars emit less energy and peak at longer, redder wavelengths—a relationship defined by Wien's Displacement Law.

By analyzing blackbody radiation curves and identifying specific absorption lines in a star's spectrum, astronomers categorize stars into the spectral sequence: O, B, A, F, G, K, and M.

Watch the video to explore Wien's Law, Planck's Law, and how temperature determines a star's spectral classification.