This textbook investigates the fundamental principles and recent discoveries in astronomy. Informed by current astronomy education research, the Sixth Edition emphasizes active learning through practical engagement with the subject matter. It aims to provide students with a comprehensive understanding of the cosmos, from celestial mechanics to the evolution of stars and galaxies, utilizing an approach grounded in pedagogical best practices.

The Sixth Edition of 21st Century Astronomy, authored by Blumenthal, Kay, and Palen, is presented as an educational resource emphasizing active learning. Its focus on pedagogical research suggests an approach designed to engage students directly with astronomical concepts. The inclusion of recent discoveries indicates a commitment to providing up-to-date information within the field.