Full Name: Johannes Kepler; Profession: Astronomer, mathematician, natural philosopher; Nationality: German (Holy Roman Empire); Born: December 27, 1571; Birthplace: Weil der Stadt, Württemberg, Holy Roman Empire (modern Germany); Generation: Late Renaissance/Scientific Revolution; Chinese Zodiac: Metal Pig; Zodiac Sign: Capricorn; Age in 2025: Deceased (died November 15, 1630, aged 58); Marital Status: Married twice (to Barbara Müller, then Susanna Reuttinger); Children: Several children from his marriages, with only some surviving to adulthood; Description: Johannes Kepler was a pioneering astronomer whose work on planetary motion helped transform the understanding of the cosmos and laid the groundwork for Isaac Newton’s laws of gravitation. Initially trained in theology and mathematics, he became an assistant to Tycho Brahe and inherited Brahe’s precise observational data, which he used to discover that planets move in ellipses rather than perfect circles. His three laws of planetary motion—relating elliptical orbits, equal areas in equal times, and the relationship between orbital period and distance—provided a mathematically elegant description of the solar system that supported and refined the Copernican heliocentric model. Kepler’s work integrated rigorous mathematics with a deep philosophical and, at times, mystical interest in harmony and order in the universe, as seen in his books “Astronomia nova” and “Harmonices Mundi.” He also contributed to early optics, explaining how lenses form images and improving telescope design, and he engaged with issues of calendars and chronology. Despite personal hardships, religious conflict, and financial difficulties, Kepler’s persistence and intellectual courage made him a central figure in the Scientific Revolution. Today his name is associated with space exploration missions and fundamental astronomical concepts, underscoring his continuing relevance.