Kepler

Kepler may refer to several topics in science and space. The most prominent is Johannes Kepler (1571–1630), a German astronomer, mathematician, and a key figure in the scientific revolution. Kepler formulated three laws of planetary motion, describing how planets orbit the Sun in ellipses, how a line connecting a planet and the Sun sweeps out equal areas in equal times, and how orbital periods relate to their distances from the Sun. His works include Astronomia nova (1609), Harmonices mundi (1619), and the Epitome of Copernican Astronomy (1622), and he contributed to optics and the development of the scientific method.

Another widely known usage of the name is the Kepler Space Telescope, a NASA mission launched in 2009 to discover exoplanets via transit photometry. It monitored the brightness of about 150,000 stars in the constellations Cygnus and Lyra, searching for periodic dips caused by planets passing in front of their stars. Kepler has confirmed thousands of exoplanets and many more candidates, enabling large-scale studies of planetary systems and occurrence rates. The primary mission ended in 2013 after the failure of reaction wheels; the spacecraft continued as the K2 mission, repurposed to observe different fields using solar radiation pressure, until 2018. Data from Kepler remain central to exoplanet science.

In addition to people and instruments, the name Kepler appears in other scientific and cultural contexts and is recognized as a surname of German origin, honoring the legacy of Johannes Kepler in astronomy and related fields.