1596 in science

The year 1596 in science and technology included some significant events.

• David Fabricius discovers the first non-supernova variable star, Omicron Ceti.
• Johannes Kepler's Mysterium Cosmographicum is the first published defense of the Copernican (heliocentric) system of planetary motion.

• Gaspard Bauhin publishes Pinax theatri botanici, an early classified flora.

• Ludolph van Ceulen computes π to twenty decimal places using inscribed and circumscribed polygons.

• William Slingsby discovers that water from the Tewitt Well mineral spring at Harrogate in North Yorkshire, England, possesses similar properties to that from Spa, Belgium.
• Li Shizhen's Compendium of Materia Medica (Bencao Gangmu) is published posthumously in an illustrated edition.

• Abraham Ortelius, in the last edition of his Thesaurus geographicus, considers the possibility of continental drift.

• June 17 – Willem Barents makes the first documented discovery of Spitsbergen in the Svalbard archipelago.^[1]

• John Harington describes the "Ajax", a precursor to the modern flush toilet, in The Metamorphosis of Ajax.

• March 31 – René Descartes (d. 1650), French-born philosopher and mathematician.
• approximate date – Peter Mundy (d. c.1667), English traveller.

• January 27 – Sir Francis Drake (b. 1540), English explorer (at sea).
• September 15 – Leonhard Rauwolf (b. either 1535 or 1540), German botanist and physician.
• September – Pieter Dirkszoon Keyser (b. 1540?), Frisian navigator (at sea).