The year 1609 CE in science and technology consisted of many events, some of which are listed below.

See also: 1608 in science, other events of 1609, 1610 in science, and the list of years in science.

Astronomy

• Johannes Kepler publishes his first two laws of planetary motion

Births

Deaths

• Oswald Croll, German chemist and physician (born c1580)
• Charles de L'Ecluse, (or Clusius), French botanist who published one of the earliest known books on Spanish flora (born 1525)