1650 in science

Astronomy

• In Ursa Major, the handle's middle star, Mizar, is noted to be a binary by Giambattista Riccioli.

Botany

• William How publishes his flora Phytologia Britannica.
• Posthumous publication begins of Johann Bauhin's Historia plantarum universalis at Yverdon.

Geology

• The Kolumbo underwater volcano in the Aegean Sea is discovered when it bursts from the sea and erupts, killing 70 people on a nearby island.

Medicine

• English physician Francis Glisson publishes the first comprehensive pediatric text on rickets, De rachitide sive morbo puerili, qui vulgò The rickets dicitur, the result of collaborative research by members of the Royal College of Physicians.

Technology

• Polish–Lithuanian nobleman Kazimierz Siemienowicz's widely translated manual Artis Magnae Artilleriae, pars prima is published in Amsterdam.

Births

• November 28 - Jan Palfijn, Flemish surgeon and obstetrician
• May 1 - John Radcliffe, English physician approx. date – Thomas Savery, English engineer, inventor of a steam pump

Deaths

• February 11 – René Descartes, French mathematician
• June 30 – Niccolò Cabeo, Italian polymath
• July 18 – Christoph Scheiner, German astronomer
• August – John Parkinson, English herbalist and botanist
• Giovanni [Battista Zupi], Italian astronomer
• Philippe d'Aquin, French physician, hebraist, philologist and orientalist