1509 in science

Exploration

• September 11 – Diogo Lopes de Sequeira reaches Malacca, having crossed the Gulf of Bengal.

  Geology

• September 10 – Constantinople earthquake.

  Mathematics

• June 11 – Luca Pacioli's De divina proportione, concerning the golden ratio, is published in Venice, with illustrations by Leonardo da Vinci.

  Births

• Bernardino Telesio, Italian philosopher and natural scientist
• possible date – Guillaume Le Testu, French privateer, explorer and cartographer

  Deaths

• Juan de la Cosa, Spanish explorer and cartographer