The year 1920 in science and technology consisted of many events, some of which are included below.

Biology

• Andrew Douglass proposes dendrochronology dating.

Meteorology

• Milutin Milankovic proposes that long term climatic cycles may be due to changes in the eccentricity of the Earth's orbit and changes in the Earth's obliquity.

Physics

• Meghnad Saha states his ionization equation
• Albert Einstein delivers his Leiden Lecture (http://www.spaceandmotion.com/Physics-Albert-Einstein-Leiden-1920.htm)
• Ernest Rutherford predicts the existence of the neutron.
• Arthur Eddington's observation of a total eclipse of the Sun seems to confirm the "bending of light" in Einstein's theory of Special Relativity.
• James Jeans discovers that the dynamical constants of motion determine the distribution function for a system of particles.

Technology

• The first transatlantic two-way radio broadcast is made.
• First domestic radio sets come to stores in USA – Westinghouse radio costs $10

Nobel Prizes

• Charles Edouard Guillaume is awarded the Nobel Prize for Physics
• Schack August Steenberg Krogh is awarded the Nobel Prize for Medicine
• Walther Hermann Nernst is awarded the Nobel Prize for Chemistry

Births

• January 2 - Isaac Asimov (d. 1992), author.
• February 7 - An Wang (d. 1990), computer designer.

Deaths

• February 20 - Robert Peary (b. 1856), American polar explorer.
• June 14 - Max Weber (b. 1864), sociologist.