Which physicist won the 1936 Nobel Prize for discovering cosmic rays?

Victor Hess won the 1936 Nobel Prize in Physics for the discovery of cosmic radiation, commonly called cosmic rays.

Hess made the breakthrough through a series of balloon flights in 1912. He carried electroscopes high above Earth and found that ionizing radiation increased dramatically with altitude, especially during a near-total solar eclipse. This showed that the radiation was arriving from space rather than coming mainly from radioactive materials in the ground.

The Nobel committee shared the 1936 Physics Prize between Hess and Carl David Anderson. Anderson was honored for discovering the positron, the antimatter counterpart of the electron, using cloud-chamber experiments. Their achievements were related to high-energy physics but were separate discoveries.

A common mix-up is to call Hess the discoverer of the positron. That was Anderson’s work. Hess’s key contribution was establishing the existence of penetrating radiation from cosmic sources, opening a new field of particle physics and astrophysics.