History of Radiation Timeline

Events

Wilhelm Konrad Roentgen discovers x‑rays.

1895

Concerns first raised about possible injuries from x‑ray exposures. Elihu Thomson conducts experiments on x‑ray burns.

1896

Antoine-Henri Becquerel discovers rays produced by uranium, the first observation of natural radioactivity.

1896

Marie and Pierre Curie discover polonium and announce the existence of another new radioactive element they name radium.

1898

Marie and Pierre Curie discover that thorium gives off "uranium rays," which Marie renames "radioactivity."

1898

Paul Ulrich Villard discovers gamma rays

1898

Ernst Rutherford discovers that radioactivity from uranium has at least two different forms, which he calls alpha and beta rays.

1899

Rutherford discovers the principle of half-life and sets forth his laws on radioactive decay.

1900