Rutherford did not discover the three types of radioactivity. That discovery is credited to Henri Becquerel and Pierre and Marie Curie. Rutherford, however, made groundbreaking contributions to our understanding of radioactivity.

Here's a breakdown:

* Henri Becquerel discovered radioactivity in 1896 while studying uranium salts. He noticed that these salts emitted invisible rays that could expose photographic plates.

* Pierre and Marie Curie further investigated radioactivity and discovered two new radioactive elements: polonium and radium.

* Rutherford investigated the nature of these rays and identified three distinct types of radiation:

* Alpha radiation: Consists of positively charged particles (alpha particles) that are essentially helium nuclei.

* Beta radiation: Consists of negatively charged particles (beta particles) that are essentially high-energy electrons.

* Gamma radiation: Consists of high-energy electromagnetic radiation, similar to X-rays but with higher energy.

So, while Rutherford didn't discover the phenomenon of radioactivity itself, his work was crucial in understanding its different forms.