I will outline briefly how cosmic rays were discovered and the work that led to the discovery of the extensive air-showers now used to study cosmic rays as energetic as 10^20 eV. I will explain why there is interest in these very rare particles and illustrate the detection techniques using the Pierre Auger Observatory, a 3000 km^2 instrument, as an example. The latest results on the mass, energy spectrum and anisotropy of the most energetic particles will be described.
No knowledge about cosmic rays will be assumed.
Our General Interest Seminars are an opportunity for distinguished speakers to present new research in physics and related areas. The material presented is suitable for undergraduate level upwards and all members of the School are welcome to attend..