A New Star, as bright and as red as Mars, was discovered on October 9 1604, close to the position where another astrologically significant event was taking place, the conjunction of Mars and Jupiter. The New Star created a stir throughout Europe. At Padua the new star was observed by Galileo, while in Prague Kepler made careful observations and the Supernova now carries his name. Galileo gave 3 public lectures that were attended by a large audience in which he explained the notion of parallax with the help of familiar examples and then used the concept to demonstrate that the new star was much further than the moon. This had important astronomical consequences since it showed that change occurrs in the sky, contrary to the theory of Aristotle and his followers.

Since then Supernovae, which are nowadays believed to be the end-point in the evolution of massive stars and stars of low mass in close binary systems, play a key role in the evolution and development of astrophysics. Not only are they the observational moorings to which stellar evolutionary models must dock, but on account of their extraordinary luminosity, Supernovae constitute a sort of cosmological lighthouses that are essential to draw a map of the Universe. The latest concepts of an accelerating Universe and recent models of the Gamma Ray Bursts are based mainly on observations of the Supernovae.
A four-day international meeting is being organised by the University and the Observatory of Padua to commemorate the fourth centennial of the appearance of the New Star of 1604 but also to explore recent developments. The first day of the meeting will be devoted to the history of Supernovae, and the next three will analyse the important changes that have taken place over the last decade in their observation and theoretical interpretation. New issues will be raised and proposals for future research will be outlined and discussed.