18 Jun 2001

In his lecture, on 8 June, Dr Perryman described how measuring distances to the stars is one of the great challenges which continues to face experimental astronomy and discussed ESA's past and future contributions to this field.

ESA's Hipparcos mission (1981-97) determined accurate distances and space motions for 120 000 stars. These measurements have contributed to furthering our understanding of the formation and evolution of our Galaxy, and the stars within it.

Building on the success of Hipparcos and Europe's expertise in astrometry ESA's Gaia mission will map the three-dimensional structure of more than one billion stars extending throughout our Galaxy. The scientific return from such a mission is immense and touches on areas as diverse as extra-solar planetary systems and near-Earth objects; the age of individual stars and the age of our Universe; it will probe how stars evolve and will even impact on fundamental physics.

An annual event since 1966, the Lindsay Memorial Lecture is named for the Associate Chief of the Goddard Space Sciences Division and head of the Goddard solar physics program, John C. Lindsay (1916-1965), who pioneered the exploration of the Sun by both satellite and rocket-borne experiments.

The annual lecture coincides with the John C. Lindsay Memorial Award, which is given annually to an employee of the Goddard Space Flight Centre for an outstanding contribution to space science - the 2001 award was presented to Dr Donald Reames for his discovery of trans-iron elements in solar energetic particle events.

Dr Perryman's lecture was introduced by the Director of Space Sciences at Goddard, Dr Jonathon F. Ormes, and the lecture was attended by the Goddard Space Flight Center Director, Alphonso V. Diaz, by Mrs Lindsay, and by more than 400 Goddard employees and other guests.