Abstract:
The Hipparcos satellite of the European Space Agency, launched in 1989, was dedicated to measuring the accurate positions of more than 100,000 stars. Doing so from space represented a fundamentally new discipline in space science. After the publication of the scientific results from the Hipparcos mission in 1997, ESA adopted the Gaia mission, a vastly more advanced star-mapping satellite, in 2000. Gaia was launched in 2013 and continues to operate from its location at the Sun-Earth Lagrange point, L2. Gaia is measuring the positions of more than two billion stars in our Galaxy with extreme accuracy, and is contributing profoundly to many areas of astronomy. The talk will explain why the measurement of star positions is of such scientific importance, recall its history, and present some of the many areas of astronomy that are being impacted by these latest state-of-the-art measurements.

Bio:
Michael Perryman joined the European Space Agency in 1980, after an undergraduate degree in theoretical physics at Cambridge, and a PhD in radio astronomy at the Cavendish Laboratory. He was appointed as ESA's project scientist for Hipparcos in 1981. He led the Hipparcos project until its completion in 1997. He was one of the originators of the Gaia mission in 1995, and was ESA's project scientist until his retirement from ESA in 2009. He was Professor of Astronomy at Leiden University, The Netherlands (1993-2009), the Bohdan Paczynski Visiting Professor, Princeton University (2013), and has been Adjunct Professor in the UCD School of Physics since 2013.  Amongst recognition for his lifetime work in space astrometry, he has received the Prix Jules Janssen of the French Astronomical Society, the Academy Medal of the Royal Netherlands Academy of Arts and Sciences, the Tycho Brahe Prize of the European Astronomical Society, and the 2022 Shaw Prize for Astronomy.