Dr Michael Perryman

Image credit: ESA–D. Ducros, 2013

The Hipparcos satellite project of the European Space Agency 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. With the publication of the scientific results from the Hipparcos mission in 1997, ESA adopted the Gaia mission, a follow-on and vastly more advanced star-mapping satellite, in 2000. Gaia was launched in 2013 and continues to operate from its advantageous 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 set to revolutionise many areas of astronomy and astrophysics. The talk will explain why the measurement of star positions is of such scientific importance. It will review the two thousand year history of this branch of astronomy, called astrometry, explain why these measurements are being made from space, illustrate how the very exacting measurements are made in practice, and present some of the many areas of astronomy that are being impacted by these new experimental insights.

Michael Perryman obtained a degree in physics, and a PhD in radio astronomy, at Cambridge University. During a 30-year career with the European Space Agency, he was the scientific leader of the Hipparcos mission between 1981-1997, also serving as project manager during its operational phase, 1989-1993. He was the co-originator of the Gaia satellite mission, and ESA’s project scientist from its earliest concepts in 1995 until the Critical Design Review in 2008, establishing the instrument concept, technical feasibility, operational and data analysis principles, its organisational structure, and coordinating its scientific case. He was Professor of Astronomy at Leiden University, The Netherlands, between 1993-2009, and has received various awards for his leadership of space astrometry, including the Gold Medal of the French Astronomical Society, the Academy Medal of the Royal Netherlands Academy of Arts & Sciences, and the Tycho Brahe Prize of the European Astronomical Society. He was awarded an Honorary Doctorate from Lund University in Sweden in 2010, and was the Bohdan Paczynski Visiting Professor, Princeton University, in 2013.

The recording of this lecture is now freely available on the Virtual BRLSI YouTube channel. Please go the following link to view.

https://www.youtube.com/watch?v=g2hbITqu6a0

Roger Blandford (KIPAC, Stanford University)

Image credit: ESO/APEX & MSX/IPAC/NASA and A.Symes

The laws of physics were long thought to be unchanged when viewed in a mirror.
We have known for over sixty years that they are not.
As Sakharov first explained, this asymmetry, in action during the first moments of the universe, may account for the prevalence of matter over antimatter today.
Likewise, as Pasteur first showed, the laws of biology are similarly asymmetric, as is exhibited by the structure of DNA.
In this talk I will discuss how there might be a causal connection between these two qualities, mediated by cosmic rays.
On the way, I will illustrate this uneven-handedness using recent, exciting, astronomical discoveries, involving black holes, neutron stars and exoplanets.

Roger Blandford took his BA, MA and PhD degrees at Cambridge University. Following postdoctoral research at Cambridge, Princeton and Berkeley he took up a faculty position at Caltech in 1976 where he was appointed as the Richard Chace Tolman Professor of Theoretical Astrophysics in 1989. In 2003 He moved to Stanford University to become the first Director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) and the Luke Blossom Chair in the School of Humanities and Science. His research interests include black hole astrophysics, cosmology, gravitational lensing, cosmic ray physics and compact stars. He is a Fellow of the Royal Society, the American Academy of Arts and Sciences, the American Physical Society and a Member of the National Academy of Sciences. In 2008-2010, he chaired a two year National Academy of Sciences Decadal Survey of Astronomy and Astrophysics. He was awarded the 1998 Dannie Heineman Prize of the American Astronomical Society, the 2013 Gold Medal of the Royal Astronomical Society, the 2016 Crafoord Prize for Astronomy and the 2020 Shaw Prize for Astronomy.

The recording of this lecture is now freely available on the Virtual BRLSI YouTube channel. Please go the following link to view. https://www.youtube.com/watch?v=wjfjZQczmX8

Unless they are astronauts, humans must view the Universe through the window of the Earth’s atmosphere. Although a clear sky is relatively transparent to visible light, bright astronomical objects — most noticeably the Sun — can paint the entire sky with luminosity, colour and shadow to be captured by both landscape painters and photographers. How does this happen and what physical processes are responsible for these beautiful colours, gradations and patterns? The talk explains some of this and is illustrated with spectacular images of the sky from space and from above the European observatories in the Chilean Atacama desert.

Robert (Bob) Fosbury is currently an emeritus astronomer at the European Southern Observatory and an honorary professor at the Institute of Ophthalmology at UCL.

The video recording of this lecture is now freely available on the Virtual BRLSI YouTube channel. Please go the following link to view.

https://www.youtube.com/watch?v=P9v9pFluF-M

There is also an extended paper on this subject as a PDF file here.