Having worked on the science of Einstein’s gravitational waves for more than 30 years, I have had the great pleasure and satisfaction during the last few years of being part of the team that has been making gravitational wave detections since September 2015. I had only recently (2014) retired from my position as a director of the Albert Einstein Institute (AEI) of the Max Planck Society and returned to my previous professorship at Cardiff University in Wales, where I helped set up the new Data Innovation Research Institute. I have now stepped down from the data institute to focus more attention onto gravitational waves.
I am a signal-hunter and interpreter: I specialize in hunting for weak signals buried in background noise, and then extracting information from the ones that turn up. My contribution to gravitational wave science has been to understand what information these very weak signals could contain and then to try to perfect our ability to recognize and extract the signals that Nature provides for us, against detector noise. Although our detectors are wonderfully quiet, detecting signals and understanding what they tell us requires as much information as we can get beforehand about what the signals might look like. This involves using supercomputers to make models of sources of gravitational waves, inventing clever analysis methods to match signals with these supercomputer predictions, and keeping up with the latest information that other astronomers and astrophysicists can provide about our likely sources (black holes, neutron stars, and ??).
What I write in this blog is drawn from a range of experiences: research at the intersection of physics, astronomy, and mathematics; science administration in helping to found the AEI in 1995 and to grow it into a world-class center for research in general relativity and quantum gravity; science policy, particularly pressing the case for building gravitational wave detectors and more recently pushing for open-access publishing; growing up in the USA, then spending most of my working life in Europe, and of course making friends in the science community all around the world; and – best of all – helping to raise three wonderful daughters.
My interest in gravitational waves grew out of a fascination with Einstein’s relativity that developed in my teenage years in Bethpage, NY, and was nurtured during my undergraduate study at Clarkson University. I was then fortunate to be able to do my PhD in relativity physics at Caltech under the supervision of Kip Thorne, finishing in 1971.
In the early 1980s, by then at Cardiff University, I worked with Jim Hough (now Sir James) of the University of Glasgow to develop the British gravitational wave effort. We later joined with German colleagues to build the GEO600 detector, and my move to the AEI helped cement this collaboration. We allied ourselves with the US LIGO gravitational wave project through the LIGO Scientific Collaboration, and we used GEO600 to develop and prove a large fraction of the key technologies that enabled LIGO’s momentous detection on September 14, 2015 of the gravitational waves emitted by two black holes merging together. I continue to look forward to the enormous fun we have working with the data from detections that keep coming in, and to continuing to work with my AEI colleague Karsten Danzmann to help bring about the next revolution in gravitational wave astronomy, the LISA mission of the European Space Agency.
Along the way I wrote some books, published a lot of papers, and supervised some wonderfully talented young scientists. I have also had the good fortune to have had my work recognised by awards from my peers, for which I am very grateful: membership of the National Academy of Sciences of the US, of the German Leopoldina, of the Learned Society of Wales, and of the Royal Academy of Arts and Sciences, Uppsala; the Eddington Medal of the Royal Astronomical Society in 2019; and the Amaldi Gold Medal of the Italian Society for Gravitation (SIGRAV) in 2006.
Being a director of a Max Planck institute gave me the freedom, and indeed the responsibility, to take initiatives I could not have taken from a normal university professorial position. I feel strongly that scientists need to share their knowledge and enthusiasm with the public, so I have done a lot of outreach work over many years, especially in cooperation with the amazing Susanne Milde on the Scienceface project. I also felt there was a need and opportunity for a new kind of scientific review journal, so in 1998 I began publishing Living Reviews in Relativity — online, subscription-free, up-to-date survey articles. Fifteen years later LRR had become the highest “impact factor” open-access journal in the world. LRR and two sister journals were transferred from the Max Planck Society to Springer in 2015, after my retirement. My experience with LRR has convinced me that scientific research would benefit enormously from the conversion of its journals to an open-access business model. Such a conversion will not be easy, but it will be worth it!