Ordinary Meeting [Hybrid Meeting] with Emily Kerrison, CSIRO Space & Astronomy

Guest Speaker:  Emily Kerrison, CSIRO Space & Astronomy

Title: What good is a twinkling star? Studying scintillation from the Dreamtime to the modern day

Abstract: Some time around 350BCE, the Greek philosopher Aristotle wrote about the ‘fixed stars which twinkle and the planets which do not’. This is perhaps the earliest reference to the scintillation of compact astronomical objects, a phenomenon which is used today by many branches of astronomy, from the study of fast radio bursts to the tracking of space weather. But the path from this ancient remark to modern scientific applications is a twisted one full of challenged assumptions and (mis)communication. In this talk I shall discuss how the physics behind the scintillation of radio sources, first ionospheric, then interplanetary and interstellar, was gradually understood over the course of many years, with a focus on the angular size dependence of this phenomenon. As with the twinkling of stars noticed by the Greeks, this radio frequency scintillation was initially misinterpreted as an intrinsic effect where in fact, we now know it is related to aspects of wave propagation through a turbulent medium which are not so intuitive, but once this is understood, we have a powerful tool to probe the space weather environment without even having to go there.  

Biography: Emily is a PhD student at the University of Sydney, co-supervised by astronomers at CSIRO. She has a background in both science and Classical literature, and currently she works in radio astronomy as part of a survey team using data from the Australian SKA Pathfinder (ASKAP) telescope to map the cold gas content of other galaxies. They want to understand how the gas distribution has evolved across cosmic time and how this relates to the ways in which galaxies form, evolve, and interact with one another. Emily is focused on augmenting their understanding of this gas by extracting extra information from pre-existing datasets and combining them in new ways to complement the survey data, and thinking about how the way we do science has changed over the course of decades, centuries, and millennia.