I’m incredibly proud to reveal that I’ll be starting a PhD at the University of Sussex this September. It’s something I was considering even before I finished my masters; I was fortunate enough to get sidetracked by a very rewarding and eye opening two years in the City, but I soon realised that if I didn’t do it (a PhD) now, I never would! A lot of people have asked me what I’ll be studying, and my usual reply is just “Astrophysics”. However, I’ve come to realise that many people’s impressions of what constitutes “Astrophysics” varies substantially. So, to help my Mum and anyone else interested understand what I’ll be doing for the next three and a half years, here’s a quick break down.
The official title of my course is Astronomy, which is concerned with pretty much everything above the earth’s atmosphere; the moons, planets, stars, galaxies, and all the other weird and wonderful objects out there. The Oxford English dictionary then describes Astrophysics as a branch of astronomy, concerned with understanding the physical processes underlying these objects and their environment. In my experience, however, these terms are essentially interchangeable (see <a href=”https://telescoper.wordpress.com/2009/07/25/astronomy-or-astrophysics/” target”blank”>here</a> for a historical perspective). If forced, I’d perhaps define a methodological delineation between the terms: astronomy is more concerned with the observation of the heavens, and pays greater attention to the instruments used to do so, namely telescopes, whereas astrophysics is the study of how the heavenly bodies actually work through theory.
The astrophysicists main tool for understanding the universe is the theoretical model; often models can be very complicated, and simulations using computers are needed to solve them. The objects that astrophysicists are interested in can’t be recreated in the lab (if they could, it would probably violate health and safety regulations) so computer simulations are one of the only means of recreating them, albeit virtually. To test their models, they then use observations collected by astronomers. You can’t do much interesting astrophysics without astronomy, but astronomy without astrophysics is like a boat without a rudder (a gross simplification, that will make me a wanted man within the astronomy community, but it will suffice for this explanation).
In the past half century, astrophysics and astronomy have become closely intertwined with the field of Cosmology, which seeks to answer the grandest questions of all; how did the universe begin, how will it evolve, and (how) will it end? These questions have been the domain of philosophers for the majority of human history until the 20th century, when observational techniques have allowed us to observe further and further back in to the history of the universe.
In summary, modern astrophysics is the study of how the universe works, in part and as a whole. My particular contribution to the field is still being planned by my supervisors, Professor Peter Thomas and Doctor Stephen Wilkins, however the provisional title is Galaxy formation in the epoch of reionizaton. I’ve been given the following outline:
“Using semi-analytic and hydrodynamical simulations of galaxy formation to explore the formation and evolution of galaxies to z=6, and make predictions for JWST.”
In other words, use computer simulations to study some of the first galaxies that formed in the universe, and use the results to make predictions for what the James Webb Space Telescope will see after launch in October 2018. This captures the spirit of my introductory explanation; use models, simulated using computers, to understand how a physical process works, and then test that model against observations.
I can’t wait to get started; looking forward to achieving the childhood dream of being a real scientist!
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