|Astrophysics - Modelling the Universe
Astrophysics describes everything from stars, on upwards in size to interstellar gas and galaxies, then larger and larger clusters of galaxies until it merges into cosmology. It covers a whole range of physical phenomena, from the evolution of galaxies under the action of gravity over many millions of years to rapid bursts of energy in supernovae and the formation of black holes.
All of these diverse phenomena are subject to the laws of physics and can be modelled by mathematical equations. Solving the basic equations in realistic situations requires the use of computers. Numerical simulations of astrophysical objects have benefitted from the enormous increase in computer power over the past few years. Powerful computers often work together over international networks, sometimes on an advanced type of network known as the GRID—the system seen by many as the natural successor to the World Wide Web.
Topics especially strong in the UK include modelling the formation of stars and planets, the physics of plasmas in the interstellar medium and the theory of systems which produce energy from gravitational infall onto a compact object like a black hole.
Back to the beginning...
The universe which we see around us has been in its present form, filled with interstellar gas and galaxies, for less than 14 billion years. Quite remarkably, if we could go back 14 billion years, the universe would appear much simpler than it is today, filled with uniform hot plasma. The evidence can be seen in the form of cosmic microwave radiation, radiated by the plasma and seen today by satelite or ground based observatories.
The modern theory of cosmology is based on the big bang model. At the very beginning of the universe, there was an event of extreme violence, but which we understand very little about. Very soon after the big bang, it seems likely that the universe expanded, more and more rapidly for a short time, in a process called inflation. We think that tiny perturbations of the vacuum during inflation lead to the origin of the structure of the universe, which has been since amplified by gravity, leading to the birth of a hierarchy of structures in the universe, from the smallest galaxies, to groups, clusters and superclusters.
In order to understand the early universe better, a new branch of physics, particle astrophysics, has been developed. It is becoming increasingly recognised as a key research area in the UK.
Degree Programmes in Astrophysics/Cosmology
Postgraduate training can consist of taught masters (MSc) courses or research degrees (PhD or Mphil). Masters courses are usually of one year in duration and consist of lectures and project work. PhD courses are usually three or four years in duration. It may come as a suprise that much of the UK research into astrophysics and cosmology is to be found in applied mathematics departments.
Postgraduate candidates in theoretical astrophysics typically come from mathematics or physics backgrounds. Good academic qualifications are essential for postgraduate study, but they are not everything. Hard work, commitment and a genuine passion for the subject are no less important.
Students on these programmes develop experience and competence at a level where they can continue further research in the field. A possible route into a research career might begin with an MSc, followed by a PhD and then on to a sequence of temporary postdoctoral research positions before becoming a member of staff in a university or reseach institute. However, the competition for places at each stage means that only a small proportion of postgraduate are able to follow this route.
Most students use the opportunity to spend one to three years studying a subject they enjoy before using their qualification to go on to a quite different type of career. Their mathematical and numerical modelling skills are very much in demand. Some are teaching physics or mathematics in univesities or higher education institutes around the world. Others take up careers in industry, finance or software companies.
Professor of Theoretical Cosmology
University of Newcastle