University of Durham
Our universe seems a bizarre place. Only 5% of its content is the
ordinary matter of which stars, planets and people are made. A further
20% is the dark matter responsible for the force of gravity that has
shaped our universe. Its identity is unknown but it probably consists
of exotic elementary particles known as ``cold dark matter.'' The
remaining 75% is a mysterious form of ``dark energy'' that opposes
gravity and is causing our universe to expand at an accelerating rate.
Our universe has a rich, complex structure with galaxies as the
building blocks. In the cold dark matter theory, this rich tapestry
developed from tiny primordial perturbations, seeded just after the
Big Bang and amplified to enormous proportions by gravity over 14
billion years of evolution. Growing concentrations of dark matter form
in which gases cool, condense and fragment into stars. Feedback loops
are established as gas is heated by stellar winds and supernovae and
supermassive black holes form at the centre of the protogalaxies.
My research focuses on understanding the dark matter and the physical
processes by which galaxies form. I use state-of-the-art
supercomputers to simulate how the early simplicity of our universe
metamorphosed into the observed complex network of galaxies and
clusters. In this way, I investigate problems such as the formation of
the first stars that light up the universe, the structure of the dark
clumps of matter that harbour galaxies and the formation of
supermassive black holes. I also work with actual galaxy data in order
to test the theory against the real world.
Fundamental research of this kind has no immediate practical
application although it does have important spin-offs such as novel
computational methods and the training of students in physics and
advanced supercomputing techniques. Its main value, however, stems
from our desire to understand our world, a desire that has led to the
technological developments upon which our modern world depends.