Abstract
The theory of General Relativity has been in existence for 90 years and has stood
up to all tests it has been subjected to in that time. The PPN parameter
is
a measure of the accuracy of theories of gravity and assumes different values in
different theories. By measuring the Shapiro time delay of light it is possible to
constrain
and thereby constrain gravitational theories. This Shapiro time delay
can be measured in our solar system but it is only in the vicinity of extremely
compact objects such as pulsars and black holes that it can be tested under the
immense gravitational fields that can only be found there. A pulsar in a binary
orbit about another compact object is the ideal system in which to test this
effect. In this work we have gone from Kepler’s laws of simple planetary motion
to deriving the equations that explain binary orbits to incorporating General
Relativity into these equations in order to obtain the equations for relativistic
particle orbits. We then evolved this theory even further so as to be able to
explain relativistic light ray orbits and then used this knowledge to model the
Shapiro delay in a binary system. With a working model it became possible to
simulate the Shapiro delay in a wide range of possible systems and then to use
these simulations to say something about what type of system should be focussed
on in future so as to measure the Shapiro delay and thereby constrain more tightly
the parameter
Dr. C.A. Engelbrecht
Dr. F.A.M. Frescura