Welcome to Norman Murray's Homepage
Astrophysics offers the physicist the opportunity of using techniques from every field of physics. The problems involved are often of great interest to the public, a fact reflected in the rather high level of support offered to astronomers. An example is the area of solar system formation. Fluid dynamics and magnetohydrodynamics are crucial in the early stages, while non-linear dynamics, in the guise of celestial mechanics, was invented to study the late stages. Five new planetary systems have been discovered over the last few years, and many proto-planetary disks have been imaged by the Hubble Space Telescope. NASA is currently planning a large program to search for and image extra-solar planets, so the field is likely to experience tremendous growth. I am interested in the formation of planets from proto-planets, and the capture or ejection of small bodies from the solar system, both in the past and currently. Why are the planets spaced as they are? Why are there so many asteroids between Mars and Jupiter, and so few elsewhere? What are the possible configurations of a planetary system?
Active galactic nuclei offer a very different panoply of problems. Quasars are the brightest objects in the universe, emitting the light of 10^{13} suns in a volume the size of the solar system. Their spectra show very broad emission lines, indicating the presence of gas moving at velocities up to a tenth the speed of light. It is believed that they are powered by material falling into a massive black hole. What produces the emission lines? How is the accreting material that is feeding the black hole distributed in space? How does it rid itself of angular momentum so that it can fall into the hole? In order to address these question, one must employ knowledge of general relativity, MHD, radiation hydrodynamics, radiative transfer, and photoionization physics. Experimental data come from radio telescopes, infrared and sub-millimeter arrays, earth and space based optical and UV telescopes, x-ray satellites, and gamma-ray observatories.
Last modified September 8, 2006