Module Information

Module Identifier
Module Title
Astrophysics and Cosmology
Academic Year
Intended for use in future years
Other Staff

Course Delivery

Delivery Type Delivery length / details
Lecture 34 hours


Assessment Type Assessment length / details Proportion
Semester Assessment 3 Hours   Written Examination  80%
Semester Assessment 2 x Assignment Sheets  20%
Supplementary Assessment 3 Hours   written examination  100%

Learning Outcomes

On successful completion of this module students should be able to:

1. demonstrate an understanding of the basic features of observational astronomy.

2. explain the physical processes whereby a section of the ISM collapses to a star.

3. demonstrate an understanding of the nature of the final states of stars.

4. explain the importance in stellar evolution of the size and rate of a mass loss of stars.

5. demonstrate an understanding of the simple physics of galactic systems.

6. describe the basic principles of the theories of relativity and answer relevent problems thereon

7. appreciate the new branches of astronomy that have developed over the past 50 years;

8. explain the basic physical processes that generate signals over the whole spectrum;

9. compare the observations with the theoretical predictions of cosmology;

10. recognise the problematic areas of modern cosmology and appreciate how future tests may resolve or accentuate these problems


This module brings together the astrophysics elements of the Physics with Planetary and Space Physics course, placing special and general relativity in their astronomical context.

Brief description

This module considers the physics of stars and galaxies and the large-scale structure of the universe. The module begins by discussing the methods used to determine the distance of stars and hence their luminosity, radii and mass. A description of the Herzspring-Russell diagram illustrates an account of the physical processes involved in stellar formation and evolution, leading to the end-states of white dwarfs, neutron stars and black holes. The physical properties, structure and morphology of the galaxies are studied. The subject of galactic dynamics is introduced.
The development of different branches of astronomy, such as radio, x-ray and y-ray astronomy, has greatly enlarged the radius of the observable Universe and uncovered many strange objects that have provided a major stimulus to the whole of physics. The kinetics of galactic rotation indicates the controlling influence of hidden mass distributed throughout a volume of space much larger than the limits of the Galaxy previously imagined. The presence of hidden mass is also indicated by the kinetics of clusters of galaxies. The accretion of mass under the pull of a strong central gravitational field, possibly centred on a black hole, is thought to provide the energy to fuel quasars and radio galaxies. These objects are so powerful they can be observed at very great distances and hence their study illuminates the nature of the early Universe. Such observations suggest a Universe that started in a "Big Bang" and has expanded to form our present Universe. This suggestion is strongly re-inforced by measurements of the microwave background radiation which originated when the Universe was only 100,000 years old. Penetrating even further back, inflation theory reconciles the isotropy of the background radiation with the limits of observation and explains why the Universe has a geometry that is almost "flat".



Coordinate systems. Observable properties of stars. Stellar distances. Mass-luminosity relation. Introduction to the Hertzsprung-Russell diagram. Observation methods - the visible and radio "windows".
Star formation and evolution to the main sequence
Interstellar medium. Conditions for gravitational collapse of a molecular cloud. Free fall time, hydrostatic equilibrium. The virial theorem, protostar temperatures, complications beyond the simple theory. Observations of star formation, T-Tauri stars. Entry to the Main Sequence. Energy sources in stars. The nature of matter under stellar core conditions. Hydrogen Burning in MS stars. The CN cycle and p-p chain. Energy transport.
Post main sequence evolution
Post-main sequence evolution for low and high mass stars. The end states of stars: Black holes, neutron stars, white dwarfs. Supernovae, planetary nebulae.

Galactic astrophysics:

Structure of the Galaxy: core, spiral arms, halo, clusters. Galactic dynamics: the virial equation, hidden mass. Types of galaxies: spiral, elliptical, irregular. Active galaxies: Seyfert, quasars.


Special Theory i.e. Lorentz transformation; relativistic interval; Minkowski diagram; causality; transformation of velocities
Relativistic optics: aberration of light; Doppler effect
Relativistic Dynamics: energy momentum transformations and four vector.

Compton Scattering:

General Theory i.e. Inertial and gravitational mass; Principle of Equivalence.
Gravitational redshift; Clicks in a gravitational field. Einstein's theory of gravity; geodesics; non-Euclidean space-time. the Schwarzschild solution; black holes.


Olber's paradox; the Cosmological Principle; Hubble and the expanding universe; Einstein-de Sitter model and the 'Big Bang'; steady-state and continuous creation; tests of cosmological models (number counts, microwave background); over-dense and under-dense universes; problems with expanding universe (isotropy; flatness; galaxy formation) inflation theory.

Reading List

Recommended Text
Kutner, M.L (1987) Astronomy a Physical Perspective 2nd edition Cambridge University Primo search Roos, M. (2004) Introduction to cosmology 3rd edition J. Wiley Primo search


This module is at CQFW Level 5