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An Introduction to Astrophysics

As far as we know, every ancient society practised something we would recognize as astronomy. Extrapolating from centuries of observation to predict the motion of the moon and planets was normal for ancient astronomers in several parts of the world. Perhaps most fascinating of all is the ancient Greek astronomical clockwork known as the Antikythera mechanism. The Copernican revolution (although partly anticipated in ancient and medieval times) was of course a fundamental change from ancient astronomy. Yet in another sense, Copernicus and Kepler still represent a continuation of ancient astronomy, because they were will trying to solve the same problem as the Antikythera clockmaker: predict where things will be on the sky. With Newton, the very problem to be solved changes: when Newton formulated universal gravity, he was not providing better formulas for predicting celestial motions, he was deriving the motions from physical principles. This was the beginning of astrophysics.

In this course we will try to gain some insight into how physical principles have helped understand something of the universe, from Newton's annus mirabilis of 1666 to circa 2000. Naturally, given the time available we must be highly selective, and so we will focus on the most important physical concepts of astrophysics, in approximately their historical order. The study of individual astronomical objects, fascinating though they are, we must leave for later modules. Here the main character is not a star or a galaxy or even the whole universe, but Gravity, to be joined by a supporting cast from Microphysics. You can think of this course as the branch of physics where gravity is important.


General Information

Lecture notes and problems

Python resources
Magic Envelope pages   Additional information, from a related course.

Some nice books

  1. The physical universe: an introduction to astronomy   by Frank H. Shu is at a more elementary level than this course, but its wide coverage (remarkably current considering it appeared in 1982) and crystal clarity make it one of the best introductory texts in any subject.
  2. Fundamental astronomy   by H. Karttunen, P. Kröger, H. Oja, M. Poutanen, and K.J. Donner is very good for connecting the observable cosmos with the more theoretical-physics approach that this course will take. (German edition)
  3. Astronomie und Astrophysik by A. Weigert, H.J. Wendker, L. Wisotzki.
  4. Astrophysics in a Nutshell   by Dan Maoz was very influential in preparing this course. For the first third of our material (pure gravity) we will proceed very differently to Maoz, but the latter two-thirds (stars and cosmology) we will cover in a fairly similar way.
  5. An introduction to modern astrophysics   by Bradley W. Carroll and Dale A. Ostlie or the Big Orange Book, is perhaps the most widely-used introductory astrophysics textbook at present. Much more material than we can hope to cover in one semester, but worth consulting on many different topics if you want to know more or would like to see another approach.
  6. First principles of cosmology   by Eric V. Linder, though at a somewhat more advanced level than we will cover, is in its general approach and philosophy the very model of this course.
  7. An invitation to astrophysics   by T. Padmanabhan is really intended for readers who have already studied theoretical physics to the masters level and are interested in seeing how it applies in astrophysics. Nevertheless, you may find some sections insightful already in the semester. Padmanabhan is also quite entertaining.

A few websites