Expert: Philip Stahl - 12/3/2008

Question
QUESTION: Mr. or Dr. Stahl,

Can you direct me to where I might find FORTRAN or MAPLE code for analyzing some of the more simplistic solutions to Einstien's general relativity field equations? For example, the Schwartzchild solution? Would this be a good place to start?
http://en.wikipedia.org/wiki/Deriving_the_Schwarzschild_solution

Perhaps flat vacuum space would be a better starting point?

I am a mechanical engineer and am doing this as a hobbie to learn about the theory. Working the math quantitatively always elucidates deeper understanding in my experience.

Can you recommend any good papers or websites?

Thank you for your time.

Respectfully, Ken George

ANSWER: Hello,

I am aware of no code such as those you reference which deals with the Einstein Field equations for general relativity. However, as a user of Mathcad 14, I have downloaded two Mathcad files which addresses these. They are quite comprehensive and useful, but alas....only to a Mathcad user!

If you have Mathcad, you can go to their online site using your  entry code info and access any and all types of user files in a variety of areas (cosmology, celestial mechanics, thermal physics etc.)

If you don't there isn't much I can do to help, since I have only used Mathcad myself and wouldn't presume to be able to remotely transcribe any Mcad file into Fortran or any other language.

As an aside, while I appreciate your zest to get going with quantitative work, I strongly suggest you understand the principles and theories (both special and general) FIRST!

Perhaps the best place to begin is with Einstein's book, 'Ideas and Opinions'. In the last section (pp. 227-335) he goes into the basics of his relativity theories, thence into tensors at a cursory level and how it all fits into the framework of theoretical physics.

From there, I'd try to get hold of 'The Principle of Relativity' (Dover Publications) and peruse it carefully, since Einstein is conveying it from his own words in papers he actually published, ee.g. in Annalen der Physik (of course the English translations are given).

Then, go on to Peter Gabriel Bergman's text 'Introduction to the Theory of Relativity' which contains a primer in tensor calculus (which you will need to know to appreciate the field equations) and other material including the field equations (Ch. XII), rigorous solutions (Ch. XIII) and experimental tests (Ch. XIV).

Hope this prescription helps!

---------- FOLLOW-UP ----------

QUESTION: Dr. Stahl,

Thank you for info and time. I own Mathcad 13. What particular site are you suggesting? I tried PTC.com and came up with nothing. Are you referring to user group or a student forum? It has been a while since I have used this software. Also, I have requested "Ideas and Opinions" from my school...I am a part-time PhD student at Lehigh U.

If these files are freely distributable, you may email them to me if are willing at . I will understand if your not comfortable with that.

Thanks So Very Much Again - Ken

Answer
Hello,

The files I have were accessed via the Mathcad User forums. I did it by clicking on 'Help' in the Mathcad 14 menu (upper right) which brings up assorted selections and also 'user forums'.  Then click on 'user forums' and all the links are brought up for each forum, a total of 3649 at last count. Click on any and a prompt comes up for your log in info, including username and password. If you purchased any commercial version of Mathcad you ought to be able to access it. I regret I am not comfortable with sending the files via email as it would be a violation of the terms & conditions for use which I signed onto.

I truly hope you can access the files on your own.

Btw, another great book to get is Max Born's: 'The Theory of Relativity'. Breaks it down into even simpler terms than the other books I noted (except for the last part of 'Ideas and Opinions') . You may also wish to consider obrtaining 'The Theory of Relativity' by Einstein, a more popular rendition of his work.