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The most beautiful theory

economist.com

64 pointsprostoalex6 comments

for anyone who is interested in Einstein's ideas/theory and philosophy within the context of social and science history, there is an wonderful mooc offered by Peter Galison from Harvard.

https://www.edx.org/course/einstein-revolution-harvardx-emc2...

Highly recommended.

This has probably being said many times before, but Einstein's book on Relativity is still worth reading as an introduction to his ideas on Special and General Relativity. A 100th Anniversary Edition has been released [1] which includes extra commentary that acts as a reading companion and includes a look at the various foreign-language editions of his book that makes you realise just how far his ideas spread.

[1] "Relativity: The Special and the General Theory", 100th Anniversary edition by Albert Einstein, With Commentaries and Background Material by Hanoch Gutfreund and Jürgen Renn [ http://press.princeton.edu/titles/10434.html ]

One interesting notion exemplified in this article is the importance of intuition in science. There is a lot of noise made about empiricism and accumulation of data - but scientific endeavor necessarily begins with a hypothesis, an act of pure intuition. In this case, Einstein was acting on the data and inferences from well-known experiments. What he added was only a new understanding. This is perhaps the most visible and celebrated example of this sort of intuitive leap, but really every scientific endeavor must contain this kind of thinking.

I have a question. Given an u derstanding of special relativity plus Einstein's equivalence principle, can one derive the Ricci curvature formulation of GR? By that I mean, is the math of GR an inevitable consequence of those assumptions?

That gives you only the equation of motions for a test particle, i.e. the geodesic equation. The field equations are another thing. I think historically there was a lot of guess work. But using that the sources of the field are the energy/momentum density you can make them plausible: looking for a divergence free 2-tensor that depends on the curvature the Einstein tensor is easiest choice. The coupling constant can be determined by looking for the non-relativistic limit which must be identical to Newtons law.

On the other hand, the Einstein-Hilbert action[1] is so beautiful it just has to be right :) It simply says that the the solutions to the field equations are the stationary points of the averaged scalar curvature.

[1] https://en.wikipedia.org/wiki/Einstein-Hilbert_action

full title: General relativity

The most beautiful theory

A century ago Albert Einstein changed the way humans saw the universe. His work is still offering new insights today

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