Jeroen van Dongen, Einstein’s Unification, Cambridge University Press (2013) [doi:10.1017/CBO9780511781377]
Introducing general relativity (the modern theory of gravity):
On the (eventual) experimental confirmation of general relativity:
Peter Coles, Einstein, Eddington, and the 1919 Eclipse (arXiv:astro-ph/0102462)
Gerard Gilmore, Gudrun Tausch-Pebody, The 1919 eclipse results which verified General Relativity and their later detractors: a story re-told (arXiv:2010.13744)
The first article that correctly derived gravitational waves from the Einstein equations is
In particular this correctly stated that gravitational waves require a quadrupole moment as a source (e.g. a rotating binary star system) and not just a dipole moment (e.g. an oscillating charge) as for electromagnetic waves (the graviton has spin 2, the photon has spin 1…), thereby correcting a mistake to this effect in the earlier article
The reality of gravitational wave solutions however kept being a cause of concern for many years (Einstein himself was concerned that the linearization approximation used in their derivation might have been too coarse), for a brief account of the early history see
Wolfgang Steinicke, Einstein and the Gravitational waves, Astron. Nachr. / AN 326 (2005), No. 7 – Short Contributions AG 2005 Köln (pdf)
Introducing the idea of spacetime wormholes in gravity (Einstein-Rosen bridges):
Introducing the Einstein-Podolsky-Rosen paradox concerning quantum entanglement:
On the assumption of a spacetime continuum in view of quantum physics (quantum gravity):
Es ist allerdings darauf hingewiesen worden, dass bereits die Einführung eines raum-zeitlichen Kontinuums angesichts der molekularen Struktur allen Geschehens im Kleinen möglicherweise als naturwidrig anzusehen sei. Vielleicht weise der Erfolg von Heisenbergs Methode auf eine rein algebraische Methode der Naturbeschreibung, auf die Ausschaltung kontinuierlicher Funktionen aus der Physik hin. Dann aber muss auch auf die Verwendung des Raum-Zeit Kontinuums prinzipiell verzichtet werden. Es ist nicht undenkbar, dass der menschliche Scharfsinn einst Methoden finden wird, welche die Beschreitung dieses Weges möglich machen. Einstweilen aber erscheint dieses Projekt ähnlich wie der Versuch, in einem luftleeren Raum zu atmen.
To be sure, it has been pointed out that the introduction of a space-time continuum may be considered as contrary to nature in view of the molecular structure of everything which happens on a small scale. It is maintained that perhaps the success of the Heisenberg method points to a purely algebraical method of description of nature, that is to the elimination of continuous functions from physics. Then, however, we must also give up, by principle, the space-time continuum. It is not unimaginable that human ingenuity will some day find methods which will make it possible to proceed along such a path. At the present time, however, such a program looks like an attempt to breathe in empty space.
On the role of mathematics in physics:
I am now occupied exclusively with the gravitational problem [i.e. general relativity/gravity], and believe that I can overcome all difficulties with the help of a local mathematician friend [Marcel Grossmann]. But one thing is certain, never before in my life have I troubled myself over anything so much, and that I have gained great respect for mathematics, whose more subtle parts I considered until now, in my ignorance, as pure luxury! Compared with this problem, the original theory of relativity [i.e. special relativity] is childish.
(from: Einstein to Sommerfeld, October 29, 1912, The Collected Papers of Albert Einstein (CPAE, Vol. 5): The Swiss Years: Correspondence, 1902–1914, Klein, Martin J., Kox, A.J., and Schulmann, Robert (eds.), Princeton: Princeton University Press, 1993, Doc. 421, cf. also p. 3 of Weinstein arXiv:1210.6929 and p.1 of Earman & Glymor 1978)
In his Spencer lecture, delivered at Oxford in 1933, Einstein stressed the importance to be accorded to formal beauty:
Experience can of course guide us in our choice of serviceable mathematical concepts; it cannot possibly be the source from which they are derived; experience of course remains the sole criterion of the serviceability of a mathematical construction for physics, but the truly creative principle resides in mathematics.
Concerning what are now called Einstein equations (equations of motion for Einstein gravity):
I have learned something else from the theory of gravitation: No ever so inclusive collection of empirical facts can ever lead to the setting up of such complicated equations. A theory can be tested by experience, but there is no way from experience to the setting up of a theory. Equations of such complexity as are the equations of the gravitational field can be found only through the discovery of a logically simple mathematical condition which determines the equations completely or [at least] almost completely.
(From A. Einstein, Autobiographical Notes, as translated in P. A. Schilpp: Albert Einstein – Philosopher-Scientist, MJF books, New York (1949, 1951, 1969, 1970), p. 89, scan)
Last revised on July 4, 2024 at 10:34:45. See the history of this page for a list of all contributions to it.