Spacetime and the Quantum World

Fall 2025

"... until at last it came to me that time was suspect!" - A. Einstein (Shankland interview 1950)

"... the concept of time is nothing more than a convenient, although potentially treacherous, device for summarizing compactly all the relationships holding between clocks." - N. D. Mermin It's About Time, pg. 63

"... be prepared to give up every preconceived notion, follow humbly wherever and to whatever abysses nature leads, or you shall learn nothing." - T. Huxley (letter to Kingsley 23 Sept. 1860)

News:

Thanks for the feedback today! Based on this you can take Quiz I on two possible dates: October 9 or October 23 during class time. If you choose to take the quiz October 9 arrive a bit early and go to G047 to start the 75 minute quiz. On October 9 class will be as usual in G041, but I will record it. The topic will be a one class intro to spacetime curvature and general relativity with a focus on black holes. October 9 quiz takers can view this class during the October 23 time slot, when the rest of the class will be taking Quiz I.

Links for exploring:

These are identifed by topic: "SR" means special relativity, "GR" means general relativity, and "QM" means on the quantum world.

Relativity:

SR: Beautiful animations of the apparent geometry of relativistic moving objects. The dice and the ride down Marktgasse in Tuebingen are particularly good. Note, however, that redshift is not accounted for.

SR: Notes on the "Happy Birthday Alice" question, number 33 on the lecture questions.

SR: Pictures of Berne's Clock Tower in early 1900's and 2005

SR: The homepage for the Sloan Digital Sky Survey database (example spectrum and example 2)

SR: The electromagnetic spectrum. An old video on the electromagnetic spectrum primarily for children, but still helpful.

SR: Simple animations on special relativity at NYU.

Notes (pdf) for the derivation of length contraction.

SR: On Wikipedia, a quote of the "Galileo's ship" passage from Dialogue Concerning the Two Chief World Systems

SR: A translation of "Electrodynamics of Moving Bodies", Einstein's original 1905 paper on special relativity. Here's a pdf (1.9 MB) of the original article in German pubished in Annalen der Physik.

A video with a description of the Hamilton speed of light experiment. (This version is from a little hile ago.)

SR: For a little more on Ole Roemer's determination of the speed of light see the wikipedia article.

SR: From the United States Naval Observatory, the UTC reference time.

SR: A video highlighting the use reference frames in the Olympic coverage of the men's 200 meter event. See also the race at the London 2012 games. The interesting bit starts at about 3:30.

History

SR: An online exhibit on Einstein hosted by American Insitute of Physics.

Additional Reading

SR: Dan Styer, Relativity for the Questioning Mind

SR and Einstein: Dennis Overbye, Einstein in Love (A ``1st half" biography of Einstein. It ends in 1915.)

SR and Einstein: Abraham Pais, Subtle is the Lord (A full biography of Einstein that has a careful treatment of the science.)

QM: Louisa Gilder, The Age of Entanglement

Last modified 2 October 2025