Time contracted bus rides

Leonard Susskind's 2017 book on special relativity and classical field theory was such a joy to read. [1]

As the book is essentially a transcript of his theoretical minimum lectures, it felt like I was having a conversation with him the whole time. My desire to read this book was to brush up on my SR and to see how classical mechanics integrates relativistic effects, gearing up to tackle quantum field theory. My philosophy to studying physics is to get the big picture first, the physical principles and subsequently fill in the gaps. Sometimes, this happens out of curiosity but usually in time for when I need to apply the theory. As my Oxford Canvas login gave me the ability to watch other departmental lectures, I watched all the classical mechanics 2nd year short option and was better able to appreciate this book.

During the summer, I practically lost track of time on the bus and tube going up and down London. One time on my way home, this book actually made me miss a tube stop! I got really engrossed in how Susskind was merging electric fields with lagrangian mechanics that the tube announcements slipped into the background. At some point I looked up, realising I needed to get off at the current stop, in a rush, I scrambled, jumping up and grabbing my bag simultaneously, only to have the doors close on me... Defeated, I sat down, closed the book, and sighed. At this point, an elderly lady sitting next to me, slowly leaned over and said: 'I'm surprised you are so interested in field theory!' Still recovering from my defeat and absolutely confused, I looked at her with visible shock on my face.

How? What? How?

She subsequently revealed that she was a medical physicist before retiring and that she was taking the grand kids to the science museum today. She thought I was a physics PhD student! Flustered, I said I was only an undergraduate and that my interest in this was to build up my knowledge for applications in condensed matter and materials science.

If you are wondering where special relativity could be useful, look no further than at the device you are currently reading this on! To get the data that makes up this web page, satellites had to transfer the information to your device. For them to accurately send signals, they need accurate clocks. Special relativity is used to ensure the atomic clocks on the International Space Station and satellites are correct! Additionally, in chemistry, relativistic shortening of bonds partly contributes to mercury's low melting point and the colour of gold and caesium. 1.7-1.8 V of 2.11V in a lead-acid battery is due to relativity! [2]

The build up to the derivations provide so much excitement and the payoff is tremendous when the solutions are so elegant. The best make it look so easy.

I look forward to whatever Leonard Susskind writes next! Please be general relativity! 🙏

[1] Special Relativity and Classical Field Theory: The Theoretical Minimum 2017

[2] Ahuja, Rajeev; Blomqvist, Anders; Larsson, Peter; Pyykkö, Pekka; Zaleski-Ejgierd, Patryk (2011). "Relativity and the Lead-Acid Battery". Physical Review Letters. 106 (1): 018301. arXiv:1008.4872. Bibcode:2011PhRvL.106a8301A. doi:10.1103/PhysRevLett.106.018301. PMID21231773. S2CID39265906.