Tag: relativity

As simple as possible, but no simpler

Posted on by Ashutosh Jogalekar

by Ashutosh Jogalekar

Physicists writing books for the public have faced a longstanding challenge. Either they can write purely popular accounts that explain physics through metaphors and pop culture analogies but then risk oversimplifying key concepts, or they can get into a great deal of technical detail and risk making the book opaque to most readers without specialized training. All scientists face this challenge, but for physicists it’s particularly acute because of the mathematical nature of their field. Especially if you want to explain the two towering achievements of physics, quantum mechanics and general relativity, you can’t really get away from the math. It seems that physicists are stuck between a rock and a hard place: include math and, as the popular belief goes, every equation risks cutting their readership by half or, exclude math and deprive readers of a deeper understanding. The big question for a physicist who wants to communicate the great ideas of physics to a lay audience without entirely skipping the technical detail thus is, is there a middle ground?

Over the last decade or so there have been a few books that have in fact tried to tread this middle ground. Perhaps the most ambitious was Roger Penrose’s “The Road to Reality” which tried to encompass, in more than 800 pages, almost everything about mathematics and physics. Then there’s the “Theoretical Minimum” series by Leonard Susskind and his colleagues which, in three volumes (and an upcoming fourth one on general relativity) tries to lay down the key principles of all of physics. But both Penrose and Susskind’s volumes, as rewarding as they are, require a substantial time commitment on the part of the reader, and both at one point become comprehensible only to specialists.

If you are trying to find a short treatment of the key ideas of physics that is genuinely accessible to pretty much anyone with a high school math background, you would be hard-pressed to do better than Sean Carroll’s upcoming “The Biggest Ideas in the Universe”. Since I have known him a bit on social media for a while, I will refer to Sean by his first name. “The Biggest Ideas in the Universe” is based on a series of lectures that Sean gave during the pandemic. The current volume is the first in a set of three and deals with “space, time and motion”. In short, it aims to present all the math and physics you need to know for understanding Einstein’s special and general theories of relativity. Read more »

Reality Has Left The Building

Posted on by Thomas O'Dwyer

by Thomas O’Dwyer

Our world (made of atoms) is crammed with paradoxes. Particles act like waves, waves like particles And your cat can be dead and alive at the same time. Just step through your looking glass and welcome to the quantum world. “If you think you understand quantum mechanics, you haven’t understood quantum mechanics,” the physicist Richard Feynman once said. Of course, the non-scientific reader may respond, “Why would I want to understand it?” If a genius like Feynman became lost in the twisting labyrinth of the quantum world, abandon hope all ye who expect to become enlightened here.

Schrödinger's cat: Every event is a branch point. The cat is both alive and dead but the "alive" and "dead" cats are in different branches of the universe that are equally real but cannot interact with each other. (Wikipedia)
Schrödinger’s cat: Every event is a branch point. The cat is both alive and dead but the “alive” and “dead” cats are in different branches of the universe that are equally real but cannot interact with each other. (Wikipedia)

Quantum theory is famously opaque, and it drew dismissive grumbles from Albert Einstein. He was one of many superior minds who worried that science was abandoning its high road of rigorous clarity to dabble again in the murkiness of faith and superstition by even pondering the notion of quantum reality. Alive-dead animals, parallel universes, the existence of all times past present and future? These were for April 1 spoofs, right guys? Yet, whether one is aware of it or not, quantum mechanics has given us lasers, smartphones and many esoteric electronic components, like tunnelling diodes, from which we build our devices. They come with a weird label that says, we made them, and they work, but we don’t quite know how. Quantum computers will soon solve problems well beyond the reach of present-day digital machines – complex chemical analyses, dynamic biological processes. These will be of use to the pharmaceutical industries, and they will also model complex systems like financial transactions and climate changes. Read more »