Lisa Randall’s new book is about to come out, it’s entitled Knocking on Heaven’s Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World. It turns out that it’s really two books in one, both of which are much better and more clearly written than her previous effort, Warped Passages. One reason might be help from well-known novelist Cormac McCarthy who is thanked (together with Lubos Motl) for extensive feedback during the book’s writing.
One of the books here is not surprising, it’s somewhat of an update of the earlier book, emphasizing the story of the LHC. This includes a very detailed explanation of the history of the LHC and how it works, together with a wonderful and clear examination of the design of the ATLAS and CMS detectors, as well as the physics they are looking for. All in all, this is about the best popular-level explanation of what is going on at the LHC that I’ve seen, up-to-date as of a few months ago.
The second book inside the book is of much wider scope. Randall’s prominence as a scientist has brought her into contact with a wide range of people (Bill Clinton’s endorsement is on the book’s cover), including artists, government officials, financiers, technologists, and a wide range of thinkers of different sorts. She has taken on the role of a public face of physics, and has written a book which is in part a very general defense of science and the materialist, rationalist world-view that modern science is based on. Her experiences with non-scientists are reflected in how she writes about a range of topics, including the notion of beauty in science, the question of how to analyze risk, the relation of religion and science and much more. Her discussions of these topics are uniformly sensible, although rather conventional and unsurprising.
In the end though, the book left me somewhat uncomfortable. Understandably, Randall is overly enthusiastic about the prospects of Randall-Sundrum models, describing them as “an idea that probably stands as good a chance as any of being right” (most theorists would assign a much higher probability to SUSY). She writes that, if correct, the LHC is expected to see KK gravitons at a mass of around 1 TeV. Recently limits on masses of such particles have been pushed up to nearly 2 TeV. These extra-dimensional models were considered interesting but not especially plausible by most theorists pre-LHC. Like SUSY, they’re starting to be ruled out by the LHC, a process which may take a while until their defenders finally admit that the expected signals just aren’t there.
The time period of Randall’s career roughly corresponds to my own (she’s a few years younger), and, as she acknowledges, her field of model-building throughout this career has been dominated by string theory-inspired SUSY and extra dimensional models. These were never very convincing, and they are now biting the dust. From the experimental side, this is an inspirational story of the triumph of the scientific method and the huge achievements of the LHC machine and detectors, but from the theoretical side, the story of this period is darker and much less inspirational. It’s not something that makes the best topic for a defense of how science is conducted.
One odd thing about the book is the title, which for Randall carries a positive meaning that she acknowledges doesn’t correspond to the very dark one of the Bob Dylan song from the soundtrack of the Sam Peckinpah film. It’s a beautiful song, but one not about finding truth, but about getting shot in the gut and facing death, hopefully not relevant to particle physics in the LHC era:
Mama, put my guns in the ground
I can’t shoot them anymore.
That long black cloud is comin’ down
I feel like I’m knockin’ on heaven’s door.