cosmos: the untold story

PerplexedjenlucIt's been a whirlwind couple of weeks, and thus I am only now getting around to writing about the first "Journal Club" workshop on communicating science here at KITP. (You can find the audio/video and PowerPoint slides here, and a complete list of upcoming workshops here, if you're truly interested in the weird kinds of things I'm trying out to further the cause. Honestly? I suspect a couple of the more experimental workshops might bomb. I still think they're all approaches worth trying. One never makes any progress unless one is willing to take the occasional risk.) The theme was about "Finding Your Narrative: A Different Kind of Reductionism." I've learned over the course of my varied career that the trick to all good science communication is being able to boil a complicated science story down to its most basic components — the "core narrative" — to which one can then add layers of detail and complexity to tailor the narrative to a wide range of target audiences.

The main point I tried to get across in that first workshop is that this is not the same thing as the "dumbing down" epithet that many physicists like to fling at popular approaches to difficult subjects. That accusation stems from a misunderstanding about the process at work. It's fundamentally no different from the reductionism that drives most of physics: reducing the complexity of nature to universal fundamental mathematical laws that can be broadly applied to many different types of phenomena. The core narrative serves much the same purpose, providing the driving force behind every story. Don't underestimate the power of the core narrative! A large fraction of the broad appeal of the Harry Potter books stems from J.K. Rowling's skillful weaving of a narrative tapestry filled with every major literary archetype under the sun. (Just how many times did she read Joseph Campbell's Voyage of the Hero?)

This ability to identify the core narrative elements of any story is more important than ever, frankly, given how the media enterprise is simultaneously branching out into new multimedia formats and distribution methods, and seeking to integrate all of those into one cohesive whole. It's no longer just about the morning newspaper or the evening news anymore. The harsh truth is that those who are serious about effective science communication have to be more flexible and adaptable than ever. Online content has changed the ways in which we communicate, whether we're talking about the blogosphere, YouTube, wikis, Websites affiliated with newspapers, books, TV, and so forth — yes, even PowerPoint lectures (TED talks, anyone?). Even if scientists have zero interest in communicating their research more broadly — and that's entirely their prerogative — the same set of skills will help them communicate far more effectively with their peers.

So anyway, I tried out this whole "core narrative" approach at my first "Journal Club" workshop, with the help of a few assembled KITP physicists. Specifically, I wanted to explore a potential narrative I latched onto, somewhat randomly, my first week in Santa Barbara, during a talk by Juegen Berges, who's visiting KITP from the Technische Universitat in Darmstadt, Germany. Like most of the technical talks here, the details were way over my head, but I could grasp the barest outlines sufficiently to realize that the standard cosmological model of inflation has a mysterious gap, and that gap needs fillin'.

First, a bit of backstory: the prevailing theory of cosmic inflation (at least partially supported by observational evidence to date) is that the universe started out as a singularity, popping into being thanks to a quantum fluctuation, and instead of having its short life perfunctorily snuffed out by its own strong gravitational field, it underwent a brief, very rapid period of expansion during the first fractions of a second of its "life" through one of those mysterious flukes of quantum uncertainty. (For those hungering for the details, there's an excellent summary for beginners by John Gribbin here, courtesy of Lawrence Berkeley Laboratory, although it employs the dreaded balloon analogy that the Spousal Unit loathes so deeply.)  

Inflation was first proposed in 1981 by Alan Guth to explain why our universe looks the way it does today. For starters, the universe apparently looks the same on opposite ends of the sky — dubbed "the horizon problem" — which indicates that those regions of space were once very close together. Second, spacetime is pretty much flat; the cosmos is constantly teetering on the edge "between eternal expansion and eventual recollapse," to borrow Gribbin's phrasing. Inflation explains how this state of affairs originated.

Now, I rarely cover theoretical physics or cosmology, so my knowledge is a bit, um, scatty on the details. Rather than boning up on inflationary theory to make a good impression — I'm married to a cosmologist, it would have been so easy — I opted instead to swallow my vanity and let my ignorance be displayed for the assembled physicists to see. This is tough to do, especially as a woman operating in a male-dominated environment, but I think it's important to do so when you're striving for better communication. It brings the level of discourse way down, for starters, and drives home just how wide the communication gap is between physicists and the general public. As an added bonus, it helped deepen my own understanding in the process.

For instance, I discovered that I harbored a fundamental confusion about the inflationary model that I suspect many non-scientists share: the Big Bang actually comes after inflation and the initial "birth" of our universe from a tiny singularity/quantum fluctuation. We have a prequel (inflation), and a sequel (the Big Bang), but the problem is, physicists don't really know what happened in between those two narratives. They know there has to have been a "reheating" period, because that's what provided the energy behind the Big Bang. But next to nothing is known about the actual mechanism by which this came about.

Don't take my word for it, either. Check out the Wikipedia entry: there's literally just a few sentences about this "reheating phase," to wit: "The end of inflation is called reheating or thermalization because the large potential energy decays into particles and fills the universe with radiation. Because the nature of the inflaton is not known, this process is still poorly understood, although it is believed to take place through a parametric resonance." That segment reminds me of the famous Sid Harris cartoon where two physicists are looking over a complicated equation, and at one point, the chalkboard simply reads, "Then a miracle occurs." One of the physicists comments, "I think you need to a be more specific here in step 3…."

So the cosmos has an untold story, at least so far as the general public is concerned. Why did I pick this particular narrative out of all the first two weeks of talks I attended at KITP? Well, the birth of the universe has broad appeal, so you don't have to cast about too hard for a compelling overarching framework. It's got a couple of those universal archetype story arcs: the classic "origins" myth, and also elements of a "coming of age" motif. Our main character is the universe itself, from the moment it popped into being as The Little Singularity That Could, and we proceed to follow its evolution as it develops into the mature cosmos we see today — the Voyage of the Hero. Plus, there's a mystery as the story's central conflict — how did our protagonist get from that tiny singularity to the vast, awe-inspiring cosmos we have today? ("The Universe: The Missing Years.") And everyone loves mysteries.

Finally, Berges is a good speaker, and when he was discussing the prevailing theoretical mechanism for reheating — "parametric resonance," still very much a stub on Wikipedia — he stopped briefly to demonstrate a simple pendulum motion (a classical physics example of parametric resonance), and explained that it was like the pendulum, with each pass, got a little extra "kick" of energy, which gradually built up to cause the reheating. So I had a visual element to grab onto. What can I say? It caught my imagination, and a tiny spark was lit. I wanted to know more. So that's what I picked as my focus for the interactive portion of my first workshop. (Scientists take note: it really can come down to something that basic. You must ignite that tiny spark in your audience and make them want to know more.)

In short, I had all the requisite elements to craft a compelling narrative. I just needed to flesh out the details — which can be tricky when you're dealing with highly technical physics stuff, and even trickier when the physicists themselves haven't quite got a handle on the problem. But we worked through it, step by step, and slowly put together a workable framework. Once upon a time, there was a little singularity, plucked from short-lived obscurity by sheer quantum will and a bit of random luck — a violent outward push that countered the more "natural" tendency to collapse out of existence, courtesy of a mysterious "benefactor."

And just what was that benefactor? Cosmic inflation! Guth's original inflationary model has since been improved upon, most notably by Andrei Linde, Andreas Albrecht, and Paul Steinhardt, among others, and there are now a bewildering array of inflationary models to choose from — variations on a theme, if you will. See, Guth's original model didn't account for the critical reheating phase. (The shortest explanation is that the cosmic evolution decays through bubble nucleation, which doesn't generate radiation, ergo, no reheating.) So the three gentlemen mentioned above proposed an alternate model ("new inflation," or "slow roll inflation") in which inflation results from a scalar field (and associated particle) — known as the Inflaton! — rolling down a potential energy hill. Think of coasting downhill on a bicycle. As the hill becomes steeper, you roll faster and faster. Inflation occurs at the point where the hill isn't very steep, and ends when the slope becomes steeper. The extra energy acquired as the scalar field picks up speed gives rise in turn to reheating, setting the stage for another critical growth spurt: the Big Bang. Our protagonist has been expanding and maturing ever since — apparently at a faster and faster rate.

That seems to be the prevailing thinking. And that extra "kick" of energy at the steepest point of the potential energy well is the parametric resonance. Another useful analogy for parametric resonance emerged during the discussion: a parent pushing a child on the swing. With each push, the parent matches the speed/frequency of the swing, and those energies add together, so the child swings higher and higher, getting extra infusions of energy rather than letting entropy run its usual course. (My question, naturally, when applied to reheating, is, who's doing the pushing for the cosmos? That's what physicists are trying to figure out.)

And thus, Berges' simple demonstration of a pendulum to illustrate parametric resonance has been transformed into a well-developed narrative framework, with (I'd wager) broad commercial appeal. In fact, I smell bestseller, with just a whiff of movie rights. I'm thinking high concept: Batman Begins for the cosmological crowd. Christian Bale could play the Inflaton, in black tights with a scalar field pattern and a giant "I" emblazoned on his chest, with Liam Neeson guest-starring as Parametric Resonance. That just leaves the casting of the Cosmos — maybe Daniel Radcliffe of Harry Potter fame?

So that's what I learned in school these first few weeks: a crash course on the status of the inflationary model. I also cleared up some lingering confusion over the connection between electroweak symmetry breaking and the Higgs boson — but that's a topic for another post. At this rate, I'll be talking like a physicist with the best of them, just in time for March 14.

Talklikeaphysicst

7 thoughts on “cosmos: the untold story”

  1. Jennifer, if I may briefly hijack this topic, I wanted to say that I’m almost done with “Black Bodies and Quantum Cats” and I’m really enjoying it. I think if I’d have read something like it while still in high school it could have helped me make up my mind about studying physics a lot sooner. Thanks for writing it, as well as this blog.

  2. It is interesting that reality begins with chaos at the subatomic realm of reality and develops into a system of order at the human perception realm of reality. It appears that not all reality is equal. It is also interesting that at the subatomic level of reality there is no rational activity where as at the human perception of reality there is an abundance of rational activity that provides a functional reality that is comprehensive and ordered. Could this be a proof of a universal intelligence?

  3. I would also like to comment on the logical fact that “things that ae equal to the same thing are equal to each other”. It follows that no matter what you call something; it is still what it actually is.
    No matter what you call the ability to produce rational and comprehensive effects; it is still the same phenomena. Producing a person or producing an automobile takes different processes. However, the ability to understand physical reality and to manipulate physical reality is the same process.
    Any comments on this theory will be much appreciated.

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