Guest Post: Lisa Randall on Writing Knocking on Heaven's Door

By Sean Carroll | September 20, 2011 8:20 am

Lisa Randall is a friend and collaborator, as well as a science superstar. She is one of the most highly cited physicists of all time, for a variety of contributions to field theory and particle physics, especially her work with Raman Sundrum on warped extra dimensions. Her first book, Warped Passages, was a major success, which naturally raises the question of what one does next. (Besides writing papers, I mean.)

So we’re very happy to welcome Lisa aboard to guest blog about her new book, just out today: Knocking on Heaven’s Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World. (Among other virtues, this book has the single most impressive collection of blurbers of any book ever written, from Bill Clinton to Carlton Cuse.) From personal experience I can verify that writing a book doesn’t just happen; it’s a tremendous commitment over an extended period of time, and once it’s done there’s not much chance to go back and change it. So deciding to write a book at all, and more importantly how exactly to target the writing, is a delicate and critical process.

While Lisa hasn’t yet become a regular blogger, she is active on Twitter, where you can follow her at @lirarandall.


In conjunction with the publication of Knocking on Heaven’s Door, I thought I’d take advantage of Sean’s kind invitation to post on Cosmic Variance to explain my motivations in writing my book. I haven’t done a lot of blogging myself but I am impressed at the care and interest that go into science blogs. They are a way of sharing developments as they happen and an opportunity to have meaningful discussion of results.

I talk about a lot of science in my book. So I thought rather than summarizing it all—at least in this post—I’d focus on the question of why I wrote this particular book. I waited several years before even considering embarking on a second book project. I certainly didn’t want to simply repeat the content of my previous book, and my own personal goal is always to branch out into new arenas—in this case into new types of writing–while still remaining true to my physics roots. I didn’t know the exact book I was after but I did know some of the topics I considered important and timely.

These topics fell into several categories. First, I wanted to give an accurate picture of what is happening in particle physics and cosmology today—both with experiments and with theory. Particle physicists know this to be the era of the Large Hadron Collider (LHC), the machine that is colliding together protons at unprecedented energies to test the nature of matter and forces at smaller distances than ever explored. The interactions between theorists and experimenters is more intense than it has been during the time I’ve been actively pursuing physics. That is because everyone realizes this interactions are essential with these challenging experiments to get to the right answers. I wanted to convey the excitement and implications of the research taking place there, so when discoveries are made, anyone interested can understand what was found and what it could mean.

Cosmologists too find this is an important time and I wanted to share some of the interest in that major topic as well. One arena that both particle physicists and cosmologists are excited about are experimental studies of the nature of dark matter. Many find this topic perplexing, whereas even if difficult to tackle experimentally, the underlying idea really is not. I wanted to explain a bit how I think about dark matter and how experiments are searching for its feeble and elusive effects.

But I wanted to do more than just summarize the physics. The second important category of ideas I wanted to address has to do with the nature of science itself, and how active scientists go about advancing their field. After writing my first book, I was struck by how we take for granted the key underlying principles in our research, and don’t always remember to share these basic, sometimes subtle, and critical ideas.

Although perhaps I shouldn’t admit this, I had an even more ambitious agenda in mind. The ideas that underlie science are critical to rational thinking in general and should be widely known, even by those silly few who don’t care about any specific science research topic. These ideas are broad and deep, and it would make a difference in many of today’s debates if they were more widely understood and applied.

So interwoven with the physics story I wanted another story about the way science works. At this point, you might have surmised that the book I ended up writing included these topics, so rather than talk about what I wanted to write, I’ll just tell about a few of the topics I cover in the book I eventually settled on.

I begin with some key ideas–frequently introduced through anecdotes. One such concept that is essential to the way physicists in particular go about their work is an “effective theory,” which tells us to focus on what is measurable when making predictions. The underlying ideas here are the notions of “scale” such as energy or distance scales, and what it means to be right and wrong—both themes that resonate in other topics I’ll later address. I’ll later use scale to categorize what we know about matter— from the interior of an atom to the remote edges of the cosmos–and how the LHC and other particle accelerators, as well as various astrophysical probes, help us access successfully more remote scales.

The first section also expands on the nature of science, taking Galileo, whose work recently held its four hundredth birthday, as a departure point. Given my book’s title, I figured I also had to address the relation of religion and science (though that is not what the title really refers to). Aside from the obvious historical relevance, what I was really interested in were the questions of why we have this debate, as well as how thinking about scale as a way of categorizing what science really tells us helps us understand and clarify some of the confusions

There are many other ideas about science including risk and uncertainty that are woven into chapters with more detail than you might even want about the actual physics. General discussions of truth and beauty and how physicists suggest models of matter or the universe, as well as top-down versus bottom-up physics and how model building contrasts with string theory are used to frame discussions of how we theorists go about our business. The book also delves into the role of creativity in science and the relation between science and technology–both important topics I enjoy thinking about.

Yes Knocking on Heaven’s Door covers a lot of territory. But it’s a big story, and one well worth telling And in case you were wondering, the title refers to accessing the edges of knowledge—a worthy goal for all of us.

CATEGORIZED UNDER: Guest Post, Science, Top Posts, Words
  • psmith

    Oh woe is me, there is no Kindle version.

  • Ron Crockett

    There is a Kindle edition, which I will download shortly.
    I have been waiting all year to read this book. Why? I believe Dr Randall is performing a most important function. Over my lifetime the creation of a well trained and educated society has lagged. But now with this book she is opening the gates for everyone and anyone to learn about everything.
    Good luck to all of you.

  • DBrown

    Galileo is not a good example to bring up – despite everyone knowing at the time that circular orbits for planets just didn’t aggree with experimental observed data (after great efforts and valid experimental data being used) Galileo just KNEW that the planets did travel in circular orbits (the Greeks and many later experts weren’t dumb, people.) So, despite facts Galileo still believed he planets did move in circular orbits – in his ‘free fall’ experiments and resulting laws of action/motion Galileo required circular motion for all his ‘natural’ objects when placed in motion (when not acted on by an outside force!) Talk about failure of the scientific method and getting it wrong because you believe something and refuse to accept observed facts. No wonder he refused to exchange ideas with Kelper since to acknowledge Kepler would be to admit he got it totally wrong and that he had tried to imposed his false beliefs on the real world. Yes, Galileo knew the planets went around the Sun but he refused to accept that the orbits weren’t circular.

  • Roger

    The problem with the Galileo story is that he had no proof that the Earth went around the Sun, and his arguments were no more scientific than those of the Church. Motion is relative, according to 20th century relativity. He is not such a good example of science, and not a good example of dealing with religion.

  • Phillip Helbig

    I know this is off-topic but maybe I’ll get a response here. I would really like a separate RSS feed for comments. Many of my favourite blogs have them. Especially on a blog with many comments like this one, one needs some method of following new comments which is better than looking at (in theory) all old posts.

    If I just can’t find it, someone point me to it. If there isn’t one, why not?

  • Joe Shobe

    Thanks, Sean, for inviting Lisa to your blog. I read the first book and loved it, and am excited about the goals of this book. Science needs to take on the real world; to take its rightful position in helping to better understand our environment and to set our direction and courses of action as a species. Gallileo as a starting point is fine.

  • Navneeth

    5. Phillip Helbig,

    The RSS button on the address bar of my browser lists one feed, among others, for the comments in this post. So if you’re looking for separate comment feeds for each post, it’s available.

  • Smith Powell

    DBrown and Roger miss the point about Galileo, science, and religion. Of course, Galileo’s ideas were not perfect and, of course, he ignored Kepler. I am sure ego had a lot to do with the fact that he gave no credit to Kepler, but I suspect Galileo, as noted, was not willing to give up on circular orbits for the planets. Circular orbits for the planets was a powerful idea and difficult to dismiss. Note that Copernicus also relied on circular orbits in the construction of his model. Note that Galileo did change many of his opinions over the course of his life. My goodness, he wasn’t perfect.

    But, he did make great strides in our understanding of astronomy and, in the process, made great strides in developing the scientific method. He did put considerable effort into observations. His observations of the phases of Venus clearly disproved the Ptolemaic view upheld by the Church. It is true that his observations did not rule out the Tychonic model in which the planets revolved around the Sun that, in turn, revolved around the Earth. Galileo relied on his flawed theory of the tides–made after extensive observations–to rule out the Tychonic model.

    At any rate, in addition to his reliance on observations, Galileo relied on models that fit his observations. Model building based on observations are hallmarks of modern science.

    In addition to his reliance on observations and models, Galileo relied on simplicity or beauty as guides in choosing one theory over another. One might even characterize this step as one that invoked Occam’s Razor. Again, this line of argument is in line with modern science.

    Thus, I think Roger’s assertion that “his arguments were no more scientific than those of the Church” are in error. Roger goes on to state that Galileo is “not a good example of dealing with religion”. I am not sure what he means by that statement. Clearly, if one invokes the wrath of the Church, as Galileo did, one is in danger of severe punishment should the Church have the power to impose its will. Secondly, Galileo’s reliance on his new scientific method provides a powerful contrast with the Church’s reliance on authority and tradition as opposed to observation and model building.

    I look forward to reading Knocking on Heaven’s Door.

  • Roger

    Smith, Galileo did not build a cosmological model, as did Tycho and Kepler. It is not clear that he even understood Tycho’s and Kepler’s models. The Church was prepared to accept either of those models, if the evidence proved it. As you admit, the Galileo theory of tides was bogus, and the Venus phases did not disprove Tycho. The Church knew that Galileo was wrong scientifically. It was the Church that was relying on observation and scientific reasoning, not Galileo. If Galileo had simply written a book on the contemporary models, with the arguments for and against, he would never have gotten into trouble. It is embarrassing to see Galileo’s bogus arguments held up as good science, when they had been refuted.

  • Phillip Helbig

    “The RSS button on the address bar of my browser lists one feed, among others, for the comments in this post. So if you’re looking for separate comment feeds for each post, it’s available.”

    No, that’s not what I want—that would be too many. I want to see new comments on any and all posts. An RSS feed for each post is not much better than checking each post individually. Again, many of my favourite blogs have this feature. (Ideally, it would show just the oldest unread comment for each post for non-threaded comments like those here.) I guess it will be another 10 years before blogs get up to the same level of features as a good newsreader on usenet 20 years ago. :-(

  • spyder

    the title refers to accessing the edges of knowledge

    Mama, put my guns in the ground
    I can’t shoot them anymore.
    That long black cloud is comin’ down
    I feel I’m knockin’ on heaven’s door.

    Knock, knock, knockin’ on heaven’s door
    Knock, knock, knockin’ on heaven’s door

  • Aron Levie

    I hope the book brings something new-and not again the same hero stories about the great scientists with the same old anecdotes we already have heard a 100 times.It’s very diffucult to write a popular science book without recycling the endless stories about Gallieo and the tower of Pisa-Newton and his apple Einstein and his thougt experiments Feynman and his bongo’s Hawking and his brave fighting against his ilness.Most of the time a glimpse inside a new popular science book is enough to say-there we go again-.Because the general public has a big interest in difficult things there will be always a market for new books which a promise to explain everything.Like the books of Hawking they sell like mad but almost nobody of the general public understands it-and so they buy the next book and hope that that one will bring salvation,etc. The publishers and writers make good money-but in the end it’s a waste of time for a good scientist to write them-better use your time to do real science!

  • Ray Gedaly

    Several years ago I was reading Warped Passages on the deck of a cruise ship. Music was playing in the background. Each chapter of the book begins with a song quote. By incredible coincidence, the song from the chapter I was reading started playing.

  • Albert

    Is it worrisome that the LHC has not turned up a shred of evidence for “extra-dimensions” or Randall-Sundrum “gravitons”?

    Is it a mistake to rigidly assume that the dark matter must be in the form of hypothetical subatomic particles, the mythical “WIMPs” which have not turned up in experiments for over 40 years?

    Do we need to question some of the “unquestionable” assumptions that led us into this present state of malaise?

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  • Shahidur Rahman Sikder

    From the inception of imagination the very incidence of our intelligent mankind and from the very formula of imagination, there have been the expeditions of science viz. the start. With the improvement of imagination, the development of science is achieved and at the extremity of imaginative power came the result that everything of the universe is dwelling on the sea of imagination. That is to say- All the visible things of the real world are comparable to the imagination of nature of absolute space in absolute dimension i.e. in everything of the Nature’s plan is the play of imagination. See into- Cosmic answers-

  • Ian

    @8, It’s also worth noting that Galileo insulted the Pope (his sponsor) in his ‘Dialogs’ incurring his wrath, and desired the re-interpretation of Scripture (a task reserved to the Church).

    Whilst Keplar is mentioned, no-one seems to reference his excommunication from the Protestant Church.

    What is also often ignored is that Roger Boscovich, the Jesuit polymath, was allowed to study the Copernican model in developing his atomic theory, and was instrumental in convincing the Royal Society in adopting it.

    Eitherway, I too look forward to reading this book.

  • Michael O’Brien

    I’m not looking forward to reading this book. I would expect to have to wade through too many poorly constructed sentences (grammatical errors being the least of the offences), just like in her introductory posting to this blog.

    To wit: “to explain my motivations in writing my book”.
    People are not motivated “in” writing, they are motivated TO write.

    Or: “One arena (that both particle physicists and cosmologists are excited about) are experimental studies of the nature of dark matter.” (parentheses mine)

    Where did the word “are” come from? I mean the second occurrence of the word “are”. The one which should be preceeded by a comma. If the word “arena” is singular, then why not ‘is’ instead of “are”?

    Further: “One such concept that is essential to the way physicists in particular go about their work is an “effective theory,” which tells us to focus on what is measurable when making predictions.

    Is the “concept that is essential” an effective theory, as the sentence claims, or rather is the concept that is essential, one that a physicist ought to HAVE an effective theory, as a guide to the direction of progress?

    Finally: “The first section also expands on the nature of science, taking Galileo, …, as a departure point.

    Have we not had enough already?! Everybody (especially the technically oriented among us) ought to have an unmistakable intuition of the definition of the word EXPAND. It does not mean EXPOUND. Look it up!


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  • Lisa Randall

    Thanks all for the comments and interest. As for hero worship, not my thing either. The focus is not Galileo. It’s just a launching point in a single chapter (out of over twenty chapters) where I talk a little about key elements of science and one in which I talk about religion. The book is more geared to other aspects of science that I mentioned in my post as well as physics today.
    As for grammar, it’s been a busy week (Charlie Rose, launch, three talks on consecutive days (one of which was taped for C-Span Book TV), a couple of interviews, not to mention recommendation letter writing and going over physics projects). I spent a lot of time on the writing of the book to try to integrate many disparate ideas into a coherent whole. I (and others) read it and I corrected and rewrote it as carefully as I could while getting the book out in a timely fashion. It was hard work but I loved it too. I hope you can recognize some of the positive aspects of what enters this book.
    PS This comment is also quickly written. I have a plane to catch!

  • tony nicholson

    There is so much misuse of grammar these days that I am amazed the subject has arisen in this instance. Is it an attempt to denigrate the highly respected scientist? Or is it a chance to prove
    one’s superiority in a particular sphere? Whatever the motives, it certainly does nothing to
    illuminate the subject being discussed.

  • Doug

    And half of those aren’t grammatical rules, but rather stylistic preferences that certain segments have fetishised following Strunk and White.

  • Dilaton

    Bringing up the “grammar issue” in this particular way illuminates only the state of mind of commenter 18. who did it … :-)

  • Cloe

    The professor of my husband’s english literature class, didn’t believe in commas. I use them, at the point, in which I literally, take a breath. :) Each of us has our own style, if you’re unsure, then read: The Color Purple. Perhaps most of us are aware, that the english language has degenerated and continues to do so? I’m sure that no one here can speak caveman, err correction, caveperson?

    I look forward to the read (oh my, such bad grammar!). I’m rather sure, that what I find of importance (science) will be well explained, and her (yes, “her mathematical language”) mathematical language will be perfect. :)

  • raymundo

    grammar overrated is

  • JimV

    I would not have brought it up myself, but having been raised by an English major (i.e., someone who majored in English in college, not a member of the British military) and relentlessly corrected, seeing bad grammar can be painful to me also, like listening to music which is out of tune.

    However, I would certainly trade my grammar abilities for Dr. Randall’s scientific abilities, with as much cash as I could muster thrown in also, as well as perhaps my left arm (if that would tip the scales).

  • jackd

    Wow, when did Sean’s place get so infested? Aside from the grammar whiners, we also have “Roger” who is either Roger Schlafly (of Conservapaedia infamy) or a fan of his.

    Dr. Randall, I’m another who has read Warped Passages and appreciated it. I’m looking forward to Knocking.

    If you have the time to look back to the first book, I’m very curious which, if any, of the ideas explored there have been strengthened or weakened by results from more recent experiments?

  • Thomas Barton, JD

    Perhaps the science superstar that Ms. Randall is , and I do not dispute that the word is has several meanings depending on which version of string theory is indisputably correct or is it verifiable ? But I digress. I think Ms. Randall who is a superstar should team up with Brian Cox who also is a science superstar and the duo that they are and always will be can star in a remake of Moonlighting in which she plays the part played by Cybill Shepperd and Brian who is a superstar of science can star as the character played by Bruce Willis. In the first episode the two superstars of science can infiltrate the LHC site and working feverishly and in secret find the Higgs Boson hiding in plain sight in all the background noise down in the 115 to 144 GEV level. They will undoubtedly win the Emmy award in the US for best science superstar couple . That is all.

  • Ray


    Until testable predictions are verified with copious amounts of data taken from plenty of reproducible experiments, I’m not going to give string theory, extra dimensions, et al., any consideration.

  • sievemaria

    Mama take this badge off of me
    I cant use it any more
    its getting dark, to dark to see
    I feel Im accessing the edges of knowledge …

    accessing the edges of knowledge
    accessing the edges of knowledge …

  • Hill

    Can you productive leading physicists — I have people like Lisa Randall, Sean Carroll, Brian Greene, Stephan Hawking in mind — justify taking away so much time from doing research to write popular science books? Wouldn’t that be a waste of time when you could be writing groundbreaking articles instead? Leave popular science writing to professional science journalists and second-rate physicists. Just how much time do you waste writing a popular science book anyway? A year or two?

  • Phillip Helbig

    Note that John Barrow could turn out a dozen single-author refereed-journal papers and a couple of popular books in a single year. I once asked someone who knew him how much he works, and the reply was “pretty much 9 to 5”.

  • TimG

    #18, Dr. Randall spoke correctly with regard to “effective theories”. “Effective theory” is a technical term (see for instance, and she was saying the concept of “effective theories” is an important one to understand.

  • SLC

    OT but is Prof. Carroll or another of the bloggers on this site going to comment on the rather controversial result from CERN which claims to have detected neutrinos traveling faster then the speed of light in vacuo?

  • Bob Flisser

    I’m currently reading Warped Passages on my Kindle. I’ll definitely buy the new one when it’s released.

    And yeah, what SLC said! Is this Revenge of the Tachyons?

  • Stormy Sloane

    The standard story is indeed incorrect, and the actual issues involved with the Galileo affair were scriptural interpretation and church politics, not “science versus religion.”.

  • Imgahn2u

    There is nothing wrong with scientists writing popular books. Thats one way the spark of curiosity and wonder about the universe is ignited in the minds of the next generation of scientists. Writing scientific papers that push the edges of science is hard and difficult work. Taking time off, to write popular books spreading the idea of logical thinking and thought processes is very worthwhile as well. As far as grammar goes (mentioned above). Those who cannot think creatively usually rely upon rigidy and rules for a sense of comfort and a sense of accomplishment. Give a little slack to the creative genious of scientists. Most of scientists have terrible handwritting as well – but who cares? I don’t!

  • Pete Dunkelberg

    What a sorry lot of carping commenters! I feel like I should buy the book as a small measure of compensation. Amazon tells me it’s already on my wishlist, but they moved it to the top, so maybe I will.

  • Imgahn2u

    Physicists, Cosomologists, String Theorists etc… know and understand the grammar of the universe (Real/Complex analysis, Group theory, Differential geometry, Lie groups, Differential forms, Homology, Cohomology, Homotopy, Fiber bundles, Characteristic classes, Index theorems, Supersymmetry and supergravity, etc…) Harping on grammer is pedantic :)

  • melvin goldstein

    Numbers are the Supreme Court of science. However Godel proved that we may not prove everything. There are Physics Foibles!! Don’t give up!!

  • the lord thy god

    Written communication has rules, if the rules are not followed ,communication suffers.

  • Shantanu

    Lisa, are you still sanguine that LHC will find evidence for extra dimensional models, given that nothing has been seen so far in LHC , Tevatron or other experiments designed to look for extra dimensions?

  • Phillip Helbig

    I’m pretty sure I replied to some comments here, but now those comments and my comments on them are gone. It would be nice if the number stays and “comment removed” (perhaps with a reason) replaced the original text.

  • Wes

    I am so glad that this book was written. It is good for my head and heart, and I’m not finished with it yet. I don’t WANT to finish – I wish it were (for the grammarians above) longer!

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  • John Anderson

    How far can popularized science go?
    Multiverses and M-theory will never be made comprehensible to a general
    audience even by expert expounders like Randall and Greene. (I do not claim to
    understand these subjects.) It results in a priesthood of technology and
    science who profess concepts beyond the layman’s ken. The new elites are
    practically as elevated and unassailable as Aristotle was in the Middle
    Ages. This isn’t good for the current intellectual environment and it has
    implications for participatory government. Can education effect this?

    A thought from Percy Bridgeman in Harpers about the meaning of
    uncertainty way back when it was a new idea: “The immediate effect will be to let loose a veritable
    intellectual spree of licentious and debauched thinking.”


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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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