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“Gravity is a habit that is hard to shake off”

April 20, 2013

It turns out that I couldn’t stay away.

About 15 months ago I decided that it was time to close down this blog.  My reasoning, more or less, was that I needed to be more “serious.”  I had just finished my PhD and started my first postdoc, and I reasoned that if I really hoped to “make it” as a physicist then I couldn’t afford to waste time writing long, rambling posts about physics and semi-physics topics that are outside of my real research.

But I have missed blogging during the last year+.  And I have come to realize that blogging was more than just a fun way to spend idle time.  In fact, I think blogging provided me with something really valuable that I will need going forward.

It seems to be true, at least for me, that the only way to really learn something is to teach it to someone else.  From my perspective, teaching an interesting idea to someone else has three important effects on the teacher:

  • First, teaching forces the teacher to sharpen their own thinking: to identify the features of the idea that are most essential, to develop multiple parallel ways of understanding and explaining the idea, and to tie the idea firmly to a wider base of knowledge.
  • Second, teaching cements the idea in the teacher’s own memory.  There is no better way to learn a story than to become the storyteller.
  • Third, and perhaps most importantly, teaching allows one to reconnect in a personal way with the excitement behind the idea being taught, and to rekindle one’s love for the topic.

In short, this blog has been my outlet for teaching ideas that I love.  And I have realized that such teaching is immensely valuable for me, not just as a hobby, but as a tool for professional and personal development.  I love physics, and I want to make a career as a physicist.  This is a surprisingly daunting goal sometimes, but, in my final analysis, it turns out to be precisely the reason why I need to “waste time” blogging about physics.

So Gravity and Levity is back!  Try to contain your excitement.



I think the time has also come for me to make a slight shift in policy.  I had originally imagined that Gravity and Levity would serve as a locus for conceptual discussion of ideas in upper-level physics, and for this the idea of preserving my own anonymity (and that of other commenters) was valuable.  Physics students are often quite insecure, after all.

But now I have come to understand that this blog is by necessity a very personal endeavor.  To be simplistic, Gravity and Levity is not really a blog about physics; it is a blog about myself and the way I think and feel about physics.  And so it makes sense to acknowledge that personalness directly, and to explicitly tie this blog to my own identity.  It was never much of a secret anyway.


So let me introduce myself.

005My name is Brian Skinner.  I am a 29-year old postdoc in theoretical condensed matter physics at the University of Minnesota, where I also completed my PhD.  My undergraduate years were spent at Virginia Tech, where I studied physics and mechanical engineering.  My childhood was spent in lots of  different places, since my father was a fighter pilot in the US Air Force and our family moved every year or two.  I have an arthritic right knee and a receding hairline.

To the right is a picture of me looking like I’ve never seen a camera before.

One benefit that will perhaps come of introducing myself directly is that it will allow me to communicate in a more personal way the uncertainty and fear that comes from trying to make a career as a scientist.  My job is one that makes me feel inadequate every day.  More or less every day I feel insufficiently intelligent, insufficiently motivated, and insufficiently hardworking to achieve my goal of becoming a competent physicist and/or physics professor.  And I suspect that many other hopeful scientists feel this way.  I truly don’t know whether (or to what degree) I will “make it” as a physicist, but perhaps some public documentation of my own attempts to do so will provide a bit of catharsis to others who feel similarly inadequate.

Finally, I think the future of this blog will also contain less hesitancy about getting “off topic.”  To whatever readers I may have, be warned that I intend to consider Gravity and Levity as my outlet for discussing and developing any ideas that seem interesting and/or profound to me.  Such ideas will mostly have to do with physics, but I consider myself to have no allegiance to any particular discipline or professional banner.


I look forward to the future of G&L!  Thank you to all of you who read it.  It is a pleasure to meet you.



[The quote in the title of this post comes from Terry Pratchett’s novel Small Gods, which I have never actually read.]

7 Comments leave one →
  1. April 21, 2013 12:07 am

    Welcome back! We missed you. Blogging made me a believer in Sapir-Whorf.

    What do make of this?

    Click to access PhysRevLett_110-168702.pdf

    • Brian permalink*
      April 26, 2013 10:44 am

      Sorry to be slow to reply. The truth is that I’m not really qualified to comment on that paper. I do, however, feel like there’s something fishy with the way they’re treating entropy. Treating entropy as a “force that keeps your future options open” seems funny and unconvincing to me. But, again, I will assume that the authors have more qualifications than I do.

      I found some more intelligent commentary here:

      • April 26, 2013 11:32 am

        Well you’re better qualified than 99.9% of us! The entropic force idea might have kind of bad rep because it was originally proposed by Verlinde as an explanation for gravity. Have no idea the merits of that proposal, but it certainly doesn’t seem to have gained much traction. (Pun intended.)

        But this paper sure made me think that something might be there. I find the idea of using of inital paths to parametrize the configuration space kind of interesting. It’s a weird combination of the calculus of variations with thermodynamics. I wouldn’t have given it much credence if that hadn’t managed to produce some pretty rich “behavior” with some relatively parsimonious assumptions.

  2. Erin permalink
    April 21, 2013 8:28 am

    This was one of my favorite blogs — it’s great to see you back!

  3. sabre51 permalink
    April 22, 2013 10:30 am

    This sat at the bottom of my feed aggregator for the whole year, and seeing this today was awesome. I like the new direction, let’s do some (sort of) physics!

  4. Lagrangian Mechanic permalink
    April 22, 2013 9:48 pm

    Good to have you back! When I saw the non-zero number sitting next to the blog name in my RSS reader I figured it was just a reader glitch mistakenly picking up old posts. Very glad to see that wasn’t the case!

  5. mctizzz permalink
    May 22, 2013 10:35 am

    Glad you started this back up, I just finished my BS in physics and am headed to grad school soon. I discovered this blog in 2011 and have since read just about every post. I’ve used your blog as a source of inspiration, reminding me why physics is awesome and why I’m in this for the long haul. Look forward to catching up on your posts again.

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