Peter Steinberg

Boom?

In the blog-about-a-blog, blogging-about-a-blog department: here is a fascinating post from yesterday's issue of Clive Thompson's always-excellent Collision Detection. 

Apparently if you look very closely at this video of Discovery lifting off (click on "WB-57 Chase Plane Video"), about 50 seconds in you'll see a white puff of cloud form around the shuttle. I watched the video myself and can't quite spot it, but I've been assured it's there -- it's just that the video is really shaky. Anyway, the cloud is caused by the deeply cool Prandtl-Glauert Singularity -- a sudden, supercold pocket of air generated by a wing that is moving at near the speed of sound.

A full explanation is here:

The clouds appear for the same reason that clouds always form, namely, that the air has cooled to the point that the ambient water vapor condenses. Flows around bodies and wings always change the temperature and pressure of the fluid ... At speeds near that of sound, the temperature and pressure variations occurring at every speed can also be exaggerated in steady level flight. The mechanism for this near-sonic exaggeration of the temperature variations is the so-called Prandtl-Glauert singularity which requires that pressure and temperature perturbations approach ±¥ as the flight speed approaches the ambient sound speed.

Someone once told me that just before the Concorde broke the sound barrier, if passengers looked out the window they could "see" sound waves forming along the wings. That's got a lovely poetry to it, but it's not true: What Concorde passengers were seeing were Prandtl-Glauert condensation clouds.

(Thanks to Boing Boing for this one!)

(Thanks Clive, now back to mine:) Now of course this is incredibly interesting, since almost everyone I know who sees this image thinks it is an image of a sonic boom.  Even more interestingly, colleagues of mine have started getting very interested in seeing sonic booms in RHIC collisions as a jet traverses the hot, dense medium we make there (as suggestedby the "triangular" emission patterns seen on the top right and lower left).  Not to try and propose anything here, but could we be mistaking some sort of "condensation" effect with a shock wave?  Of course, both of these phenomena are non-trivial consequences of objects interacting with a medium -- amazing in itself -- but perhaps it's a little premature to claim we really "understand" these new data.  Then again, with Quark Matter coming up next week, I may well have my worldview rocked yet again.

National Sysadmin Day (Thanks RCF!)

As most people know, we physicists are complete and utter slaves to our computers.  We can't be separated from email for more than 8 hours at a time (e.g., when we lie down, when we rise up, etc.).  We can't take data without enormous installations of PCs in our counting houses (often running a variety of operating systems...) and we couldn't even begin to think of considering looking at our data (beyond signals on a scope) without even larger installations of (nowadays) thousands of PCs, e.g. the RHIC Computing Facility.  RCF has been serving up billions and billions of cycles since the late 90's and continues to work long hours in a wildly diverse and evolving ecosystem of CPUs, disks (centralized and distributed), networking equipment, operating systems (most linux), mail servers, software packages, large experiments, small experiments, and annoying "liasons" from those experiments (yours truly representing PHOBOS these days).

You may have figured this out already (and thanks to Ofer for alerting me to this) but it's System Administrator Appreciation Day (which has been on the last friday in July since 2000).  So this is a personal (and collective) thanks to the hard-working people at RCF: we couldn't do anything without you guys!

Quark Matters

Reflecting on recent posts, I notice that I've been drifting away from work issues.  There's a simple reason however, in that Quark Matter 2005 the major conference in the field is coming up next week in Budapest, Hungary, and PHOBOS is gearing up for a new set of results.  I had some friends recently ask me what I do for 11+ hours a day during periods like this.  While it's hard to remember each particular day, suffice it to say that it's a linear combination of data analysis (mainly by the students and postdocs, who are always the real heroes of these conferences!), data review (HEP guys call this "blessing", but we nuclear people aren't as religious and fall into more agnostic camps), talk preparation, and rehearsals, rehearsals, rehearsals.  And it's not just singing and dancing better -- which does happen eventually -- but it's a kind of collective brainstorming process whereby ideas for each talk get clarified and then executed during the afternoon and evenings following.  I think the other collaborations have similar experiences, and there's really nothing like it.  Of course, it's very draining, so most of us are glad these things roll around only every 18 months or so!

Repeated Performance

 

A band so nice, I saw them twice.

I'm not really that kind of person that gets so obsessed with a longtime favorite band that he gets tickets to all their shows when they come through town.  OK, I lied: I'm completely that kind of person.  Teenage Fanclub is a Scottish power-pop that I've admired and followed closely since probably 1991, from their first album (A Catholic Education), to their most recent, the excellent Man-Made (made in my hometown Chicago, no less).  We're talking memorizing lyrics (through osmosis, not deliberate work) and guitar parts (more on guitars later) and seeing them live whenever possible.  But there's the rub: I've only had 4 chances to see them in my lifetime.  Once in college (1992, for Bandwagonesque), but I forgot to use my ticket due to a midterm (physics, probably), once near the end of my PhD opening for Radiohead (1997, for Songs from Northern Britain), once during my previous life in NYC (2001, for Howdy!) and now this past weekend in 2005, when they played two shows at the Bowery Ballroom.  Now you understand why I saw them twice, just to smooth things out a bit. 

"See you in 2009," Norman Blake (singer/guitarist) proposed, with Glaswegian accent and a wry smile.  What is this, the Olympics?  Just don't break up before then, guys.

Krumpers, Clowns, Quads, and Quarks

I really couldn't decide whether to classify this post as "Film" or "Sports".  Over the weekend I ended up seeing not one, but two documentaries: "Murderball" and "Rize".   In some sense these couldn't be more different  from one another.  "Murderball", which I saw at the Landmark Sunshine Theater down on Houston St., follows the lives of quadraplegic athletes who have risen to the elite ranks of Quad Rugby (essentially guys in custom wheelchairs who crash into each other -- when not trying to dribble every 10 seconds -- to get a little ball into their endzone).  "Rize" follows the lives of teenage "clown dancers" and "krumpers" as they rebel against dead-end lives in South L.A. by forming various troupes based on a hyperkinetic, and continuously evolving, dance style.  The odd part of seeing these movies in the same weekend was being faced with scoreboards superimposed at the bottom of the screen during climactic moments.  In the Quad Rugby case, it was usually "USA 10, CANADA 9" or something (the North American rivalry being the focus after a championship USA QR player defected to coach Team Canada after being cut from the US team).  In the Rize case, it was "CLOWNS 7, KRUMPERS 4", these being the competing factions (of course the oldest Krumpers having apprenticed in the group of Tommy the Clown, inventor of...well you get the picture).  So you see what I mean about not being sure if this post was about Film or Sports?

The thing which really struck me after walking out of Rize on Sunday night was that I had just paid $10+ each to see two documentaries in real movie theaters.  Where were the Hollywood products that I was trained to see?  And then I realized that I hadn't seen a good (original - remakes don't count) story coming out of Hollywood in a long time.  Even "Crash", which I also saw recently, had an elegant Altmanesque interweaving of multiple storylines that danced around each other and eventually all converged, but you could sort of see it coming, and you knew that the screenwriter knew that you wanted them to converge, to reach some satisfaction.  These documentaries, while not devoid of cheesy dramatic devices (e.g. scoreboards), which were introduced by clever deployment of footage gathered over years, boggled my mind since I couldn't imagine anyone making them up -- or if someone had, no-one would consider them plausible.  And yet, the Quad Rugby league is international, and these guys meet beautiful girls in bars and in the league -- i.e. the world has caught up with them. And yet, the Clowns and Krumpers compete in huge sports arenas, dragging most of LA's teenagers to come watch.  These are mass phenomena, even if you and me in the masses haven't heard of them yet.

So here's the sleight of hand where I make this a Quantum Diaries post, rather than a "what I did this weekend" post.  As we've been prepare for this year's Quark Matter conference, upcoming in August in Budapest, Hungary, which may be our last one for PHOBOS as a working experiment, I've been reflecting on how strange each of them have been in the last five years.  You walk into the conference with one picture of how the world is, based on the experimental data you're familiar with and scores of papers by theoretical physicists trying both to describe the world as it is, and how it really should be (if you could ignore certain pesky features of the data...)  And then you see a talk which shows you some facts that just don't "make sense", so clearly no-one could have made them up -- and suddenly you can't remember *not* knowing that fact as your previous view of things morphs to accomodate it, recontextualizing some of those old facts, and seriously problematizing some of those theory papers you've held so close.  So given the various rumors I've heard about how weird the copper-copper collisions are, which were meant to be so much smaller than gold-gold, and thus somehow simpler (or more like proton-proton) collisions to think about, I'm expecting nothing less this year. 

Kind of like being in a documentary, but the director is still getting more footage.

Quantum Diarists on Parade

So finally (in Part III of this series) I get to the actual conference itself.  The Gordon Conference in Nuclear Physics was held at Bates College in Lewiston, ME (about 30 minutes inland from Portland).  It covered a lot of ground (nucleon structure, RHIC physics, nuclear structure, astrophysics, fundamental interactions, etc.) with a wide sampling of the nuclear physics community, spread out over about 60 scientists, postdocs, and students.  Here we all are heading back from the conference photo on the way to a coffee break.

Among the participants was someone familiar to many of you: Sarah Phillips, fellow diarist and nuclear physicist.  Contrary to popular belief,  collisions of quantum diarists do *not* lead to any destructive side effects, even when nuclear physics is involved. 

Anyway, it was a nice conference overall, with wall-to-wall talks in the morning and evening and long periods of free time in the afternoons (which I used to keep up with a major PHOBOS meeting that I missed by being in Maine...)  It's really crucial to keep up with the other subfields in your line of work, and Gordon Conferences are usually focussed on precisely that, with lots of review talks.  Quite a few times I noticed issues that may be common between high energy nuclear physics and much lower-energy physics -- but too bad I won't have much time to think about it until after Quark Matter in August!

Lighthouses and Lobster Rolls

Let me skip the details of the drive from NYC to Maine, it being long (about 5-6 hours) and fairly uneventful (highway to highway - so not much scenery).  The real scenery was accessible when I got to Maine and poked around the south coast, which is saturated with beaches (overfull and touristy) and lighthouses (underfull and amazing).  The one right here is the Portland Head Light, on Cape Elizabeth (but not really *in* Cape Elizabeth, it seems...)  which is itself spectacular and has spectacular views of the ocean. 

Just a few minutes away, farther south on the Cape was Two Lights state park, which is right next to...well, two more lighthouses.  I managed to see one of them, since it was right next to where I got the best Lobster Roll I've ever seen or tasted.  Of course, I realize now that I screwed up by not venturing up the hill, since I only now realize that this is the lighthouse immortalized by Edward Hopper in 1929. Live and learn!

Street Life

So just before leaving for the Gordon Conference, I had a couple of errands to do (mainly getting myself sheared, a bimonthly tradition).  But as NYC is, one just has to walk a few blocks when you stumble on things like this, an Arab-American Cultural Festival on Bond Street.  Good excuse to get a merguez sandwich for lunch, hear some moroccan music as I ate, and catch a photo of these two as I headed back to the subway uptown.

Chronicles

Sorry to have been out of commission for the last week.  I was at the Nuclear Physics Gordon Conference in Lewiston, Maine (more on that soon), where we weren't allowed to hook up our laptop to the network.  Still, without network I was given the chance to hunt down the paper version of the Quantum Diaries article in the Chronicle of Higher Education.  And yow - they didn't post this stuff online.  Anyway, nice photo, Caolionn!  Not sure why they picked the most nefarious looking one of me...

Rockin' the 4th

So taking a moment's break from a busy schedule attending a major DOE review of RHIC Science & Technology, I thought I'd post some photos of what I did Monday afternoon.  In between struggling out of bed the day after getting back from Amagansett, and seeing lots of fireworks with some folks a few miles north of Manhattan (7 different shows up and down the Hudson), I jumped on the 1 train to take advantage of one of New York's greatest resources: free music in Battery Park, by by a raft of Matador Records artists.  I didn't stay long enough to see Yo La Tengo, but I did manage to catch sets by Laura Cantrell and Stephen Malkmus & the Jicks. 

Excellent sets both, but watching Stephen Malkmus, late of Pavement (one of my, and everyone's it seemed, favorites from the 90's) jump around, quasi-free-associate, and rock out in front hipsters, kids, elderly, and general neighborhood types alike was particuarly inspiring.  His style is not exactly accessible, but he evinces such intelligence and enthusiasm (as did the rest of the band, who seemed able to keep up, amazingly) both in songwriting and performing that most people seemed to find it a really winning show, despite some of the glum faces of the hipsters...

The real mind-bender, however, was that while the concert was free, there were absolutely huge lines to get in, mainly because they screened each and every person's bags.  And eventually they clamped down: no more entries into the park, and no-one leaving would be readmitted.  So while it was downright pleasant for those of us on the inside, with lots of room to wander around and for people to lay out blankets and have picnics (and for me to zip around w/ my camera), those outside were crammed together against the fences.  And when I finally strode out of the park, past the throngs, I felt faintly guilty, but some remembered (and probably misunderstood) words by ex-Byrd Gene Clark helped me adjust to my temporary good fortune:

Some walk out winners; of those who've lost
Can it be said at any price this is the cost?

Exercise for the student, clearly.