steuard: (lake)
Tuesday, January 17th, 2017 10:16 pm
[I’m making an effort to avoid serious spoilers, especially in the main body of these comments, but I’m sure there are little ones there and more in the list of specific thoughts that follows.]

A week or two ago, I finally finished reading The Three-Body Problem by Liu Cixin (as translated by Ken Liu). It was a fun story that touched on some neat science, and I quite appreciated the experience of reading fiction based on a rather different cultural background than my own. (The translator commented in his afterword that he had done his best to walk the fine line between an overly literal translation that failed to capture the author's sense and intent and an overly idiomatic translation that failed by purging everything that gave it its own sense of place and history. I think he was very successful.) I did have some issues with the structure of the tale itself, and over the course of the book I felt like the sci-fi elements went from “realistically plausible” to “well-done apart from some errors in the details” to “what the heck are you talking about?” So while I mostly enjoyed the book as a whole, a lot of its conclusion left me frustrated.

It was to some degree a humbling experience to read a story whose historical grounding and references (whether 50 years ago or 1500) were so, well, foreign to me. I had heard *of* some of the emperors mentioned, and about bits and pieces of the Cultural Revolution, but not remotely enough to feel oriented in the way that a person fluent in Chinese culture would. Would a Chinese reader have had the same "this is all madness" reaction to the various factions of Red Guards and others that I did, or did the author intend readers to feel sympathy toward some and not toward others? I was torn between feeling frustrated by those unclear moments and feeling excited by them (since I was learning something new, in just the right "organic" way). I'd estimate that about half of my moments of uncertainty along these lines were immediately addressed by a relevant translator's note filling in some cultural background. By and large, I really liked this aspect of the story.

As for the story itself, my impressions were mixed. I thought that a lot of the core conceptual premises were fresh and interesting: I haven’t read anything quite like it before. But there were also a lot of aspects that just didn’t work for me, for a variety of reasons. I’ve mused on some specifics down below, but the big issues for me were the main character’s lack of meaningful participation in the events of the story and a number of ways in which the behavior of characters or society seemed unrealistic or cliched.

I also had mixed impressions of the actual science/sci-fi elements of the story. One of Isaac Asimov's great strengths as a science fiction writer was his ability to build entire stories (or series of stories) around the consequences of a single, simple sci-fi premise: the Three Laws of Robotics, say, or the "Psychohistory" that shaped the Foundation. That same spirit of "let's really delve into the deep societal consequences of this sci-fi change" provides much of the richness and fascination of books by authors like Le Guin or Bujold, to name just a couple who leap to mind. Liu Cixin... does not work this way.

The early sci-fi elements (involving attempts to communicate at interstellar scales) were handled quite well with some clever, mostly plausible “new science” involved. A little later, the titular "three body" physics (and its in-story context) seemed well done on the whole, too. It's a really neat take on not just the dynamics involved, but how life might react to that. (I had minor to moderate issues with a handful of the details.) And then there’s the final reveal about “two protons” and their effects. I think there would be plenty of premises associated with those alone for about a dozen different sci-fi stories. Unfortunately, the science involved is nonsense even as a fictional new discovery, and the effects are so ridiculously overpowered that it seems to rip half a dozen gaping plot holes in the story in its attempt to explain earlier mysteries.

And with that, before I go on to chatter about specifics (which will tend to be more spoilery), I feel like I ought to close with a recommendation. Sadly, I’m torn on that. I suspect that some of my eye rolling near the end was just from being too close to the science involved, but some of the issues would likely grate on a lot of readers. The story and its structure are a bit spotty, too. Nevertheless, the novel premises and perspective are worthwhile and interesting. So I guess my final conclusion is, "Go not to the Elves for council, for they will say both no and yes."

A handful of random specifics about the story and its telling:

  • My biggest complaint about the story itself: much of the time, it felt like the main characters weren't really doing anything consequential. Rather, they were just on a roller coaster ride hearing about major historical events past and present, and scrambling to keep up. Even the main character's primary contribution to solving the climactic dilemma is saying "Oh, we've actually got a bunch of that back in my lab" after someone else proposes a strategy that would require a novel substance, and then watching others use it.

  • Maybe the description just didn't capture it for me, but the computer game in the story made no sense to me as a game. It sounded like an interestingly vivid simulation and teaching tool, and maybe a sort of participatory theater, but as presented within the story I just didn't buy it as something that players would be so drawn to (or more importantly, as something whose rules or goals they would understand, given the interface and explanation we were shown).

  • The secondary character who's "not a GOOD cop, but one heck of an effective one" and turns out to become a solid friend felt awfully close to a pure archetype, within his first few paragraphs on the page, and nothing ever happened to change that.

  • It was weird to me how we were introduced to the main character's wife and kid at one point and then he (and the author) proceed to show almost complete indifference to what they must be thinking or feeling at any future point (even as the main character practically has a mental breakdown, disappears overnight, and otherwise begins behaving very erratically).

  • There’s this weird assumption in the backstory that substantial fractions of the highly educated population of the world (and almost exclusively the intellectual elite) think humanity is hopeless and would be willing to basically sell out our entire species in one way or another. That just doesn’t fit with my experience at all. I can’t tell if this is a reflection of actual attitudes in Chinese society, or if it’s some sort of political statement by the author, or what.

  • The final confrontation with the most dangerous (human) faction felt almost perfunctory to me (gruesomely so). I guess that's exactly what they were aiming for, but I felt like they'd spent a fair bit of time developing a villain and a villainous organization, only to see the whole thing resolved completely tidily in a few paragraphs.

And a handful of specifics about the science:

  • As noted, I thought that the titular "three body" physics (and its in-story context) were generally well done. (Apart from the weird "invisible stellar outer atmosphere" thing that went with it, anyway.) It's a really neat take on not just the dynamics involved, but how life might react to that. Given the title and the physics I know, I guessed pretty quickly what was going on when it first came up, and even began to guess where it was going on. That said, some of the various "hot disaster" scenarios described felt just entirely "off" to me, on a "wait, that wouldn't happen, or at least not that way" level. (And I'm pretty sure that the most common fate of small bodies coupled to a 3+ body system like this is not "collided with something" but rather "hurled out of the system". Also, I don't think there's any way to deduce the past history of such a chaotic system in any detail, certainly not well enough to deduce all the details of its structure in the distant past.)

  • The final twist/explanation involving the four protons (or rather, "protons") just plain upset me. Not only was practically everything about the science of it nonsense, but the technology described was so insanely powerful that I'm pretty sure it could have solved all of the aliens' problems on its own, without any need to interact with the folks on Earth at all. (These last bits are especially spoilery.)

    • Nonsense: First, a proton is well established to be a composite particle, no matter what the ultimate theory of nature turns out to be, but every way I can try to make sense of the higher dimensional stuff can only sensibly apply to fundamental particles. Second, one of the essential properties of quantum systems like a proton is their indistinguishability: there is literally nothing you can do to a proton even in principle to make it different than any other proton: they are absolutely and unalterably identical. (This is a necessary ingredient for almost every system obeying "Fermi-Dirac statistics", a category including more or less half of all quantum systems.) That means that no matter what wacky extra dimensional extent it might have, is simply couldn't work to "paint on" even a serial number, much less to embed an entire functioning AI computer. Third, quantum entanglement doesn't work the way it's presented here: you can't use it for instantaneous communication at all, and I'm pretty sure that even if you didn't care about "instantaneous" two pairs of entangled protons could only carry two bits of information, total. This isn't an ongoing high-bandwidth communications channel! Fourth, even if they sent these "protons" to Earth somehow, it's clearly implied that the protons themselves have some sort of near-lightspeed propulsion to move them back and forth around the planet. What is it, and what's its energy source?

    • Solving problems: When the computer circuits are being etched(?) into the world-enveloping 2D-expanded protons, the surface blocks any and all light from reaching the planet below: the world was frozen as surely as in the long dark stretches of a Chaotic Era. It seemed pretty thoroughly impermeable! But... isn't that exactly what they would need to protect their world from close calls falling near a sun? (Heck, it might have even protected them from a close call with a solar atmosphere.) And the story provides evidence that these dimensionally altered protons can act as parabolic mirrors to focus sunlight, too: they might even be able to provide warmth during cold parts of Chaotic Eras, too! (Even if they can't reliably predict their planet's orbit decades in advance, they ought to be able to manage a few weeks or at least days: enough to be able to reconfigure their planet-sized superprotoncomputers for whatever protection is necessary. [But then, if they can reconstruct their solar system back to millions(?) of years earlier in enough detail to deduce that it once had many more planets, why can't they predict its future as successfully?]) Or as an offensive weapon, why worry about subtly tricking human scientists to keep our tech level down when they could just set the things to enclose our whole planet and cut off all sunlight for, say, a week or so? That would probably not do irreparable harm to the ecosystem, but it would probably devastate crop yields worldwide and lead to the total collapse of modern society, leaving our planet ripe for the picking. The short version is that these things are ridiculously overpowered, enough so to more or less break the plausibility of the rest of the story.

steuard: (physics)
Monday, March 17th, 2014 06:26 pm

So that physics announcement that I posted the rumors about happened, and it was indeed just as big of a deal as rumor had made it. Here are a few links I've found that summarize the results nicely:

This is really cool, and there are some neat, neat implications. (The data points to an energy scale for inflation that happens to be very close to the expected energy scale of grand unification of fundamental forces in simple supersymmetric models of particle physics, for instance.) It'll be great to see if this result holds up.

steuard: (physics)
Monday, March 17th, 2014 12:11 am
If you happen to be the sort to follow a few cosmologists on blogs or social media, you've probably seen rumors swirling around like mad for the past few days. I'm not sure if this was triggered by the Harvard press release promising that a "major discovery" in astrophysics would be announced Monday at noon, or whether that release was hurried out the door only after the rumors got out. But it sounds like it could be a Big Deal, so keep your eyes open tomorrow. (One rumor is that they've invited Guth and Linde, the first theorists to propose cosmic inflation, to attend the announcement.)

Probably the best description I've seen of what people think the press conference is going to be about came from my friend Sean Carroll at Caltech: it seems that an experimental group observing the Cosmic Microwave Background is going to announce that they have seen direct evidence of perturbations of that background caused by gravitational waves in the first instants of the Big Bang. (As Sean explains, today our direct experimental data on the early universe extends back to about one second after the start of the Big Bang. This observation would push that back to an astounding 10-35 seconds after the start.)

I won't try to explain the physics here, since it's really not my specialty. The intriguing thing is that, as far as I can tell, most people were not expecting to see any actual detection of this signal from the current generation of experiments: other data suggested that the current experiments would only be able to set "less than this threshold" sorts of limits. So this impending announcement would seem to imply one of four things: 1) The signal is much stronger than expected, which would be Very Exciting(TM) for physics, 2) The experiment turned out to be more sensitive than expected, which would presumably involve either really good luck or some neat improvements in data analysis algorithms, 3) The announcement is merely of strongly suggestive evidence rather than a true discovery-level result, which would make the "major discovery" press conference seem quite overblown, or 4) Someone messed up their analysis and/or got fooled by a statistical fluctuation, which after all this hoopla would probably wind up ending multiple careers. (I can guarantee that the experimental team here is painfully aware of all these possibilities. But then, so were the folks who claimed to have seen neutrinos moving faster than light a few years back.)

So yeah. It sounds like the actual science talk will begin at 10:45 (with papers and data going online at the same time). So watch the news, or at least the blogs! It should be exciting.
steuard: (physics)
Monday, September 2nd, 2013 10:02 pm
You've probably heard at some point that tides on Earth are mostly caused by the moon, along with some smaller but still noticeable effects from the sun. In other words, the two objects' tidal forces are comparably strong (rather than being many orders of magnitude different: Uranus doesn't appreciably affect our tides!). You've probably also heard (or seen, during an eclipse) that the moon and the sun appear to be about the same size in the sky, even though the sun is vastly larger (but farther away). Remarkably, it turns out that these two facts are directly related.

Here's the idea. Let's say that the distance from Earth to some distant object is D, the radius of that distant object is R, and its density is p (I won't bother typing the usual "rho"). Ignoring constant numerical factors that would be the same for every (spherical) object, the mass of that distant object is proportional to p R3. The gravitational acceleration due to that distant object is proportional to M/D2 = (p R3)/D2, but if you're experienced in the math of Netwon's gravity it's fairly straightforward to show that tidal forces are instead proportional to M/D3 = (p R3)/D3. (Tidal forces refer to the difference in gravitational force on opposite sides of the earth, and that extra power of 1/D essentially comes from a linear approximation of the changing force that's proportional to REarth/D.) Factoring that a little differently, that means that tidal forces are proportional to p (R/D)3. But using a little trig, R/D is just the tangent of (half of) the angular size of the object in the sky, and for small angles that equals the angular size.

In other words, the tidal force exerted on the Earth by a distant object is proportional to the density times the cube of its angular size. Since the moon and the sun have about the same angular size, it's only the sun's lower density that makes its effects on our tides less significant. And as expected, planets like Uranus have a much less significant effect, since their angular size is tiny by comparison (and their density is in the same ballpark).

Neat, huh?
steuard: (lake)
Tuesday, April 9th, 2013 11:23 am
I just received the American Physical Society's monthly newsletter, APS News. In the "Letters" section, they published a letter entitled "Nothing Wrong with Fewer Women Physicists" by someone names Jeffery Winkler from Hanford, CA. Winkler was evidently "shocked" by a February article about how encouraging women to pursue careers in physics is a priority for the APS.

I won't try to formally rebut his arguments, but it's like shooting fish in a barrel: this guy thinks he's boldly standing up for some moral principle, but his entire letter is a classic example of sexism and ignorance. He insists that targeting any particular male/female ratio is equally wrong, whether 50/50 or 100/0. He then says, and I'm not making this up, that nurses, elementary teachers, and secretaries are 90% women and "Nobody thinks that's a problem." So clearly, he says, it's just as unreasonable to push for greater equality among physicists.

I have no idea how this tripe got published in the newsletter; maybe they were low on content this month. (I've already written to ask.) Not that I'd object to having a serious discussion about how and why we should encourage women to study physics! But this clearly isn't an example of that. Instead, it's an example of how much sexism is still present in the physics community and of how that sexism gets reinforced. And that's deeply frustrating.
steuard: (lake)
Saturday, April 6th, 2013 10:33 am
Every time I start teaching quantum mechanics in intro physics, I wind up feeling a little disappointed. To most students it's just another set of equations to memorize; they don't understand how much of a radical departure it is from everything we knew before. I suppose that's inevitable to some degree, since modern kids are raised on a diet of atoms and electrons and what seemed radical a century ago is familiar today. But I'd still like them to understand that this is something New, and Important.

So I spent entirely too much of the past week writing something akin to a live-action role playing game. In class on Friday (and continuing into at least part of this coming Monday), the students became world class scientists trying to figure out the "newly discovered" photoelectric effect. They're each a supporter of one of two competing theories of how light (classical electromagnetic waves) interacts with a metal surface to eject electrons and cause current to flow. On Friday, I welcomed them to the conference in the role of the physics department chair at the host institution:

[I stole this picture from a student's public Facebook post, by the way: thanks David T!] In their two big groups and then in six smaller lab groups, the students assembled a set of graphs illustrating their competing predictions, and then the leader of each main group presented their results to the conference.

And after that, the experimental data came in ("from the experimental conference down the hall"). Both groups got some things right, but fundamentally, everyone was wrong! So on Monday we reconvene to see if we can puzzle out the true story. I have absolutely no idea how that's going to go. I've tried to seed elements of the real (quantum!) explanation among them, and if anyone is particular clever or eager to get it right they might think to actually read the textbook. (On their own!) We'll find out! If nothing else, it was clear that they had a lot of fun with the activity, and they really were thinking hard about what their predictions should look like. I feel good about it.

In case you're curious, I'm including a glimpse of one character sheet here. I'll stick it behind a cut: The first page of Prof. Parma's character sheet. )
steuard: (Default)
Monday, August 20th, 2012 10:13 am
I was thinking about color this morning (yes, I do these things), and I was struck by a disturbing thought: when did I last see violet? Not purple, which I see all the time, but actual violet. [I'm not the first person to wonder this: here's a very thorough discussion.]

Purple, as you no doubt recall, is a compound color: it's what we perceive when we see a mixture of red and blue light. But violet is a pure color: light with wavelength somewhere a little over 400nm. (Side question: anyone have a clue as to why purple and violet are perceptually similar?) So what's the problem? RGB monitors, that's what. The shortest wavelength of light produced by an RGB monitor is blue, which is probably around 460nm or so. That means that your monitor is incapable of producing a violet color. Looking at a picture of a rainbow on your computer screen is inevitably a less vibrant experience than seeing one in person.

So, fine, look at a printed photograph. Well... not so fast. I don't know how all the different types of photo printing work, but a lot of printers are RGB or CMY themselves (and I think that CMY has the same problems as RGB in this regard, or worse). I have no idea what the process is (or was) for traditional photo printing from the analog era, but I'm willing to imagine that there are photo printers today who are capable of printing with actual violet dyes. But wait: what sort of camera took the photograph? Again, I don't know how good traditional film cameras were at capturing violet, but today's digital cameras are (as far as I know) also RGB.

So: when did you last see violet? Think back: what does it look like?
steuard: (physics)
Wednesday, July 4th, 2012 11:58 am
The rumors were true! Both experiments at the LHC that were searching for the Higgs announced discovery-level evidence early this morning. This is a Big Deal, even if we did pretty much expect that the LHC would produce a result like this eventually. There's a lot to say (and lots of good discussions out there at various technical levels), but for a nice layman's overview I might recommend Bad Astronomy's Higgs post. The quotes near the beginning of this post by Tommaso Dorigo are good, too.

The very short version is this: a new particle has most definitely been discovered, and CERN found it by looking in all the places that one would look for the Higgs. Its properties aren't nailed down very well yet, but they appear to be broadly consistent with the properties we expect for the Standard Model Higgs. But, enticingly, there are tentative hints of some differences from that expectation, too. Further data over the next few years will (we hope) show us whether those differences are just random noise in the detection system or whether they reflect entirely new physics. (Most of us really, really hope it's the latter.)

Edit: I've seen some folks linking to a nice video explaining the Higgs from PhD Comics a couple of months ago. Also, since the topic of Comic Sans came up in my blog last week, I'm sad to see that the things I grumbled about last December were still a problem for the real announcement.

Edit2: Strassler's post lists a few more specifics in a nice, clean way.
steuard: (physics)
Tuesday, July 3rd, 2012 11:04 pm
Wednesday may prove to be a very exciting day in physics: the two LHC teams searching for the Higgs boson are scheduled to give a seminar, and pretty much the entire particle physics community expects their announcement to amount to a discovery (though either experiment on its own may or may not pass the official threshold this time). This is a Big Deal: finding the Higgs was one of the primary goals of the LHC (perhaps the primary goal), and it's the very last piece of the Standard Model of particle physics whose existence has not yet been confirmed. These groups presented some very tantalizing evidence last December, but now that they've taken more data we may finally be there for real.

The really interesting thing to watch for in this announcement is whether the particle they're seeing seems to behave exactly as the Standard Model predicts, or whether its interactions are different in some subtle way. Most of us really, really hope that there are differences, because the behavior of the Higgs is sensitive to many types of "new physics": it could give us the first fundamentally new experimental evidence about the ultimate laws of nature that we've had in a decade (or maybe even three decades or more, depending on what you count as "new" and how narrowly you focus on particle physics). Nobody expects tomorrow's announcement to make solid claims about any of that: it will take years of data to really start to understand the details. But December's data seemed to have weak hints of something unexpected, so people will be watching carefully to see whether those hints get stronger or whether they fade away as the statistics improve.

I'll presumably post something all excited in the morning. But if you're interested, keep an eye on Cosmic Variance or your favorite particle physics blog for news. The seminar is at 9am in Geneva, so that's 3am Eastern. I expect to be envious of everyone on the west coast who gets to see the results live at midnight!
steuard: (physics)
Tuesday, April 24th, 2012 09:19 am
I am really excited by what I've heard about Planetary Resources, a private company that has just announced plans to mine near-earth asteroids for precious metals and other resources. Here's a write-up from the Bad Astronomy blog that goes into details: it sounds like these folks have a plausible business plan (as well as the necessary level of patience, and a dedication to the underlying cause of advancing humanity in space that will be an important complement to their profit motive).

Maybe it's just too much science fiction in my youth, but I've always felt that it will be important for humanity to Get Out: to avoid having all our eggs in this one basket called Earth. There are a whole lot of reasons for that (more of them than I had as a youthful sci-fi reader), and I won't go into them now. But it's been clear to me for a long time that while governments were the obvious choice to take the first steps into the solar system, we won't really be a spacefaring species until private industry and even private individuals are able to go there on their own. Asteroid mining seems like a really good stepping stone in that direction: small and close enough to be achievable, and with enough potential profit to make it appealing to investors. As soon as one of these ventures pays off, dozens more will spring up overnight, and space industry will go from being an epic project to a commodity. I don't know if we'll ever get out of our own solar system, but I look forward to the day when we can at least use more of it than we do today.

Meanwhile, in other news (only tangentially space related), it's possible that the Fermi gamma ray telescope satellite has seen a direct hint of the long-sought dark matter particle! There's a full write-up at the Résonaances blog, but the gist is that if you look straight at the galactic core (where dark matter should be most concentrated) the telescope sees an excess of photons with a very specific energy, as if there were some unknown source at that energy on top of the known gamma ray sources (which are all spread out over a range of energies). The only model in the literature that could explain such a pattern is the decay of a dark matter particle with that same energy (or something close to it). The most likely particle mass that would explain this data is about 130 GeV: that's 130 times the mass of an entire proton (and, by an odd coincidence that might not be a coincidence, just 5 GeV or so above the current best estimate of the Higgs boson mass).

This will be a big deal if it turns out to be true: the first direct evidence of particle physics beyond the 30-year-old "standard model" (and the first concrete reason to believe that particle physics won't be dead as a practical matter after the LHC). It's thrilling stuff. The one thing that's puzzling to me about this is that I saw this news a week ago on that one blog, and I haven't heard anything else about it since. (I talked to an Alma graduate who studies experimental cosmology while he was back for graduation, and he said he'd heard about it but didn't know enough to comment beyond that.) Is there some reason for skepticism that has kept all of my other physics/astronomy blogs silent on the story thus far? Only time will tell. But it will be a lot of fun to watch.
steuard: (physics)
Wednesday, March 7th, 2012 09:24 am
Last December, the LHC experiments from CERN looking for the Higgs boson announced some pretty promising evidence that they had started to see it, and had measured its mass-energy at about 125 GeV. It wasn't clear enough to claim a true "discovery" yet, but it was promising. Today, scientists from Fermilab presented analysis of some of the last data collected before the Tevatron shut down (along with some improved analysis of their years of previous data), and they found evidence consistent with what the LHC saw. It's not as strong as the LHC signal was, but that's expected because their accelerator isn't as powerful. But the fact that two entirely separate machines have produced results that agree is an awfully good sign that this is the real thing. If you want to read some details, I heard about this from blog posts here and here.

The worrisome thing right now is that we're awfully close to the "nightmare" scenario for data from the LHC: finding the Higgs but not finding any evidence at all of physics beyond the Standard Model. All of the searches for things like extra dimensions and supersymmetry have thus far found nothing, even though the most natural supersymmetry models would quite likely have started to give strong hints by now. (Those ideas all have lots of variations and thus aren't remotely close to being ruled out yet, but it's getting harder to believe in the variations that got people excited about them in the first place.) If we find the Higgs, then that means the Standard Model is complete and internally consistent... as far as it goes. But we also know that the Standard Model can't be the whole story: its math simply isn't capable of being a "final" theory of nature. (For example, on its own it predicts effects that would make us measure the Higgs mass to be infinite! And of course it's ultimately incapable of coexisting with a universe that contains gravity, but that's true of any quantum field theory.) So it would be Really Unpleasant to have (on some level) finished studying the particle physics that we've already known for thirty years without the slightest hint of what the next step ought to be.

But still: finding the Higgs is really exciting, and there's plenty of time to worry about future prospects later.
steuard: (Default)
Saturday, February 11th, 2012 04:04 pm
My "Physics of Video Games" talk at AlmaCon went beautifully. (The con as a whole seems to be going really well, too. Thank goodness!) Many thanks to those of you who suggested ideas: some of those confirmed the value of thoughts I'd already had and others filled exactly the gaps that I had been worried about finding good examples for. My turnout was surprisingly good. I got nods of familiarity and/or understanding for lots of my "good physics" examples, loads of laughter for some of my "bad physics" examples, and some great questions and discussion when talking about using games to teach the scientific method.

In case you're curious, here's a list of videos that I used (though I often showed only a relevant clip from each). I kinda wish that I'd videotaped it!

Good physics examples:
Angry Birds (as well as some graphs of bird motion).
World of Goo (another physics puzzle game)
Dwarf Fortress (fluid flow & melting points)
Myth: The Fallen Lords (an early example of a really complete physics environment)
Skyrim (lots of cheese) (this got a laugh, but illustrated the quality of modern physics engines)

Bad (or rather, unrealistic) physics examples, that might be either good or bad for game play:
Skyrim bug with a sabertooth tiger (this had them laughing louder and louder for about a minute straight)
Resonance (flash game where jumps have no momentum)
Grand Theft Auto: San Andreas (decent laugh here; I just had a short little clip on loop)
Grand Theft Auto IV (big laugh, but as I pointed out, in many cases this behavior probably makes the game more fun)
Portal (a fictional element in an otherwise realistic game)
Portal infinite fall (what happened to conservation of energy?)
Mario 3D Land (steering during a jump)
Mario 64 (kicks in midair push you higher)

Video games teaching the scientific method (with excerpts from the full paper)
steuard: (Default)
Thursday, February 9th, 2012 06:14 pm
I'm looking for ideas!

I'm giving a talk on "The Physics of Gaming" at a small convention this weekend (run by our college anime/gaming club). My plan is to first talk about "good physics" (games where some aspect(s) of physics are done well and important), then about "bad physics" (games where some aspect of physics is horribly inaccurate), and finally about how gamers wind up thinking like scientists (based largely on "Scientific Habits of Mind in Virtual Worlds" by Steinkuehler and Duncan).

What I'd really like would be some neat, current examples of "good" and "bad", and ideally YouTube videos to illustrate them. I've got some ideas already, but any suggestions would be welcome. Thoughts, all you gamers out there?
steuard: (Default)
Tuesday, December 13th, 2011 04:20 pm
I have a final to finish writing, but I wanted to share a quick summary of the Higgs news from this morning (for those of you who care but somehow haven't seen it yet). You can read Sean Carroll's summary for a few more details (and links to lots of posts with more detailed commentary), but my take on the talks boils down to this:

  1. The current LHC data makes it look awfully likely that the Higgs boson exists and has a mass (energy) of about 125GeV. Similarly strong evidence has appeared and then proven to be statistical noise in the past, but the agreement between two experiments and the strong expectation that the Higgs ought to exist somewhere in the ever-shrinking viable mass range make this time seem more promising.

  2. The data from the CMS experiment seems more thoroughly analyzed, and its result (considered alone) is real but weak enough that I would hardly have paid attention to it. The data from the ATLAS experiment is perhaps less complete, but it shows a clearer signal. The two signals don't quite line up at the same mass, which could be a bad sign, but they're awfully close to being consistent with each other.

  3. If the LHC runs as planned, we should have a definitive discovery or exclusion of the Standard Model Higgs boson by the end of 2012, and quite possibly as early as next summer.

  4. CERN needs a better video streaming server, and physicists in general might possibly benefit from lessons on how to create good presentation slides. (The number of groans about Comic Sans on Twitter was impressive, but I thought the real issue was that a lot of the slides felt cluttered. To be fair, they were trying to convey a lot of information to a highly expert audience.) Also, the term "God particle" should be immediately banned from public discourse.
steuard: (Default)
Sunday, December 11th, 2011 01:28 pm
This Tuesday, keep your eyes open for physics news. If you follow any physics blogs, you may have already heard rumors that CERN has scheduled a seminar to present the latest update on the Higgs search. It is being billed as a report on "significant progress", but not "any conclusive statement": assuming the Higgs boson turns out to exist, it looks like its mass is right in the range that's hardest to detect, so we shouldn't expect any definitive results until next summer or even fall. Still, it could be some pretty exciting news... I'll be watching very eagerly. Here's a long writeup on the state of the Higgs search, and a shorter note of caution about statistics in particle physics.

I'll also be writing exams and grading papers and doing all the other things that come along with finals week, of course. Not so much fun (especially since my finals are all at the end of the week, with just a few days before grades are due). But the semester is winding up, and I've got a long block of research leave time to look forward to after we're back from our Christmas travel. I'm looking forward to it!
steuard: (strings)
Sunday, June 19th, 2011 12:11 pm
Just in time to avoid delays due to childbirth, I've finished and submitted a new paper for publication: The KK-Monopole/NS5-Brane in Doubled Geometry. I'm excited about this work; it's the same topic that I presented on a couple of months ago at the Great Lakes Strings conference in Chicago. Since the title is once again largely jargon, I've written up a summary of what it's all about for non-specialists. To be honest, I have no idea how much sense that summary will make anyway, so let me know if you think it's unreadable. I hope you at least like the pretty pictures there!

[Oh, and I've also replaced my user icon with something that looks a little more obviously like strings: strings interacting with D2-branes, to be exact. It's one of my more popular string images out in the wild, and hey, it's pretty, too.]
steuard: (physics)
Friday, June 10th, 2011 05:14 pm
Alas: "The probability of the D0 data being consistent with the presence of a dijet resonance with 4 pb production cross section at 145 GeV/c2 is 8×10−6." Or translated to non-expert-speak, that strong hint of new physics that the CDF group at Fermilab announced a week or two ago (see my last blog entry) has been pretty thoroughly shot down. Oh, one could hold out hope that it's the D0 group that's wrong (and that maybe the LHC will release data later this summer to support the new claim), but it's almost always safest to bet on the folks who aren't making the bold claim in a case like this.

Ah well. Next year in post-Standard-Model data!
steuard: (physics)
Tuesday, May 31st, 2011 05:11 pm
It's been a long, long time since I wrote anything here: I've just finished teaching an intensive one month "Spring Term" class on Medical Physics that met two to three hours a day, five days a week. This might have been less stressful if I'd ever taught (or taken) a class on the subject before (or if I hadn't spent the whole week between my previous final exams and the class starting writing and giving a conference talk in Chicago). But it seems to have gone well, and I've now officially hit summer vacation! That means that I get to procrastinate on baby preparation and paper writing by sharing cool recent science tidbits.

The first is serious physics, and has the potential to be tremendously exciting if it pans out: the CDF experiment at Fermilab may have found the first direct evidence of physics beyond the Standard Model of particle physics! For a nice layman's summary, my friend Sean Carroll has a good writeup at Cosmic Variance; for some more detail, follow the links to posts at Résonaances. I won't try to repeat them here; I'll just show the exciting data:

and comment that the red line is the expected Standard Model result and the blue bump above would presumably correspond to an entirely new neutral particle about 150 times heavier than a proton. This result still isn't 100% solid: it's a "4.8 sigma" result, which is extraordinarily unlikely to happen by chance, but until it's reproduced by Fermilab's D0 experiment or by the LHC there's always the chance that someone forgot to carry a two during the data analysis.

The second thing to share is a beautiful time-lapse video of the Earth rotating under the stars that was recently adapted from an earlier video of stars rotating in the sky. It's a vivid demonstration of the Earth's motion through the heavens that makes you rethink your assumptions about what's really moving when you watch the sky. Here's the video; seriously consider watching it full-screen in HD!
steuard: (Default)
Wednesday, April 6th, 2011 12:39 pm
Man, I love teaching about electromagnetic waves. Today in intro physics I explained Faraday's law, which says that a changing magnetic field will create an electric field, which may cause current to flow around a loop. I then talked about Maxwell's realization that the opposite should also be true: a changing electric field must create a magnetic field. (It's an algebra-based intro class, so I leave out essentially all the details.) Putting those together, you realize (or at least, Maxwell did) that if the two fields can create each other then they can just travel through space on their own as a wave.

And that's where I found myself starting to literally jump up and down in excitement in class. (Well, only a little.) (Ok, I'll be honest, only a little at first.) Waves were the first topic we covered this semester, so we've come full circle. But then I showed them the speed that Maxwell derived for the waves, written in terms of the force constants for electricity and magnetism (which they've all used and measured in lab). I had students with calculators work out the resulting speed: 3.0 * 10^8 m/s. And wonderfully, in both sections, some student spoke up without any prompting and said, "Isn't that the speed of light?"

That's when I really started jumping up and down and talking rather loud. (Not just a little.) Optics was another big topic earlier this semester, and suddenly we've discovered (following Maxwell) that it's all just electromagnetism! Everything we've done really was all one topic after all! Not only do we know some methods for dealing with light, but we know why light works the way it does. I even had each class come out into the hall, form a line, and act out the part of an electromagnetic wave as they ran past a charged particle (me) and made it oscillate up and down.

It's a good class day, and I always forget how cool the topic is until I'm actually in the process of talking about it.

[And now I wonder: have I posted about this in previous years? 'Cause I totally could have. Ah well... it's cool enough to be worth saying again.]
steuard: (physics)
Saturday, March 12th, 2011 01:56 pm
My colleague Cameron shared this poem with me (and with my class) yesterday. Speaking as a cat-owning physicist, I think it's pretty cool. The title is "Five Pounds of Sunlight", by Geoffrey A. Landis.