steuard: (lake)
2017-01-17 10:16 pm
Entry tags:

Thoughts on "The Three-Body Problem"

[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: (lake)
2016-11-03 08:27 pm
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"They're both awful"? Clinton vs. Trump

I've seen lots of people talk about this year's Presidential candidates in terms of equivalency: "They're both so awful this year," or "Why do we have two people who ought to be disqualified this time?" I doubt anyone's going to change my mind at this point, but I always really want to understand viewpoints that differ from my own. And yet when I try to list huge, potentially disqualifying problems for each candidate, I honestly can't see anything approaching parity. (Especially when we limit it to topics specific to this pair of candidates, rather than longstanding policy differences between the parties.) Here are the top few points cited as "deal breakers" for each candidate that I can think of:


  • Suggested the US might not honor NATO mutual defense obligations, which runs the risk of destabilizing the entire post-WW2 deterrence structure and courts global war between nuclear powers. (Even hints at this by a President would lead to those consequences, especially given Russia's behavior these past few years. I've seen claims that Trump having considered it publicly as a major candidate could have a negative effect, even if he loses.)

  • Suggested that the US could intentionally default (partially) on its debt, which could very easily lead to a collapse of the entire global financial system and would at least drive our cost of borrowing absolutely through the roof.

  • Actively encouraged racist and radical nationalist sentiments among his supporters, contributing to the public normalization of those attitudes to a degree we haven't seen in years (decades?): this is likely to persist well beyond the election even if he loses.

  • Bragged about his willingness to do sexual things to women without asking for consent. That's sexual assault, by definition, and even if you want to insist that doesn't mean he really did those things (despite women's claims), his words show at a minimum that he believes that behavior to be something that other men would admire. (This is just the most egregious of his many terrible behaviors toward women.)

  • Said he would insist that the US military kill the families of terrorists. This is morally breathtaking, and an obvious war crime. (He's also advocated other war crimes, like torturing terror suspects because "they deserve it" whether or not it's useful, or )

Again, that's just the absolute deal breakers that come to my mind offhand. There are plenty of truly awful policy positions that he's advocated (some of which trample on the Constitution and might deserve to be on this list for that reason), and in general he's demonstrated both serious ignorance of issues and structures in national and international policy and seemingly an unwillingness to learn what he needs to fill in those gaps (which might also be taken as a deal breaker).


  • Seriously mishandled classified information over email, using a private server for some State Department business. (Note, though, that the investigation was mostly completed over the summer and did not result in evidence clear or serious enough to merit prosecution.) If new evidence came to light that was substantially worse than all of the previous evidence collected, she could potentially be charged with a felony.

  • ...?

  • (Some might add "Would nominate Supreme Court justices who support Roe v. Wade", but that doesn't explain why she's framed as being so much worse of a candidate than any other Democrat in the past 30 years.)

I honestly don't know what the next item in that list is supposed to be. There have been countless investigations of her over the past 30 years (I think she has been subjected to more intense scrutiny than just about any other politician in my lifetime: you can decide how much of that was primarily politically motivated), but literally none of them have turned up actual evidence sufficient to convict her of a crime (or maybe even charge her) or to demonstrate that she abused her position or was negligent in her duties. Also, she's sometimes seen as "unlikable", but that's a different issue than "disqualifying".

I would really, really welcome help in understanding the perceived awfulness of Hillary Clinton, and while I won't promise not to push back against assertions I think are false or overblown, I'll do my best to be respectful and to try to understand.

steuard: (lake)
2015-09-01 10:03 pm
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Style, and how to get some

I hate shopping for clothes. I'm terrible at it, and it takes forever, and it is miserable. I have stories.[1] This is no doubt part of the reason that I'm getting close to the point where my entire wardrobe needs replacing.

And that strikes me as an opportunity. Part of my problem, I'm sure, is that I've never had even a slightly concrete sense of a personal style: what sort of look might be a good fit for me, and what sorts of clothes could get me there? I realized a few years back that I'd actually appreciate having some rudimentary answers to those questions, and I have a decent guess that it would make shopping less horrible.

The challenge, of course, is that there's presumably quite a bit of effort involved in figuring this stuff out from very nearly complete ignorance, and I've got plenty of higher priorities for ways to spend my time. (That's not even including the fact that trying to contemplate this stuff hits all my usual "oh god I'm shopping" buttons.)

So this is my question, or my plea: are there shortcuts? Can I find some algorithm or assistant who (perhaps for some not too painful investment of my time and money) could help me skip over most of the dreaded "personal style 101" tedium and get quickly to a halfway decent wardrobe? (In a perfect world, I'd be able to emerge from the process with at least a rudimentary idea of what made it decent. Enough so that I could have some confidence in my ability to shop for new clothes later, and maybe even use that as a starting point to learn more as time and interest permitted.) I'd welcome any suggestions, general or specific. Note, incidentally, that I live in a rather small town nearly an hour's drive from the nearest decent-sized city, and that my work schedule these days is roughly 9-5 (plus lumps of evening class prep and grading).

[1] Well, really just one, but it makes the point. A few years ago, I was trying to buy a few shirts at a local department store. I spent entirely too long wandering back and forth through the store figuring out what the options were and which ones I liked and whether the ones that fit came in other colors. How long, you ask? Long enough that about 3/4 of the way through, a security guard walked by to ask why I'd been hanging around for so long. "I just really hate shopping," I said, and I guess I was convincing enough that he left me alone.
steuard: (lake)
2015-07-29 11:48 pm
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Things that I want

I want the whole concept of "juvenile charged as an adult" to be eliminated from the American legal system. (Maybe the US could then stop being the only UN nation other than Somalia not to have ratified the Convention on the Rights of the Child.)

I want police officers to be trained under the assumption that protecting innocent civilian lives is even more important than their own safety. (And reminded that our society believes in a presumption of innocence.)

I want police officers and departments to consider any death (or injury) at police hands to reflect a failure. Officers should be trained to prioritize deescalation whenever possible. (Among other reasons, many violent or threatening individuals are mentally ill.)

I want black people carrying fake guns to be treated with at least as many rights as white people carrying real ones.

I want law enforcement officers to be legally classified as ordinary civilians under all circumstances unless their actions are recorded by a body camera and successfully uploaded to a public server. (Live wireless backup could be an important part of this.) (Any recording relevant to an actual civil or criminal trial should be publicly viewable, but I could accept restrictions on general access to all recorded footage.)

I want statistics to be kept on every police officer and every police department, including counts of officer-involved deaths, major injuries and minor injuries, as well as percentage of encounters that escalate to violence, all annotated with race and gender. Departmental statistics should be public, and tracked at the state and federal level. Individual officer's statistics should be confidential but regularly reviewed at the local and state levels. (For both individuals and departments, careful statistical analysis is of course necessary: some outliers are statistically inevitable even under normal behaviors and conditions, and careful attention would be necessary to develop proper apples-to-apples comparison groups. Statistics alone should never lead to censure or punishment, but they could prompt a more individual review, including recordings of the incidents in question.)

I want police officers (and society at large) to recognize that one bad apple ruins the bunch, and that their fellow officers must be held to standards at least as high as the general population.

I want a guarantee that the proceeds of civil forfeiture will never be shared with the officers, department, or local government directly responsible for confiscating the property in question. (Proceeds could be given to local community service organizations, or to state or federal governments.)

I want a (low) nationwide cap on the fraction of a municipality's revenue that can come from fines. (Excess could be returned to local citizens as some sort of tax rebate or given to local non-profits.)

I want a ban on military-style equipment for most police officers and departments. The use of such tools should be limited to small, highly trained teams to be deployed only in the most dangerous situations, and whose numbers are subject to strict caps based on local/regional population and violent crime rates. (Note that British police are almost entirely unarmed, and overwhelmingly want it to stay that way. That might not work here, today, but clearly our current model isn't the only way.)

I want the importance of affirmative, active consent to be taught in every school (and discussed as explicitly applying to sexual activity beginning at least by middle school).

I want drug possession to be treated as a public health issue rather than a crime. (Retroactive reductions in prison sentences to match would be a good corollary.)

I want the sale of any drug whose likely harm to the individual and to society is no worse than tobacco's (or maybe even alcohol's) to be legalized, taxed, and carefully regulated for safety. (More nuanced updates of that Lancet study would of course be very welcome.)

I want the US population to collectively decide that convicts deserve humane conditions and that rape and assault are just as important to prevent in prison as they are outside of it. (And that it's worth the investment of money and attention to ensure all that. I'm willing to accept a lot of cameras for this one.)

I (probably) want most of our national social safety net programs to be replaced by a universal basic income (along with some sort of access to Medicare/Medicaid or a similar program), too, but that's a more complex issue than most of these.

There's probably a lot more that should be on this list, but that's a start.
steuard: (lake)
2014-12-28 05:24 pm
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Recently read: Shadows, by Robin McKinley

During our travel to and from Nebraska this Christmas, I finally read Robin McKinley's latest novel, Shadows. It's an (urban) fantasy story set in a small city in "Newworld", which seems to be a fairly close copy of modern America (to the extent that highschoolers still read books like "Anna Karenina", which of course must have been written somewhere in the Slavic parts of "Oldworld"). The setting is intriguing: two or three generations earlier, the government of Newworld banned everything to do with magic, and required all children with magical ability to have the gene for it medically removed. Now, when dangerous "cohesion breaks" appear (due to intrusions of other worlds), instead of magicians handling the problem the Newworld military rushes in to contain and close them using scientific equipment. That's the setting; the story itself is about a high school senior who can't stand her new stepfather and the unsettling way that the shadows around him seem much more alive and threatening than they have any right to be.

I'm not quite sure what to say about the book. I liked the setting, both the parts that were spelled out in detail and the parts that were just hinted at: it felt similar in some ways to the setting of Sunshine, though with more of an "oppressive government" vibe rather than Sunshine's "post-war recovery" feel. I liked the characters, too: the high school kids seemed realistically done (though I was sad that the lead character was was so down on math), and the adults were a fine supporting cast (as seen through high school eyes). Even the general shape of the story was good.

But overall, I think that the pacing just felt a bit off. That became clear to me when the action was just on the verge of taking off and I realized that I was already 2/3 of the way through the book. In terms of the ebb and flow of the story, this whole book feels a lot like Sunshine might if that book ended just after Rae woke up at home the morning after her escape (the end of "Part 1": its first third). The slow initial pace may have also contributed to a bit too much telegraphing of some "mysteries" that are revealed midway through the story. I can't begrudge the attention that McKinley gives to establishing the characters and their relationships, which she does quite well, but I really wish we had an Act 2 and Act 3 to realize a bit of the potential that's hastily suggested in the final few pages of the novel. (I might feel more content to accept that unfinished business if McKinley ever wrote sequels.)

So what's my take-home review? If you enjoy McKinley's writing, Shadows is worth reading. I'd place it happily in the second tier of her work, below the Damar books and Sunshine but clearly above, say, Chalice. It's fun, but I wish it had been just a little bit more than that.

[spoiler aside] )
steuard: (physics)
2014-11-25 07:42 pm
Entry tags:

An unexpected party

Backstory: In my classes, I put my email address on the syllabus and tell students that I'll write back as soon as I can (sometimes even at crazy hours, if I happen to be up). Kim is even nicer: she even gives her students her home phone number (with strict instructions not to call past bedtime).

Fast forward to last night: Just as we were starting to clean up from dinner, the phone rang. Kim answered, and then said, "So you're having trouble with quantum mechanics? Sure, I'll get him." She handed the phone to me, and in response to my inquiring look she explained, "It's A---."

It turns out that A--- has the dubious fortune of taking classes from both Kim and me this semester, so when her study group got stuck on stuff for my class, she knew how to reach me. After a couple minutes of attempting to help over the phone, one of the folks in their group said, "We've got lots of questions on this stuff: can we just come talk to you in person?"

I paused for a moment as several thoughts flashed through my head: "Are you kidding? We've got to clean up and start moving toward bedtime." "This would be delightfully random." "Studies show high retention rates for students who make strong connections with faculty in their first semester of college." So I responded, "Sure! Here's our address." And a few minutes later, three students showed up at our door.

They stuck around for half and hour or so, maybe a bit more, and it went really well: with some extra hints and nudging from me, I think all three of them really solidified their understanding of the topic.[1] They also looked like they were having fun, and none of them could quite believe that it was real. (After ten or fifteen minutes, one of them randomly exclaimed, "Hey, remember that time in freshman year when we went to a professor's house at night for help on our homework?") It was fun, and I like to think that it had a positive impact, too.

[1]Namely, how to calculate probabilities when measuring the spin of an electron in a specified superposition state. Maybe I should have looked for some visually simpler way to represent superposition states than Dirac's ket notation, but I don't really know of a better alternative.
steuard: (lake)
2014-06-30 07:58 am
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Thoughts on Worm

I recently finished reading a web serial called "Worm". (In other news, I forgot to bring any fun books to read to last week's physics conference.) I'm not sure what to say about it, or even whether to recommend it, but it was a heck of a read. Worm is a very long superhero story whose main character is a 15-year-old girl with the random and not obviously useful ability to control nearby bugs. The quality is a bit uneven, it's often pretty dark, and there were times that it was outright annoying or just too darn long. But its fictional world is quite good at aiming for "the inner consistency of reality", which is important to me, and it weaves a complex and (I think) satisfying story within that setting.

I obviously enjoyed Worm enough to read all of its ~1.8 million words on and off over the course of half a year or so (or more?). (That's something like 10-11 long novels, or almost 6 Wheel of Time books). I cared enough about the characters to want to know how things turned out for them, and enough about the fictional world to want to find out what was really going on. Many chunks of the plot were gripping (both on the scale of scenes and chapters and on the scale of novel-length arcs). It's an enjoyable story.

But on the other hand, there were multiple points along the way where I almost stopped reading (or where I did stop, only for unsatisfied curiosity to suck me back in weeks later). There are several points early on when the main character makes choices that seem blatantly at odds with her well-established goals (which may be forgivable in-story because she's so young, but that didn't make it less annoying to me as a reader). The pacing is inconsistent: in some places the character development and action flow beautifully, but in others it feels like a single plot arc is dragging out about twice as long as it needs to, and in others (well, one other) it skips right over a vast expanse of time that really ought to have been fleshed out more. The story could definitely benefit from a round or two of revision, and probably some professional editing.

There were a few times when Worm's tone rubbed me the wrong way, too. Especially near the start, there's a significant vibe of "adults don't care enough to help" that felt unfairly broad and lacking in nuance to me. Later on, there are a handful of minor places where the story seems to buy in to juvenile anti-feminism. (But then you keep reading, and close to the end there's a completely tangential moment of explicit opposition to rape culture thrown in out of nowhere, so I was left more neutral on that score than I expected to be.) And it sometimes feels too cynical about its people: nobody's perfect, sure, but I wish more characters in the story were more or less decent.

Overall, though, the underlying ethos of the story was right up my alley. A big theme is watching characters find ways to succeed by thinking carefully and making the most of small advantages. Sometimes (sometimes) that's even enough to overcome opposition that is intrinsically stronger or more politically powerful. Even more central to the story is moral ambiguity: there are frequent questions of ends vs. means, conflicting loyalties to family, friends, and society, and it's very rare that there are any easy answers. Even a lot of the worst "villains" have some degree of depth. And the thing that makes all that work for me is simple: the main character is trying to do the best she can for the people around her, even when her choices aren't what they ought to be.

So should you read it? I really couldn't say. I don't even have a good answer to how far you should read before you decide whether it's for you. But there are things about the story that I think will stick with me for a while.
steuard: (lake)
2014-05-31 08:41 pm
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Memories of the present

I saw this comic recently.

Somewhere in the house is a box containing the plans I drew up around age 12 for pretty much exactly this. (Without the Oculus Rift part, but instead with a complicated multiple controller setup for large-scale team play.) As I recall, my drawings were heavy on the concepts and light on engineering details. :)

My childhood vision began as "Battlestar Galactica fleet vs. Cylon Basestar fleet in the sky", but I gradually expanded it to include at least two additional very distinct teams. I don't think I quite recognized at the time just how far out of reach my ideas were for the technology of the day, but it's awesome to think that someone could conceivably do it for real right now.
steuard: (physics)
2014-05-24 04:19 am

We have left our mark on the face of the heavens

We live in a remarkable era. If you brought an ancient Greek astronomer to the present day and dropped him off in a field somewhere, he would be awestruck, and maybe terrified. (Heck, it probably wouldn't even need to be an astronomer: I think that most people were quite familiar with the night sky until recent times.)

The meteor shower was pretty much a bust: I was outside for a decent stretch and only saw two for sure, plus a couple more "maybes" that were too brief and dim for me to judge whether they came from the expected radiant point. (To be fair, from where I was in our backyard I was seeing far less than the full sky.)

But in the same time, I saw at least half a dozen satellites, ranging from "almost too dim to see" to "easily the brightest object in the sky". It's obviously been too long since I just lay back to watch the stars: those things are now a near-constant presence. So I really do wonder how that Greek time traveler would react to the modern sky: what would those swift-moving, variable brightness points of light mean to him? What would Plato make of it? What stories would Homer tell?

For that matter, I'm sure that there are still plenty of societies and communities today that have little knowledge of high technology, from isolated tribes to rural villages. What do *they* make of the satellites that now pass constantly over their heads? This is a recent phenomenon: its origin is easily within living memory, and it has only gradually become as frequent as it is today. What stories do those people tell? Do they know or guess that these are the work of human beings? Do they fear that the newly mobile stars are an omen of some approaching doom?

And what stories might we tell about ourselves, as we alter the face of the heavens so deeply without ever pausing to think what an astounding achievement that is?
steuard: (physics)
2014-04-28 04:40 pm
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Wanted: Time travel short story recommendations

I'm teaching a First Year Seminar class this fall entitled "Time Travel in Science and Literature", and I'm looking for suggestions on the "Literature" part. I honestly don't know how much reading is reasonable to assign in this context, so my main request here is for short story suggestions. (I'm also considering a couple of short-ish books: Einstein's Dreams by Lightman, and possibly The Time Machine by Wells.)

There are a lot of angles I could take on the "literature" side of things, so I'm open to a wide range of suggestions. The important thing is for time travel itself to be central to the story in some way: there should either be a focus on the "science" itself or it should be an essential ingredient of the plot or the meaning of the story. (That makes me hesitate a bit about the Wells, in fact: his science is quite nice, but I'm a little worried about whether "time travel primarily for purpose of social commentary" strays a little far from my aims. But it is a classic, and that's clearly a valid use of the time travel plot device. I just wonder whether it's a whole novel's worth of value in my context.)

[Edit: Oh, and for the record, I'd love to have a good "twin paradox" story, too.]

Other background info:
I'd like to have included the phrase "the Nature of Time" in the title, too, but it started to feel cluttered... both as a phrase and as a course.

On the science side I have an initial sense of what I'm going to do (probably), including talk about space-time diagrams and having them read (at least part of) Sean Carroll's book "From Eternity to Here". (There are no prerequisites for the class, so I can't really use much math at all: concepts and pretty pictures it is!) I may not have time in the class to talk more than a little bit about entropy and the arrow of time, though, so I'm still contemplating options here, too.
steuard: (lake)
2014-04-06 10:36 pm
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Belated self-congratulatory link

I meant to share this earlier (and I don't think I already have), but I've been swamped. I'm still swamped, but I want to close some browser tabs. So here's my fifteen five three and a half minutes of fame in the Alma College student newspaper: Physics professor Jensen receives special recognition for effort inside, outside of classroom; students concur.

This was an award from one of our campus sororities, and I was truly touched when the student who nominated me repeated her nominating speech to the assembled group. She had good things to say about my physics teaching and my dedication to helping her and other students learn the subject and be successful, which was great. But the thing that she really appreciated most was the attention that I have given to women's issues in the classroom: I don't do a whole lot (and for the most part I don't even devote class time to it), but she said that I'm the only male teacher she's ever had (here or at her previous college before she transferred) who ever commented on those topics at all (without it being his actual academic specialty, anyway).

It's a shame that "this guy pays the slightest bit of attention" is enough to merit an award, but if doing my little bit is appreciated that much then I'm awfully glad to keep it up.

On a side note, I have no idea why there's a black and white photo accompanying this online article while the printed newspaper had a color one.
steuard: (physics)
2014-03-17 06:26 pm

Rundown on inflation and gravity waves

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)
2014-03-17 12:11 am
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Physics/cosmology news incoming

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: (Tolkien)
2013-12-30 10:40 pm
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The Hobbit Part 2

Wow. That was something. I can imagine that for folks who don't know the book well, it was probably a pretty entertaining movie. But, well, is it a bad sign for a serious epic fantasy story that I spent a fair bit of the film laughing?

My chief impression after watching "The Desolation of Smaug" for the first time today was puzzled surprise: given that Peter Jackson has taken a single short book (far shorter than any volume of The Lord of the Rings) and expanded it to fill three very long movies, how (and why) did he manage to condense or omit so much of Tolkien's story?

Hyre be spoileres... )
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steuard: (lake)
2013-09-04 10:12 pm
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Robot Turtles: A board game to teach programming to preschoolers

I've been sharing links to this all over social media since I heard about it earlier today. "Robot Turtles" is a board game project on Kickstarter by Dan Shapiro (a fellow Mudder). From the looks of it, it's a fun game that's designed to teach kids (3-8 years old, he says) some basic programming concepts along the way (and that gives the kids the chance to be in charge of the adult playing with them: always fun). It sounds like there are multiple layers of complexity, depending on what a given kid is ready to handle.

Have a look! It's rocketed past its funding goal in the day or two that it's been out, and it sounds like the game design and logistics for production are pretty much set.

(While I'm at it, what are some other good board games for the preschool set? Bonus points if they're sneakily educational like this one.)
steuard: (physics)
2013-09-02 10:02 pm
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Comparing tidal forces by eye

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)
2013-07-27 10:36 pm
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xkcd: Time has ended!

Wow: the xkcd webcomic had an entry called "Time" a while back that was notable because the image updated every hour(?), gradually telling some sort of story. Some dedicated people have been following it carefully, and it just reached "The End" in the past day or so (3099 frames total!). The story starts out pretty slow, but it builds to a strong conclusion, and it's awesome.

Here's a site where you can let all of the frames play back automatically at high speed (with brief pauses for frames with dialog or noteworthy events). It's worth watching!

Incidentally, there's clearly a lot of backstory that is never fully revealed along the way. Evidently there's a whole community trying to piece some of it together. Just as one thing to watch for, near the end you'll get to see two maps. Pay attention to the second one (and maybe tilt your head a little). Evidently even the details of the stars are important.
steuard: (lake)
2013-05-25 11:48 pm
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Two sci-fi stories

I've recently read two science fiction stories that proved to be more closely related than I expected, given that they were recommended by entirely different sources in (as far as I recall) entirely different contexts. Some of that may just be a matter of who I am right now and what I've been thinking about lately (apart from physics teaching and research), but I thought I'd share them. Both are worth reading, though the second has had a firmer grip on the back of my mind in the time since I read it. I may say more about my thoughts on these later, but I'd rather give anyone who's interested the chance to read them first, so for now I'll just give the titles and links:

The Women Men Don't See, by James Tiptree, Jr. Much of the point of this story lies in the choice of narrator. And yes, trust me, it's sci-fi, though it's fair to say that the overt sci-fi isn't itself the point of the story.

Bloodchild, by Octavia E. Butler. This is one that sticks with you, which may be why it won a Hugo and a Nebula. [Edit note: This deserves a trigger warning for pregnancy complications. My apologies to anyone who was caught off guard.]

Edit: Since I've commented on awards for "Bloodchild", it may be worth mentioning that well-known anthology editor Gardner Dozois said of the 1974 Hugos that, "The award in novelette should have gone to a story that wasn't even on the ballot, Tiptree's 'The Women Men Don't See'."
steuard: (lake)
2013-04-21 10:22 pm
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Sharing non-physics ideas with my students

Quite a while ago, I mentioned the "#WowGood2Know" facts that I'd started including with the homework assignments in my intro physics classes; folks seem to like them. Well, this semester I mostly ran out of my existing list of those, and I decided to do something a little different: I shared a slightly longer discussion inspired by a (linked) blog post. That went over pretty well: according to my anonymous midterm course feedback survey, most people were at least a little interested and read what I'd written (even if they didn't usually follow the links), so I kept it up sporadically throughout the semester as I found more relevant links to share. I've now collected all of those discussions onto a web page: "Important Stuff Nobody Thought to Tell You (probably).

If you have a look at that list, you'll find that I wound up focusing on a specific theme: broadly on our social attitudes toward women, and more specifically on sexual violence. I might go further and say that the topic was fundamentally "rape culture", except that I made a point of not using that bit of jargon anywhere (though of course some of the articles I linked to do). I think that every single week that I included one of these discussions on the homework, I had at least one student stop by either after class or at some other time to thank me for drawing attention to these issues and for sharing such thought provoking reading. (A few became downright enthusiastic about what I was doing.) That made me feel awfully glad that I was doing it... and kinda cruddy that the bar was so low.

Not surprisingly (but disappointingly), every single person who gave me that sort of feedback was a woman.
steuard: (lake)
2013-04-09 11:23 am
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Ignorant physicists

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.