I tuned in halfway through. The first 15 minutes I saw were about the evils of the Catholic Church. But then he got into us all being starstuff and the awesome scope of things.
I should probably like NdGT more than I do, but I just can't get past the stupid manned-space-program boosterism.
I don't think there's anyway to do the vast amount of public outreach that he's been doing for awhile now and keep doing top-notch academic work.
Also, I doubt he smokes as much pot as Carl Sagan did.
At first I was worried this was from heebie and I was a failure for not giving my kids anything to picture as a "typical" astrophysicist, but I am okay for saving it for when it's not past their bedtime. And I do love times a million that he's black and smart and right about a lot.
We've had a lot of drama about skin color lately and I just put this in the other place, but the big girls had a joint meltdown about how unfair it is that when I'm upset or cry my face turns red and they can't do that. Poor little beans!
You know what's a good show, that still holds up well? Ascent of Man with Jacob Bronowski. There was a opinionator about it.
Sagan gave a talk at the now-demolished Woodward Court when my wife lived there.
He certainly said "Billions" with an unforgettable stress; probably "Billions and Billions" came from Carson's fond impression of him--he was a frequent guest.
Oh, I was kind of wanting to watch this, but forgot to set the DVR before I left home. I guess I can catch it somewhere on the web.
On a visit with my grandfather several years ago, I was really surprised that he'd checked out a set of DVDs about astrophysics with NdGT. He was watching one a day and found them sufficiently engaging. I asked why he was interested, and he said it was helping him understand my father's work. I thought it was kind of funny that he didn't just, you know, ask his eldest son about his work, but I thought it was pretty cool that NdGT was engaging enough that my then-89 year old grandfather could learn a bit of astrophysics.
4: Tyson tells an interesting story about his first go at grad school at UT-Austin. He got stopped by campus police multiple times going into his lab on the weekends (but never going to the gym), had a horrible time of it, quit, and started over at Columbia.
Also, as far as I understand, Tyson hasn't really done academic work in the last fifteen or twenty years; he got a PhD and did a postdoc or two and since then his job has been all about public engagement. Also I don't think he was ever a theorist; I think he was more of an observational astronomer/astrophysicist. Not that there's anything wrong with any of that, of course.
I like the career track in 8. I should work out how to do tha, except instead of introducing people to the wonders of the universe I can convince them the killer robots are their friends.
The last sentence of 8 is there only because I apparently read the OP too fast and thought it said something about a theoretical astrophysicist instead of a typical astrophysicist. I blame jetlag.
I don't know anything about his academic work, but he smacked down Pluto's sorry ass, so he's okay by me.
THAT'S NOT USEFUL DATA, IT'S JUST NOISE!
I do not care one whit if NdeGT has been publishing or not. He is willing and well-enough qualified to be a public enthusiast for science, and America needs him.
There's a big book, so far as I know yet to be written, about science popularization as a Genre. I'm thinking the full Constance Rourke treatment, the working-out of the endlessly-repeated themes: Brave pioneers against organized superstition, the wonder of exploration--this is where manned spaceflight comes in; shut up, James Van Allen!--the whole bit.
And every last show of this kind has been full of it in my lifetime, and I'm guessing the true survey will find examples going far back, perhaps to the original Chautauqua lectures.
I fondly remembered Ascent of Man above, but I also remember how often, while watching, I would think "What a naive reading of Hamlet," or "Wow, he's completely missed Hegel's point." The original Cosmos was so over-the-top that I can remember laughing at it.
I'm going to wait for the TV documentary explaining the basic gist of the book about science popularization.
I'm watching Next Stop, Greenwich Village because I keep forgetting to go to a Radio Shack and get one of those converter boxes we are far too intellectual to get channels on our tv.
I don't currently own a television, so I'm feeling particularly I don't even own a TV during this TV moment.
And every last show of this kind has been full of it in my lifetime
I want to show my kids James Burke's Connections, because I loved it as a kid, but I fear that I may arrive at the same conclusion.
Just watched Rear Window & very sad to report "over night case" of G Kelly not as implausibly undersized for amount of lingerie as I had remembered. For years thought she'd discovered a rent in the space/time continuum to the black hole of filmy things. Alas, could realistically fit that outfit into the case in question. Sad disillusionment.
I kind of wish I'd been exposed to more Carl Sagan stuff when I was a kid, because now I'm kind of fascinated by, but almost wholly ignorant of, stuff in the vicinity of astrobiology and planetary science. Although I think probably Lynn Margulis is an even more interesting person in science history (who I'm even more ignorant of), despite her weird contrarian impulses like the 9/11 truther thing in her old age.
I'm so I don't even own a TV that I was totally unaware of this TV moment until I saw this post.
I don't currently own a television, so I'm feeling particularly I don't even own a TV during this TV moment
It looks like it may be showing up on Hulu shortly.
I doubt he smokes as much pot as Carl Sagan did.
I honestly don't know whether this is meant to be a slight on Sagan or a slight on Tyson.
A sad commentary on how how the times, and astrophysics, have changed? I doubt there are any astrophysicists today who smoke as much dope as Carl Sagan.
Astronomers are more likely to take meth.
"We've discovered an extrasolar planet! And another! Three more! Two hundred and eighteen! Three hundred and eighty-four! They're twice as big as Jupiter and orbit every eight hours! Does anyone have any snacks?"
Maybe we should keep our eyes on developments in astrophysics in universities in Washington and Colorado.
25: Random but semi-relevant tweet this AM via Felix Gilman. Gandalf hands Frodo a package of blue crystal crank. "Many that live deserve meth." He whispers, wild-eyed, "Can you give it to them Frodo?"
26: if your hypothesis is correct, there won't be any.
23 Why must it be a slight on either of them?
18 I loved Connections as a kid too and have similar fears.
So is this worth subscribing to Hulu Plus for? I'm certain Joey will watch it with me.
Honestly, I was underwhelmed. But I was kind of underwhelmed by the Carl Sagan Cosmos too -- while I love pop science, there's something about the "look at the awesomeness of it all" tone that doesn't do anything for me. Mostly, we were watching it because the kids are big NdGT fans.
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A very sweet student of mine is taking a test right now, because she was travelling for sports last week when I gave the test.
"I've never flown before, and I'm SO JETLAGGED!" she said. They were in Kentucky. "But," she explained, "we had a layover in Baltimore."
Ah, sweetie. I didn't make the case that daylight savings time should cancel out the very minor jetlag she might feel.
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31: Dude! Have you ever really looked at you TV?
31.last: The fact that NdGT is a celebrity gives me some hope for the future.
Daylight savings time, however, can die in a fire. If the ancients had had it (which they did not, more evidence that we live in a fallen world), I'm sure it would have been regulated by Chronos's most dickish children.
32: What time zone does she think Baltimore is in?
I've noticed before that people who don't travel much sometimes conflate "I just took a plane trip and now I'm tired" with "I'm jetlagged". Maybe she doesn't know what the word means. Air travel that doesn't change time zones at all can still be exhausting, but that's a different thing.
Air travel that doesn't change time zones at all can still be exhausting, but that's a different thing.
That's soul-lag. The human soul can't travel faster than a de Havilland Mosquito*. So when you're travelling by jet airliner, your soul is left behind in the wake turbulence at a relative speed of about 300 knots, and when you land you may have to wait several hours before it catches up with you. The lassitude and unease that set in as soon as you take off are the natural symptoms of having your immortal soul wrenched out of your body.
*obviously
Flying from CA to NZ in December really brought home to me the difference between the two. It's an 13 hour flight with only a 3 hour time change. I think the "jetlag" portion of "jetlag" is overrated and the exhaustion of flying combined with often having an unusually early wakeup to begin the trip contribute at least as much.
37 should be by Calvin's opinionated dad.
It's actually partly stolen from, I think, OPINIONATED WILLIAM GIBSON, who partly stole it in turn from Terry Pratchett.
Since this is the TV thread, is this the thread wherein we discuss True Detective? Or is there another thread for that somewhere?
40
Or from Douglas Adams? ISTR that idea in one of the later, lesser Hitchhiker's books.
I liked the new Cosmos, what little of it they managed to squeeze in between commercials. Tyson is affable, smart, and several times teased us by not saying "billions and billions." Good job so far.
The bit about Bruno was actually pretty nice, although the animations were not to my taste. Bruno doesn't get much press (except from John Crowley).
42.1: maybe you're thinking of the idea of "tiny flapping tendrils of guilt" connecting you to your home?
It's definitely Gibson, it's on page 1 of "Pattern Recognition"; and Pratchett had it in "Strata" as an inexplicable effect of faster-than-light travel. It may well have popped up in lots of other places too.
Since science thread, I would caption this "Urple's Dinosaurs in Transit."
Just talked to another student from the same trip. "We literally travelled all day," she said, stunned. "We had a layover. In Baltimore. And then, when we finally got back to the airport, we were still in San Antonio! Not even home yet. More driving to get back to our apartment."
They're not claiming that there was any delay. They're just shellshocked that a day of travelling is so unpleasant. It's really rather sweetly provincial.
They're just shellshocked that a day of travelling is so unpleasant.
To be fair, it is shocking how unpleasant a day of traveling is.
To be fair, it is shocking how unpleasant a day of traveling is.
Is it really that unpleasant? I mean, assuming there are no cancelled flights or unexpected delays, I've never found air travel to be particularly stressful or exhausting.
48 How tall are you. Planes are also the most excruciatingly boring form of travel, and that's partly due to the extreme space constraints. Airports are alienating and annoying what with all the security constraints. Plus you can't smoke anywhere these days - rightly so on planes, wrongly so in airports.
44
I remember it in Gibson, too; been a long time since I read "Strata." Ah, well, writers borrow from each other all the time; NP.
49: What I find astonishing is that I'm uncomfortably cramped in airline seats, and I'm 5'7". I have no idea how tall people survive.
re: 51
Aye, ditto. I'm 5ft 10, and I find air travel really uncomfortable.* People who are well over 6ft, it must be miserable.
* although it varies from airline to airline, and not always in a way that maps neatly against price.
51. They bully the check in clerks into giving them a bulkhead seat a lot of the time. Or try to wheedle an upgrade on the grounds of some real or imagined condition which makes it impossible for them to remain in a foetal position for eight hours. In the last resort, they spend most of the flight standing up. My source for this is my BiL who is 6' 4" and flies both ways across the Atlantic at least once, usually twice a year.
I'm 5'10", and while I do find myself wishing I had more leg room and elbow room in airline seats, it doesn't particularly bother me all that much. I guess I'm just good at fitting into small spaces.*
I'm also a non-smoker, so no issues there.
I find the relative boredom of air travel to be a plus, actually. It's one of the few times when I can read for a few hours without feeling like I ought to be doing some other more urgent or important task.
Yes, the security is annoying, but not in a way that leaves me stressed out or exhausted.
* . . . laydeez.
This summer I'll have what's sure to be the least pleasant travel experience of my life: for unavoidable schedule/budget reasons, we have to get from Austria to Pittsburgh between a Sunday evening and a Tuesday morning in time for school*. The hitch is that the flight is from Frankfurt (near my FIL's house) to JFK (near my dad's house). So ~5 hour overnight drive, 8 am flight, 11 am arrival, and then 7 hours back to Pgh. Whee!
*they're already missing the first day of school, so we really don't want to miss the second
51: I sleep. I find it very difficult to stay awake on aircraft: maybe it's the white noise from the engines or the low cabin pressure or something, but I'm normally out for the count within a few minutes of the door closing and get woken up again by the safety demonstration, go back to sleep again and that's me for the flight, unless hunger supervenes.
Travelling by myself? I love it. Just time with nothing to do but read or get shit done and I don't have to talk to a single person unless I want to.
they're already missing the first day of school, so we really don't want to miss the second
I honestly think you're splitting hairs here, if it will make a big difference in how pleasant the return trip is.
I like long train journeys, and I don't mind short-ish [2 hour-ish] flights if the journey to the airport isn't evil.*
* e.g. from fucking Stansted.
58: Honestly, it's more about Iris than anything. I, personally, don't really care how much the kids miss school, but Iris is already upset at missing one day. I think she'd truly freak at missing 2.
It doesn't help that I suspect we'll be away for the open house where kids get to meet their new teachers. Thank goodness she'll be staying in the same school, so most of the situation will be familiar.
56: Lucky dog. I've never been much of a sleeper, so under airplane circumstances, I'm lucky to get a few hours on an overnight flight.
57: I've almost never done it, but agreed. My 2 solo trips down to TX were a treat (especially the one where I got upgraded to 1st class, albeit on a tiny commuter plane).
Train journeys are great. Plane journeys are terrible. The main problem with plane journeys (though there are so very many), is the amount of time spent in crappy environments not actually travelling. Queue for check-in. Stand in a security queue for half an hour. Sit (if you're lucky) in the world's shittiest shopping centre for an hour. Stand in a boarding queue for half an hour. Shuffle along a narrow passageway to get to your seat while people in front of you block the way. Sit in your seat while waiting for the plane to take off. Then repeat pretty much all of that in reverse when you land.
And that's without even getting into the crappiness of airplane seats, food, air etc.
Also I can't sleep on planes (except for the extremely rare occasions I get one of those flat seats), so long-haul flights are a special hell all of their own.
I fly rarely enough that I still find it kind of fun, which I think is a holdover from being a little kid who really wanted to fly on a plane but had to wait until twelve to do so. But yeah, the takeoff, the landing, staring out the window at all the Sim City-looking scenery, the weird bathroom. At some point, if I flew regularly enough, the novelty would wear off, but as it is, flying maybe once or twice a year, I'm an annoyingly wide-eyed tourist, having a ball.
Oh look, a bunch of people who don't get motion sickness if they turn around too fast. Planes are the pits. Thin dry air, cramped quarters, and the motion sickness, dear god, the motion sickness. And airports are stressful if you're not familiar with them, which most people aren't. Where do I go? When do I need my ID? Will there be a bathroom near the gate? Food? All under the cloud of DON'T MISS YOUR FLIGHT and DON'T GET ARRESTED.
And that's all if you're not flying with kids. If you are, oh em gee.
Also, fuck you ajay and all the people like you who can sleep on planes.
My most recent flight I had to go through security 3 different times because each time I transferred planes I had to go between terminals where there was no way to do so without going through security.
65: mate, I can sleep on helicopters. Chinooks are the best. They seem to rock gently back and forward as they fly, it must be something to do with the twin rotors. Sends me right off.
For what I imagine is a limited time, the Cosmos episode is on YouTube. Not at all my style, but I can imagine kids enjoying it.
Now I want to take ajay to an amusement park and see what he does on a rollercoaster.
Too late, LB. I have killed and eaten ajay. It seemed only fair.
When I was flying a lot for my old job, I hit a breaking point and it just became miserable. Any plane travel now invokes some kind of traumatic memory for me, so even a 1 hour flight that's no big deal at all just seems miserably unpleasant and stressful. In many ways though airports right now are nicer than they've been for a while and security is less horrible than it's been since 9/11, plus in-flight internet is nice. It still is super horrible though, unless you're flying private or in first class.
When I was flying a lot for my old job, I hit a breaking point and it just became miserable. Any plane travel now invokes some kind of traumatic memory for me, so even a 1 hour flight that's no big deal at all just seems miserably unpleasant and stressful. In many ways though airports right now are nicer than they've been for a while and security is less horrible than it's been since 9/11, plus in-flight internet is nice. It still is super horrible though, unless you're flying private or in first class.
God, finally. I was wondering when we were all going to start killing and eating each other.
No one expects the carnivorous primates!
http://mcphee.com/shop/horse-head-squirrel-feeder.html
"Dad, you know how we are cannibals?"
"Aye, son."
"Well, is it not wrong to eat people?"
"Look, son, if the Great Father hadn't meant us to eat people, he wouldn't have made them out of meat."
70: "To go on," ogged said. "Odysseus, as I understand him--"
http://www.gutenberg.org/files/28554/28554-h/28554-h.htm
ajay! I knew the plane-sleepers were practitioners of Dark Magic!
78: You're not getting to be one of these cranks who think that eating people is cruel, are you? Seeing the man sitting in the pot and you think he's suffering? Oh, it's not like that at all. Why, he's just had an invigorating chase through the forest, and he's sitting there in the nice warm water with all the carrots and dumplings and things, thinking, "Oh, the pleasure and happiness I'm going to give to all those people". That man in the pot there, he enjoys it!
https://www.youtube.com/watch?v=oUcFXijEoA0
79 should be https://www.youtube.com/watch?v=dCdshepGguI, sorry.
And airports are stressful if you're not familiar with them, which most people aren't.
Airports are stressful* even if you are familiar with them. Chicago's international terminal seems to have been designed to be as aggravating as possible, forcing you to go back through security if you, say, decide you want cooked food.
* With a handful of well-designed exceptions, like the newish Hong Kong airport, and some tiny airports where it's basically a check-in desk and a gate.
sorry, I mean 81 should be that. Oh, lord. Getting late.
Ogged has returned to serve Unfogged.
84: Time to snuggle into a nice cozy helicopter?
Definitely.
On a related topic, I feel I should mention that I will be in NY in a couple of weeks and at liberty on the evening of Thursday 27th to head to, oh, Fresh Salt or somewhere for a quiet pint or two. If anyone else can join me, great: if not, I will liveblog my solitary drinking, Moby style.
86: Helicopters blasting lullabies* as they attack.
*Which would actually be much more disturbing than "Ride of the Valkyries" , or "Hell's Bells."
67: you were the inspiration for Hudson from Aliens?
I am still free for a meetup in the vicinity of Manchester airport on Thursday the 20th! Or maybe somewhere in actual Manchester proper, if I can figure out how public transit works in the UK. Or maybe I'll just sit in my hilariously named hotel and grade midterms.
89: and I was really hoping for Blaine from Predator.
For one reason or another I haven't flown in a dozen years. I remember being extremely cramped every time I flew, although I could sleep if I could screw myself into some sort of stable position. Rumor has it that accommodations have become even tighter, so that will probably only be worse than I remember it. One of these days I'll fly again, I'm sure but I certainly don't miss it.
I was really hoping for Blaine from Predatortty in Pink.
90.last: who names a hotel The Factory?!?!
94: "Hacienda" isn't the worst name for a generic block of flats, though, I guess.
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I guess it's the counterpart to the Texas GOP platform, but I'm still pleased that the CA Dem platform now includes legal recreational marijuana, fracking moratorium, single-payer health care (in principle at least), and inflation-indexed minimum wage / living wage.
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The hassles of air travel, however you rate them, pale in comparison to the hassle of refinancing a mortgage. You need me to provide endless reams of documentation and paperwork just to prove I can afford payments that are less than what I've been paying every month for the past ten years? Seriously?
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Also, fuck you ajay and all the people like you who can sleep on planes.
Srsly. When the best thing you can say about air travel is that at least you didn't die from deep vein thrombosis, it sucks objectively. Sure, it gets you wherever fast. Wevs, I'd rather walk. I was up the whole time on a seemingly eternal flight to Rome while one of my friends slept through thanks to narcotics, and all I could think was, you have a friend dying of AIDS who has leftover drugs? You lucky bastard.
My big complaint about air travel, aside from the unproductive time spent waiting in lines, is the person who reclines his seat in front of you and makes laptop use impossible. But I am not sure that will be well received here.
97: The legal profession regrets any inconvenience caused by making your lenders afraid of their own shadow. But, frankly, you'll thank us when the entire world financial system doesn't implode again for at least a few more years.
the person who reclines his seat in front of you and makes laptop use impossible
You could try Knee Defenders.
No, we've had this conversation before. Reclining your seat is poor etiquette and generally poor manners, at least if it's clear that someone is using a laptop and/or is tall. Though it's the airlines fault for crowding everyone into tiny spaces and then giving everyone an option to become even more annoying for the gain of some minor additional comfort, and I'm unsympathetic to those who think they have a "right" to have people not recline into them. The seat recline button is the worst idea ever.
99, 101: Discussed on multiple occasions.
Knee Defenders
Worst comic book movie adaptation ever.
Holy shit, Terry Tao predicts finite-time divergence for Navier-Stokes equations.
101-02: Sorry for not RTFA. I don't think it's a question of rights at all, just an added annoyance.
103: I wouldn't have guessed a comic book movie exactly.
It's a really interesting idea. The approach is to build a computer (with error protection) built entirely of water. If you can do this then you should be able to construct a situation with finite time blowup. A water computer (note: no pipes allowed!) is such a cool idea. It'd be really really cool if this works out.
There was that recent, terrible looking Liam Neeson movie about him being an air marshall, but it might be good if he just starts wasting dudes who have bad airplane etiquette. "Oh, sighing loudly at a crying baby? ENJOY YOUR REST . . . IN PEACE."
The United Airlines Writer's Residency has been slow to attract applications.
It would be good if the Air Marshalls started acting more like the US Marshalls in Justified.
It would be good if the Air Marshalls started acting more like the US Marshalls in Justified.
I wonder what it's like to go through Sky Marshal school, and you're all jazzed up about busting some bad guys—in the sky! And then one day, a few months out from boot camp, you're sitting there at work and it hits you: it really is just riding on planes.
Haven't read it yet. I like TT a lot, mostly read him with an eye to these equations and this question. The consequence would be that NS is not right for a physical fluid under some initial conditions. Cavitation and compressibility are both pretty interesting.
89: Aliens, of course, portraying the utopia in which everyone gets to sleep through long-haul space travel until waking to the sight of Sigourney Weaver in her underwear.
113: Alternatively, the utopia of 2001 where you have a nice long sleep and HAL kills you and you never even have to know about it.
Utopia and dystopia are very close. If you got in the wrong capsule, you might wake up to the sight of Paul Reiser in his underwear.
I had a political science professor who taught Walden II and Brave New World as essentially identical - but one a utopia and the other a dystopia. This is probably a very pedestrian insight for you sophisticates of politics and literature, but I remain impressed by it.
87: May I be the first to suggest Fresh Salt? I'll put up a post reminding people that week. Or, actually, I kind of liked Dive Bar, and that's halfway home for me.
117: If you're putting up meetup posts, can you put up one for Boston for the weekend of the 22nd/23rd?
118: I'm not explicitly shaming you into sending me an email, but I've only caught sight of these fleeting mews about a meet-up when I've been about to leave the computer, and I thought "Well, I'm sure he'll send me an email."
I like "fleeting mews". I usually visualize the blog as a tropical fishtank, but a roomful of kittens works well too.
Careful, they're playing Bad FPP/Good FPP with you, Josh.
Fleeting Mews sounds like a street of houses on the outskirts of London.
119: they're not fleeting, they're immortalized for all time!
A fishtank full of kittens, OTOH, would be a mewing fleet.
. . . they're not fleeting, they're immortalized for all time!
Reminds me, again, of this XKCD.
Just in the last week or so, I discovered that a short-lived but active group blog I participated in during 2007 no longer loads. (I think it is still there, but the WordPress "code" for it no longer works Deprecated: Assigning the return value of new by reference is deprecated in [/thingity-thing/bloggity-blog.com/wp-includes/cache.php] on line 36 etc.) Like the archives here, I used it as a reference to find things I recalled posting on it. I had scraped it onto a thumb drive which is somewhere ...
A very minor, but tangible personal sadness.
Is there anyone chance someone could explain the Terence Tao thing in terms that would make sense to someone who knows some math but has never heard of the Navier-Stokes equations? It looks interesting (building computers out of fluid? Conway's game of life?) but I can't follow the blog post at all.
Just in the last week or so, I discovered that a short-lived but active group blog I participated in during 2007 no longer loads.
I remember going to look for old threads from r.g.f.advocacy, sometime after google took over dejanews, and being completely unable to find anything (is it just me or is the google newsgroup search not very useful?). I read it regularly for about two years, 95-97, and hadn't really looked at it since, but it made me sad.
I do think about it occasionally, wrt unfogged, because when I discovered it I thought that it was one of the best things online, but I was strictly a lurker; I wasn't even tempted to post. I'm not quite sure what it was that made that barrier to entry here seem lower (though it it was a long time after my first comment here that I actually felt comfortable commenting).
The Navier-Stokes equation describe the behavior of an ideal fluid. "Ideal" means you ignore all the messy small details (like that liquids aren't infinitely divisible, potential chemical or nuclear reactions, or quantum mechanics). A good analogy here is the "ideal gas law" from high school physics, which you work out by assuming that the gas is made from arbitrarily small particles bouncing off each other. Here you do a similar thing where you assume your fluid is made of arbitrarily small bits and work out based on their surroundings where the bits would go.
The big question about Navier-Stokes is whether given some starting condition whether you can actually solve them in a nice smooth way. The alternative is that there's some way to set up a system of moving ideal fluid so that the energy in some little region will grow without bound. In such a situation something really weird would have to happen physically that wasn't just described by the ideal fluid laws (but instead by fusion or quantum mechanics or something). In the instances Terry's looking at the fluids are incompressible, so like water and not like air.
What Terry did was take a modified version of the ideal water laws which has many of the same key properties and show that there you can have solutions which blow up. This tells you that if you want to show N-S does have nice solutions you can't just use the properties that this share's with Terry's version. It also suggests that maybe one could modify Terry's techniques to show that N-S can blow up the same way.
Very roughly what he did was construct a bunch of "gates" made entirely of "water" (in his modified setup) which allowed him to build a self-replicating water machine. Furthermore at each stage it makes a smaller version of itself and does so faster at each stage. Thus in a finite amount of time it builds a more and more complicated machine in a smaller and smaller space causing the solution to blow up. The goal is to modify his technique to work with the actual N-S equation. That is one wants to build a computer made entirely of water that's sufficiently strong that it can copy itself. Roughly this splits into a N-S problem (constructing enough logical gates out of water, and then a software engineering problem of using them to build a sufficiently powerful self-replicator to get blowup.
This Terry Tao thing sounds like fun. I'll have to take a look when I get a chance.
The N-S equations are just the leading terms in a derivative expansion and it wouldn't be surprising at all if one can push them into a regime where they stop making sense.
Or so the Physics Talking Heads would have you believe.
Thanks 132! Could you be a little more precise about what it means for a solution to "blow up"?
The N-S equations are just the leading terms in a derivative expansion and it wouldn't be surprising at all if one can push them into a regime where they stop making sense.
No clue what this means but I like pushing things into a regime where they stop making sense.
Re the OP: No one expects someone to defend the Spanish Inquisition!
Because the Inquisition brought order and justice where there was none, it actually "saved uncounted thousands of innocent (and even not-so-innocent) people who would otherwise have been roasted by secular lords or mob rule."
...
As for Bruno, he was a renegade monk who dabbled in astronomy; he was not a scientist.
133 I didn't realize that your senior colleague was *that* senior colleague. Anyway, nice to see crankpot theories getting a chance.
138.last is just kidding, btw.
101 I tend to try to reach a compromise where the person in front of me only reclines part of the way. If that fails, well, your right to recline your seat all the way comes with a right to get regularly kneed in the back and generally jostled throughout your transatlantic flight. Some of that is involuntary - I'm above average height and even if I tried I couldn't avoid it entirely. Some of it is entirely on purpose.
137 When is Bill Donahue going to come out of the SSPX closet?
You can imagine your incompressible fluid as being given by a velocity vector for every point in space. That is, for each point in space you imagine that there's a little particle and that it's moving in some particular direction. For a "nice" solution you want that these vectors to depend smoothly on the point in space (that is you can take derivatives as many times as you want). So there are various ways you could fail to have a smooth solution. For example, it could "blow up" which means that the length of one of the vectors gets larger and larger as you approach some particular time. Basically at some point in space the water picks up infinite speed in finite time.
(This is all pretty far from my field, so it's likely that something I've said is subtly wrong.)
I can see an airline writer-in-residence working. The BA Ballard Memorial Grant. Fly whereever you like on SkyTeam for a month. Write. Make it first class for the sake of basic humanity.
upetgi is mostly right. A minor correction-- the N-S equations do apply to air for velocities much less than the speed of sound-- wind past a building or a car is an N-S calculation.
For actual fluids, this suggests that there's some initial configuration where the tiny dissipative vortices will be composed of fluid moving at velocities which approach the speed of sound, so a configuration at odds with the assumptions of the NS equation. This is pretty surprising if it pans out to say the least.
For whatever it's worth, people are still sorting through why tornadoes are a consequence of turbulent forcing in 2-dimensional fluids but not in 3-dimensional ones. Also, there have been lots of investigations into equations similar to NS, but less complicated in hopes of gaining transferrable insight-- Burgers equation, Kuramoto-Sivashinsky. Nonlinear integrable systems are another related field.
If I remember right, somebody here objected to the name of one such, the nonlinear Schrodinger equation, which is useful for a bunch of otherwise intractable phenomena in liquid helium, maybe other bose-einstein many particle systems.
This is pretty surprising if it pans out to say the least.
It doesn't seem surprising to me, at least at a very coarse-grained touchy-feely intuitive sort of level. We know the equations are only an approximation, valid in certain regimes and not others. It doesn't seem too surprising that you can find a configuration that evolves into the bad regime. In general relativity, singular solutions are completely generic. I'm not sure why I would expect N-S to be very different. (In fact, I sort of would have thought that the fluid-gravity correspondence would let you turn singular solutions of GR into singular solutions of N-S, but I haven't thought that through and I guess it can't really work or people would have done it years ago.)
It's a configuration not yet observed in any actual 3-dimensional fluid. Let me guess, you are a theorist?
144: My impression here was that Tao's modified version was a modified version of *incompressible* N-S. So even though N-S applies to compressible fluids, Tao's techniques may not. But I could very easily have misunderstood.
No, no-- NS is also incpmpressible by assumption, and so approximates real fluids excellently at low Mach number. A real-time divergence would necessarily violate this assumption, so an instantiation in actual fluid would lead to a regime inconsistent with the assumption.
NS applied to fluids like air leads to density variation via the empirical relation between density and pressure. Another configuration where the correspondence between NS and physical fluids breaks down is cavitation, which occurs where the NS equations produce solutions with 0 pressure.
Ah ok, thanks!
146: We're talking about an abstract question of mathematics here. The initial conditions that lead to a blow-up wouldn't have to be realistic. If I started with initial conditions that are physically unreasonable-- like very large spatial gradients-- then I don't have any reason to think the N-S equations are going to do anything like what a real fluid would do. This doesn't mean the solution is going to blow up, but it at least suggests that it could. I'd like to understand your intuition for why it wouldn't, but go ahead and just make snide remarks at me if you want.
I can see an airline writer-in-residence working. The BA Ballard Memorial Grant. Fly whereever you like on SkyTeam for a month. Write.
Amtrak just launched a residency program.
I don't know why people believe NS existence and smoothness, but it has been open for quite a long time which might be thought of as some evidence.
I just finished watching the premiere episode of Cosmos and that bit at the end when he talks about his meeting Sagan when he was a 17 year old kid was wonderful. And having Sagan's day planner with "Neil Tyson" penned in for that meeting was a really nice touch. Well done.
151: Standpipe's blog got an exclusive on the announcement.
150. OK, It's surprising to me because people have been looking at related simplified equations for many decades that preserve as much of the physics (shock formation, boundary layers) as possible, hoping to carry the insight back to NS. The systems like this that I know about don't have divergent solutions. On the other hand, models which don't lead anywhere useful are not published. The model which does diverge that I knew about (I only knew about Yakov Sinai's) seems to me like it is in Martian.
Infinite gradient is OK for a continuum but not a real fluid-- Knudsen number and assumption of uniform viscosity break down. Personally, I am more interested in realizable systems than in math.
WordPress "code" for it no longer works Deprecated: Assigning the return value of new by reference is deprecated in [/thingity-thing/bloggity-blog.com/wp-includes/cache.php] on line 36 etc.)
This means your host has updated to PHP 5.x
If your log in to your WordPress back-end and update your version of WordPress, it should take care of this problem. On the other hand, if you have old plugins that haven't been updated in 3-4 of years, they may break.
Sorry for the pre-coffee typos.
156: Thanks for the insight. (Unfortunately, a group blog in which I was *not* involved in the back-end work.) But I can try to track down one of the co-bloggers who was. Not sure if anyone would even have an account, or paid a hosting fee recently etc. So this day was inevitable.
If I can at least grab it one way or another; find the thumb drive or scrape from archive.org (pretty good snapshot there), will probably try to massage into a format where I can more easily maintain it (with some lossage undoubtedly). A good Python exercise, for instance.