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CERN Experiment Indicates Faster-Than-Light Neutrinos

ErkDemon Causality issues outside Special Relativity (1088 comments)

Outside of special relativity, having particles travelling faster than the background speed of light doesn't necessarily introduce causality violations, if the local /velocity/ of light, at that location and moment, in that same direction, is even greater.

Consider the case of a drifting particle falling into a black hole from null infinity. The inward velocity of the particle would be expected to hit v=c at the event horizon, and to continue increasing (unobserved) as the particle continued to fall, to an arbitrarily high multiple of background lightspeed. But the particle doesn't illegally time-reverse, because it never overtakes its own signals (which are falling inwards even faster). So gravitational event horizons provide an example of predicted (censored) super-fast motion, without involving exotica like negative energy-densities. Like Newcomb's old argument against heavier-than-air people-carrying craft, general disproofs of superfast motion are mathematically tidy, but not necessarily physically reliable.

Outside of black hole problems, super-fast motion can be legal if you use a relativistic acoustic metric instead of the Minkowski metric (in an r.a.m., the motion of a particle is associated with a local offset in nearby light-velocities, allowing the particle to move faster than background c without ever exceeding local c).

Relativistic acoustic metrics are fun, and seem to reconcile quantum mechanics with several key aspects of general relativity - they're tentatively used by some people exploring "quantum gravity" options, when modelling Hawking radiation.
... The reason why we don't use relativistic acoustic metrics seems to be partly historical/social: Special relativity got there first and established the Minkowski metric as a standard, and some relationships come out differently with an r.a.m. than they do with special relativity, so we tend to say that unless someone has convincing evidence that says otherwise, the SR version of events is considered to be "canon". And it's difficult for evidence to be considered convincing if it runs counter to one of the best-known scientific theories, so there's a kind of positive-feedback loop in operation.

Mainstream relativity guys tend not to study r.a.m.'s, not because anyone's come up with a logical reason why they shouldn't work, but because they're told that SR-compliance is mandatory for any credible relativistic field theory, and it's generally thought that violations of SR (like particles moving faster than background c) simply don't happen. So other than the quantum gravity guys, almost nobody's been looking at this class of relativity theory, and the QG guys tend to stop at the point where the thing starts to diverge from special relativity.

Short Answer: Yes, if this thing is right, it probably involves rewriting the physics rulebook, and probably junking special relativity, but ... no, the requirement for special relativity was never really as strong as many people seemed to believe. Yes, losing special relativity would be major from a theoretical and social point of view, but no, it's not too difficult to construct a relativistic alternative, if you're prepared to lose the simplifying assumption of flat spacetime.

(So yes, it might simply be a duff experiment. But it's not yet safe or sensible to assume that that's the case).

Have a Cool Day,
Eric 0955706831

more than 3 years ago
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Why Does the US Cling To Imperial Measurements?

ErkDemon Re:Mod up (2288 comments)

31/5 -inch desktop PC harddrives are mounted with screws that are pre-metric. Newer laptop-size (" 2.5" ") harddrives have mounting screws that are metric (3 mm, I think).

more than 3 years ago
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Why Does the US Cling To Imperial Measurements?

ErkDemon Re:The US already adopted the Metric system (2288 comments)

There was also a nice piece on the subject in the Journal of the Franklin Institute. Apparently the US officially went metric by Act of Congress way back in 18-something, but the individual States were a little slow in ratifying and implementing it. :)

more than 3 years ago
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Why Does the US Cling To Imperial Measurements?

ErkDemon Re:Not so bad to have different systems. (2288 comments)

Some of the older systems also embedded a "baker's dozen" of 13 rather than the more common modern dozen of 12 (eg they used thirteen inches to the foot, and 39 inches to the yard).

more than 3 years ago
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Why Does the US Cling To Imperial Measurements?

ErkDemon Re:No! It is really, really bad. (2288 comments)

Yeah, and before one publishes a paper quoting rainfall in gallons per square yard, they have to decide whether they'll be using the Imperial gallons or US gallons, because the two are significantly different. Apparently the Imperial gallon was 4.54609 litres, and the US gallon is 3.785411784 litres, making the US gallon very close to 5/6 of the Imperial measure with the same name. If someone doesn't realise that there's no single internationally-agreed definition of a "gallon" -- it's not an international unit -- then if they're unlucky, their calculations can be off by 20%

more than 3 years ago
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Why Does the US Cling To Imperial Measurements?

ErkDemon Re:Not so bad to have different systems. (2288 comments)

Actually, the Imperial hundredweight is 112lb, but the US hundredweight is 100lb. That's why there's a different number of pounds to the US ton and the Imperial ton, and why commodity traders talk about "long tons" and "short tons". The metric tonne is conveniently in middle. And talking of commodities, the US gallon is different to the Imperial gallon, and the US oil barrel //I think// corresponds to the eel-barrel rather than the wine-barrel? The trouble with these "natural" measures that everybody supposedly understands is that they were different all over the world. Imperial and American inches were different sizes before they both got standardised on 2.54 millimetres, and this made US and Imperial feet and miles slightly different, too. It was a nightmare for engineering work if you bought in a load of foreign machine tools and they were marked up in the wrong sort of inches. Even basic cookery measurements are locally different: a cup of sugar in the US is different to a cup of sugar in the UK. And don't get me started on pounds and ounces ... an ounce was a different weight depending on whether you were measuring liquid, grain, solid, wine, spirits, gold ... and as for feet, there might have been, what, ten different local definitions of a foot, with some using twelve inches and some using thirteen? Before the metric system, international weights and measures were a disaster. After it was introduced, people could at least define their local measures in terms of a single universally understood reference, rather than have a bookshelf of arbitrary and approximate third-party conversion tables and almanacs comparing different quantities with the same names using different materials in different countries. And often these conversions weren't officially sanctioned by anyone, because there simply wasn't an official conversion factor for the same nominal unit in Country X and Country Y. We could say that the Imperial and US inches seemed to be different by a factor of ... something ... but the US inch wasn't going to be //officially// defined as X Imperial inches, and vice versa, so the conversions were always measured approximations rather than strict engineering definitions.

more than 3 years ago
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Explosive-Laden California Home To Be Destroyed

ErkDemon Re:The government IS causing the loss of value (424 comments)

To be fair, the Government guys managed to remove the first nine pounds of explosives by hand before they gave up and threw in the towel. Apparently the place is so packed with explosives-related equipment (half-built fragmentation grenades and the like) that they felt that taking anything else out would be too dangerous. Robots aren't an answer if you're dealing with a junkyard of explosive gear stacked high, where a robot fumble is liable to knock things over. Sure, if the robot gets blown up, nobody's dead ... but it could blow up the whole remaining stash. Which means that all the expensive protection work they're doing now to try to protect the surrounding neighbourhood would have to be done anyway.

more than 3 years ago
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Explosive-Laden California Home To Be Destroyed

ErkDemon Re:Complete incineration of toxins - how? (424 comments)

Hey, don't diss thermite! For genuinely nasty explosive chemicals, try hydrazine.

When I was a kid, my chemistry book warned that hydrazine had a tendency to explode unexpectedly in response to vibration. Or heat. Or light. Or cold. Or sound. Or electrical charge. Or chemical reaction with contaminants on the surface of the holding vessel. Or roughness on the surface of the holding vessel.

Or ... basically, if you looked at it kinda funny.

And on top of all that, it's supposed to be horribly toxic.

more than 3 years ago
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Explosive-Laden California Home To Be Destroyed

ErkDemon Re:Pyros. All of them (424 comments)

Some explosives can become more unstable with time. Depending on the range of materials he was playing with, the fact that he might have safely put something away in a box ten years earlier wouldn't necessarily mean that it'd be safe to attempt to move that box now.

more than 3 years ago
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Explosive-Laden California Home To Be Destroyed

ErkDemon Re:why? (424 comments)

So are we allowed to shout "Bear!" in a crowded cinema?

more than 3 years ago
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H.R. Giger Returns To the Alien Franchise

ErkDemon Aliens and Xenobiology (144 comments)

The Aliens are intelligent. They've got VERY big brains, they're possibly socially telepathic, and they've gotten around the cultural problem of a lack of information-continuity between generations by developing (or adopting from another parasitised species) a form of inherited memory. That's how the Ripley-Alien hybrid clone has memories of being Ripley.

The nasty question posed by the inherited-memory thing is: The aliens have a fetal stage (implanted by the face-huggers) during which they adapt to their new environment by adapting to and adopting elements of their host's biology ... and presumably they also retain memories from the Queen that laid their egg. During the adaptation process, does the alien fetus, which potentially has telepathic abilities, also imprint on the memories and personality of its host?

In other words, when Little Aliens burst out of humans and become Big Aliens, do those Big Aliens then have false memories of being human? That might go some way to explaining why they're so pissed off.

While there's stuff like that that still needs to be addressed, I think there's space for at least one more film, and if we're going to be seeing unexplored aspects of the Alien biology, it's cool that they've got Giger onboard to extend and elaborate on some of his original designs.

more than 3 years ago
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H.R. Giger Returns To the Alien Franchise

ErkDemon Re:So is Alien finally getting a proper follow up? (144 comments)

Alien was essentially an old-school "haunted house" movie. Or, more specifically, a "trapped in an isolated haunted house at night, with a monster, unable to leave, with no way to call for help, trying to survive until daybreak" movie. The spaceship made an exceptionally good haunted-house-substitute. Isolation - check. Nothing outside to escape to, and no neighbours - check. Substitute "survive until daybreak" with "survive until the ship reaches Earth". Classic setup, well executed.

more than 3 years ago
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Should Wikipedia Just Accept Ads Already?

ErkDemon Re:I used to donate. (608 comments)

I think Manga's still supposed to be a multi-billion-dollar industry, and people who work in or around the industry are expected to be conversant with this stuff. Being able to quickly find a relevant Wikipedia page when you need to check something can be really, really useful.

more than 3 years ago
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Should Wikipedia Just Accept Ads Already?

ErkDemon Re:losing opportunities to involve qualified profe (608 comments)

Yep, it's partly the =absence= of qualified professionals that made Wikipedia so great.

Wales still seems to have trouble understanding this. It's like, he still wants Wikipedia to be a "proper", legitimate, "official" encyclopedia that he can be proud of when he talks about it at dinner parties, staffed by proper academics and proper encyclopedia professionals. He wants it to be a certified, corporate, properly quality-controlled enterprise. Like Microsoft, or Disney, or , uh, Fox News.

Trouble is, if you take a successful and thriving volunteer programme, and you get a chunk of money and hire a bunch of academics to "sort it out", the project dies. The guys you hire won't be as involved or as dedicated or as knowledgeable or enthusiastic or as involved as the people they replace, because if they were ... they'd already be contributing.
Wikipedia is huge. Any academic who isn't already a serious contributor isn't worth hiring, and any academic who already //is// contributing, you already have for free, so ... why spend donor's money fixing what ain't broke?

The other problem is that Wales sometimes seems to be fairly reeking disdain for the Wikipedia project. If he starts hiring-in "proper" academic editors from "outside" in an attempt to change the culture, then by rating those individuals as more important than the people who actually built and maintained Wikipedia, he'd be basically pissing in the faces of the people who made WP such a success. How do you stay motivated as a contributor, if the organisation basically declares you to be inferior to some newbie outsider who's going to get all the credit, and public glory, and superuser priveleges, and get paid for it too?

Wikipedia does have some serious issues that need sorting out, but those are arguably partly Wales' fault. For instance, he keeps complaining about the lack of serious researchers contributing to WP, and cites this as a reason why the WP project has failed, and why other encyclopedia projects are necessary.
Truth is, the reason why more experts don't contribute isn't just because of WP culture, it's because one of Wales' own favourite WP rules expressly ==prohibits== anyone from adding or editing information that relates too closely to their own original research. A lot of good technical info seems to be added to WP by people breaking this rule, and editing under aliases. If Wales wants more expert-written articles, the obvious thing to do (without spending any money!) is to relax the current rule that explicitly bans experts from writing about their own specialist fields (on the grounds that they're biased). Or maybe to accept that WP actually has a large number of articles written and edited by known experts, who are smart enough to do it anonymously, because their priority is that the article be great, and that it not be turned into a political debating forum between people with something to lose. Articles should be judged by their content, not their authors' reputation. Using named experts means that article debates become personalised.

Another problem with hiring academics who aren't already contributing is that some of them won't be prepared to put up with being edited by less qualified folks, and some of them, although they might be top-notch as experts, are likely to absolutely suck as encyclopaedists. A world-class organic chemist or mathematician or particle physicist may have no idea at all as to how to write a coherent Wikipedia article. They may not have ever used Wikipedia. They may not have used any encyclopedia at all since they were kids. They may be completely clueless about what an encyclopedia is, and what people use it for.

Wikipedia, when it's working well, it a ruthless meritocracy. Edits and articles live and die purely on perceived quality and usefulness. It doesn't matter what your qualifications might be, or how many years you spent studying a subject, or whether you won the subject's Nobel Prize last year ... it still might be that you know less about how to write a clear, efficient properly-formatted introductory WP sentence and paragraph on your specialist subject than some spotty eighteenyearold.

I think that one of the things that damages Wikipedia is its continuing association with a founder who doesn't seem to believe in the project's core values, who seems to think that the project is fundamentally flawed, and who always seems to be trying to reshape WP to be more like one of the other, more "pro" encyclopedia projects, which so far have all been dismal failures, or trying to set up competing projects that he seems to think ought to replace WP. Someone who believes that the WP project was a mutant that shouldn't have been successful and that it ought to die and be replaced with something else of his own devising, isn't really the best person to be promoting WP or working seriously on its improvement.

I'm not even sure why Wales is still involved with WP, except that it gives him a useful platform for promoting himself, and through that, helping to increase the visibility and fundability of his future non-WP projects. Right now, I think he's a net liability.

more than 3 years ago
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Facebook Competitor Diaspora Revealed

ErkDemon Naming (was: Re:I dunno, man...) (306 comments)

I suppose that they still have the option of keeping "diaspora" as an organisation name or project name, and calling the user release something else that's related to the diaspora branding, but with a cuter primary-coloured logo ... "dandelion" might be cool.

(Note to the Diaspora developers: if you like that idea please use it, I promise not to sue.) :)

more than 4 years ago
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Facebook Competitor Diaspora Revealed

ErkDemon Re:I dunno, man... (306 comments)

Yep. The idea is that it links into all your existing social networking sites, but also has its own stuff. So you can continue using all your existing contacts and links while considering whether to migrate stuff over to Diaspora itself.

If you do decide to use Diaspora for all your new material, the advantage is that all your Diaspora stuff is free from any sort of vendor lockin - if you decide that you don't like your current Diaspora hosting company, you can pick up your "house" and move it to someone else, or even to your own server, hopefully without losing your address or links. Download your data, delete it off the server, upload it to another server, re-register your seed on the new server, and ... hopefully ... nobody will notice.

It becomes //your// homepage, not Yahoo's or Facebook's or Google's.

more than 4 years ago
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Spaceflight Formation Flying Test Bed Takes Off

ErkDemon Re:It will be a critical ability. (64 comments)

Well, if we're going to be picky, if you check what your dictionary defines as a "wing", you'll probably find that the corresponding first definition is something to do with the flappy things on birds. Dictionary.com doesn't mention the "aeronautical" definition of "wing" until definition #9, so by the argument you used, we probably shouldn't call what aircraft do "flying", either, because their "wings" aren't biological structures, and don't flap.

AFAIK, "spaceflight" is pretty much the standard term for the technical subject, for instance, here's an introductory NASA page on the subject.

more than 4 years ago
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Spaceflight Formation Flying Test Bed Takes Off

ErkDemon Re:It will be a critical ability. (64 comments)

"Traveling" is too vague. Spacecraft "travel" when you trundle them to the launchpad on trucks, and if we're doing astrometrics, motion is relative and the concept of whether something is "traveling" or not becomes complex. You're "travelling" right now as the Earth orbits the Sun.

If we want a term to describe orderly controlled non-surface relative motion through a rarefied medium, "flight" isn't bad, "fly" has the advantage of only being one syllable, and we already have the concepts of "powered" and "unpowered" flight. Sure, it's not aerodynamic flight, but there are other cool environmental things to make use of, like the gravitomagnetic fields of passing planets, for slingshotting.

more than 4 years ago
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Apple Announces New iPods, iTunes 10, Social Network, AppleTV

ErkDemon Re:They had to name it ping, didn't they? (579 comments)

PS: Ever noticed how much the "bing" logo looks like the logo for "Blender"?

Okay, "looked", past tense. They've now changed it. But the "bing" favicon on my browser is still a blender-like blue b with an orange target bullseye.

more than 4 years ago
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Apple Announces New iPods, iTunes 10, Social Network, AppleTV

ErkDemon Re:They had to name it ping, didn't they? (579 comments)

May 2009: Microsoft launch a new ... search engine ... and call it bing
Sept 2010: Apple launch a last.fm ripoff and call it ping.

The people who own the ding.com and qing.com domains must be hoping that someone makes them an offer soon.

People are really running out of ideas.

PS: Ever noticed how much the "bing" logo looks like the logo for "Blender"?

more than 4 years ago

Submissions

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Happy Birthday Frank Hornby!

ErkDemon ErkDemon writes  |  about a year and a half ago

ErkDemon (1202789) writes "Today is the 150th anniversary of the birth of inventor and toymaker Frank Hornby.
Hornby invented the Meccano metal construction toy (currently sold as Erector in the US) that inspired generations of children to become engineers, patenting the basis of his system in 1901. Originally sold as an educational system for teaching mechanics, “Mechanics Made Easy” became “Meccano” in 1907, and Hornby’s company, Meccano Ltd. went on to become one of Britain’s biggest toymakers, with Hornby creating a further string of product lines including Hornby Trains and Dinky Toys.
Hornby’s is a rare “British inventor” success story — his creation turned him from being a clerk in a meat importing company with no real qualifications or schooling into a millionaire industrialist and Member of Parliament."
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BumpTop 3D Desktop - Last chance for PC/Mac

ErkDemon ErkDemon writes  |  more than 4 years ago

ErkDemon (1202789) writes "The BumpTop 3D physics desktop has been around in beta form for a while (see SlashDot June 2006) and the commercial version, BumpTop Pro, appeared in April 2009.

Google have just bought the company, and immediately pulled the plug on the PC and Mac versions of the software, presumably so that BumpTop can become the new face of Google's own operating system (and nobody else's).

If you want to grab last-minute freebie copies of the PC and Mac versions, you only have until May 7th 2010 to get them from the site. After they're gone, they're gone."
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Lego shops test "augmented reality" technology

ErkDemon ErkDemon writes  |  more than 4 years ago

ErkDemon (1202789) writes "The toymaker Lego are no strangers to robotics and virtual reality Lego, but for the last few months the company has also been trialling new 'augmented reality'-based point-of-sale displays (the Lego Digital Box Kiosk) in some of their shops, that allow customers to see themselves interacting with Lego models, on-screen.

It's a great thing to play with. Trouble is: at what point does the sales tool become more fun than the toy?"
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"Rubik" skyscraper announced

ErkDemon ErkDemon writes  |  more than 6 years ago

ErkDemon (1202789) writes "Architect David Fisher has announced plans to build the world's first "dynamic tower" in Dubai (BBC News).
The tower is a 420-metre, eighty-storey design consisting of eighty separate independently-rotatable floors. Since the floors don't have a circular cross-section, the building's profile changes in response to the relative positions of the apartments at any given moment.
There are also plans for a similar, seventy-storey tower in Moscow. The floors can be rotated by voice command to provide varying views, to order: is this the ultimate apartment for a gadget-minded control freak?"
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Beyond the Mandelbrot Set

ErkDemon ErkDemon writes  |  more than 6 years ago

ErkDemon (1202789) writes "We've all seen the Mandelbrot Set , and some folk with an interest in fractals also know about the Mandelbrot's complexly-conjugated "evil twin", the three-cornered "Tricorn" fractal (also known as the "Mandelbar" set). But how many people are familiar with the larger three-dimensional fractal solid that includes both the Mandelbrot and the Tricorn fractals, on different planes? Pictures and video are here."
Link to Original Source
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Einstein letter goes on sale

ErkDemon ErkDemon writes  |  more than 6 years ago

ErkDemon (1202789) writes "For any SlashDotters who want a piece of frameable Einstein memorabilia, a letter from A.E. to Eric Gutkind goes on sale at Bloomsbury Auctions today (May 15th). The content of the letter mostly deals with Einstein's views on religion (Einstein pronounces himself rather unimpressed by the whole idea and rejects it as "childish"). The Guardian has printed a news article about the sale along with a translated excerpt from the letter."

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