Physicists Do What Einstein Thought Impossible 193
An anonymous reader writes "Einstein worked on Brownian motion (the movement of small particles in a fluid as they collide with the fluid's molecules) in 1905, but said it would be 'impossible' to determine the speed and direction of a single particle during this dance. Now researchers have gone and done it, by suspending a dust-sized glass sphere in air (which slowed down its dance moves, since it had fewer collisions with spaced-out air molecules than it would have had with water molecules). The researchers held the sphere in place with 'laser chopsticks,' and then watched how the glass bead bounced around to determine its direction and speed (abstract)."
Magic words... (Score:5, Funny)
Re:Magic words... (Score:5, Funny)
Re:Magic words... (Score:5, Funny)
Laser chopsticks suck. They keep cooking your sushi before you can get it to your mouth.
Re:Magic words... (Score:5, Funny)
Bhey alfo burn your mouf.
Re:Magic words... (Score:5, Funny)
You typed that with your mouth?!
Ouch!
Re:Magic words... (Score:5, Funny)
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Laser chopsticks! It dices, cut, cooks and fries! Call now and receive a free shark!
Made in China!
Re:Magic words... (Score:5, Funny)
Do not look at chopstick with remaining eye.
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Re:Magic words... (Score:4, Funny)
You had me at "laser chopsticks".
Interesting... How do you suppose laser chopsticks would compare to, say, a laser spanner, or a sonic screwdriver?
Re:Magic words... (Score:5, Informative)
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I drank a sonic screwdriver once. They don't taste nearly as good as you might think.
Re:Magic words... (Score:4, Interesting)
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Only on Slashdot would my previous comment be modded "interesting" instead of "funny".... :-)
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'Interesting... How do you suppose laser chopsticks would compare to, say, a laser spanner, or a sonic screwdriver?'
Well, there's a definitive answer to the screwdriver question here:
http://www.youtube.com/watch?v=ue4On8QINxQ [youtube.com]
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You had me at "laser chopsticks".
So you could say it was the optical tweezers that caught your eyes.
Re:Magic words... (Score:4, Funny)
Then the eyes caught fire.
And the fire caught your hair.
Until the firefighters caught your smoldering remains in a urn.
Now it’s your turn. ;)
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I thought the magic word was “impossible”. Because every time someone says that, someone else will prove it possible only seconds later. Or at least die trying. ^^
Also: Someone, ages ago, said that something is impossible, and now we can do it... News at 11. :)
Re:Magic words... (Score:4, Funny)
Master Miyagi: Man who catch dust-sized glass sphere with laser chopsticks accomplish anything.
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They don't produce Earth Shattering KA-BOOMs?
To avoid confusion (Score:5, Insightful)
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Nonsense. No one, except me apparently, actually eats chow mein.
I've never actually ordered chow mein without the clerk checking to make sure I didn't really mean lo mein.
Once they checked twice. Ordered chow mein.
Them: "You want chow mein not lo mein?"
Me: "Yep, chow mein."
Them: "You SURE you want chow mein right? Chow mein have no noodle.".
I get the feeling that they have to redo most chow-mein orders . . .
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That's strage because Chow Mein IS a noodle dish, the name means literally "stir fried noodles" whereas lo mein means "mixed/stirred noodles".
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Must be regional variation. Around here chow mein is mostly cabbage with onions, celery and your choice of meat cooked in. No noodles at all. Looking at the wiki article on chow mein, that particular dish looks like what is usually called chow mei-fun in the local restaurants.
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Must be regional variation. Around here chow mein is mostly cabbage with onions, celery and your choice of meat cooked in. No noodles at all. Looking at the wiki article on chow mein, that particular dish looks like what is usually called chow mei-fun in the local restaurants.
Yeah, but the thing is that the word which "chow mein" is a transliteration of literally means "fried noodles." Offering a dish called "fried noodles" which doesn't contain noodles, does seem a wee bit odd.
Silly regional dialects [articlesof...cation.com]...
Re:To avoid confusion (Score:4, Insightful)
Infinite Improbability Drive (Score:5, Funny)
How will the Infinite Improbability Drive work now? It depended on Brownian motion. Now probability can never come off 1:1 and it'll never work!
We must discover time travel immediately so we can go back and stop these researchers immediately! I mean, sooner!
Tomorrow is Towel Day! We cannot allow a travesty like this to stand.
Re:Infinite Improbability Drive (Score:5, Insightful)
So are you suggesting that the infinite probability drive is improbable? Maybe it can run off of it's own improbability.
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Well, since it is pretty much impossible, it might be too powerful for this universe. ;)
Then again, we might have a brand-new trans-universe vehicle. Tadaaaa!
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By design, all claims that the Improbability Drive doesn't actually work are false.
Claims that it doesn't work well are also false.
Nice try, though. Tea is the secret. They only MEASURED Brownian motion, no word on how they might either predict it, control it, or even duplicate it. But if they could in fact duplicate a Brownian circumstance, the Improbablity Drive stil works, because, well, despite the elegant engineering, it is improbably successful. Or something like that. Keep your towel handy.
But is it infinitely improbable? (Score:4, Funny)
In the way that a nice cup of tea is?
Keep in mind (Score:5, Insightful)
When people say "impossible" they generally mean "not possible given what I currently understand about XYZ"
Unless Einstein explicitly said "this will not be possible, ever"
I mean, heck the article demonstrates this itself:
"In 1907, Einstein likely did not foresee a time when dust-sized particles of glass could be trapped and suspended in air by dual laser beam “optical tweezers.”"
I'm sorry but: No freaking shit. In 1907 I doubt many people would have foreseen that
Re:Keep in mind (Score:5, Funny)
Warning: Do not attempt to foresee any more laser-related developments with remaining eye.
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Re:Keep in mind (Score:4, Informative)
I'm pretty sure that they didn't measure the position and momentum to better than half of Planck's Constant [wikipedia.org].
Re:Keep in mind (Score:5, Funny)
Re:Keep in mind (Score:5, Informative)
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When people say "impossible" they generally mean "not possible given what I currently understand about XYZ"
People don't understand the scientific method, and many don't want to. I had a discussion on slashdot yesterday about Galileo (brought on by the story about Copernicus) and someone had the simple mindedness to suggest that since Galileo didn't know that the orbits of bodies were elliptical rather than circular, that the Roman Catholic church was justified in their treatment of him and suppression of his ideas. A clearer demonstration of misunderstanding of the scientific method I could not have thought up.
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They were justified to some extent. The geocentric theory based on epicycles had predictive power too: it could be used to predict eclipses to a reasonable accuracy. The heliocentric model explained the retrograde motion of planets, but also made predictions about parallax of heavenly bodies, which was not observed (since the measurements available at the time were not sensitive enough).
Bot theories had merit, and given the information available at the time, neither was perfect. That doesn't excuse the chur
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Also, he was a pretty big dick to everyone.
Then punish the man. Do not suppress what he had to say.
The fact that his evidence was extremely difficult to duplicate, and contained major flaws, were also strikes against him. For example, he was completely wrong about comets.
There is nothing in the scientific method that says a scientist should be ignored unless his or her work contains absolutely no flaws. There's certainly nothing that says the work should be suppressed or that he should be tortured, denied medical treatment and imprisoned.
Furthermore a lot of his work was trivial to duplicate. For example showing the crescent shape of venus, or the moons of Jupiter required only that a telescope be aimed at them.
Currently Impossible (Score:3, Insightful)
Unless Einstein explicitly said "this will not be possible, ever"
He did not - as you suspect what he meant was that it was "not possible with current technology" and certainly not that it was impossible in the same vein as "it is not possible to travel faster than light". It would be like someone today saying that it is impossible to build a 500PB hard disk - what they clearly mean is that it is impossible AT THIS MOMENT IN TIME to build a 500PB disk not that it will never, ever be possible to do so.
Of course being a famous physicist the media have no qualms about hy
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Also keep in mind that they did not measure the speed and direction of a free Brownian particle. They confined it so it's not really the same problem. However I it is possible to watch a small fluorescent labeled protein molecule move around too. In that case if the protein is small enough and the concentration is dilute enough one can basically film their trajectories.
Bad Experiment or Bad Reporting (Score:3, Insightful)
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If you "hold it" doesn't that effect the out come of the experiment? Is this a bad test or just bad reporting?
After years of observing experimentations and reporting, I would venture to guess that the later is more probable than the former... but I may be wrong.
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Because you can come up with a question that is not explicitly answered by the article does not necessarily imply either a bad experiment or bad reporting.
It means you probably want to read the paper.
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Excellent! (Score:2)
So does this tell us how to travel faster than light?
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no, but it explains why the ride will always be at least a little bit bumpy
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No, but it tells us how to travel faster than heavy.
What an idiot (Score:5, Funny)
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Ha. Einstein. What an idiot.
Yeah. Not only did he predict that it would be impossible to measure Brownian Motion, he predicted that no Slashdotter would ever get laid.
Oh, wait...
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Way to go, Einstein </sarcasm>
Re:What an idiot (Score:5, Funny)
Yeah he's no Einstein, that's for sure.
This Einstein Fella is a Hack (Score:5, Funny)
Re:This Einstein Fella is a Hack (Score:5, Funny)
Slightly Squiffy Reporting... (Score:5, Insightful)
Did they *really* prove they exactly measured it? (Score:5, Insightful)
If the glass bead were moving in such a way that was too subtle for them to measure, would they even know they couldn't measure it? What if Einstein was right and was simply implying that the movements eventually broke down so far that they were unobservable (similar to Planck's work)?
Re:Did they *really* prove they exactly measured i (Score:5, Insightful)
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The uncertainty principle is irrelevant to this experiment.
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Observation is granular because detectors trigger at a point so of course it gives results in terms of quanta... But it IS all waves.
I expect you both are right.
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> And to his credit, [Albert Einstein] has admitted mistakes before.
I don't think he'll do it again, though.
New unit of size.... (Score:2)
Since when is 'dust' a unit of size?
Re:New unit of size.... (Score:5, Funny)
Since when is 'dust' a unit of size?
Since they made chopsticks out of monochromatic light.
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Since when is 'dust' a unit of size?
Since they made chopsticks out of monochromatic light.
Don't you mean....
*EXPLOSIONS*
Laser Chopsticks!! ?
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You're right, never has been. It is a range of sizes:0.001-10,000 micron
Just a heads up (Score:2)
"... host finally gives up dies."
Shouldn't there be an "and" in there?
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Yup; the ironic thing is I've used this signature on /. for years - you win a prize for being the first person to spot the missing word.
(I've got sig display turned off so never spotted it myself either)
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They're measuring motion in a fluid.
Gas is a fluid like liquid (or plasma for that matter).
Impossible for his time (Score:5, Informative)
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It worked on you though, didn’t it? ;)
This doesn't break the uncertainty principle. (Score:5, Informative)
I've seen a couple of comments (more than one thread or else I would have posted a reply there) that seem to suggest that this breaks quantum physics by accurately predicting the speed and direction of particles, but it should be noted that the Heisenberg Uncertainty Principle states that it is impossible to accurately calculate both the velocity and its position. Speed and angle are components of velocity, therefor the only conclusion of this experiment is that velocity can be calculated under these conditions.
Re:This doesn't break the uncertainty principle. (Score:5, Informative)
That's correct. What's at issue here is a matter of engineering, not physics.
Physicists reserve "impossible" for the truly mathematically unavoidable, while engineers expand it to the wildly impractical. When you say something "is" true, you're speaking in the former sense. When you say you "believe" something to be true, as Einstein did, you're speaking in the latter sense.
So it's not overthrowing any physical principles. It's merely confirming something else Einstein said: the universe is not only stranger than we imagine, it's stranger than we can imagine.
Re:This doesn't break the uncertainty principle. (Score:4, Funny)
It's merely confirming something else Einstein said: the universe is not only stranger than we imagine, it's stranger than we can imagine.
I don't know.... Einstein might want to revise that statement... he never had a chance to try to follow Lost [imdb.com]
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Thanks for pointing that out!
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Uncertainty is not relevant here because the "particles" involved are macroscopic bits of dust, not elementary particles.
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The Uncertainty Principle only kicks in where the particle (wave packet) size and the wavelength of the observing "light" are approximately of the same order of magnitude. A "dust particle sized" (whatever that means) glass bead is much larger than the wavelength of visible light, else, you couldn't see it.
This is a huge misunderstanding of the uncertainty principle. This isn't about uncertainty in the experiments themselves; this is covered quite well by simple experimental error terms. This isn't even about measuring the position, and somehow knocking the particle out of its old path, though that can happen. This is a fundamental part of the universe: you cannot know perfectly, ever, a particle's position and momentum. No matter how perfect you make the experiments! It's like they're both stored in the same
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However, these dust particles are so large that the Heisenberg uncertainty is small compared to the measurement error. This is a classical system.
Am I missng something? (Score:2)
Maybe pollen grains aren't "small" but I remember observing them doing Brownian motion in high school. Assuming the microscope is calibrated (i.e. you know the gain) and you can mount a camera on it to capture the movements (or even use a gridded background and call out to an assistant with pen and paper), how can it not be possible to measure the velocity?
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but... (Score:2, Insightful)
Dumb summary (Score:5, Insightful)
If you read the PhysicsWorld [physicsworld.com] article, you'll see it actually says:
But he believed that it would be impossible in practice to track this motion, given the incredibly short timescales over which the Brownian fluctuations take place
Ahhh... still don't have the original source quotation from Einstein here, but it sounds like Einstein believed it was "impossible in practice" - in other words, that the technology didn't exist at that time to measure rapid fluctuations over microsecond or even nanosecond time scales, and maybe he couldn't even imagine such technology existing.
So he never actually said he thought it was beyond the physical limits of the universe. There was no proof or physical law involved.
Now call me up when somebody figures out how to move matter or information faster than the speed of light (i.e. group velocity greater than c). Einstein really did believe that was *impossible*.
Based on Research by Steven Chu, et. al. (Score:3, Informative)
One thing interesting that isn't mentioned specifically: This work, using "optical tweezers", is based on research done by Nobel Laureate Steven Chu's group at Berkeley. Dr. Chu also happens to currently be the US Secretary of Energy.
No job too big, no job too small, Steve Chu does 'em all.
Comment removed (Score:3, Insightful)
Nature of Brownian Motion (Score:5, Informative)
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Precisely. Mathematical Brownian motion has a *wonderful* property known as infinite variation. This means that if you took an accurate plot of Brownian motion over a finite time interval, say the interval [0,1], and tried to measure the length of the curve, you would find that it is infinite. You can take one "piece" of Brownian motion and stretch it out the whole way across the universe.
If a particle was moving according to mathematical Brownian motion, its velocity would be infinite, which is clearly imp
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The subject is not the mathematical idealization of Brownian motion. It's the real thing.
Now they're even (Score:2)
Einstein did what many physicists thought was impossible, so now they are even.
IAAAP.....*NSFW!* (Score:2)
(I Am An Armchair Physicist)
I propose to test these results on Brownian Motion by direct and lengthy observation of the phenomenon of the forty ounce bounce. [40ozbounce.us]
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The ability to make something so aerodynamic that it actually creates motion at rest would be so awesome.
Too bad it would be something small like an atom or a neutrino.
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Einstein - what a fucking noob! He thought he could hide his ignorance behind $10 words. We got you now you SOB!
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You changed the outcome by observing it.
True dat. If they hadn't seen it, it wouldn't have happened.
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Depending on what definition [merriam-webster.com] of "particle" you go with, it can be.
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