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Physicists Do What Einstein Thought Impossible
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)."
You had me at "laser chopsticks".
It must have been something you assimilated. . . .
Laser chopsticks were invented to keep chow mein hot until the end of the meal.
I am the richest astronaut ever to win the superbowl.
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.
"This post contains words, known to the State of California to cause thought. Wash brain thoroughly after reading."
In the way that a nice cup of tea is?
Best Slashdot Co
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
You changed the outcome by observing it.
It sounds like they got close, but no refutation.
If you "hold it" doesn't that effect the out come of the experiment? Is this a bad test or just bad reporting?
Think Deeply.
Would be most useful in tracking my psycho neighbor's kids.
heisenberg compensator sounds so much better than laser chopsticks.
Supplies!
It's about time they put that upstart Einstein in his place!
History is so yesterday!
So does this tell us how to travel faster than light?
Proud member of the Weirdo-American community.
As Schrodinger might say, "the cat is out of the box and moving toward the door at a velocity of 2m/s."
But what I think would be a lot cooler is if they could take all that random kinetic energy and point it in some particular direction.
It's probably not possible in reality, but the imagination reels when envisioning the velocities that could probably be achieved if it could be done.
Ha. Einstein. What an idiot.
Won't someone please think of the optical tweezers!
This Einstein fella - I keep on hearing about how he's been proven wrong or might be proven wrong or how people are picking his ideas apart. It's like he hasn't even SEEN a modern physics paper in like, the last 50 years.
Google: "All your data are belong to us."
Einstein only said it was impossible from a tecnical point of view. Given he used brownian motion as direct evidence for the atomic/molecular nature of matter I am pretty sure he appreciated that with future technology it may be possible to do this kind of experiment...
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)?
Since when is 'dust' a unit of size?
--- Users are like bacteria -> Each one causing a thousand tiny crises until the host finally gives up and dies.
TFA doesn't refute any of Einsteins conclusions about Brownian motion. It only shows that it was something impossible to do at Einsteins time. What a cheap way to grab attention!
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.
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?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
The stuff collects along the back shelves, dont'cha know.
there's no such thing as 'instantaneous'.
Never say never. Ah!! I did it again!
. . . wouldn't Fox News have reported on it? I thought Murdoch had an exclusive on 'impossible' news.
Exactly - they went and spouted "Oh, look at us, we disproved (Great Person X)'s work!" when all they really did was use selective reading and ignore the other half the book about the Uncertainty Principle
If you read the PhysicsWorld 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*.
There appears to by a typo in your sig
"... host finally gives up dies."
Shouldn't there be an "and" in there?
Finally, physics brought in a way I can understand it ;)
Be yourself and aim high!
Has anyone told Heisenberg about this?
They will ban this experiment in Texas.
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.
this has got to be the coolest science ive seen on slashdot in a while. find a suitable nano-shark and we can start talking laser sushi.
Good people go to bed earlier.
Well I guess Einstein was no Einstein...
As far as I understand:
You can only determine velocity as a function of distance over time. But in the interpretation of particles as wavefunctions, particles can be found anywhere on the wavefunction. You are still able to ring a bell when it has position 1, and then ring a bell when it has position 2, and you could then calculate the "velocity" it must have had as it moved from 1 to 2 over a certain amount of time. It should however be impossible to separate out the portion of movement that is down to simple movement on wavefunction, and movement of the wavefunction itself. The concept of speed only starts to make sense if you start to treat wavefunctions as particles, which ignores that they more around randomly and is therefore only usable for positions and not speed - whilst if you treat wavefunctions as wavefunctions, you can calculate velocity, but position stops making sense.
Any physicist to correct me here?
Brownian Motion is a mathematical construct, which, among other things, is nowhere differentiable (almost surely). You can pin a BM down into sets with high probability, but no, you can't really predict it. It is merely used to *model* the movement of a particle in a fluid, it is not actually the process by which the molecules move. Indeed, "such a path represents the motion of a particle that in its wanderings back and forth travels an infinite distance in finite time. [BM] does not in its fine structure represent physical reality." (Billingsley, "Probability and Measure"). At least the science is interesting.
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)?
Well, quote from the original article, which the article in the summary copied, states what Einstein said better:
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
Doesn't sound like Einstein was implying anything at all, but making a statement. A true one back in his day. Heck, it was true right up until these physicists did it (Which I assume was before the news article today)
So for what you attribute to Einstein was actually right, then that means Einstein himself was wrong :}
(I don't think he is, but he has been wrong before. And to his credit, he has admitted mistakes before.)
all the "crap" einstein came up with also seemed impossible before that... oh good, we are still evolving
In Soviet Russia, Physicists Do What Einstein Thought Impossible
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 hyping it as if somehow they have done something that contradicts Einstein because it attracts attention and cannot be proven to be wrong even it is extremely clear what he really meant.
Einstein did what many physicists thought was impossible, so now they are even.
insert joke here about sharks, lasers, chopsticks, and sushi.
(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.
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
The uncertainty principle is irrelevant to this experiment.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
> And to his credit, [Albert Einstein] has admitted mistakes before.
I don't think he'll do it again, though.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
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.
I don't know the meaning of the word 'don't' - J
How is it measuring the position and velocity of a particle under brownian motion when you are holding it in place? They are measuring the forces acting on a held object. They are not measuring it velocity and position in the medium.
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Speed of thought versus Speed of light
Which one is faster?
I'd like to buy homeland for our 10 million people. http://twitter.com/mahadiga
You can buy laser chopsticks on
www.EinsteinGravity.com
www.EinsteinUnveiled.com
They're really very inexpensive.
when we can disprove or move beyond one of the greatest minds of our times, it is a good day for science....this means we are advancing....somewhat. now if we could just get the governments to improve as much as our science has, that would be even better.