A New Spin On Physical Phenomena 249
f00Dave writes "Researchers have discovered "a new physical phenomenon, electrostatic rotation, that, in the absence of friction, leads to spin". I'm a bit skeptical about the implied relationship between physical "spin" (as in rotation) and quantum "spin", however. Still, this is the sort of scientific advance that renews my faith in the system. Go nerds! =]"
Output? (Score:4, Interesting)
Sponataneous Spinning? (Score:3, Interesting)
Re:Output? (Score:3, Interesting)
Jasom
ProfQuotes [profquotes.com]
Re:Output? (Score:5, Interesting)
You have to understand that article was first translated from scientific talk to reporting talk, and now it's being translated back to /. nerd talk... (which isn't scientific talk btw).
An example is how they first found the value of the constant of gravity. They put two humoungous iron balls near eachother, and noted the very tiny torque they induced just by being near each other.
The fact that the observed effects were tiny doesn't mean they don't exist.
new type of motor (Score:2, Interesting)
1. they apply a current through a metal ball. Which induces a magnetic field.
2. They place a second metal ball near the first ball. The proximity to the first magnetic field in the second ball induces a electric potential in the second ball.
3. The third ball may be electrically connected to the suspension wires of either or both balls 1 and 2. Hence, it induces a magnetic field of it's own. The relationship between the magnetic fields in the balls, is the cause of the rotation.
Of course Murphy and I could be wrong. I've been wrong before, but Murphy never has.
Rotation of the earth? (Score:3, Interesting)
Just read the paper, cute trick but no new physics (Score:3, Interesting)
Sphere A is charged up; the two others, B and C, are at different distances from A. Each sphere is polarized in a non-uniform way (because each sphere has two hemispheres, one closer to the charged sphere and the other farther... just as tides form on Earth due to the moon).
The potential at the surfaces of B and C might be uniform but the charge distributions are not: they are dipole. Due to this dipole interaction (the more negativey charge hemisphere of one sphere wants to be closer to the more positively charged surface of the other sphere), Spheres B and C then tourqe to a different angle and will either a) stay there in the presence of some friction or b) oscillate back and forth in the absence of friction. Of course, there is always some element of friction due to the air and wire, but one can compensate by also oscillating the potential of A to make positive feedback, I imagine.
The press release was, in this physics grad student's opinion, horrible. Implications that this research has some impact on our understanding of electrostatics or (gasp) quantum mechanics is irresponsible. It's a cute trick, though, and I'll bet it will find applications in mico-,nano-tech and perhaps other research areas (e.g. experiments requiring precision angular measurements [washington.edu]).
"Electric Wind"? (Score:3, Interesting)
I wonder if they've adequately controlled against the phenomenon of "electric wind"?
They're "holding the potential constant" on the central sphere, despite any leakage from irregularities in its surface. The two uncharged spheres nearby should create a stronger field in their direction. Corona discharges toward the space between the spheres could result in a net outward motion of air there, and inward motion of air between the outer and central spheres. Friction of this air against the outer spehres would provide a rotational force, in opposite directions on the two spheres, with no net force on the central sphere.
Try again in a HARD vaccuum.
Re:Why only frictionless? (Score:4, Interesting)
Yup, thats what they said.
Why won't this phenomenon cancel out at equilibrium amount of friction and keep the object spinning at constant angular momentum forever?
They didn't say it wouldn't. Presumably that is what would happen.
I[t] should also accelerate an object with a small amount of friction but at a slower rate than a frictionless object.
Yup. In their experiment the wire supporting the sphere was applying a counter-torque, it was just small enough that the new force was able to overcome it. By calculating the amount of torque generated by the wire after the number of revolutions made by the ball, they would have the static force generated.
In any case, we're talking about building a perpetual motion machine here and throwing the first law of thermodymics out the window.
Not likely. The kenetic energy of the rotation is probably balanced by a reduction in the net charge on the object. What they've got is basicly a really, really weak electric motor. A charged object in free fall would probably increase its angular momentum until it didn't have any charge left (then gravitational effects would probably eventually bleed all that energy back off again).
What I wonder is if its reversable, so rotation can be converted into a charge on the object.
Re:Renewed faith? (Score:4, Interesting)
Even so, one needs to keep perspective. At risk of sounding religous: if that sort of thing makes one "lose one's faith" in "the system", then that faith can't have been very strong to begin with. Meaning, if you really understand the scientific method, then you'd realise that over time it WILL expose the fakes, and we can actually be quite relaxed and confident about that. The system itself is sound: the only thing we should worry about is society giving up this system in favour of another. To quote Carl Sagan: "At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive, and the most ruthlessly skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense." ... "At the same time, science requires the most vigorous and uncompromising skepticism, because the vast majority of ideas are simply wrong, and the only way to winnow the wheat from the chaff is by critical experiment and analysis.".
This essay by Jearl Walker [haxial.com] is an interesting and insightful read that relates this notion of "faith" in physics (read right up to the end).