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FTL Currents May Power Pulsar Beams
thomst passes along news out of the recent AAAS meeting of a new explanation for pulsar beams that involves faster-than-light currents. Here are Los Alamos's press release and three related papers on the arXiv. "The new model explains the beam emissions from pulsars as products of superluminal currents within the spinning neutron stars' atmospheres. According to the authors' model, the current generated is, itself, faster than light, although the particles that compose it never individually exceed the universal speed limit, thereby preventing Einsteinian post-mortem rotation. The new model is a general explanation of the phenomenon of pulsar beam emissions that explains emissions at all observed frequencies (and different pulsars emit everything from radio waves to x-rays), which no previous model has done."
Can we replicate this and add information to the current to transport information faster than the speed of light? (The real problem.)
Has Google filed its patent yet on "Method and Materials to Power a Pulsar Beam Using a Faster-Than-Light Current"?
No.
For a detailed explanation, see the next guy's post.
The world is made by those who show up for the job.
A disco ball. Shine a light on a disco ball, and project those cool reflections onto a surface more than a few light-seconds away. You'll see that the spots move much faster than light.
Still no FTL movement or information transfer. Still no violation of GR or causality. Just another nice, attention-grabbing headline.
If you wave a laser pointer around at the moon, you can make a dot on the moon that moves faster than light. That doesn't mean your laser photons are moving faster than light.
[ I'm referring to the concept of seeing something that moves faster than the speed of light, not anything else here, just so it's clear ]
Consider this situation --
You've got a big sphere. Let's say it's 93 million miles in radius (the size of our radius around the sun -- it's a figure we're all familiar with anyways.)
In the middle of this sphere is a man. He has a laser, and he's shining it on the sphere. Since the man is still, the laser is not moving.
But, then the man starts spinning, once per second. The laser takes about 8 minutes to reach the edge of the sphere, but once it does, the dot starts going around the outside of the sphere, once per second. If you do the math, that means the dot is moving 584,000,000 miles per second -- which is about 3100 times the speed of light.
The light from the laser is still going at the speed of light, but the dot appears to be moving at over 3000 times the speed of light. But it's just a location -- the spot that the laser is hitting right now -- it doesn't mean that something tangible is exceeding the speed of light, and therefore Einstein isn't proved wrong by it.
My point is, it doesn't require some really strange neutron star situation to picture a situation where something might appear to be traveling faster than the speed of light.
Sort of.
Try this for an analogy: imagine a circular wall around us located one light-year radius away. Point your laser pointer at the wall, then sweep it so that it points to another spot 1 light year away on the same wall. Do that in 1 second.
1 year later, a dot of light will appear on the wall. The dot will then exceed the speed of light, traveling 1 light-year in 1 second. If that dot also induced an electric charge, it will look like some sort of current pulse just traveled along the wall millions of times the speed of light.
So, you've created a current, faster than the speed of light, that appears to carry information FTL, but not in a meaningful way.
The world is made by those who show up for the job.
Ah yes it's time again to break out the old phase vs group velocity explanation again. There are plenty of things that can go "fast than light", but repeat after me, you cannot transmit *information* faster than light. There are many concepts in our current understanding of physics that you just take to be inviolate like conservation of energy, momentum, speed of light. That's not to say we those concepts might eventually be superseded but as a general rule of them any theory that doesn't follow them is probably pseudoscience and wrong. Physics develops from what proceeded it, from Newton to Einstein to Quantum Mechanics to String Theory, and those conservation laws always held. Perhaps reformulated in a different manner to stand for different things but they still held. You don't need to know the details of how a proposed "perpetual motion machine" may work to know that if the crackpot building it says that it violates the law of conservation of energy then it doesn't work.
Do you have any idea how hard it is to modulate a pulsar?
It's light... it's a big wave, with its source at your laser.
The real solution to this "problem" is that you can't transmit information from point A to point B faster than light, despite the fact that the beam can change focus between A and B, faster than light. You can use the triangle inequality to show this.
After all, I am strangely colored.
Reading -- you're doing it wrong.
Point your laser pointer at the wall, then sweep it so that it points to another spot 1 light year away from the first.
1 light year = 1 light year
The angle swept was 1 radian, not Pi radians.
Maths. You are doing them wrong. The point of light will not travel 1 light year in one second. It will travel Pi light years in one second as it traces out a half circle with a radius of one light year. If you meant to indicate the linear difference, that is also wrong, it would have been 2 light years.
Reading: You're doing it wrong.
They did not say he was rotating the light source by pi radians. They said they were rotating the source so that it struck a point 1 light year from the original. The arc-length -- or linear distance, either way -- was in the statement of the problem. If you want to do maths, then you can work your way backwards to the total angular displacement and angular velocity. Your answer will be different depending on whether they meant a circular wall or a flat wall, but either way the statement of 1 year of displacement is not wrong and cannot be wrong.
The enemies of Democracy are
We know the speed of light in some mediums is less than c (see cherekov radiation). Is it possible the speed of light is greater than c in some mediums? You have to admit that a neutron star is pretty exotic stuff. What about negative-index metamaterials? Beyond that (and this may be non sequitur) maybe a concentration of "dark energy" has properties we don't understand.
Birth is the leading cause of death.
It's interesting to watch as the /. crowd's replies to the technical question in the post become both less succinct and more smarmy as you get further down the comments. I have not yet attempted to correlate this phenomenon to user id number.
Oh for heaven's sake, somebody post a car analogy!
Take yer hotrod up to about 25 MPH at night and spin some donuts. From far enough away, the headlights reflecting off the walmart wall will move way faster than 25 MPH, maybe 1000 MPH who knows.
Now does the cop give you a ticket for speeding because your headlight reflections are moving 1000 MPH? No, nothing was speeding. The reflection is just a mathematical construct that means nothing. The cop gives you a ticket for being a dumbass and disturbing the peace, not for speeding.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
FWIW, this is from the American Astronomical Society (AAS), not the American Association for the Advancement of Science (AAAS). One of my more frequent typos.
Well done. Pretty cool, really.
Now make an analogy using a cow, 5 bags of salt, and the Pacific Ocean. :)
Now make an analogy using a cow, 5 bags of salt, and the Pacific Ocean. :)
A cow, 5 bags of salt, and the Pacific Ocean are in a car doing donuts...
The enemies of Democracy are
Ok, back to physics 102.
This is where you need special relativity. Nothing can move faster than the speed of light relative to anything else, regardless of what reference frame the observer is in. If each train is traveling 1/10c relative to the train below it, an observer on the ground will see the twelfth train traveling at 0.869c.
Also, due to length contraction, if the first train was long enough to reach around the globe when stationary, it will be some 200 km too short when traveling at 0.1c, each subsequent train will be shorter yet.
You just proved that there isn't such a thing as a rigid body. There is this upper limit, imposed by relativity.
You can make some calculations, about the electric pulse propagating through the matter at light speed, but they're trivial and boring.
entropy happens
Now make an analogy using a cow, 5 bags of salt, and the Pacific Ocean. :)
So, near Hawaii, we have a cow and 5 bags of salt. Force feed the salt to the cow, which promptly dies (sorry PETA). The rotting cow corpse expands and finally detonates (sorry cDc), at, for example, the speed of light. Flaps of leather strike SFO, nothing unusual, but it is odd that they strike LA at about the same time. Scientist watching from a satellite says its as if leather was smeared in a line thru SFO and LA however the line must have moved at about a zillion times the speed of light, like the Enterprise had an accident while transporting some steers at full warp speed. No, scientist has it wrong, because the direction of motion is actually perpendicular to the line between SFO and LA, the motion was actually from Hawaii at merely light speed.
The difference in time of impact and distance between SFO and LA are just a math abstraction which by no means implies the leather moved along that path at a zillion times the speed of light.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Well done. Pretty cool, really.
Now make an analogy using a cow, 5 bags of salt, and the Pacific Ocean. :)
Assume a spherical cow in a vacuum...
Read this: http://www.eskimo.com/~billb/miscon/elect.html
and then come back to educate other /.-ers. I'm a civil engineer and even I didn't know some of the stuff in there. Did you know that electrons flow through metal at a few cm/minute? I sure didn't, but after reading this text a lot of other stuff made a lot more sense to me.