Posted on 09/16/2002 7:26:53 AM PDT by aculeus
Electric signals can be transmitted at least four times faster than the speed of light using only basic equipment that would be found in virtually any college science department.
Scientists have sent light signals at faster-than-light speeds over the distances of a few metres for the last two decades - but only with the aid of complicated, expensive equipment. Now physicists at Middle Tennessee State University have broken that speed limit over distances of nearly 120 metres, using off-the-shelf equipment costing just $500.
Jeremy Munday and Bill Robertson made a 120-metre-long cable by alternating six- to eight-metre-long lengths of two different kinds of coaxial cable, each with a different electrical resistance. They hooked this hybrid cable up to two signal generators, one of which broadcast a fast wave, the other a slow one. The waves interfere with each other to produce electric pulses, which can be watched using an oscilloscope.
Any pulse, whether electrical, light or sound, can be imagined as a group of tiny intermingled waves. The energy of this "group pulse" rises and falls over space, with a peak in the middle. The different electrical resistances in the hybrid cable cause the waves in the pulse's rear to reflect off each other, accelerating the pulse's peak forward.
Four billion km/h
By using the oscilloscope to trace the pulse's strength and speed, the researchers confirmed they sent the signal's peak tunnelling through the cable at more than four billion kilometres per hour.
"It really is basement science," Robertson said. The apparatus is so simple that Robertson once assembled the setup from scratch in 40 minutes.
While the peak moves faster than light speed, the total energy of the pulse does not. This means Einstein's relativity is preserved, so do not expect super-fast starships or time machines anytime soon.
Signals also get weaker and more distorted the faster they go, so in theory no useful information can get transmitted at faster-than-light speeds, though Robertson hopes his students and others can now rigorously and cheaply test those ideas.
Physicist Alain Hache at the University of Moncton in Canada adds that it may be possible to use this reflection technique to boost electrical signal speeds in computers and telecommunications grids by more than 50 per cent.
Electrons usually travel at about two-thirds of light speed in wires, slowed down as they bump into atoms. Hache says it may be possible to send usable electrical signals to near light speed.
© Copyright Reed Business Information Ltd.
Okay, you build it. If I like it, I'll buy it.
Without reading through all of the posts, I would say yes.
The fact that phase velocity can be faster than the speed of light means nothing about relativity. Phase velocity isn't actually the velocity of anything. Phase velocity could concieveably be nearly infinite. And the phenomenon is so NOT a new thing.
Besides, the pulses ARE light(electromagnetic waves), so how can they be faster than themselves!?!?!
I get so sick of the Discover the World of Science mumbo jumbo designed to amaze the ignorant.
Oh, boy!!!! A word problem!
Let's see. If the pan is 9" across, then its radius, and each cut side of a piece, is 4.5".
The widest part of the cut piece is 3", which is a chord of the pie circle.
Consider the cut piece to be composed of two right triangles, back to back, with their adjoining right angles at the center of the chord.
Then, each triangle has one side (the hypoteneuse) of 4.5" and the side opposite the central angle of 1.5".
The sine of this ratio, 1.5/4.5 or 1/3, is approximately 19.47 degrees.
Since the slice is made up of two such triangles, its included angle is 38.94 degrees.
Therefore, the entire pie would consist of 360/38.94 slices of this size, or about 9.244 slices.
Now, if you remove one slice of this size from the whole pie, the number of pieces which remain is,
ummmm,
one.
Neh! Sie ist gleichzeitig tod und auch lebendig!
On the bulletin board in our university computer lab was an article that reported the evaluation of the speed characteristics of a new type of transistor logic. (This was in the 1960s, mind you, when you had to submit everything on punched cards and get the results back the next day on wide printout paper.)
They discovered that over a certain range, the propagation time through a basic gate was an inverse function of the supply voltage. This was shown in a graph.
They then extrapolated to a much higher supply voltage, at which time the prop time was extrapolated to go to zero, and then negative.
They reported that they measured the logic at this new, much higher, supply voltage level, and began to see output states on the test gates that could not be correlated with any stimuli except those which they were about to apply.
And the gap continued to widen. Pretty soon, they were getting outputs from the test gates from inputs that were to be applied the next day.
Things continued to get more confusing for weeks, until they finally received printouts in their inboxes that were undecipherable, until they realized that these were from programs that were yet to be written, on a machine that was yet to be built, using their newfound ultraspeed logic.
Player: Score:
Erasmus 1
Wasn't Erasmus the name of the trading ship in the book Shogun; Darwin's first name; and the author of Praise of Folly, and better known as the Prince of Humanists?
You keep good company.
1. Didn't know that;
2. Charles Darwin's grandfather, who had a profound influence on him;
3. Yup.
This must be the latest FR joke, sort of like AYBABTU. I'm seeing it everywhere.
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