Skip to comments.Sound Pulses Exceed Speed of Light
Posted on 09/02/2017 12:06:20 AM PDT by 2ndDivisionVet
A group of high school and college teachers and students has transmitted sound pulses faster than light travelsat least according to one understanding of the speed of light.
The results conform to Einstein's theory of relativity, so don't expect this research to lead to sound-propelled spaceships that fly faster than light. Still, the work could help spur research that boosts the speed of electrical and other signals higher than before.
The standard metric for the speed of light is that of light traveling in vacuum. This constant, known as c, is roughly 186,000 miles per second, or roughly one million times the speed of sound in air. According to Einstein's work, matter and signals cannot travel faster than c.
However, physicist William Robertson at Middle Tennessee State University in Murfreesboro, along with a high school teacher, two college students and two high school students, managed to, depending on how you look at it, transmit sound pulses faster than c using little more than a plastic plumbing pipe and a computer's sound card.
"This experiment is truly basement science," Robertson told LiveScience.
The key to understanding their results, reported online Jan. 2 in the journal Applied Physics Letters, is envisioning every pulse of sound or light as a group of intermingled waves. This pulse rises and falls with energy over space, with a peak of strength in the middle.
Messing with Light Speed
In an unrelated previous experiment, Robert Boyd at the University of Rochester used similar principles to make pulses of light travel backward and faster than c.
Robertson and his colleagues transmitted sound pulses from the sound card through a loop made from PVC plumbing pipe and connectors from a hardware store. This loop split up and then recombined the tiny waves making up each pulse.
This led to a curious result. When looking at a pulse that entered and then exited the pipe, before the peak of the entering pulse even got into the pipe, the peak of the exiting pulse had already left the pipe.
If the velocities of each of the waves making up a sound pulse in this setup are taken together, the "group velocity" of the pulse exceeded c.
"I believe that this is the first experimental demonstration of sound going faster than light," Robertson said. Past research has proven it possible to transmit electrical and even light pulses with group velocities exceeding c.
Robertson explained this faster-than-light acoustic effect is likely commonplace but imperceptible.
"The loop filter that we used splits and then recombines sound along two unequal length paths," he said. "Such 'split-path' interference occurs frequently in the everyday world."
For example: "When a sound source is located near a hard wall, some sound reaches the listener directly from the source whereas some sound travels the longer path that bounces the sound off the wall. The sounds recombine at the listener," Robertson said. However, the weakness of the signals and the fact that any resultant differences in timing are very slight "mean that we would never be able to hear this effect."
None of the individual waves making up the sound pulses traveled faster than c. In other words, Einstein's theory of relativity was preserved. This means one could not, for instance, shout a message faster than light.
Still, this research might have engineering applications. Robertson explained that although it is not possible to send information faster than light, it seems these techniques could make it possible to route slower-than-light signals in electronic circuits faster than before.
The epitome of this effect is the propagation of a plane wave, at or near the speed of light, at a slightly oblique angle to a surface.
The point of detection of this wave will propagate at a speed faster than the speed of light, and in the limit will be observed simultaneously along an arbitrary length.
This is a set piece in the elementary exposition of relativity theory, so don’t get excited!
Well now, this is interesting!
So that’s why the engine room in JJ’s Enterprise contains so many pipes.
>> Robert Boyd at the University of Rochester used similar principles to make pulses of light travel backward and faster than c.
I’m still stuck on trains, stations, and clocks fearing my observations nullify what I’ve observed. Not sure I can deal with The Completion Backward Principle.
The only thing faster than c is the amount of time it takes for the MSM to blame Trump for something.
Like most news stories about science, it’s absolute gibberish.
The study used the heads of the teachers and students as the vacuum to test this theory.
The speed of light is Trump’s fault because it limits how fast one can move.
186,282.4 miles/sec — Any faster, then you DIE!
I guess NASA was still too busy changing Muslim terrorists baby diapers to assist in any of the experiments. OR they could have been seeing how fast odor travels in air compared to a vacuum while changing these diapers. Important stuff (shiite sheeet)
Exactly and as those two surfaces are bought together compressing the plane wave, the speed of the sound is heightened far exceeding the speed of sound and the Road Runner but never the Waskally Wabbit.
So what is this bit about making light pulses travel backward?
So is Japanese. Unless you understand the language.
Not true! They travel light years in hours on Star Trek all the time, sheesh!
No, they didn’t.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.