breaking the speed of light article on howstuffworks.com

Here it is, I located it again.

"In Wang's experiment, a pulse of light passed through a small chamber filled with atoms of elemental cesium. A light beam traveling through such a medium has two different velocities - a velocity for the individual light waves in the beam and a group velocity for the entire beam. Oddly, some light waves in the beam can actually travel backward for miniscule amounts of time, creating a sort of "tail" behind forward-moving waves. As such, a light wave and its tail can leave the gas cavity at different times, creating the effect that the light beam has left the cavity before it's even entered."

Same sort of thing, altering the shape of a pulse and thinking that makes it go faster. Optically, an oscillatory burst can appear to exceed C if you sort of stand back and squint, but no photons are going faster than C.

John

No, actually quite different.

--
 Thanks,
    - Win

You can realize anything but that does not mean that the physical universe will ever cooperate with your musings.

Mathew Orman, FTL dream? I must have missed something. Yes, I suppose its true that "You can realize anything but that does not mean that the physical universe will ever cooperate with your musings." After all, it was considered common knowledge that a cause must always precede an effect, yet it is believed the light left the tube before it entered.

All please note: I am only 14 and am one year ahead in math, the most I know is basic algebra, so don't try to tell me anything with a lot of equations as I will probably be unable to comprehend it. The one part of all this I cannot yet understand is the math. No calculus, please.

As John Larkin said... "Same sort of thing, altering the shape of a pulse and thinking that makes it go faster. Optically, an oscillatory burst can appear to exceed C if you sort of stand back and squint, but no photons are going faster than C."

You can never be positive. If you cannot measure the position and velocity of the photons simultaneously, how can you be sure they are not going faster than c? Nobody can really measure the speed of the particles as they exited the container, because you'd need to specify the position defined as "exiting the container." This could disprove the experiment, but it could also disprove the arguments of everyone who does not believe the photons moved faster than c.

As John Larkin said... "Same sort of thing, altering the shape of a pulse and thinking that makes it go faster. Optically, an oscillatory burst can appear to exceed C if you sort of stand back and squint, but no photons are going faster than C."

You can never be positive. If you cannot measure the position and velocity of the photons simultaneously, how can you be sure they are not going faster than c? Nobody can really measure the speed of the particles as they exited the container, because you'd need to specify the position defined as "exiting the container." This could disprove the experiment, but it could also disprove the arguments of everyone who does not believe the photons moved faster than c.

google

quantum

Will

occur

I suggest you look up Einstein's special theory of relativity. This is not just "E=M(C squared)" (that is just the value of energy in matter, and only at rest at that) it is the theory that explains why C is the universal speed limit. Most of it can be understood without using calculus if you find a decent book.

You can build a fast shutter close to a source that only lets light through for a nanosecond or less, and then measure arrival times some distance away. Or do interferance experiments, which are exquisitely sensitive to the speed of light. There are lots of techniques that could detect ftl photons if they existed.

Well, you can't disprove the conjecture that something, maybe a rogue photon, does move ftl. But no experiment has ever demonstrated such, and there's lots of theory that says it can't happen. The burden of proof is to show a real case. "Laws" like the conservation of energy get much of their force from the fact that no counter-case has ever been observed.

You can observe a quasar flash that happened 8 billion years ago, on the other side of this universe, and look at it in wavelengths from radio through gamma rays; everything arrives at Earth at the same time, which is pretty impressive.

John

This sounds a lot like the electrical effects observed by our friend Mathew Orman during his FTL dream.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

I designed a logic level convert circuit once that I spec'd with a negative delay, at least until someone read it. I was *forced* to do rise-times from 20-80 and delays from 50-50. The threshold wasn't at 50, so until I showed the PHBs how stupid their requirements were, it had a negative delay. ...and no, no electrons were hurt in testing the circuit.

--
  Keith

"John Larkin" a écrit dans le message de news: snipped-for-privacy@4ax.com...

Well, I've just done mucho faster than light with a 100kHz sine wave. Pretty easy: don't terminate the line and once the transient is settled (which you can't notice) the sine wave "travels FTL" (read the phase shift is much smaller than what light speed would imply for the line length). Terminate the line and the effect is gone.

This saved me on a precision phase measurement board.

--
Thanks,
Fred.

Yes, he offered the original laboratory cable at a high price, as a sort of historical valuable artifact, but at about the same time he also offered a student cable for $10, IIRC. There were no bidders.

--
 Thanks,
    - Win

Short story, he was a guy here telling about his cables he tried to sell on ebay for an outrageous price, that he claimed could transmit a signal faster than the speed of light.

Calculus isn't that bad, it's all about rate of change (at least the differential part). I recall the teenage years as having a high rate of change, so you should have no problem understanding it. :)

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Reply to...

"I suggest you look up Einstein's special theory of relativity. This is

not just "E=M(C squared)" (that is just the value of energy in matter, and only at rest at that) it is the theory that explains why C is the universal speed limit. Most of it can be understood without using calculus if you find a decent book."

I have already learned that. E=mc^2 is only unification of mass and energy. But, nothing I've read has described significant evidence that there is proof nothing can cross the barrier. I understand special relativity fine, it's modern relativity that really gives me trouble.

Ok, I found online somewhere that E = mc^2 has been revised to E = mc2/mc^2 - 1. Is this true or is it just some bogus thing?

Also, say wormholes existed and you traveled through one. There would be hyperspace around you, and so you would age quickly. Wouldn't you be dead before you exited?

To whoever said calculus is easy... it's more than just rate of change, isn't it? We learned that in Algebra 1!

[snip]

See! I told you! Burridge IS the standard ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

This is a question I have had since reading about Maxwell's equations... in each one of them, there is this upside-down triangle symbol that looks just like the delta triangle flipped over. What is this symbol and what does it mean???

I took a quantum physics test on allthetests.com (to find it just type "quantum" in the search box, there is only one) and I scored 8 out of

12.

If there was some way to achieve a negative volume (it seems SO impossible but who knows?) what would happen to the matter? Say we had a piece of metal, and accelerated it past C. From another frame of reference, you'd see it getting shorter as it approached C. If it went faster than C, would it eventually become something with mass but no volume, and then start regaining its volume in the opposite direction? (ugh I don't think I'm explaining myself very well, I need a picture of some sort.) It's kind of this idea, and absolute value comes in somewhere, but I can't really express it well. Say speed was a number line, and C was zero. We so far can only move on one side of C. What would be on the other side, if it exists? Which side are we on? Or is this way of thinking about it totally one hundred percent impossible and wrong?