# Umm...can anything travel faster than the speed of light?
**URL:** https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193
**Category:** Factual Questions
**Created:** [July 20, 2000, 3:06am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193 "2000-07-20T03:06:06Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@johnson](https://boards.straightdope.com/u/johnson)
#### Post date: [July 20, 2000, 3:06am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/1 "2000-07-20T03:06:06Z")
[Apparently](http://www.washingtonpost.com/wp-dyn/articles/A9431-2000Jul19.html) so.
I’m sure there are more technical explanations than an article in the Post, and I’m sure there are many out there who understand it better than me, but it’s fascinating nonetheless.
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### Author:  [@Myrr21](https://boards.straightdope.com/u/Myrr21)
#### Post date: [July 20, 2000, 3:24am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/2 "2000-07-20T03:24:44Z")
Me (but in order to do so, I have to become one with the “Speed Force” and therefore die).
Nevermind, that’s just comics…actually couldn’t get link to work (stupid slow CPU).
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### Author:  [@spluurtaf](https://boards.straightdope.com/u/spluurtaf)
#### Post date: [July 20, 2000, 3:48am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/3 "2000-07-20T03:48:27Z")
I did not read your link, but about 1.5 years ago, in a lab somewhere they slowed the speed of light to 34mph(somewhere near there anyway), they did this by emitting some kind of light into an extremely cold goo(they actually said this at cnn’s website) and it was slowed down to 34 mph
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### Author:  [@Silver\_Fire](https://boards.straightdope.com/u/Silver_Fire)
#### Post date: [July 20, 2000, 3:56am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/4 "2000-07-20T03:56:31Z")
Myrr21, in a nutshell:
> [@](#):
>
> \*\*In a landmark experiment, scientists have broken the cosmic speed of light, causing a light pulse to travel at many times the speed of light-so fast that the peak of the pulse exited a specially prepared test chamber before it even finished entering it.
>
> This seems to contradict not only common sense, but also a bedrock principle of Albert Einstein’s theory of relativity, which sets the speed of light in a vacuum, about 186,000 miles per second, as the fastest that anything can go.
\*\*
And that’s as far as I’m going to go.
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### Author:  [@meek](https://boards.straightdope.com/u/meek)
#### Post date: [July 20, 2000, 4:08am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/5 "2000-07-20T04:08:01Z")
Coldfire on the Autobahn comes to mind.
Or… me driving CanadianSue to the Airport…
Hmmmmmmm - Did I wander into GQ accidentally?
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### Author:  [@silent\_rob](https://boards.straightdope.com/u/silent_rob)
#### Post date: [July 20, 2000, 4:44am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/6 "2000-07-20T04:44:12Z")
I thought that there were miniscule particles in the upper atmosphere that would instantaneously shoot from one place to another faster than the speed of light.
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### Author:  [@Tymp](https://boards.straightdope.com/u/Tymp)
#### Post date: [July 20, 2000, 5:16am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/7 "2000-07-20T05:16:26Z")
Yes. Darkness always seems to be there first.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [July 20, 2000, 6:46am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/8 "2000-07-20T06:46:18Z")
Oh, good lord… Not this asinine drivel again. There are, in fact, some “things” that can travel faster than c (the speed of light in a vacuum), but none of them can transmit any information… For instance, the spot on a wall projected by a laser pointer can travel at any speed. this is well-known to physicist, and is generally considered boring. What this article is talking about is something even more boring… What they’re saying is that the front of a pulse of light can leave a material before the back of the pulse enters… If you think about it for a moment, this makes perfect sense. If you want to know how fast a train moves through a tunnel, you can’t compare when the locomotive leaves to when the caboose enters; you’ve got to use the same part of the train. Similarly, you can’t just use different parts of the pulse, like they’re doing here.
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### Author:  [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)
#### Post date: [July 20, 2000, 4:09pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/9 "2000-07-20T16:09:12Z")
Here is a reference for those with access to Nature magazine.
Nature
20 July 2000
Gain-assisted superluminal light propagation
L. J. WANG, A. KUZMICH & A. DOGARIU
Ok, I read this article, for all the good it did me. I am lost in the math as of the third paragraph. That’s a shame, too, because it is interesting stuff. But, I think that I am certain of one thing. It is the shape of an interferance pattern waveform which is achieving superluminal velocities, not the light itself. That still leaves me fairly stunned, just not quivering in intellectual fear. Anyone out here who has read this article and understands it?
Tris
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### Author:  [@UncleBeer](https://boards.straightdope.com/u/UncleBeer)
#### Post date: [July 20, 2000, 5:00pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/10 "2000-07-20T17:00:38Z")
I’m moving this to GQ, with all the others like it that appeared when _Time_ & _Newsweek_ reported this same phenomenon.
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### Author:  [@Diceman](https://boards.straightdope.com/u/Diceman)
#### Post date: [July 20, 2000, 7:07pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/11 "2000-07-20T19:07:54Z")
> [@](#):
>
> \*Originally posted by Chronos \*
> \*\*What they’re saying is that the front of a pulse of light can leave a material before the back of the pulse enters… \*\*
I knew there was something fishy about that story! The author of the article I read seemed to imply that shooting the laser through cesium mist somehow allowed the light to travel faster than C. (And as we all know, everything in Myst moves with glacial slowness :D) This story set off my mental alarms right away, and I was hoping someone here would know what the straight dope was. Is it just me, or does it seem like you can always count on the media to get any science/medical/computer story completely screwed up?
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### Author:  [@Punoqllads](https://boards.straightdope.com/u/Punoqllads)
#### Post date: [July 20, 2000, 7:16pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/12 "2000-07-20T19:16:25Z")
> [@](#):
>
> \*Originally posted by johnson \*
> \*\*[Apparently](http://www.washingtonpost.com/wp-dyn/articles/A9431-2000Jul19.html) so.
>
> I’m sure there are more technical explanations than an article in the Post, and I’m sure there are many out there who understand it better than me, but it’s fascinating nonetheless. \*\*
[Actually](http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v406/n6793/abs/406277a0_fs.html), no, they didn’t go faster than the speed of light. After all, they conducted the experiment with light itself, tautalogically insuring the pulse would travel at the speed of light. However, the speed of light depends upon the medium it’s passing through. The quantity _c_ that we always talk about is more accurately the speed of light through a vacuum (no Hoover jokes, please). Normally, any other medium causes it to decrease. However, the amount that it decreases for that medium depends on the wavelength of the light passing through it.
What the researchers did, then, is create a medium in which, for a particular wavelength, the speed of light is faster than its speed in a vacuum. With an atomic cesium vapor cell set to 30 degrees Celsius, they caused what appeared, from our perception of the speed of light, the peak of an attuned pulse to emerge from the media prior to the peak of a non-attuned pulse.
Previous experiments had flaws such that the strange peak-displacement could be explained by saying that the media amplified the attuned pulse on its front edge, and absorbed energy on its trailing edge. In this experiment, they insured that no amplification could occur, leaving the only explanation that the speed of light through the cell for that wavelength as greater than its speed in a vacuum.
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### Author:  [@Phobos](https://boards.straightdope.com/u/Phobos)
#### Post date: [July 20, 2000, 7:39pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/13 "2000-07-20T19:39:06Z")
**Chronos** - thanks for clearing that up. That experiment is still being debated/debunked.
> [@](#):
>
> \*Originally posted by spluurtaf \*
> \*\*in a lab somewhere they slowed the speed of light to 34mph(somewhere near there anyway), they did this by emitting some kind of light into an extremely cold goo(they actually said this at cnn’s website) and it was slowed down to 34 mph \*\*
That is different. The ultimate speed limit for anything moving through space is still the speed of light in a vacuum ©. The speed of light changes depending what it’s moving through (like through water or a Bose-Einstein Condensate…or “extemely cold goo” as you say CNN put it)…of course the speed limit probably still holds for that medium…nothing can go faster through a B.E.C. than light.
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### Author:  [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)
#### Post date: [July 20, 2000, 8:19pm UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/14 "2000-07-20T20:19:17Z")
> [@](#):
>
> \*Originally posted by Phobos \*
> \*\*The speed of light changes depending what it’s moving through (like through water or a Bose-Einstein Condensate…or “extemely cold goo” as you say CNN put it)…of course the speed limit probably still holds for that medium…nothing can go faster through a B.E.C. than light. \*\*
Actually, electrons routinely exceed the speed of light in water when travelling through the water in a nuclear reactor.
Arjuna34
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### Author:  [@johnson](https://boards.straightdope.com/u/johnson)
#### Post date: [July 21, 2000, 1:41am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/15 "2000-07-21T01:41:12Z")
I do apologize for my misleading colloquial use of “speed of light” when of course I meant _c_. In that respect, this issue is fascinating, in part because it shows once again that the “science” we all know (all the laymen, anyway), is overly simplified, not to mention the inadequacy of mainstream media in reporting on science issues (of course, this problem isn’t restricted only to science).
I don’t apologize for finding this interesting, and not “asinine drivel.” I’m just guessing that not everyone who reads these boards is a professional physicist working on the cutting edge (I also hadn’t realized that _Nature_ was in the business of publishing studies that are boring).
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### Author:  [@Diceman](https://boards.straightdope.com/u/Diceman)
#### Post date: [July 21, 2000, 1:50am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/16 "2000-07-21T01:50:45Z")
I still don’t understand why Cesium vapor at 30 degrees has some special magical property that allows light to travel faster than it does in a vacuum. After all, this is the direct opposite of how every other known substance works, isn’t it?
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### Author:  [@Larry\_Borgia](https://boards.straightdope.com/u/Larry_Borgia)
#### Post date: [July 21, 2000, 2:25am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/17 "2000-07-21T02:25:08Z")
Jesus, Chronos, calm down! Some of us non-physicists found the article interesting. The Scientists who performed the experiment were startled by it as it was the first time, according to the article, that a light pulse moved faster than c.
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### Author:  [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)
#### Post date: [July 21, 2000, 2:47am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/18 "2000-07-21T02:47:37Z")
> [@](#):
>
> \*Originally posted by Chronos \*
> \*\* What this article is talking about is something even more boring… What they’re saying is that the front of a pulse of light can leave a material before the back of the pulse enters… If you think about it for a moment, this makes perfect sense. If you want to know how fast a train moves through a tunnel, you can’t compare when the locomotive leaves to when the caboose enters; you’ve got to use the same part of the train. Similarly, you can’t just use different parts of the pulse, like they’re doing here. \*\*
The point is that the front part of the pulse came out MUCH too soon. Using your train analogy, you CAN measure the train’s speed by comparing the time locomotive leaves and the time the caboose enters, if you know the length of the caboose and the length of the tunnel. From what I gathered in the article, the analogy would be a 1 mile tunnel and a 100 ft long train that you thought was going 40 mph. The train enters the tunnel, and the front of the train comes so quickly that the caboose is still entering!
What actually happened, though, is that the light emitted “early” wasn’t the same light that went in. The strange part, though, is how the emitted light knew to be emitted so quickly.
Arjuna34
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### Author:  [@Rysdad](https://boards.straightdope.com/u/Rysdad)
#### Post date: [July 21, 2000, 3:31am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/19 "2000-07-21T03:31:28Z")
Indeed, when I read that article, it made me say, “hmmmm.”
Like the train analogy above when the locomotive exited before the caboose entered, the laser light that exited the vapor wasn’t {i]quite\* the same laser light that entered. Sorta like a coal burning locomotive entered the tunnel, but a diesel burning locomotive came out…while the caboose was just entering.
It did say that information couldn’t be transmitted. But why couldn’t the information be: I am a laser pulse that just went through a cesium fog?
Hmmmm.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [July 21, 2000, 5:42am UTC](https://boards.straightdope.com/t/umm-can-anything-travel-faster-than-the-speed-of-light/26193/20 "2000-07-21T05:42:43Z")
I’m sorry I reacted so harshly… First of all, I have no problem with the folks posting these questions, and I’m sorry if I gave that impression. As the saying goes, if you don’t know something, there’s nothing like asking. What I do have a problem with, is the popular media taking something like this and blowing it all out of proportion like this. Yes, the original experiment was interesting, and valuable… but not because it’s supposedly an FTL phenomenon. A science writer ought to be able to get the story straight, and if he can’t, the magazine or newspaper he works for should get another science writer.
The other reason that I reacted so harshly, is that there were two different stories about alledged FTL experiments just a month or two ago, and one of them was almost identical to this one. I understand perfectly that many of the folks on the board didn’t notice when it happened then, but I don’t understand other journalists not noticing.
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