# Bye Bye, Speed of Light
**URL:** https://boards.straightdope.com/t/bye-bye-speed-of-light/122891
**Category:** Great Debates
**Created:** [August 8, 2002, 1:29am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891 "2002-08-08T01:29:41Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@monty2\_2001](https://boards.straightdope.com/u/monty2_2001)
#### Post date: [August 8, 2002, 1:29am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/1 "2002-08-08T01:29:41Z")
We hardly knew ye…
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>
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If it’s not constant, it’s up for grabs to how fast we can go… Perhaps it takes infinite energy/mass to reach c, but if c is flexible…
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### Author:  [@JS\_Princeton](https://boards.straightdope.com/u/JS_Princeton)
#### Post date: [August 8, 2002, 1:57am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/2 "2002-08-08T01:57:12Z")
Davies does an excellent job at appealing to the media’s and the general public’s imagination. The observational data that he’s thus far based his theoretical conclusions on are still not completely accepted as demonstrating what they appear superficially to demonstrate. More data is coming in, and soon we shall see whether quasar absorption is really behaving poorly and if so, then by how much. Furthermore, Davies is very careful to say we don’t really know what’s going on. It could be a change of something else we don’t quite understand yet and not need to appeal to a change in any constant. We just don’t have enough information at this point.
Don’t toss out your relativity texts, please. And don’t think that you have free reign to say, “the speed of light’s not constant”. It’s one set of observations so far, and we don’t have a coherent reorganized theory that makes sense if these observations really do hold up.
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### Author:  [@monty2\_2001](https://boards.straightdope.com/u/monty2_2001)
#### Post date: [August 8, 2002, 3:03am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/3 "2002-08-08T03:03:40Z")
My post was somewhat tongue in cheek.
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### Author:  [@Squink](https://boards.straightdope.com/u/Squink)
#### Post date: [August 8, 2002, 3:13am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/4 "2002-08-08T03:13:42Z")
> [@](#):
>
> Don’t toss out your relativity texts, please.
Damn, **Now** you tell us.:smack:
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### Author:  [@december](https://boards.straightdope.com/u/december)
#### Post date: [August 8, 2002, 3:47am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/5 "2002-08-08T03:47:43Z")
We should have known that the speed of light was slowing down.
Just look at the response time on this message board! 🙂
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### Author:  [@Beagle](https://boards.straightdope.com/u/Beagle)
#### Post date: [August 8, 2002, 4:21am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/6 "2002-08-08T04:21:04Z")
[I could not get that link to work](http://www.msnbc.com/news/791205.asp?0dm=C11NT#BODY). If this was unnecessary, sorry.
Oh, the speed of light. Ah, quantum photon fluctutation seems like the likely culprit to me.
[sub]Did that at least sound good?[/sub]
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### Author:  [@elucidator](https://boards.straightdope.com/u/elucidator)
#### Post date: [August 8, 2002, 4:50am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/7 "2002-08-08T04:50:18Z")
So the cat _isn’t_ dead? For sure, this time?
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### Author:  [@squeegee](https://boards.straightdope.com/u/squeegee)
#### Post date: [August 8, 2002, 5:39am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/8 "2002-08-08T05:39:03Z")
> [@](#):
>
> \*Originally posted by elucidator \*
> \*\*So the cat _isn’t_ dead? For sure, this time? \*\*
Sure. So far as you know. Take a peek in that bottle and let us know.
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### Author:  [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)
#### Post date: [August 8, 2002, 7:25am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/9 "2002-08-08T07:25:30Z")
Okay, so we’ve got some “maybe’s” as far as what’s going on, and we know that we may have to throw out the currently accepted value of what lightspeed is if the data turns out one way, but if the data turns out the other way then it means the electron’s charge had to change. So what cans of worms does that open up if _that_ turns out to be true, and not the changing of the SOL (speed of light)?
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### Author:  [@grimpixie](https://boards.straightdope.com/u/grimpixie)
#### Post date: [August 8, 2002, 7:38am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/10 "2002-08-08T07:38:31Z")
From the article:
> [@](#):
>
> After considering that a change in the electron charge over time would violate the second law of thermodynamics, they concluded that the only option was to challenge the constancy of the speed of light.
…or maybe the second law of thermodynamics is not inviolate???
Grim
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### Author:  [@taggert](https://boards.straightdope.com/u/taggert)
#### Post date: [August 8, 2002, 7:40am UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/11 "2002-08-08T07:40:43Z")
I think that the basic picture will remain the same. If this pans out, it will eventually be explained as the framework for a larger equation and Einsteinian mechanics will be as useful (it is now) as Newtonian mechanics has been for centuries. Much of what we know about the formation of the universe is deduced from other observations, and who is to say that anything is really constant without relating it to other conditions? In the past few years there has been strong evidence that the galaxies are not just moving away from each other, but accelerating, and nobody knows why. The Pioneeer spacecraft that has left the solar system is not coasting along as one would expect, but decelerating. Is the Hubble constant a constant? We don’t really know what gravity is yet, and we sure as hell don’t understand quantum mechanics.
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### Author:  [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)
#### Post date: [August 8, 2002, 2:34pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/12 "2002-08-08T14:34:00Z")
Until there’s a lot more data and analysis by other scientists, I’m not gonna give this a whole lot of weight. But who knows? It’s certainly possible that _c_ is in fact variable (although the success of relativity probably constrains how much _c_ can vary).
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### Author:  [@tracer](https://boards.straightdope.com/u/tracer)
#### Post date: [August 8, 2002, 2:57pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/13 "2002-08-08T14:57:16Z")
> [@](#):
>
> \*Originally posted by elucidator \*
> \*\*So the cat _isn’t_ dead? For sure, this time? \*\*
GUSTY WINDS may exist.
[sub]Douglas Adams, we hardly knew ye.[/sub]
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### Author:  [@Liberal](https://boards.straightdope.com/u/Liberal)
#### Post date: [August 8, 2002, 4:05pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/14 "2002-08-08T16:05:33Z")
What are the implications with respect to YEC?
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### Author:  [@JS\_Princeton](https://boards.straightdope.com/u/JS_Princeton)
#### Post date: [August 8, 2002, 6:20pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/15 "2002-08-08T18:20:51Z")
**Taggert** , the deceleration of the Pioneer Space Craft really doesn’t have anything to do with cosmological Hubble Flow or theoretical changes in the speed of light as it isn’t nearly on cosmological scales. Also, the “constancy” of the Hubble Constant is more of an implication of solving the Friedman Equation rather than anything else. It works perfectly well with the current _en vogue_ model cosmology known as lambda-CDM. It allows for the current expansion era that we now seem to inhabit very nicely in fact, no mysterious tampering with H needed. The Hubble Constant really isn’t a fundamental constant of the universe, more of a cosmological parameter that allows for different scaling lengths for the universe. It really doesn’t make much sense to talk about it changing.
If you are referring to Young Earth Creationism, **Lib** , you can forget any implication you may have had in mind. The only implications that this and other cosmological observations have on such kooky ideas is that the universe really is rather old (confirmation of Hubble Flow and such). The corrections to the speed of light would not be incredibly huge, unlike [what various Creationist nutjobs](http://www.ldolphin.org/constc.shtml) have proposed to explain their young cosmology idiocy.
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### Author:  [@Truth\_Seeker](https://boards.straightdope.com/u/Truth_Seeker)
#### Post date: [August 8, 2002, 6:30pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/16 "2002-08-08T18:30:38Z")
I don’t think this is exactly a death knell for relativity. People often forget that the speed of light isn’t a constant in the sense that it is unrelated to anything else. The speed of light is actually “defined” by two other constants: permittivity and permeability. While these two constants are important in Maxwell’s equation, most physicists do not consider them as potentially even more fundamental constants than the speed of light.
Yet, they may be. We simply have no idea what, if anything, determines the values of these constants. It is entirely possible that they were slightly different in the early universe for any number of reasons.
In another thread, someone wanted to know what “caused” quantum fluctuations. The correct answer is, as far as we know, nothing. Ultimately, however, there may well be a set physical laws that describe the vacuum on a much more profound level than we are currently able to do. If so, it is things like this which will lead to their discovery.
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### Author:  [@Liberal](https://boards.straightdope.com/u/Liberal)
#### Post date: [August 8, 2002, 6:51pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/17 "2002-08-08T18:51:53Z")
> [@](#):
>
> The corrections to the speed of light would not be incredibly huge, unlike what various Creationist nutjobs have proposed to explain their young cosmology idiocy.
Good heavens. 😃 No wonder you people lose so many debates in popular forums.
Anyway, what do you mean exactly by “corrections”? Does this represent merely a possible change in the constant’s value or a possible change in the status of light’s speed as a constant? Is there some range of speeds? And doesn’t the speed depend, at least in part, on the medium through which light travels?
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### Author:  [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)
#### Post date: [August 8, 2002, 7:37pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/18 "2002-08-08T19:37:48Z")
> [@](#):
>
> \*Originally posted by Libertarian \*
> \*\*And doesn’t the speed depend, at least in part, on the medium through which light travels? \*\*
The constant in question is the speed of light in a vacuum, so that rules out changes in different media.
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### Author:  [@Liberal](https://boards.straightdope.com/u/Liberal)
#### Post date: [August 8, 2002, 7:45pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/19 "2002-08-08T19:45:18Z")
Thanks, Ultra. So, it is a change in the status of constancy, then? If so, what is the range of speed that Princeton mentioned? Is that unknown at this point? If so, how is it known that it is “not incredibly huge”?
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### Author:  [@JS\_Princeton](https://boards.straightdope.com/u/JS_Princeton)
#### Post date: [August 8, 2002, 7:53pm UTC](https://boards.straightdope.com/t/bye-bye-speed-of-light/122891/20 "2002-08-08T19:53:07Z")
**Lib** , indeed, the medium through which light travels does change the speed of light. However, we’re dealing with space which is empty. It is a far better vacuum out there than we can come close to making here on Earth.
As was mentioned before, there are probably a great deal of constraints that can be made on the speed of light “changing”, as it were, over time that can be derived from considerations of relativity and causality.
There are two possibilities if we were to go down the beaten track of saying that these observations do end up holding up. One is to say simply that the speed of light is still the speed limit, but the relationship the constant has between itself and distance per time is different. In effect, the speed of light is still the top speed, it’s just different for different times. There are some flipping over backwards ways of treating Einstein’s postulates and his field equations to allow this to be true which exploit the the fact that time is basically uni-directional, while the speed of light has to be the same for two inertial frames, the equivalence principle may somehow be modified to allow for differences over different periods of time (assuming that there is no problem getting two different reference frames to agree whenever they are forced into simultaneity). This is somewhat similar to “tired light” hypotheses that are confirmed now to be untrue for a variety of reasons I will not hijack into here. In fact, these new observations, if they are what they claim to be, will have to explain equally well why tired light isn’t true… thus changing of the speed of light would have to be on smaller scales through time than the changing of light’s energy as it travels through the ever-expanding universe (right now that would mean slower than 100 km/sec/Mpc… and I would say that it would have to be a few orders of magnitude below that in order to allow for the fact that structure does not change size appreciably over cosmological scales. Thus, for example, gravity still talks at pretty much the speed of light we observe gravity talks at in our local universe even if we are near the edge of the universe. In effect, we’re talking peanut changes with respect to the 3 x 10^5 km/sec that is the speed of light “today”). However, another equally bizarre explanation is that the speed of light isn’t necessarily the top speed and that there may be a way around this and physical processes we don’t understand causing these effects. I see this possibility to be wishful thinking more than anything. Equally (im)plausible would be some way of getting around the second law of thermodynamics and changing the charge of the electron, say (which is by the way, equivalent to changing ONE of the two constants of permitivity and permeability). We just don’t have a viable way of doing it.
More likely, IMHO, is that there was a measuring error. Extraordinary claims demand extraordinary evidence. Mark my words, there will be more attempts to see this phenomenon. We haven’t heard the last of this. Stay tuned for future developments.
Oh, and sorry for slamming all the young-cosmology cosmologists. They just are so looney, **Lib**. Real cranks! I have yet to hear one (1) theory that allows for a young creation that did not completely ignore a significant portion of the evidence that convinces the vast majority of people in the field that the cosmological time-scale is basically correct. Call me a bigot, call me intolerant, but they who parade their ignorance as such don’t deserve to be handled with kid gloves!
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