# I just invented something that I think I'll call "Radio." Tell me where I'm wrong.
**URL:** https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728
**Category:** Factual Questions
**Created:** [June 23, 2013, 9:56pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728 "2013-06-23T21:56:31Z")
**Posts on this page:** 14
**Page:** 3
### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [June 29, 2013, 4:05am UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/41 "2013-06-29T04:05:44Z")
**Leo Bloom:** I wasn’t aware that this was the pit. Oops. Would that be considered unacceptable snark? I’m so confused now. If you have a problem with me, perhaps it would be best to take this to the pit for a proper airing.
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### Author:  [@dropzone](https://boards.straightdope.com/u/dropzone)
#### Post date: [June 29, 2013, 7:44pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/42 "2013-06-29T19:44:35Z")
Jesus, guys! I know that street toughs can’t hold a candle to scientists when it comes to talking smack, but a Pit thread? Here, shake hands and agree that, though the other is full of shit and that you can’t believe someone could be that stupid and still use a computer, you respect his right to be a moron. I would hate to be the one who came between you.
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### Author:  [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)
#### Post date: [June 30, 2013, 8:03pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/43 "2013-06-30T20:03:22Z")
Rudeness aside, just to be clear that there is not a fundamental conflict between quantum physics and relativity A theory such as QED is inherently quantum and inherently relativistic, which is no surprise really as a particle like the photon is both relativistic and quantum and cannot be described by non-relativistic quantum mechanics or classical electrodynamics (which is relativistic unless you introduce something like the luminiferous ether to repress it’s natural symmetries).
The goal of quantum gravity is to create a quantum field theory of gravity and all quantum field theories worth discussing are relativistic (e.g. quantum electrodynamics, quantum chromodynamics, the electroweak theory and the standard model). Whilst bringing relativity into the mix adds complications, ff there was an inherent conflict between quantum physics and relativity we’d still be trying to sort it out in the quantum theories describing electromagnetism, the strong and weak nuclear forces, etc.
The biggest problem for quantum gravity is that the field that describes general relativity also describes the geometry of spacetime, however a quantum field, like any field , needs a background to be defined on, but can’t do a good job of defining that background itself as it doesn’t always define definite physical values.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [June 30, 2013, 8:23pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/44 "2013-06-30T20:23:18Z")
[From a 1999 Physics World article:](http://physicsworld.com/cws/article/print/1999/dec/06/quantum-gravity-presents-the-ultimate-challenge-to-theorists)
> [@](#):
>
> Physics in the 20th century is founded on the twin pillars of quantum mechanics and the theory of relativity. However, in spite of the enormous successes of each theory individually, the two appear to be incompatible. This embarrassing contradiction at the very heart of theoretical physics remains one of the great outstanding challenges in science.
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### Author:  [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)
#### Post date: [June 30, 2013, 8:41pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/45 "2013-06-30T20:41:50Z")
> [@deltasigma](#):
>
> [From a 1999 Physics World article:](http://physicsworld.com/cws/article/print/1999/dec/06/quantum-gravity-presents-the-ultimate-challenge-to-theorists)
Yes, but if you read the article it is abundantly clear what they are referring to is the supposed incompatibility between quantum theory and the general theory of relativity, not the special theory (usually ‘relativity’ unqualified means the special theory, however sometimes in popular physics writing it is used to refer to the general theory, which is the cause of the confusion).
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [June 30, 2013, 8:49pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/46 "2013-06-30T20:49:41Z")
I don’t think anyone using the term relativity in a conversation of this sort would mean special rather than general, but OK.
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### Author:  [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)
#### Post date: [June 30, 2013, 9:19pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/47 "2013-06-30T21:19:48Z")
> [@deltasigma](#):
>
> I don’t think anyone using the term relativity in a conversation of this sort would mean special rather than general, but OK.
Well you’d be wrong then as that is generally how it is used. There are two reasons for this:
1. Historically the special theory of relativity was known exclusively as the theory of relativity. This is simply because it came first.
2. General relativity is only one particular extension of the special theory and not all extensions of SR are compatible with GR. Therefore everything that falls under the broadest heading of (Einsteinian) relativity will respect the principles of SR, but may ignore the principles of GR.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [June 30, 2013, 9:24pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/48 "2013-06-30T21:24:13Z")
Except we were talking about the incompatibility of QM and relativity so given the context, I would have had to have been referring to general relativity - right?
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### Author:  [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)
#### Post date: [July 1, 2013, 3:42am UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/49 "2013-07-01T03:42:18Z")
> [@deltasigma](#):
>
> Except we were talking about the incompatibility of QM and relativity so given the context, I would have had to have been referring to general relativity - right?
My objection to the article was that it talked about time and space being treated differently in the Schrodinger equation.
A misconception that sometimes occurs is that, because time and space coordinates are of different orders in the Schrodinger equation, whereas in an equation describing the propagation of a relativistic wave they must be of the same order, there is a fundamental incompatibility between relativity and quantum mechanics. This is not true: the Schrodinger equation is the problem and the problem can be solved ‘simply’ by choosing the correct wave equation in which time and space have the same order and it’s wrong to mention the Schrodinger equation in this context as it’s not the appropriate equation to describe relativistic quantum physics.
Now to be fair to the author of the article by the Schrodinger equation they could’ve (lazily) been referring to it _and its relativistic equivalents_ and more nuanced problem such as, for example, that particles require a family of preferred reference frames and hence preferred time coordinates in order for them to have a well-defined meaning in spacetime. But even this problem is not really the crux of the problem between quantum theory and general relativity, for example even in quantum field theory in flat spacetime the concept of what exactly is a particle can become a bit fuzzy at times, e.g. the Unruh effect. I still do not think it is a good article though.
I think I’ve made reference to compatibility of quantum physics and special relativity and the difficulty in combining quantum physics and the general theory in the majority of posts I’ve made on this thread
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [July 1, 2013, 3:57am UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/50 "2013-07-01T03:57:38Z")
Actually, the author does a pretty good job of ‘dumbing it down’ for people like me. He explains that the first step is to analogize gravity to to electromagnetism and postulate a force carrier like the photon called the graviton:
> [@](#):
>
> Similarly, one could envisage the gravitational attraction between two bodies as being due to the exchange of virtual “gravitons” - the quanta of the gravitational field. The fact that nobody has ever detected a graviton is no surprise, because gravity is so much weaker than electromagnetism. It turns out that an exchange of single gravitons between point masses does indeed yield an expression for the gravitational field with its familiar inverse-square law.
>
> Problems set in, however, when more complicated processes involving many gravitons are examined. Gravity differs crucially from electromagnetism inasmuch as the gravitational field is nonlinear. This nonlinearity arises because the gravitational field possesses energy, and energy has mass, which gravitates. In quantum language, this implies that gravitons will interact with other gravitons, unlike photons, which interact only with electric charges and currents and not with other photons. Because gravitons respond to each other, particles of matter are surrounded by complex networks of virtual gravitons that form “closed loops”, as well as “branching trees”.
>
> In quantum field theory, closed loops are a sign of trouble; they normally produce infinite answers in calculations of physical processes. In QED, such loops occur when an electron emits and reabsorbs its own photon. The resulting infinities are removed by a mathematical procedure that is known as renormalization. If this is done properly, sensible answers are obtained. QED is termed a renormalizable theory because all such infinities can be removed by a systematic procedure; in effect, a single set of mathematical operations is sufficient to remove the infinities.
Also, the real problem is the fact that time is not an essential element of how you handle the analysis of quantum phenomena but in general relativity it is a dimension of reality.
I suppose that you can refute what I’m saying by using more terminology that I’m only marginally going to understand and I guess eventually I’m going to get tired of doing this, but at the risk of being rude, I think at best you’re being disingenuous.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [July 1, 2013, 3:44pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/51 "2013-07-01T15:44:22Z")
> [@deltasigma](#):
>
> I suppose that you can refute what I’m saying by using more terminology that I’m only marginally going to understand and I guess eventually I’m going to get tired of doing this, but at the risk of being rude, I think at best you’re being disingenuous.
This is kind of a bizarre attitude. You possess an admittedly lay understanding about certain things, but when **Asymptotically Fat** or **Simplicio** offer you a little of their expert understanding to correct some misunderstandings you have, you get all defensive. But nobody is attacking you: no matter how many lay publications you follow, there’s bound to be some misapprehensions and confusions—that’s simply because those publications can’t, and don’t aim to, offer a comprehensive picture of the field; lots of things, some subtle, some less so, simply fall by the wayside.
I mean, you quote part of the New Scientist article above as an example of ‘doing a good job’ at presenting a lay audience friendly picture of the problems in reconciling gravity and the quantum. But what standards do you apply produce this rating? It might be the best of lay publications, but even that just might mean it’s the best of a bad lot. I mean, to me, there’s numerous things that seem wrong, or at best misleading, even in this small snippet, most obviously the assertion that it’s the presence of graviton self-interaction that causes the problems with renormalizability. It’s not: the theory of the strong force, quantum chromodynamics, has force carriers (the gluons) that are likewise charged under the interaction, and thus, self-interact, yet it’s nevertheless renormalizable.
That’s not to lambast science reporting in general (though there is an awful, _awful_ lot of bad science reporting), I think that often, a writer does indeed the best possible job with the limited tools available to and the constraints imposed on them; but it’s still not (and obviously isn’t intended to be) a substitute for the kind of knowledge you get from textbooks and the like.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [July 1, 2013, 6:22pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/52 "2013-07-01T18:22:35Z")
> [@Half\_Man\_Half\_Wit](#):
>
> This is kind of a bizarre attitude. You possess an admittedly lay understanding about certain things, but when **Asymptotically Fat** or **Simplicio** offer you a little of their expert understanding to correct some misunderstandings you have, you get all defensive.
Hmm. Defensive? I suppose one might look it at it that way. Although if you continue you speak to someone in Bahasan when they have repeatedly told you they don’t understand the language, what does that say about YOU?
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [July 1, 2013, 6:44pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/53 "2013-07-01T18:44:11Z")
> [@deltasigma](#):
>
> Hmm. Defensive? I suppose one might look it at it that way. Although if you continue you speak to someone in Bahasan when they have repeatedly told you they don’t understand the language, what does that say about YOU?
Well, if you don’t understand something, you could always ask. And replies like the first couple you gave to **Asymptotically Fat** are a funny way of letting somebody know you don’t understand them.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [July 1, 2013, 6:53pm UTC](https://boards.straightdope.com/t/i-just-invented-something-that-i-think-ill-call-radio-tell-me-where-im-wrong/661728/54 "2013-07-01T18:53:18Z")
> [@Half\_Man\_Half\_Wit](#):
>
> Well, if you don’t understand something, you could always ask. And replies like the first couple you gave to **Asymptotically Fat** are a funny way of letting somebody know you don’t understand them.
Now who’s being disingenuous? We both know that the whole vocabulary is based on advanced mathematics that I’m just starting to get into and that most of the people here won’t even recognize the terminology being used. But sure, resolving such things are as simple as just asking a few questions - right? :smack: :rolleyes:
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