# I can travel FTL. Okay, now how do I violate causality? **URL:** \ **Category:** Factual Questions\ **Created:** [September 28, 2012, 12:07am UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075 "2012-09-28T00:07:59Z")\ **Posts on this page:** 14\ **Page:** 3
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [September 29, 2012, 6:52pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/41 "2012-09-29T18:52:20Z")
> [@Randy\_Seltzer](#): > > …(GLaDOS jokes welcome, but let’s please address the actual question first.) GLaDOS 😕 ---
**Author:** ![Punoqllads](https://avatars.discourse-cdn.com/v4/letter/p/d2c977/32.png) [@Punoqllads](https://boards.straightdope.com/u/Punoqllads)\ **Post date:** [September 29, 2012, 8:19pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/42 "2012-09-29T20:19:21Z")
> [@Leo\_Bloom](#): > > GLaDOS 😕 [GLaDOS](http://lmgtfy.com/?q=GLaDOS) ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [September 30, 2012, 3:54am UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/43 "2012-09-30T03:54:11Z")
> [@Leo\_Bloom](#): > > Missed edit window: > I’m pleased I had the opportunity to use the word “ineluctable.” It opens a chapter in _Ulysses_. And it is no doubt followed by the word ‘modality’. ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [September 30, 2012, 4:20am UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/44 "2012-09-30T04:20:10Z")
> [@Half\_Man\_Half\_Wit](#): > > Well, either what he would have come up with would have been equivalent to the space-time picture, or wrong; whether or not there are relativistic effects is not really a question of what theory you use to describe physics. In fact, there exists an alternative theory of gravity based (more explicitly) on Machian principles, Julian Barbour’s [shape dynamics](http://arxiv.org/abs/1105.0183), which is known to be (mostly) equivalent to general relativity. It’s true that shape dynamics makes do without ‘spacetime’ in a sense (in fact, abolishing time as fundamental is one of Barbour’s recurrent themes), but the physics is nevertheless the same. You could also look to the [ADM-formulation](http://en.wikipedia.org/wiki/ADM_formalism) of general relativity, which partitions space-time up into three-dimensional spatial slices together with a prescription of how to link them; time only appears as a parameter indexing the individual slices of space. Really? Because everything I’ve ever seen or read lists space-time as being at the top of the list of reasons for why there has never been a successful grand unified field theory. I guess I must have heard wrong. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [September 30, 2012, 3:32pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/45 "2012-09-30T15:32:16Z")
> [@allotrope](#): > > Really? Because everything I’ve ever seen or read lists space-time as being at the top of the list of reasons for why there has never been a successful grand unified field theory. I guess I must have heard wrong. Technically, a grand unified theory has nothing to do with space-time; it’s a unification of the ‘microscopic’ forces, i.e. electromagnetism and the weak and strong forces, alone, without gravity. Incorporating gravity so you get a unified description of all the known forces is often called a ‘theory of everything’, though I’m not too fond of that name. But this is just a terminological quibble. Content-wise, you’re right, basically – the way space and time are treated in quantum theory and relativity are indeed different, which is a source of difficulty. Roughly, space and time are taken as absolute, static background parameters in quantum theory, while they themselves are the dynamic quantity of general relativity. It’s a more serious problem with respect to time. This is a reason why one often prefers the ADM formulation of GR in quantum gravity research. But this doesn’t mean that in a different approach to gravity, there would be ‘no such thing as space-time’; these problems are not due to some choice of Einstein, and are also present in other approaches, though they may assume a different guise there. (Though I should mention for completeness that there is indeed a theory that breaks, in a sense, the symmetry between space and time, and which may be successfully quantized – however, this theory (known as Horava gravity) has problems of its own, in particular, it’s not clear if it is actually phenomenologically adequate.) ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [September 30, 2012, 3:47pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/46 "2012-09-30T15:47:56Z")
Here’s an [article](http://www.princeton.edu/~hhalvors/papers/db-intro.pdf) you might find interesting, but given your response, I’d like you to then explain the author’s error in the following quote - emphasized passage in particular. > [@](#): > > According to Summers, the primary tool needed for this characterization is the Tomita-Takesaki > modular theory, and in particular, the geometrical interpretation of modular theory provided by > Bisognano and Wichmann. However, Summers proceeds to recount a more ambitious program > that he and his collaborators have undertaken: a program that would use modular symmetries as a > basis from which the very structure of spacetime can be recovered. **As Summers points out, such a > reconstruction would have profound conceptual implications. Indeed, one is tempted to say that the > success of such a program would be a partial vindication of Leibniz-Machian relationalism about > spacetime.** But whether or not the reconstruction supports certain philosophical views about the > nature of spacetime, a more clear understanding of the vacuum is crucial for the development of > future physics—especially since future physical theories will most certainly not posit a fixed back- > ground Minkowski spacetime structure. > Summers also discusses the fact — without mentioning explicitly that it was first proved by > himself and Reinhard Werner—that the vacuum state is nonlocal, indeed violates Bell’s inequality > maximally relative to measurements that can be performed in tangent spacetime wedges. In doing > so, Summers notes the importance of making fine-grained distinctions between different types of > nonlocality.This theme is treated at length in the chapter by Redei. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [September 30, 2012, 4:04pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/47 "2012-09-30T16:04:41Z")
Huh? What error? ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [September 30, 2012, 4:19pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/48 "2012-09-30T16:19:53Z")
OK. Let me back up. You see no conflict between Leibniz-Machian relationism and the concept of spacetime? ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [September 30, 2012, 4:43pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/49 "2012-09-30T16:43:36Z")
I think that if you want to have a philosophical debate, you should head over to GD… (And for the record, the notion of space-time in GR is not a substantivalist one, as demonstrated by the famous hole argument – only wordline coincidences (actual meetings of, for instance, particles) have physical meaning, not the background space-time in itself. This is not a priori in conflict with relationalism, though one can discuss certain finer points.) ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [September 30, 2012, 4:50pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/50 "2012-09-30T16:50:43Z")
I believe the article I cited proves otherwise, but perhaps this [article](http://discovermagazine.com/2012/mar/09-is-einsteins-greatest-work-wrong-didnt-go-far) spells it out more clearly. edit: There’s also [this one](http://www.scientificamerican.com/article.cfm?id=was-einstein-wrong-about-relativity) for Scientific American subscribers. ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [September 30, 2012, 11:09pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/51 "2012-09-30T23:09:18Z")
All of these arguments ignore one big fact-there is no “Past”. The past does not exist-it ceases to exist as time advances. This is proven by chemical reactions, increase of entropy, and conservation of energy. You cannot “enter” the past because it does not exist. There is only the present. All the while you are entering your “wormhole”, time is advancing, as the present displaces the past. Whatever frame of refernece you are using as a “baseline”, time is advancing in it, and there is no way that the past state of this reference point can be entered. ---
**Author:** ![Junkman209](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/junkman209/32/5522_2.png) [@Junkman209](https://boards.straightdope.com/u/Junkman209)\ **Post date:** [October 1, 2012, 6:52pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/52 "2012-10-01T18:52:37Z")
My understanding is that the Würm generator from Ikea draws a LOT of power. **SenorBeef** ’s neighbor should be able to give you tips on how to keep your electric bill down. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 1, 2012, 9:12pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/53 "2012-10-01T21:12:58Z")
> [@Dr.Strangelove](#): > > There’s nothing more right about either perspective–neither the magnetic or electric force is privileged in this regard (though the electric force squeaks out a minor win until we observe a monopole). You might be in luck then: > [@](#): > > **Higgs transition of north and south poles of electrons in a magnet** > A potential route to a dissipationless monopole current of spins for spintronics > > Minimal evidence of a Higgs transition_1 of north and south poles of electron spins was observed in a magnet Yb2Ti2O7 at the absolute temperature_2 0.21 K. A fractionalization of these monopoles from electron spins was observed on cooling to 0.3 K. On further cooling below 0.21 K, the material showed the ferromagnetism to be understood as a superconductivity of monopoles. > > SOURCE: [http://www.riken.jp/engn/r-world/info/release/press/2012/120808/index.html](http://www.riken.jp/engn/r-world/info/release/press/2012/120808/index.html) ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [October 1, 2012, 9:39pm UTC](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075/54 "2012-10-01T21:39:13Z")
> [@Whack-a-Mole](#): > > You might be in luck then: That’s pretty interesting. However, on first glance it appears that those aren’t “real” monopoles. It is possible in some systems to have a structure that looks a lot like a monopole, but isn’t one in the traditional sense. They’re basically equivalent to a very long and thin bar magnet–as long as you’re close to one end and far from the other, it looks very much like a monopole. I don’t know enough to say that’s exactly what’s going on in that paper, but I suspect it’s something close: that there’s some quantum mechanical effect that ends up looking like a monopole current, but doesn’t really reflect the underlying physics. There’s a lot of QM that works this way; for instance, vibrations in a crystal lattice can be modeled as a particle called a phonon. The thing is, there’s no actual phonon; it’s all just vibrations in the end. But it behaves as if there were one. [Previous page](https://boards.straightdope.com/t/i-can-travel-ftl-okay-now-how-do-i-violate-causality/636075.md?page=2)