An AI thread that starts with the hope of reasoned discscussion and debate about presiditential lunacy but descends after precious few replies into the same ping-pong flamewar about the relative merits of Einstein, space-time and violation of relativity's frame-egalitarianism.
An AI thread that starts with the hope of reasoned discscussion and debate about presiditential lunacy but descends after precious few replies into the same ping-pong flamewar about the relative merits of Einstein, space-time and violation of relativity's frame-egalitarianism.
An AI thread that starts with the hope of reasoned discscussion and debate about presiditential lunacy but descends after precious few replies into the same ping-pong flamewar about the relative merits of Einstein, space-time and violation of relativity's frame-egalitarianism.
Nerd alert! Nerd alert! Only nerds get into heated pissing matches about space-time.
Simple proof. Time moves forward in all frames (true? -- it is a universal assumption in all science). Forward time is defined by increased entropy.
No, not true (as I understand it, IANATP).
Time is far more a human perception of the 'direction' of the tendency toward entropy.
If one uses a concept of imaginary time, then the desired outcome of FTL for the communication of information becomes entirely moot. This *may* be what shetline is suggesting with his Orangeball.
Unfortunately you also need an imaginary set of 'people' to observe the communication.
you know i didnt have to use the universe as the example of an adiabatic system, and furthermore just because no one has measured the entropy of the universe doesnt mean you cannot extend the results of all other adiabatic systems to the universe unless the universe is not adiabatic.
(and that seems to me to be a far more interesting question than what if FTL can exist but only in one frame, yea as if, giggle giggle).
But I have to refuse to play along stupidly (since i already showed that your system doesnt survive to point 3 in thermo).
You are not approaching this problem scientifically. Your so called "thought experiment" is not an experiment at all because you have systematically denied the validity of any "accepted property" of the universe that I have thrown at you. You have even denied Einstein's own thought experiments. Simply put, you are assuming properties before there is evidence of them, you are creating a hypothetical universe that does not share any of the major properties of the known universe. Your concept of a frame is bizarre, it recalls the sci fi equivalent of an alternate universe. If you want an alternate universe you might as well propose one since your definition of frame is so far removed from the accepted definition of a frame that all you are effectively doing is making an internal universe that is "somehow" accessible and useful to our universe.
its fine to play games shetline, but you keep changing the rules, in fact all that is basically left (since you now have abandoned thermodynamics to not be relevent between frames) is quantum and i am sure there are plenty of properties of quantum systems that just dont fit into your scheme.
btw, contradictions and paradoxes are effectively the same. it is a paradoxical to have contradictory properties -- 2=3 is a contradiction isnt it?.
So here is the deal -- define your rules. if your rules break a theory accept it -- so far thermo and relativity have fallen. once you have your rules have fun. but remember it has nothing to do with what actually occurs in the universe. a thought experiment is supposed to provide insight on few assumptions. your "experiment" provides no insight (or at least none offered from you) on a lot of unstated and stated assumptions.
Time is far more a human perception of the 'direction' of the tendency toward entropy.
If one uses a concept of imaginary time, then the desired outcome of FTL for the communication of information becomes entirely moot. This *may* be what shetline is suggesting with his Orangeball.
Unfortunately you also need an imaginary set of 'people' to observe the communication.
Please ignore this if it is total horseshit.
yeah, horse and some cow too.
btw. while forward time is percieved (and provable within the context of perception in thermo) to follow increased entropy, we have to accept this if we are talking about time. otherwise we stare at a clock and its hands mean nothing.
So here is the deal -- define your rules. if your rules break a theory accept it -- so far thermo and relativity have fallen. once you have your rules have fun. but remember it has nothing to do with what actually occurs in the universe. a thought experiment is supposed to provide insight on few assumptions. your "experiment" provides no insight (or at least none offered from you) on a lot of unstated and stated assumptions.
I did define my rules, and the only way theromodynamics and relativity have "fallen" so far that all you want to do is parrot back completely unmodified definitions of terms that my premises are clearly and admittedly going to play with. When a completely predictable collision occurs between the starting assumptions and rigid definitions, you say "See! It fails!"
By no means am I certain that what I'm thinking of will work in any sense of the word "work", but I was hoping for something a whole lot more interesting out of the discussion than inflexible repetition of rules that are broken, with no curiousity expressed about what room there might be to play with those rules and still come out with some kind of new consistency.
i sound like a parrot because you are not listening.
this is final. you didnt define your rules. none of them. you have "predictable" collisions with every known theory of the universe that has supporting evidence out there. You cannot just randomly select the few things that could still agree and say "see, some of it is still there". You dont learn a damned thing working this way. Your wonderful properties that come out of a convoluted series of assumptions, have to jive with all that is known -- not theories but actual observations. You are like a string theorist. No you are worse. You are proposing an entirely untestable theory (like string theorist) that disbands everything before it without any evidence (like no one else). Einstein didnt work in a vacuum. Shetline evidently does.
What the hell do you think you are going to accomplish? Do you want to explain thermodynamics then in your new plane of reality? How a frame can carry properties?
Good god. I have just wasted my time trying to convince someone that they can't just toss aside parts of tested theories which do not line up with their pet theory. Worse, you havent offered a solution at all to these problems merely an "eh, it works/doesnt work; its all the same".
I am not being rigid. I accept that these theories probably do not explain all things but they certainly hold more water than your leaking dingy does.
It's nice to see that someone -- maybe not the world's foremost authority on the subject, but someone with a PhD in particle physics who doesn't seem to be wearing a tin-foil hat -- takes the idea of a preferred FTL frame seriously enough to think it worthy of discussion:
This guy (Jason W. Hinson) also discusses a clever idea I hadn't thought of for saving more of relativity than my idea does: An FTL "field" of finite size and scope, that could be created as needed in an area where you want to use FTL communication or travel, that could be in motion relative to other such fields (so long as they don't overlap), so there wouldn't have to be any special, universal preferred frame.
Edit: By the way, even using localized FTL fields that don't drag a universal preferred frame into the picture, you'd still have the problem that time coordinates of FTL events occurring within such a field, when translated into other frames of reference, could end up with "cause" and "effect" running backward in time.
You are proposing an entirely untestable theory (like string theorist) that disbands everything before it without any evidence (like no one else). Einstein didnt work in a vacuum. Shetline evidently does.
Wow, you're taking this way too seriously.
You seem to think I'm seriously proposing some huge revolution in physics, and, damn it, how dare I have such affrontary with so little to offer for it!
All I'm interested in is whether it's even imaginable to mix FTL with what we know about the real world. Something good enough for good hard sci-fi would be good enough for me here. I'm not shooting for a Nobel Prize.
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What the hell do you think you are going to accomplish?
Getting your blood pressure up?
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Do you want to explain thermodynamics then in your new plane of reality?
I don't think in any practical sense thermodynamics would be too much different than the way it's defined now. Consider this:
The laws of thermodynamics were determined empirically (by experiment). They are generalizations of repeated scientific experiments. (emphasis mine)
My guess -- and it's only a guess -- is that talk about universal entropy results from a reasonable extrapolation of experimental data, but I doubt that there's any practical experimental way to even tell the difference between a universe in which entropy is only guaranteed to decrease in one frame particular frame (the contention that I'd have to make), and one in which it decreases in all frames -- as best as you can tell with locally available data.
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How a frame can carry properties?
I'm not proposing that a frame carries any properties. The initial concept was of a physical artifact that had the ability to send FTL messages within itself. The physical artifact of the lattice is the thing that has the FTL-sending property. That artifact also has a frame of reference.
Still fanciful, but somewhat less so because it wouldn't be an artificial object, is an "FTL aether". The aether has the ability to act as a medium for FTL messages. The aether has a frame of reference. FTL messages are bound to move forward in time with respect to the frame of the aether because FTL is a property of the aether, not because it's a property of the frame.
fine. if you really wanted this to be a sci fi chat you should have insisted on that at the get go.
within current theories FTL signaling cannot occur. You lose much in the way you define FTL signaling, including the laws of thermodynamics (some of which are generalizations from experiments (but so were/are maxwell's equations) and some of which can be derived from first principles). Relativity says nothing of the practicality of measuring something, if we can measure entropy in a closed box, we can measure entropy in the universe for all intents and purposes. Regardless, if we accept your principle that FTL signaling is possible and violations of all sorts of physical laws DO NOT affect basic physical principles (which to me is paradoxical, but fine...) I don't think this changes anything since we just assumed that everything is a ok.
But for the sake of argument, lets say in a special universe -- your artifact if you will (because it is perverse to me to say this is a frame), FTL is allowed and that these signals could be sent to our universe (but nothing can be sent to it sorry we cannot give up thermo where we are and expect a quality discussion). I am still stumbling here. I want to tell you that signaling could work but I also realize that without us being able to send a signal into the void there is no chance for us to actually acquire useful information. I have to resist the urge to toss out thermo because it really is the best thing since water drop torture. We have to make another assumption that would allow cross talk, our universe is not adiabatic, that is entropy tends to increase with time in a larger globalverse (or some other sci fi ish thing) but our universe can behave like a local non-adiabatic systems so long as entropy in the entire globalverse (of which the FTL universe is not a part) increases -- we can even say there is a tendency for the localverse to have increasing entropy with time but it is not a requirement. So lets say we can talk to the FTLverse, this involves of course a decrease in our universe's entropy but it is made up for a gain of entropy in some other localverse within the globalverse basically we are burning our library's books so we can read those that remain. This can only last so long, so what the hell, we are probably going to die before we cannot increase the entropy of the globalverse anymore. Then yes, this would be a useful way of communicating (in fact shetline since we don't have to send the signal in linear space we can talk to ourselves without having to move in space-time except for epsilon). But there are so many assumptions here and that bothers the scientist in me (which is all of me).
"In this house, we OBEY the laws of thermodynamics"
I'm still having trouble seeing where thermodynamics gets so badly broken by this restricted form of FTL that it implies, as you seem to be saying, a totally alien universe.
Let's start with a colloquial statement of the laws of thermodynamics (because frankly, I have to admit, my understanding of thermo doesn't go too much further than that):
Thermodynamics is the study of the inter-relation between heat, work and internal energy of a system.
The British scientist and author C.P. Snow had an excellent way of remembering the three laws:
1. You cannot win (that is, you cannot get something for nothing, because matter and energy are conserved).
2. You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases).
3. You cannot get out of the game (because absolute zero is unattainable).
I've done some simple mathematics related to the First Law, solving basic classical physics problems by taking conservation of energy into account. I've never touched any equations related to the Second or Third Law.
Your objections seem to be related to the Second Law. I've found some of the basic equations related to the Second Law and entropy online, and, while I didn't understand them very well, the formulations appeared purely classical. I wasn't able to find much of anything relating to relativity and entropy, other than some guy struggling to explain how red shift could be understood in terms of the Second Law. I could find nothing that discussed the relationship between universal entropy and relativistic frames of reference. Anything that you can direct me to regarding these issues would be helpful.
At a simplistic level, I don't see the FTL aether causing dissolved sugar cubes to reform, broken tea cups to leap from the floor and reassemble themselves, or perpetual motion machines to whir away powered by their own waste heat. (All of which can happen in a theoretical sense, with a very, very low order of probability, even if we aren't playing with the current understanding of the rules of the game.)
I'd like make sure we're both very clear on what is meant by the word "now", the very restricted nature of the backward causality you'd get from an FTL aether, and how that would or would not relate to measuring universal entropy.
If you're familiar with standard spacetime diagrams, you know how they are divided up into areas called the "absolute past", the "absolute future", and the "absolute elsewhere". While the word "now" is, in a non-technical sense, is associated with immediacy and current experiences, the "now" of relativity is a very abstract thing -- it's a set of spacetime coordinates which, save the one single point of the observer's location, lies entirely within the "absolute elsewhere". Rather than being an immediately accessible thing, the "now" of relativity is cold and distant, a set of totally inaccessible events, save the single event of the observer's "here and now".
"Now" is also very fickle. The "here and now" follows the motion of the observer, and all of the rest of the observer's "now" swings through spacetime, "pivoting" around the observer's location, cutting a very changeable slice out of all of the events in the absolute elsewhere.
Like I mentioned in an earlier post, just by walking around my own room, I can move a huge entropy-changing event like the supernova explosion of a distant star into my past, future, or present. Are you really, really certain that the current understanding of relativity and thermodynamics takes this into account? I take one step across my room and swoosh... the supernova is in my past, and a huge associated increase of entropy goes onto my balance sheet for the universe's total current entropy, and then, with a small change of direction, I take another step and swoosh, that huge increase in entropy has to be subtracted from my balance sheet, because it hasn't happened yet...
Are you certain that, by this kind of accounting, the total entropy of the universe still goes up, even though in my next small step forward in time, I have to subtract a supernova's worth of entropy from my previous tally?
While I plainly admit to not knowing much of the math here, or what work has been done relating relativity to thermodynamics, thinking about the above kind of situation makes me strongly doubt that any current formulation of the idea "total entropy of the universe" involves the relativistic meaning of "now", and that any normally used accounting of entropy involves events gathered out of the "absolute elsewhere".
Please correct me if these doubts I have are unfounded, and if you can, please point me to any resources you know about that would help clear up my confusion.
As my understanding stands now, it makes much more sense to me if only the "absolute past" of relativity is involved in a relativistic understanding of entropy. And if that's the case, it should be clearly stated that all of the weirdness of the kind of FTL we're discussing never moves information into the absolute past, but only into the past portion of the absolute elsewhere.
The laws of thermo are frame independent (invariant). Only a few equations need modification to allow for translation between frames, but the laws in and of themselves remain the same. Einstein actually assumed this was the case, IIRC, and it turns out it is... (i think there are strange results with temperature -- i mean what does temperature mean at the speed of light)
Its not that sugar cubes will spontaneously reform if FTL were allowed, its that in some frame the signal is moving backwards and this signal is transfering its entropy to a prior time otherwise the signal implicitly carries no information. This loss of entropy from the latter universe to the prior universe is a break from thermodynamics unless the universe is not adiabatic (meaning a closed system). And even then, sending entropy backwards to another part of a larger universe would still break thermo so the FTL "frame" needs to be outside of the highest adiabat.
Think of it this way: there is a rule on the conservation of mass-energy that you will agree upon. I send back a signal that weighs 25 g. That means the universe gains 25 g of weight in the prior universe and loses it when i send it back. It is not that mass-energy is conserved over time -- it is that it is strictly conserved. This brings other problems into the playing field though.
The laws of thermo are frame independent (invariant). Only a few equations need modification to allow for translation between frames, but the laws in and of themselves remain the same. Einstein actually assumed this was the case, IIRC, and it turns out it is... (i think there are strange results with temperature -- i mean what does temperature mean at the speed of light)
You can have frame independence without implying anything about whether or not events in the "absolute elsewhere" have to be taken into consideration.
This makes it important to know if any of the procedural definitions for how universal entropy would be measured, be they realistic laboratory experiments or hypothetical exercises, involve more than what data can be gathered by an observer from that observer's absolute past.
Are you sure that goings-on in the absolute elsewhere actually matter to how universal entropy would be measured? If such events don't matter, it seems to me that an FTL aether only upsets the purity of a particular conceptualization of forward time.
With the version of FTL under discussion, an observer's measurement of universal entropy would remain frame independent as long as that measurement were only dependent on events available within the observer's absolute past.
As for whether or not the universe would start "leaking entropy"... it's not like the entropy you're worried about would be vanishing out of thin... thin aether? You could definitely account for where entropy went -- it's still in the same universe, even though the time coordinates might look a little funny outside of the preferred frame.
my ignoranti understanding of the thermo laws would make it that there is no over-arching frame but always a frame beyond . . . . or in deconstructive terminolgy: always another text that the text referrs to, and another to that.
and the same with relativistic speeds except that light is constant no matter what frame you regard it from.
But that wouldn't foreclose any possibilities . . .
excuse the physics pleb . . . *he grasps for clouds*
The entire entropy of the universe at one point in time matters. That is all.
How it is measured is completely irrelevent.
You moving around doesn't change the entropy of the universe at a point, it changes the entropy you percieve in your limited definition of perception. What I am saying is that throw perception aside, fundamentally the laws of thermodynamics apply in all frames which implies that the measure of universal entropy in two different frames at the same time should be the same. Another way to say this which does not involve tossing perception behind is using the here and now but the answer is still the same, the measurement of entropy at the same space-time point should be the same -- that means if a frame of reference was traveling at 0.5 c intersects a frame traveling at 0.00002 c, at that precise moment at the precise point they intersect if we measure universal entropy in one frame it should be identical to that measured in the other frame. So, yes, what happens in the elsewhere matters.
Accounting for entropy is not the problem -- if your universe appears to lose entropy in any frame (which means those frames that detect your FTL signal as going backwards in time) then the whole universe has to lose entropy.
The conservation of mass issue is a far more intuitive way of dealing with this problem and suggests that even a "frame" external to everything doesnt make fundamental sense. Basically your thought doesn't work. It doesn't get you anywhere. It ties you down...
Indeed it is kind of strange. All forms of worship seem to involve this sort of latent self-doubting thing, whereby one must profess to "not be good enough" in some respect or another, and thus ask that which is being worshipped for more wisdom / guidance / talents in such regards.
Whatever happened to that whole non-boastful confidence thing? "I think I can, I think I can?"
PS - sorry to derail, I realize there are some pretty good posts in the last couple pages about thermo and entropy and all, but the above quote in response to a similar-minded one by Groverat was kind of humorous.
I thought the point of Maxwell's demon was that you could not measure a system without adding to the loss of energy, or dispersal of energy through teh mprocess of measurement . . . .
... and, i ventured to fugure, a seemingly implied consequence of this thought would be that you could not have a "universal frame"
also, wouldn't different frames imply different relationships to the entropy at hand and therefor imply different measuring techniques each with a different draw upon the energy at hand?
Comments
Typical. Grow up.
Originally posted by Harald
An AI thread that starts with the hope of reasoned discscussion and debate about presiditential lunacy but descends after precious few replies into the same ping-pong flamewar about the relative merits of Einstein, space-time and violation of relativity's frame-egalitarianism.
Damn, I hate the way that keeps happening.
Originally posted by Harald
An AI thread that starts with the hope of reasoned discscussion and debate about presiditential lunacy but descends after precious few replies into the same ping-pong flamewar about the relative merits of Einstein, space-time and violation of relativity's frame-egalitarianism.
Nerd alert! Nerd alert! Only nerds get into heated pissing matches about space-time.
Typical. Grow up.
Indeed. Listen to the man.
Originally posted by billybobsky
You are killing me shetline.
Simple proof. Time moves forward in all frames (true? -- it is a universal assumption in all science). Forward time is defined by increased entropy.
No, not true (as I understand it, IANATP).
Time is far more a human perception of the 'direction' of the tendency toward entropy.
If one uses a concept of imaginary time, then the desired outcome of FTL for the communication of information becomes entirely moot. This *may* be what shetline is suggesting with his Orangeball.
Unfortunately you also need an imaginary set of 'people' to observe the communication.
Please ignore this if it is total horseshit.
(and that seems to me to be a far more interesting question than what if FTL can exist but only in one frame, yea as if, giggle giggle).
But I have to refuse to play along stupidly (since i already showed that your system doesnt survive to point 3 in thermo).
You are not approaching this problem scientifically. Your so called "thought experiment" is not an experiment at all because you have systematically denied the validity of any "accepted property" of the universe that I have thrown at you. You have even denied Einstein's own thought experiments. Simply put, you are assuming properties before there is evidence of them, you are creating a hypothetical universe that does not share any of the major properties of the known universe. Your concept of a frame is bizarre, it recalls the sci fi equivalent of an alternate universe. If you want an alternate universe you might as well propose one since your definition of frame is so far removed from the accepted definition of a frame that all you are effectively doing is making an internal universe that is "somehow" accessible and useful to our universe.
its fine to play games shetline, but you keep changing the rules, in fact all that is basically left (since you now have abandoned thermodynamics to not be relevent between frames) is quantum and i am sure there are plenty of properties of quantum systems that just dont fit into your scheme.
btw, contradictions and paradoxes are effectively the same. it is a paradoxical to have contradictory properties -- 2=3 is a contradiction isnt it?.
So here is the deal -- define your rules. if your rules break a theory accept it -- so far thermo and relativity have fallen. once you have your rules have fun. but remember it has nothing to do with what actually occurs in the universe. a thought experiment is supposed to provide insight on few assumptions. your "experiment" provides no insight (or at least none offered from you) on a lot of unstated and stated assumptions.
This is my last response.
Originally posted by Harald
I will not derail this wonderful thread.
No, not true (as I understand it, IANATP).
Time is far more a human perception of the 'direction' of the tendency toward entropy.
If one uses a concept of imaginary time, then the desired outcome of FTL for the communication of information becomes entirely moot. This *may* be what shetline is suggesting with his Orangeball.
Unfortunately you also need an imaginary set of 'people' to observe the communication.
Please ignore this if it is total horseshit.
yeah, horse and some cow too.
btw. while forward time is percieved (and provable within the context of perception in thermo) to follow increased entropy, we have to accept this if we are talking about time. otherwise we stare at a clock and its hands mean nothing.
Originally posted by billybobsky
So here is the deal -- define your rules. if your rules break a theory accept it -- so far thermo and relativity have fallen. once you have your rules have fun. but remember it has nothing to do with what actually occurs in the universe. a thought experiment is supposed to provide insight on few assumptions. your "experiment" provides no insight (or at least none offered from you) on a lot of unstated and stated assumptions.
I did define my rules, and the only way theromodynamics and relativity have "fallen" so far that all you want to do is parrot back completely unmodified definitions of terms that my premises are clearly and admittedly going to play with. When a completely predictable collision occurs between the starting assumptions and rigid definitions, you say "See! It fails!"
By no means am I certain that what I'm thinking of will work in any sense of the word "work", but I was hoping for something a whole lot more interesting out of the discussion than inflexible repetition of rules that are broken, with no curiousity expressed about what room there might be to play with those rules and still come out with some kind of new consistency.
this is final. you didnt define your rules. none of them. you have "predictable" collisions with every known theory of the universe that has supporting evidence out there. You cannot just randomly select the few things that could still agree and say "see, some of it is still there". You dont learn a damned thing working this way. Your wonderful properties that come out of a convoluted series of assumptions, have to jive with all that is known -- not theories but actual observations. You are like a string theorist. No you are worse. You are proposing an entirely untestable theory (like string theorist) that disbands everything before it without any evidence (like no one else). Einstein didnt work in a vacuum. Shetline evidently does.
What the hell do you think you are going to accomplish? Do you want to explain thermodynamics then in your new plane of reality? How a frame can carry properties?
Good god. I have just wasted my time trying to convince someone that they can't just toss aside parts of tested theories which do not line up with their pet theory. Worse, you havent offered a solution at all to these problems merely an "eh, it works/doesnt work; its all the same".
I am not being rigid. I accept that these theories probably do not explain all things but they certainly hold more water than your leaking dingy does.
This guy (Jason W. Hinson) also discusses a clever idea I hadn't thought of for saving more of relativity than my idea does: An FTL "field" of finite size and scope, that could be created as needed in an area where you want to use FTL communication or travel, that could be in motion relative to other such fields (so long as they don't overlap), so there wouldn't have to be any special, universal preferred frame.
Edit: By the way, even using localized FTL fields that don't drag a universal preferred frame into the picture, you'd still have the problem that time coordinates of FTL events occurring within such a field, when translated into other frames of reference, could end up with "cause" and "effect" running backward in time.
Originally posted by billybobsky
You are like a string theorist. No you are worse.
Worse than a string theorist! Oh, no!
You are proposing an entirely untestable theory (like string theorist) that disbands everything before it without any evidence (like no one else). Einstein didnt work in a vacuum. Shetline evidently does.
Wow, you're taking this way too seriously.
You seem to think I'm seriously proposing some huge revolution in physics, and, damn it, how dare I have such affrontary with so little to offer for it!
All I'm interested in is whether it's even imaginable to mix FTL with what we know about the real world. Something good enough for good hard sci-fi would be good enough for me here. I'm not shooting for a Nobel Prize.
What the hell do you think you are going to accomplish?
Getting your blood pressure up?
Do you want to explain thermodynamics then in your new plane of reality?
I don't think in any practical sense thermodynamics would be too much different than the way it's defined now. Consider this:
From [url=http://www.cchem.berkeley.edu/~chem130a/sauer/outline/secondlaw.html]Second Law of Thermodynamics (a Berkely chem web page):
The laws of thermodynamics were determined empirically (by experiment). They are generalizations of repeated scientific experiments. (emphasis mine)
My guess -- and it's only a guess -- is that talk about universal entropy results from a reasonable extrapolation of experimental data, but I doubt that there's any practical experimental way to even tell the difference between a universe in which entropy is only guaranteed to decrease in one frame particular frame (the contention that I'd have to make), and one in which it decreases in all frames -- as best as you can tell with locally available data.
How a frame can carry properties?
I'm not proposing that a frame carries any properties. The initial concept was of a physical artifact that had the ability to send FTL messages within itself. The physical artifact of the lattice is the thing that has the FTL-sending property. That artifact also has a frame of reference.
Still fanciful, but somewhat less so because it wouldn't be an artificial object, is an "FTL aether". The aether has the ability to act as a medium for FTL messages. The aether has a frame of reference. FTL messages are bound to move forward in time with respect to the frame of the aether because FTL is a property of the aether, not because it's a property of the frame.
within current theories FTL signaling cannot occur. You lose much in the way you define FTL signaling, including the laws of thermodynamics (some of which are generalizations from experiments (but so were/are maxwell's equations) and some of which can be derived from first principles). Relativity says nothing of the practicality of measuring something, if we can measure entropy in a closed box, we can measure entropy in the universe for all intents and purposes. Regardless, if we accept your principle that FTL signaling is possible and violations of all sorts of physical laws DO NOT affect basic physical principles (which to me is paradoxical, but fine...) I don't think this changes anything since we just assumed that everything is a ok.
But for the sake of argument, lets say in a special universe -- your artifact if you will (because it is perverse to me to say this is a frame), FTL is allowed and that these signals could be sent to our universe (but nothing can be sent to it sorry we cannot give up thermo where we are and expect a quality discussion). I am still stumbling here. I want to tell you that signaling could work but I also realize that without us being able to send a signal into the void there is no chance for us to actually acquire useful information. I have to resist the urge to toss out thermo because it really is the best thing since water drop torture. We have to make another assumption that would allow cross talk, our universe is not adiabatic, that is entropy tends to increase with time in a larger globalverse (or some other sci fi ish thing) but our universe can behave like a local non-adiabatic systems so long as entropy in the entire globalverse (of which the FTL universe is not a part) increases -- we can even say there is a tendency for the localverse to have increasing entropy with time but it is not a requirement. So lets say we can talk to the FTLverse, this involves of course a decrease in our universe's entropy but it is made up for a gain of entropy in some other localverse within the globalverse basically we are burning our library's books so we can read those that remain. This can only last so long, so what the hell, we are probably going to die before we cannot increase the entropy of the globalverse anymore. Then yes, this would be a useful way of communicating (in fact shetline since we don't have to send the signal in linear space we can talk to ourselves without having to move in space-time except for epsilon). But there are so many assumptions here and that bothers the scientist in me (which is all of me).
See I can play along.
"In this house, we OBEY the laws of thermodynamics"
Originally posted by billybobsky
one last thing:
"In this house, we OBEY the laws of thermodynamics"
I'm still having trouble seeing where thermodynamics gets so badly broken by this restricted form of FTL that it implies, as you seem to be saying, a totally alien universe.
Let's start with a colloquial statement of the laws of thermodynamics (because frankly, I have to admit, my understanding of thermo doesn't go too much further than that):
From http://www.physlink.com/Education/AskExperts/ae280.cfm:
Thermodynamics is the study of the inter-relation between heat, work and internal energy of a system.
The British scientist and author C.P. Snow had an excellent way of remembering the three laws:
1. You cannot win (that is, you cannot get something for nothing, because matter and energy are conserved).
2. You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases).
3. You cannot get out of the game (because absolute zero is unattainable).
I've done some simple mathematics related to the First Law, solving basic classical physics problems by taking conservation of energy into account. I've never touched any equations related to the Second or Third Law.
Your objections seem to be related to the Second Law. I've found some of the basic equations related to the Second Law and entropy online, and, while I didn't understand them very well, the formulations appeared purely classical. I wasn't able to find much of anything relating to relativity and entropy, other than some guy struggling to explain how red shift could be understood in terms of the Second Law. I could find nothing that discussed the relationship between universal entropy and relativistic frames of reference. Anything that you can direct me to regarding these issues would be helpful.
At a simplistic level, I don't see the FTL aether causing dissolved sugar cubes to reform, broken tea cups to leap from the floor and reassemble themselves, or perpetual motion machines to whir away powered by their own waste heat. (All of which can happen in a theoretical sense, with a very, very low order of probability, even if we aren't playing with the current understanding of the rules of the game.)
I'd like make sure we're both very clear on what is meant by the word "now", the very restricted nature of the backward causality you'd get from an FTL aether, and how that would or would not relate to measuring universal entropy.
If you're familiar with standard spacetime diagrams, you know how they are divided up into areas called the "absolute past", the "absolute future", and the "absolute elsewhere". While the word "now" is, in a non-technical sense, is associated with immediacy and current experiences, the "now" of relativity is a very abstract thing -- it's a set of spacetime coordinates which, save the one single point of the observer's location, lies entirely within the "absolute elsewhere". Rather than being an immediately accessible thing, the "now" of relativity is cold and distant, a set of totally inaccessible events, save the single event of the observer's "here and now".
"Now" is also very fickle. The "here and now" follows the motion of the observer, and all of the rest of the observer's "now" swings through spacetime, "pivoting" around the observer's location, cutting a very changeable slice out of all of the events in the absolute elsewhere.
Like I mentioned in an earlier post, just by walking around my own room, I can move a huge entropy-changing event like the supernova explosion of a distant star into my past, future, or present. Are you really, really certain that the current understanding of relativity and thermodynamics takes this into account? I take one step across my room and swoosh... the supernova is in my past, and a huge associated increase of entropy goes onto my balance sheet for the universe's total current entropy, and then, with a small change of direction, I take another step and swoosh, that huge increase in entropy has to be subtracted from my balance sheet, because it hasn't happened yet...
Are you certain that, by this kind of accounting, the total entropy of the universe still goes up, even though in my next small step forward in time, I have to subtract a supernova's worth of entropy from my previous tally?
While I plainly admit to not knowing much of the math here, or what work has been done relating relativity to thermodynamics, thinking about the above kind of situation makes me strongly doubt that any current formulation of the idea "total entropy of the universe" involves the relativistic meaning of "now", and that any normally used accounting of entropy involves events gathered out of the "absolute elsewhere".
Please correct me if these doubts I have are unfounded, and if you can, please point me to any resources you know about that would help clear up my confusion.
As my understanding stands now, it makes much more sense to me if only the "absolute past" of relativity is involved in a relativistic understanding of entropy. And if that's the case, it should be clearly stated that all of the weirdness of the kind of FTL we're discussing never moves information into the absolute past, but only into the past portion of the absolute elsewhere.
Its not that sugar cubes will spontaneously reform if FTL were allowed, its that in some frame the signal is moving backwards and this signal is transfering its entropy to a prior time otherwise the signal implicitly carries no information. This loss of entropy from the latter universe to the prior universe is a break from thermodynamics unless the universe is not adiabatic (meaning a closed system). And even then, sending entropy backwards to another part of a larger universe would still break thermo so the FTL "frame" needs to be outside of the highest adiabat.
Think of it this way: there is a rule on the conservation of mass-energy that you will agree upon. I send back a signal that weighs 25 g. That means the universe gains 25 g of weight in the prior universe and loses it when i send it back. It is not that mass-energy is conserved over time -- it is that it is strictly conserved. This brings other problems into the playing field though.
Originally posted by billybobsky
The laws of thermo are frame independent (invariant). Only a few equations need modification to allow for translation between frames, but the laws in and of themselves remain the same. Einstein actually assumed this was the case, IIRC, and it turns out it is... (i think there are strange results with temperature -- i mean what does temperature mean at the speed of light)
You can have frame independence without implying anything about whether or not events in the "absolute elsewhere" have to be taken into consideration.
This makes it important to know if any of the procedural definitions for how universal entropy would be measured, be they realistic laboratory experiments or hypothetical exercises, involve more than what data can be gathered by an observer from that observer's absolute past.
Are you sure that goings-on in the absolute elsewhere actually matter to how universal entropy would be measured? If such events don't matter, it seems to me that an FTL aether only upsets the purity of a particular conceptualization of forward time.
With the version of FTL under discussion, an observer's measurement of universal entropy would remain frame independent as long as that measurement were only dependent on events available within the observer's absolute past.
As for whether or not the universe would start "leaking entropy"... it's not like the entropy you're worried about would be vanishing out of thin... thin aether?
my ignoranti understanding of the thermo laws would make it that there is no over-arching frame but always a frame beyond . . . . or in deconstructive terminolgy: always another text that the text referrs to, and another to that.
and the same with relativistic speeds except that light is constant no matter what frame you regard it from.
But that wouldn't foreclose any possibilities . . .
excuse the physics pleb . . . *he grasps for clouds*
How it is measured is completely irrelevent.
You moving around doesn't change the entropy of the universe at a point, it changes the entropy you percieve in your limited definition of perception. What I am saying is that throw perception aside, fundamentally the laws of thermodynamics apply in all frames which implies that the measure of universal entropy in two different frames at the same time should be the same. Another way to say this which does not involve tossing perception behind is using the here and now but the answer is still the same, the measurement of entropy at the same space-time point should be the same -- that means if a frame of reference was traveling at 0.5 c intersects a frame traveling at 0.00002 c, at that precise moment at the precise point they intersect if we measure universal entropy in one frame it should be identical to that measured in the other frame. So, yes, what happens in the elsewhere matters.
Accounting for entropy is not the problem -- if your universe appears to lose entropy in any frame (which means those frames that detect your FTL signal as going backwards in time) then the whole universe has to lose entropy.
The conservation of mass issue is a far more intuitive way of dealing with this problem and suggests that even a "frame" external to everything doesnt make fundamental sense. Basically your thought doesn't work. It doesn't get you anywhere. It ties you down...
Originally posted by Wrong Robot
Worship is weird.
Heheh.
Indeed it is kind of strange. All forms of worship seem to involve this sort of latent self-doubting thing, whereby one must profess to "not be good enough" in some respect or another, and thus ask that which is being worshipped for more wisdom / guidance / talents in such regards.
Whatever happened to that whole non-boastful confidence thing? "I think I can, I think I can?"
PS - sorry to derail, I realize there are some pretty good posts in the last couple pages about thermo and entropy and all, but the above quote in response to a similar-minded one by Groverat was kind of humorous.
... and, i ventured to fugure, a seemingly implied consequence of this thought would be that you could not have a "universal frame"
also, wouldn't different frames imply different relationships to the entropy at hand and therefor imply different measuring techniques each with a different draw upon the energy at hand?