Higher dimensions and my scepticism.

[Daniel Foreman]

There is a lot of talk about higher dimensions, and this is a very misunderstood concept in science fiction. Too often I hear dimensions and alternative universes lumped into the same thing. They are not the same thing at all! Dimensions are in fact the most mundane and boring thing in the universe. Dimensions are simply the space in which we live. Our up, and down, left and right, forward and backward. So next time you hear about someone slipping into a set of parallel dimensions and discovering a whole new world. Just giggle and shake your heads at them, because they are quoting one of Science fictions biggest crimes towards public misunderstanding.

 

I in no way believe that you can slip through a higher dimension, (that’s higher as in higher than the usual 3. X Y and Z), and suddenly find yourself in an alternative universe, or alternative reality. That’s not how the universe works to my mind. What you can do, according to popular theory, is move through a higher dimension at one point in space and appear at another point in space. The general idea is that space is curved in ways we can not see, and by hopping through a higher dimension we are taking a short cut.

 

I personally don’t have much time for this either. From pure observation I know that just because I walk to my left, I can’t expect to be any closer to an object in front of me. In fact if I'm centred onto an object and move right then I am in fact increasing the distance between myself and my target. So why, from this piece of observational evidence should I assume that moving through a higher dimension can suddenly move me closer to my target? To my mind this makes little to no sense, as I can not square it with my day to day observations.

 

I understand where this concept comes from. The idea of a wormhole puts the individual on a curved planet, walking along the radius of that planet may seem like a straight line, when in fact the real straight line is to burrow through the surface of the planet to reach your target. But this has nothing to do with dimensional space. It’s the same old 3 dimensions it’s just that you’re walking on a curved planet to begin with. The original though example involved being a 2 Dimensional being with no concept of a 3rd dimension. But again we're not aware of such a creature, and the example falls flat when faced with the real world.

 

Higher dimensions were originally created to make some very advanced very clever mathematics work, but when you have to start making up evidence to make mathematics fit the observed result I have to question that mathematics validity in the first place. It may predict a few specific things, but it may predict those things in completely the wrong way. For example if I point to my left to indicate an object to the right of me, technically if you walk along the surface of the planet in the direction I indicate you'll eventually find the object on my other side. But it's a hell of a trek to go see an objects 5 cm to my right

 

So ultimately I don't square my day to day observations with the idea of this of higher dimensional space because apart from anything I can not see them. One might point out that I can't see radio waves, or even the air around me either. But the difference is that I can detect these things, and they are pretty obviously operating within the usual 3 dimensions.

[ajb]

Higher dimensions were originally created to make some very advanced very clever mathematics work, but when you have to start making up evidence to make mathematics fit the observed result I have to question that mathematics validity in the first place.

 

Higher dimensions in physics, in the sense we mean here, goes back to the works of Nordström, Kaluza and Klein who attempted to unify gravity and electromagnetism in a 5 dimensional version of general relativity. This was all published in the 1920s.

 

Today one large motivation for extra dimensions is string theory. The key is that only in 10d can the quantum theory of super strings be formulated without a kind of "sickness" known as anomalies. Basically an anomaly is when a classical symmetry does not survive the quantisation process (usually the regularisation is the trouble). This is not necessarily a problem for global symmetries, but for local ones this spoils the quantum theory. For example, note that gauge symmetry is vital in the quantisation of Yang-Mills theories. In the context of string theory this goes back to Michael Green and John H. Schwarz (1984).

 

 

So ultimately I don't square my day to day observations with the idea of this of higher dimensional space because apart from anything I can not see them. One might point out that I can't see radio waves, or even the air around me either. But the difference is that I can detect these things, and they are pretty obviously operating within the usual 3 dimensions.

 

This may be true of extra dimensions: they have observable effects in our 4d world.

 

Some possible examples include:

1. Large extra dimensions, the Randall–Sundrum model and Brane cosmologies attempt to explain the weakness of gravity as compared to the other forces. In essence, gravity can "leak" into these extra dimensions.
2. Superstring compactifications on Calabi–Yau manifold could explain the particle zoo and their phenomenology. Possibly the signal of extra dimensions could be found at the LHC. Unexpected excited quark states could be due to extra dimensions, for example.
3. Electroweak symmetry breaking, could be due to extra dimensions if the scale of the dimensions are comparable to the weak scale.

And I am sure there are many other things that people think about, all unverified, but give the possibility of detecting extra dimensions.

[Daniel Foreman]

Thank you that was a very interesting response, I'll look up the works you've described and have a read.

 

Regarding your examples of your observable effects within our (I assume you mean 3D world) I would have these brief comments.

 

1. How does one define large or small extra dimensions. With X Y and Z I presume you would define these by detecting the edge of the universe and then seeing how far beyond even that you can go until some kind of barrier is reached. I understand this idea of gravity operating at a higher dimension and somehow "filtering down to us", and it's a compelling idea as to why gravity is so much weaker than the other forces. I think this is a very clever answer. But it assumes that every force has to be the same strength, or more importantly exert the same kind of pleasures upon matter. Is it not equally possible that the matter which we observe simply presents greater resistance to gravity much like a resistor inserted into a circuit. Is it not also possible that that natural resistance simply expels gravity as some other kind of force, for example the small nuclear force that binds these things together? After all we observe gravity indirectly by the behaviour of matter rather than by detecting or dealing with the field directly.

 

2. If the LHC provides compelling evidence of extra dimensions I will be the first to get on board with it, but until such time it's not something I'll take as written fact.I would also point out that again we are detecting these particles and emissions within our usual 3 Dimensions.

 

3. Again I see this more as an error in our understanding rather than a demonstrating of higher dimensions. Again if anyone every shows me a repeatable experiment with a clear conclusion demonstrating higher dimensions, and even better a practical day to day use for it then I will certainly take a very practical interest in it!

 

Oh I absolutely do not in any way discount extra dimensions, but I mostly view it as a way of getting certain mathematical examples to work which may simply be the wrong approach.

[ajb]

Regarding your examples of your observable effects within our (I assume you mean 3D world) I would have these brief comments.

No, I do mean 4 dimensional. We have time also.

 

1. How does one define large or small extra dimensions.

Mathematically it means that every point in the "bulk" requires more than 4 numbers to specify it in a given coordinate system. The question is then why do we not directly observe these extra dimensions, assuming they exist? This leads to the notion of compactification or brane worlds.

2. If the LHC provides compelling evidence of extra dimensions I will be the first to get on board with it, but until such time it's not something I'll take as written fact.I would also point out that again we are detecting these particles and emissions within our usual 3 Dimensions.

To my knowledge there has been no experimental evidence of extra dimensions from CERN. This we agree on.

3. Again I see this more as an error in our understanding rather than a demonstrating of higher dimensions. Again if anyone every shows me a repeatable experiment with a clear conclusion demonstrating higher dimensions, and even better a practical day to day use for it then I will certainly take a very practical interest in it!

I am not very familiar with the idea that electroweak symmetry breaking could be due to extra dimensions, all I know is that people have thought about this.

... but I mostly view it as a way of getting certain mathematical examples to work which may simply be the wrong approach.

This is certainly possible.

[Daniel Foreman]

Quote: "No, I do mean 4 dimensional. We have time also."

 

I've discussed this quite a bit in http://www.scienceforums.net/topic/71644-what-is-time-does-time-even-exist/

 

Time as a dimension of space has not been demonstrated. With X Y and Z you can go forward, backwards, left, right, up and down at will. Time does not behave in this way, we can go forward and that's it.

 

If time is a separate entity, or dimension my question is, why does it affect matter within X Y and Z. After all, if I move an object along the X axis, it doesn't affect it's position along the Y and Z axis. The dimensions are something that are clearly separate from each other. The idea is as I understand it, is that time controls the speed and direction upon which everything moves, like a train on a rail way track, you can reverse the train and go back to a previous state of the universe or go forward into the future.

 

As far as I'm concerned this doesn't fall into what we observe with the first 3 Dimensions. If X, Y and Z do not affect one another, why should time affect the movement of matter within X Y and Z?

 

No time to my mind doesn't exist. Motion within the universe (again it's motion that we use to create time, time doesn't create motion) exists, so time is a man made tool it's not a fundamental force or dimension of the universe, and there's no observable evidence that says otherwise.

 

This can further be demonstrated by other models of time working in pockets or zones moving and different rates, heck even the idea that time slows down for the crew as they approach lightspeed seems unlikely to me, it's more likely that as matter approaches light speed it's own motion becomes sluggish. Heck for all we know the spacecraft might hit a maximum possible velocity and end up compressing itself into a very thin dense sheet.

 

But I digress. as these things have not been demonstrated, including this forth dimensional stuff as time as the forth dimension doesn't exist in any demonstration. But it does make for good time travel science fiction

 

 

 

Quote: "Mathematically it means that every point in the "bulk" requires more than 4 numbers to specify it in a given coordinate system. The question is then why do we not directly observe these extra dimensions, assuming they exist? This leads to the notion of compactification or brane worlds."

 

 

Again this is part of string theory, and it's a very nice idea but my problems with these extra dimensions, including time are the following.

 

1) Why are these extra dimensions so different from X Y and Z and so unobervable?

2) Why does time as a dimension behave so differently and have such a controlling factor in the matter within X Y and Z

3) If strings are a complicated "knot" of dimensions and this forms matter, how come X Y and Z aren't soild themselves, why do they not exhibit matter like qualities?

 

Quote: "To my knowledge there has been no experimental evidence of extra dimensions from CERN. This we agree on."

 

Yay! It's nice when I can agree with someone for a change (one does start to wonder if they are simply insane when no one can relate, lol).

 

 

 

Quote: "I am not very familiar with the idea that electroweak symmetry breaking could be due to extra dimensions, all I know is that people have thought about this."

 

 

Fair enough, clearly I'm no great expert either.

Edited December 18, 2012 by Daniel Foreman

[Delta1212]

Time isn't a dimension of space, it's a dimension of spacetime. It's a temporal dimension and shouldn't be thought of as behaving the same exact way as a spacial dimension. It's good to be incredulous and it definitely helps to form a better understand a subject if you continuously question parts of a subject that don't make sense to you until you figure out either how they work or why exactly they're broken. I would raise two points to keep in mind, however.

 

First, day to day experience is a very bad predictor of how things actually work on levels that we don't experience day to day, and since much of our instinct and intuition about how the world works on a fundamental level were build from experiences rooted entirely in a narrow band of universal experience in terms of speeds, sizes and energies, they're not necessarily going to operate very well when we start probing elements outside of that band (i.e. very small things, very fast things, very hot things, and very cold things). It's important to remain skeptical if you want to understand things, but it's equally important to remain open to the idea that things which don't seem to make sense might nevertheless be true.

 

Second, and possibly more important, is the fact that much of the "conceptual" element of physics is couched in analogies and language that is either imprecise or precisely means something very different than it does in a normal context because we haven't had enough experience with a lot of the concepts being described for us to have developed a day-to-day vocabulary capable of properly describing them. Imagine a zookeeper trying to describe an elephant to someone who has never seen an animal other than a dog. The zookeeper's options are limited to either saying he cares for elephants, which will be exactly accurate but entirely meaningless to the person in question, or else he has to talk about caring for very large dogs with huge ears and long noses, which is a lot more meaningful to the person in question but significantly less accurate and still quite unlikely to communicate exactly what is going on.

 

My point here is that it's important to realize that there are actually a number of ways to conceptualize a lot of the high concept physics in a way that is consistent with what is observed, and in a few cases in ways that may not even be distinguishable in any way, but that most of these conceptions are flawed in some way because they are attempts to describe phenomena that we have no real experience with in familiar, or at least somewhat familiar, terms. This means it's important to try to understand what is actually being described without getting to hung up on the idea that a dog with a ten foot nose is a ridiculous notion that doesn't make sense. The best way to do this is to understand the math involved, but not everyone has the time, inclination or aptitude to do that for all areas of science that they're interested in. Where that's the case, we need to take into account that we're often speaking to people who have actually seen the elephant, and that if what they're saying doesn't make sense, it's as likely to be an issue in communicating the concept to someone who hasn't as it is to be an issue with the idea itself.

[swansont]

 

I've discussed this quite a bit in http://www.scienceforums.net/topic/71644-what-is-time-does-time-even-exist/

 

Time as a dimension of space has not been demonstrated. With X Y and Z you can go forward, backwards, left, right, up and down at will. Time does not behave in this way, we can go forward and that's it.

 

Unconstrained motion is not a requirement. That dimensions be orthogonal to each other is.

 

Here is a demonstration that time is orthogonal to (i.e. independent of) the spatial coordinates: I will draw an X on a surface, indicating a spatial point. You place your hand there, and I will swing a sledgehammer. The hammer can hit your hand or not, depending on the time coordinate, i.e. when your hand is there matters as much as where your hand is. It is independent of the spatial coordinates.

 

Any collision is a demonstration of this.

[ajb]

Again this is part of string theory, and it's a very nice idea but my problems with these extra dimensions, including time are the following.

 

1) Why are these extra dimensions so different from X Y and Z and so unobervable?

2) Why does time as a dimension behave so differently and have such a controlling factor in the matter within X Y and Z

3) If strings are a complicated "knot" of dimensions and this forms matter, how come X Y and Z aren't soild themselves, why do they not exhibit matter like qualities?

These are open questions in string theory.

[Daniel Foreman]

 

Unconstrained motion is not a requirement. That dimensions be orthogonal to each other is.

 

Here is a demonstration that time is orthogonal to (i.e. independent of) the spatial coordinates: I will draw an X on a surface, indicating a spatial point. You place your hand there, and I will swing a sledgehammer. The hammer can hit your hand or not, depending on the time coordinate, i.e. when your hand is there matters as much as where your hand is. It is independent of the spatial coordinates.

 

Any collision is a demonstration of this.

 

 

 

You just described simple motion swansont, not time. You might swing a hammer at my finger, that just makes my finger the destination, motion is not instantaneous it must go through intervening space before it arrives. But that's not time, that's motion. Time only becomes a retrospective tool or a predictive tool when applied after or before the event has happened. We can analyse the movement of the hammer and divide that movement into frames, but the universe isn't made up of frames just because we do that.

 

Again the constant single event happening here is that people typically confuse the hammer for the nail. Or in this case, time for the motion of an object.

 

 

 

These are open questions in string theory.

 

In the case I must wait for someone more clever than I to answer them! While my own thoughts and idea's head off in different directions. I find that simplifying problems more often provides solutions that making things complicated.

 

 

 

Time isn't a dimension of space, it's a dimension of spacetime. It's a temporal dimension and shouldn't be thought of as behaving the same exact way as a spacial dimension. It's good to be incredulous and it definitely helps to form a better understand a subject if you continuously question parts of a subject that don't make sense to you until you figure out either how they work or why exactly they're broken. I would raise two points to keep in mind, however.

 

Yes I've heard the term space-time a lot, again I think it's something that's very mispresented in popular fiction. To me it sounds like a word that basically says "space and time are so close there's really no difference." so again I apply my idea of simplization, if they are so closely related perhaps people are commonly mistaking one for another. Aka again my very repetitive remark that time is a tool devised to understand the motion of matter within the universe, and that people confuse the tool for the subject.

 

 

 

First, day to day experience is a very bad predictor of how things actually work on levels that we don't experience day to day, and since much of our instinct and intuition about how the world works on a fundamental level were build from experiences rooted entirely in a narrow band of universal experience in terms of speeds, sizes and energies, they're not necessarily going to operate very well when we start probing elements outside of that band (i.e. very small things, very fast things, very hot things, and very cold things). It's important to remain skeptical if you want to understand things, but it's equally important to remain open to the idea that things which don't seem to make sense might nevertheless be true.

 

No problem there I'm skeptical of anything I can't test!

 

 

Second, and possibly more important, is the fact that much of the "conceptual" element of physics is couched in analogies and language that is either imprecise or precisely means something very different than it does in a normal context because we haven't had enough experience with a lot of the concepts being described for us to have developed a day-to-day vocabulary capable of properly describing them. Imagine a zookeeper trying to describe an elephant to someone who has never seen an animal other than a dog. The zookeeper's options are limited to either saying he cares for elephants, which will be exactly accurate but entirely meaningless to the person in question, or else he has to talk about caring for very large dogs with huge ears and long noses, which is a lot more meaningful to the person in question but significantly less accurate and still quite unlikely to communicate exactly what is going on.

 

Absolutely, this is the fundamental issue I have when people start talking about time as an entity. I phoned my brother up a couple of hours ago and asked him "What is time?" and he started going on about time being a rope. When I questioned him further his analogy quickly fell apart. Clearly it what something he heard or mishead and then tried to replicate without ever having really thought about it. I've done this myself in the past. I spent quite a long time teaching myself "not to relate these things to bits of real world matter" which is the natural thing for any human being to do! We see a tool like time, and people start saying it's apart of the universe a separate entity, dimension or force. I've come to the conclusion that I have little time for this approach After all, translating any kind of higher dimension down to 3 is going to be a total failure no matter what you try.

 

 

 

My point here is that it's important to realize that there are actually a number of ways to conceptualize a lot of the high concept physics in a way that is consistent with what is observed, and in a few cases in ways that may not even be distinguishable in any way, but that most of these conceptions are flawed in some way because they are attempts to describe phenomena that we have no real experience with in familiar, or at least somewhat familiar, terms. This means it's important to try to understand what is actually being described without getting to hung up on the idea that a dog with a ten foot nose is a ridiculous notion that doesn't make sense. The best way to do this is to understand the math involved, but not everyone has the time, inclination or aptitude to do that for all areas of science that they're interested in. Where that's the case, we need to take into account that we're often speaking to people who have actually seen the elephant, and that if what they're saying doesn't make sense, it's as likely to be an issue in communicating the concept to someone who hasn't as it is to be an issue with the idea itself.

I agree entirely, I think what you said goes back to this habit people have of relating things to 3D Matter. But my biggest issue with anything that goes outside the realm of our observable 3 Dimensions, is that it becomes more an act of imagination than anything anyone can prove let alone use. And if you can't use it, perhaps it doesn't really exist at all?

 

My issue with maths describing things is that it's really only demonstrated itself within the 3D realm, it's a fantastic set of tools for understanding how many pounds of force is required to throw a lead ball six feet. But as yet, I'm not convinced mathematics has the toolkit required to explain how the universe works, and because of his errors in our understanding has given birth to a whole brach of physics that starts telling us there's in fact more space, and more types of space around his then we can detect or see.

Edited December 18, 2012 by Daniel Foreman

[swansont]

Motion cannot be orthogonal to position. They have different units. (Time is reference as ct in 4-space)

[Delta1212]

 

 

You just described simple motion swansont, not time. You might swing a hammer at my finger, that just makes my finger the destination, motion is not instantaneous it must go through intervening space before it arrives. But that's not time, that's motion. Time only becomes a retrospective tool or a predictive tool when applied after or before the event has happened. We can analyse the movement of the hammer and divide that movement into frames, but the universe isn't made up of frames just because we do that.

 

Again the constant single event happening here is that people typically confuse the hammer for the nail. Or in this case, time for the motion of an object.

 

 

 

 

In the case I must wait for someone more clever than I to answer them! While my own thoughts and idea's head off in different directions. I find that simplifying problems more often provides solutions that making things complicated.

 

 

 

 

Yes I've heard the term space-time a lot, again I think it's something that's very mispresented in popular fiction. To me it sounds like a word that basically says "space and time are so close there's really no difference." so again I apply my idea of simplization, if they are so closely related perhaps people are commonly mistaking one for another. Aka again my very repetitive remark that time is a tool devised to understand the motion of matter within the universe, and that people confuse the tool for the subject.

 

 

 

 

No problem there I'm skeptical of anything I can't test!

 

 

 

Absolutely, this is the fundamental issue I have when people start talking about time as an entity. I phoned my brother up a couple of hours ago and asked him "What is time?" and he started going on about time being a rope. When I questioned him further his analogy quickly fell apart. Clearly it what something he heard or mishead and then tried to replicate without ever having really thought about it. I've done this myself in the past. I spent quite a long time teaching myself "not to relate these things to bits of real world matter" which is the natural thing for any human being to do! We see a tool like time, and people start saying it's apart of the universe a separate entity, dimension or force. I've come to the conclusion that I have little time for this approach After all, translating any kind of higher dimension down to 3 is going to be a total failure no matter what you try.

 

 

 

I agree entirely, I think what you said goes back to this habit people have of relating things to 3D Matter. But my biggest issue with anything that goes outside the realm of our observable 3 Dimensions, is that it becomes more an act of imagination than anything anyone can prove let alone use. And if you can't use it, perhaps it doesn't really exist at all?

 

My issue with maths describing things is that it's really only demonstrated itself within the 3D realm, it's a fantastic set of tools for understanding how many pounds of force is required to throw a lead ball six feet. But as yet, I'm not convinced mathematics has the toolkit required to explain how the universe works, and because of his errors in our understanding has given birth to a whole brach of physics that starts telling us there's in fact more space, and more types of space around his then we can detect or see.

The issue here is that in many cases we can, and actually do, use a lot more of this stuff that seems like weird hypothetical fantasy than most people realize. The average person may not be able to see and touch this stuff during the course of the day, but that doesn't mean no one is using it.

 

 

For instance, and this is a common example, we have GPS satellites and time dilation. I've seen this cited a lot, and it's a good citation, but I know that because it gets used so frequently, a lot of people mention it without really giving an understandable explanation for what is going on and why the two actually relate other than insisting that they do.

 

GPS satellites work using very, very precise timing. If you send a signal from a satellite to a car's GPS and back again, and you know exactly how fast that signal is travelling, you can time it, see how long it takes, and you will then know how far away that car is from the GPS satellite. If you do this with a number of GPS satellites in different locations, you'll be able to determine what point on the earth is 5 miles from satellite A, 10 miltes from satellite B and 17 miles from satellite C. However, because the signal is traveling very fast, and the distances are, in comparison to cosmic scales, very small, the timers that the satellites use need to be extremely precise. If the time you measure is off by 1/100th of a second, your location is going to be off by close to 2,000 miles. That's not a very accurate positioning system.

 

That means that the satellite clocks have to be very precisely calibrated on scales that, in most human contexts, would be meaningless and certainly would otherwise be completely imperceptible. I can't tell the difference between 1 second and 1.01 seconds, but it makes a huge difference to a GPS satellite.

 

Now, a GPS satellite needs two things to stay in orbit. It needs to maintain a specific height and a specific speed. Special Relativity predicts that an object moving at the speed of the satellite will experience time at a very, very slightly slower rate than if it wasn't moving. Not enough that a human being would even come close to noticing it, but enough to make a big difference to the satellite. It also predicts that, because the gravity field is stronger at the surface of the Earth, we will experience time at a slower rate than something farther away from the surface, so the satellite's clock will run slightly faster than it would otherwise.

 

So you have one affect causing the satellite to run fast and another causing it to run slow. Now, the important thing to realize here is that they don't change the rate of the satellite's clock by the same amount, which means that there is still a difference between the rate of a clock running on a satellite in orbit and a stationary clock located on the ground. Now, I've heard some arguments that there could be numerous reasons for this right on down to simple mechanical issues or design flaws. The problem there is that it would be a remarkable coincidence that every clock loaded onto a satellite experience the exact same failure, by the exact same amount, in the exact same direction every time it was shot into space, and that that error coincidentally coincided exactly with the difference in run times predicted by relativity when the effects of time dilation are taken into account.

 

Now, whether you describe time as slowing down, or objects at high speeds taking more energy to move, or whatever your explanation for why this effect is happening, it doesn't change the fact that it has been observed happening and that there are situations where we need to take it into account in order to get things to work. It's also important to recognize that how you describe the reasons for the effect doesn't really change the fundamentals of relativity, because it is a description of behavior, and the behaviors it predicts have been tested and confirmed. It doesn't require that you believe that time is another spatial dimension that you're traveling through and that you slow down in that dimension as your speed increases in others, or whatever other analogy you prefer, but it does demonstrate that any measurement of time (be it subjective experience, decay rate, the ticking of a clock, whatever) is highly dependent upon relative speed.

 

 

Now, does this relate to higher dimensions? In some sense, yes. When Einstein formulated relativity, we didn't have GPS satellites. Many aspects of the theory didn't become testable until later on, and didn't become useful until even further on than that. We don't yet have the mechanisms available to thoroughly prove or disprove the existence of higher dimensions. Based on how they are formulated, we certainly wouldn't be expected to notice them in our daily lives. Eventually, we'll reach a point where we can adequately test for them, and if they're there, we'll probably find some case where we'll need to work around them when our technology starts bumping into them, the way it has with relativity. If we reach the point where we should be bumping into them and we don't, then we'll do what we've done with most theories that have cropped up throughout history and discard it in favor of something that holds up to what we actually experience.

 

 

The key here is to draw a distinction between things that we've already measured, and things that are possible explanations or consequences of what we know. In the former case, it's certainly true that these things happen, even if it seems counter-intuitive. In the latter case, these things may be true, but we don't know yet. We can't rule them out, which makes dismissing them because they seem weird a less than fruitful idea if they bring something to the table, but they should be treated as an avenue of investigation rather than an accepted fact.

[Daniel Foreman]

The issue here is that in many cases we can, and actually do, use a lot more of this stuff that seems like weird hypothetical fantasy than most people realize. The average person may not be able to see and touch this stuff during the course of the day, but that doesn't mean no one is using it.

 

I don't see or touch radio waves, but they are a part of my day to day existence.

 

 

 

Now, whether you describe time as slowing down, or objects at high speeds taking more energy to move, or whatever your explanation for why this effect is happening, it doesn't change the fact that it has been observed happening and that there are situations where we need to take it into account in order to get things to work

 

I see several possibilities for this kind of error that don't involve time having to become an entity and changing it's properties.

 

The first, and most obvious is an issue of fractions and computers. The standard float point processor supports a double integer, this means it will calculate accurately a number as small as 0.00000000000001 as most GPS systems use ARM or similar processors I can't imagine the device themselves are any more accurate then that. As you are dealing with absolutely tiny numbers, as you say mere hundredths, or thousandths or tens of thousandths of a second.numbers.

 

The speed of light is 186 282.397 mps ​(Miles per second) over the distance of 5 miles it will take 2.684096876850903e-5 that's 0.00002684096876850903 seconds. That last 3, is rounded up from whatever number(s) came after it. when you are dealing with numbers that small how much difference to accuracy does rounding up or down a 3 make? I wouldn't even like to guess!

 

To get around this I imagine the plugin the average accuracy loss as a data set to compensate. But this won't always be effective, so using multiple GPS signals can help reduce the error by averaging the difference between these signals.

 

There's also addition issues of timing, where goes the GPS get it's time from, how does it return time to the main system, is it a matter of a super precise system communicating with an imprecise system?

 

This is what I mean by real world questions and observations. Sure to human perception these fractions of seconds are nothing to us, but the equipment we use to process this stuff is very understandable, they are systems we built after all, and as with any system man has built there is a greater or lesser margin for error. Before people start talking about time dilation and rushing off to say "this supports my theory!" they really need to look at the practical side of things. The fact that there is an error occurring in a man made system doesn't surprise me. I work with computer languages and hardware more than enough to realise they are far from accurate when it comes to scientific solutions. Make no mistake at this level we are completely dependant on the hardware and software solutions required, without trying to complicate the natural laws of the world to boot!

 

I like Einstein work, and I feel much of it has stood up to the test of time because he took real world observations and proceeded to explain them, he explained some things so well that he actually predicted certain things we had not discovered yet. having said that classical mechanics doesn't operate very well with quantum mechanics, Einstein stuff works very well in a macro world but when it comes to the micro world we had to generate the Standard Model to explain things. Much of this unified theory business is an attempt to marry both these systems for predicting under a single set of rules, so one or both systems clearly are not perfect.

 

But there is a difference between Einstein looking to explain real world scientific observations, and string theory which as no real world observation to demonstrate anything.

[swansont]

There's also addition issues of timing, where goes the GPS get it's time from, how does it return time to the main system, is it a matter of a super precise system communicating with an imprecise system?

 

No. It's a matter of a precise system communicating with an even more precise system. GPS satellites have atomic clock on board, and they synch up with their ground station, which gets its time from the DoD's time system, the master clock at the Naval Observatory.

 

AFAIK, the direct clock measurements and comparisons don't involve any floating-point processors doing calculations at all. Data collection and manipulation, sure, but you can suppress the leading zeroes.

[ajb]

 

Yes I've heard the term space-time a lot, again I think it's something that's very mispresented in popular fiction. To me it sounds like a word that basically says "space and time are so close there's really no difference."

That is almost what Einsteinian relativity tells us. You have coordinate transformations that mix space and time and so making a clear unequivocal separation is not really possible. There are of course nice circumstances to take advantage of such as globally hyperbolic space-times.

But as yet, I'm not convinced mathematics has the toolkit required to explain how the universe works...

Of course we do have lots of nice tools, but I doubt many people fully disagree with this sentiment. I believe the development of mathematics, as mathematics, does lead to developments in physics.

[Daniel Foreman]

No. It's a matter of a precise system communicating with an even more precise system. GPS satellites have atomic clock on board, and they synch up with their ground station, which gets its time from the DoD's time system, the master clock at the Naval Observatory.

Sure the GPS Satalites maybe, but what about the cheap tom tom returning the signal. Doesn't that add any kind of timing data. I presume the system has to go "Hey GPS! I'm the satalite." The portable device goes "Hi satalite, I received your communication @ X time, and returned the signal at X time". Phones, tablets, and most GPS systems are using ARM based RISC processors. Their floating point calculations are going to be truncated, and their own time keeping certainly isn't going to be based on an internal atomic clock.

 

So you've got two systems in place here. 1 satalite, with super accurate hardware, and 1 cheap consumer device responding with the signal. Add multiple satalites, and multiple returns and you're going to get an average of the returned error, but again the data isn't going to be as precise as the satalites own data. I imagine the system will have to make some assumptions long the way while doing all of this.

 

In addition to this weather, and solar flares disrupt communications like this. Solar storms can throw off systems and shut down power grids.

 

No there's a lot going on with these systems and I don't think we have to go writing the rules of the universe to point out possible flaws.

 

 

 

That is almost what Einsteinian relativity tells us. You have coordinate transformations that mix space and time and so making a clear unequivocal separation is not really possible. There are of course nice circumstances to take advantage of such as globally hyperbolic space-times.

Yes he used the rubber sheet idea, a weight in the middle of a rubber sheet creating a curve in space that allows for orbits and falling. So essentially that tells me that gravity doesn't exist at all there's only an unseen curve that forms around every bit of matter. You don't have to have "time" for that to work, you only need curved space.

 

But again, I suspect there's something completely different going on here, it's a very nice visual image but gravity is a total mystery. Why is it so much weaker than the other forces. How exactly does it draw two unconnected objects together? There's all sorts of idea's floating around about this but it's not something anyone understands.

 

So again, my approach is to go for the simple mundane answer. We know electromagnetism works on objects both repelling and attracting, so we know forces can work invisibly to draw bits of mater together. I'm pretty sure it's not curving spacetime to do it, otherwise why would it only attract certain arrangements of matter to itself? And if a magnet isn't curving space time to attract things to itself, why the heck should gravity have to start warping the very fabric of space to do it's job?

 

 

Of course we do have lots of nice tools, but I doubt many people fully disagree with this sentiment. I believe the development of mathematics, as mathematics, does lead to developments in physics.

A toolkit is a complete collection of tools. We have lots of individual tools to explain various things, but we don't have the complete toolkit. For all intents and purposes at the moment we're an Engineer trying to pry off the tyre of the universe with nothing but a greasy comb, a number 2 spanner and the tip of a pen

 

I'm sure we'll develop more of the tools as we go along, and when we do there will be a massive shake up of our thinking. At the moment we're peeking under the rim of that universal tyre, but we're certainly no near it's inner-tube!

[ajb]

Yes he used the rubber sheet idea, a weight in the middle of a rubber sheet creating a curve in space that allows for orbits and falling. So essentially that tells me that gravity doesn't exist at all there's only an unseen curve that forms around every bit of matter. You don't have to have "time" for that to work, you only need curved space.

You need to be much more careful than this. The rubber sheet and bowling ball is an analogy and should not be used to analyse general relativity. The analogy gives you a feel for what is going on, but for a proper understanding you need to explore the mathematics.

 

Gravity manifests itself as the curvature of space-time, not just space.

So again, my approach is to go for the simple mundane answer. We know electromagnetism works on objects both repelling and attracting, so we know forces can work invisibly to draw bits of mater together. I'm pretty sure it's not curving spacetime to do it, otherwise why would it only attract certain arrangements of matter to itself? And if a magnet isn't curving space time to attract things to itself, why the heck should gravity have to start warping the very fabric of space to do it's job?

 

Gravity does seem strange in this respect. But, the mathematics that describes classical electromagnetism is identical to that which describes general relativity. Okay the actions are different, but the underlying geometry is similar. One talks about principle bundles, connections and curvatures here. I don't know how much more to elaborate here.

 

 

 

 

Edited December 19, 2012 by ajb

[Daniel Foreman]

You need to be much more careful than this. The rubber sheet and bowling ball is an analogy and should not be used to analyse general relativity. The analogy gives you a feel for what is going on, but for a proper understanding you need to explore the mathematics.

 

Gravity manifests itself as the curvature of space-time, not just space.

I understand that it's an example, not the thing itself. But you're still saying "What is apparently and visually straight, is now curved".

 

So I guess the question is, how do you prove it's curved. I can fire a laser beam between two points and work out if that laser goes between two points without deviation. But how do you prove that laser beam is in face following a curve in space. From all practical observation we know that a laser beam, travelling through empty space will travel in a straight line. So how do you test if that line is in fact curved in ways we don't see? I mean we know light itself can be bent so that we can apparently see certain stars that should be behind the sun. But that doesn't demonstrate that space is curved, and adding time into it seems pretty pointless.

 

Where is the physical experiment demonstrating this?

 

 

Gravity does seem strange in this respect. But, the mathematics that describes classical electromagnetism is identical to that which describes general relativity. Okay the actions are different, but the underlying geometry is similar. One talks about principle bundles, connections and curvatures here. I don't know how much more to elaborate here.

Fair enough. When something seems strange it's just my natural inclination to assume it's wrong. Again I accept that this is a simplistic view, and that I may be wrong myself. But I guess I can only work within my own limitations.

[Delta1212]

I understand that it's an example, not the thing itself. But you're still saying "What is apparently and visually straight, is now curved".

 

So I guess the question is, how do you prove it's curved. I can fire a laser beam between two points and work out if that laser goes between two points without deviation. But how do you prove that laser beam is in face following a curve in space. From all practical observation we know that a laser beam, travelling through empty space will travel in a straight line. So how do you test if that line is in fact curved in ways we don't see? I mean we know light itself can be bent so that we can apparently see certain stars that should be behind the sun. But that doesn't demonstrate that space is curved, and adding time into it seems pretty pointless.

 

Where is the physical experiment demonstrating this?

 

It does, actually. Because there is no difference between starlight and laser light, if you were to travel to one of those stars and point your laser in our direction, that laser would wind up curving around the sun. That curvature must be introduced by a curvature in the geometry of the space that the light is traveling through.

[swansont]

Sure the GPS Satalites maybe, but what about the cheap tom tom returning the signal. Doesn't that add any kind of timing data. I presume the system has to go "Hey GPS! I'm the satalite." The portable device goes "Hi satalite, I received your communication @ X time, and returned the signal at X time". Phones, tablets, and most GPS systems are using ARM based RISC processors. Their floating point calculations are going to be truncated, and their own time keeping certainly isn't going to be based on an internal atomic clock.

 

 

There is no return signal from the receiver. GPS satellites broadcast, GPS receivers receive. You don't need a good clock in the receiver, because you are looking for timing differences that aren't very big, so you don't care what the stability is out past a small fraction of a second, and even a pretty cheap quartz oscillator is fine for that*. If the timing differences are a microsecond (meaning the satellites' distances from the receiver differ by 1000 km), you only need three significant digits to do nanosecond-level calculations. IOW, no big deal.

 

*a part in 10^6 fractional frequency stability for 1 millisecond is a nanosecond-level timing error. At a microsecond or so, this timing error can easily be ignored. Even if the quartz oscillator is worse.

 

 

 

So I guess the question is, how do you prove it's curved. I can fire a laser beam between two points and work out if that laser goes between two points without deviation. But how do you prove that laser beam is in face following a curve in space. From all practical observation we know that a laser beam, travelling through empty space will travel in a straight line. So how do you test if that line is in fact curved in ways we don't see? I mean we know light itself can be bent so that we can apparently see certain stars that should be behind the sun. But that doesn't demonstrate that space is curved, and adding time into it seems pretty pointless.

 

Where is the physical experiment demonstrating this?

 

Eddington, 1919, was the first.

 

Maybe you should do some research into all this before you dismiss it.

[ajb]

Where is the physical experiment demonstrating this?

We have to be very careful here. What we can do in physics is show that a theory agrees well with nature, or not.

 

So, general relativity tell us that space-time is curved. Importantly, we have lots of evidence, both direct and indirect that general relativity is a good theory. That is under lots of circumstances, the theory agrees well with nature. In fact, the only places that I know of where things are not so good is near singularities, so in the centre of black holes or in the very, very early Universe.

 

Thus, mathematically we have a good description of gravity in terms of space-time curvature.

[Daniel Foreman]

Blackholes are one of the biggest myths of modern society. I really have no time or patience for them. Sorry.

 

I can understand how mathematics can produce oddities like black holes if you tweak the numbers enough but I highly doubt they exist in nature no matter how many Gamma ray bursts and X Ray emissions astrologists claim to detect. These are just another invention to fill the holes in theories like this. When you can't explain why something doesn't quite work (aka relativity not quite predicting were everything is in the universe) people just end up inventing something to plug the hole be it Dark Matter, or Dark Force or whatever. Instead of saying "we don't know why it doesn't work" we end up with invented stuff sci-fi writers jump all over becoming the popular culture buzzword.

[Essay]

Blackholes are one of the biggest myths of modern society. I really have no time or patience for them. Sorry.

 

Aren't the observations, which show or "prove" that blackholes exist, enough to conquer your myth about modern society?

[swansont]

Blackholes are one of the biggest myths of modern society. I really have no time or patience for them. Sorry.

 

Argument from personal incredulity, being a logical fallacy, is not found to be very persuasive on a science discussion site.

[elfmotat]

Blackholes are one of the biggest myths of modern society. I really have no time or patience for them. Sorry.

 

I can understand how mathematics can produce oddities like black holes if you tweak the numbers enough but I highly doubt they exist in nature no matter how many Gamma ray bursts and X Ray emissions astrologists claim to detect. These are just another invention to fill the holes in theories like this. When you can't explain why something doesn't quite work (aka relativity not quite predicting were everything is in the universe) people just end up inventing something to plug the hole be it Dark Matter, or Dark Force or whatever. Instead of saying "we don't know why it doesn't work" we end up with invented stuff sci-fi writers jump all over becoming the popular culture buzzword.

 

Your crackpot ideas have no place in the science section.

[J.C.MacSwell]

 

 

When you can't explain why something doesn't quite work (aka relativity not quite predicting were everything is in the universe) people just end up inventing something to plug the hole be it Dark Matter, or Dark Force or whatever. Instead of saying "we don't know why it doesn't work" we end up with invented stuff sci-fi writers jump all over becoming the popular culture buzzword.

Setting aside the rest of your post this last bit may have some merit (IMO), though dismissing best scientific conjectures out of hand simply because they are not on as firm ground as accepted theories is hardly a more rational position.