Time and space

[Strange]

52 minutes ago, argo said:

THE one dimension of time, did you miss this? Take this one dimension of time that you say i made up and add three dimensions of space for spactime to have four dimensions, same dumb argument every time, stop compartmentalizing.

One dimension of "now" doesn't mean there is a single "now" any more than the spatial dimensions mean there is a single "here".

53 minutes ago, argo said:

If you're saying now is being fused with every point in space then it is purely a time model of relativity, not a spacetime model with a four dimensional continuum but one point with one dimension at a time.

I am not saying that because it is incoherent gibberish. 

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it is purely a time model of relativity, not a spacetime model

Space-time IS the model of relativity.

Reported for trolling.

[studiot]

3 hours ago, argo said:

Apologies for not answering studiot i will later.

Thank you, I will await with interest.

I assume the rest of your post referred to your 'discussion' with Strange.

Perhaps I can pour some oil here because I think you two are talking at cross purposes.

The reason is simple.

One way of looking at simultaneity in the four dimensional continuum you mention is to plot isolines (contours) of constant time coordinate.
 

The problem is that these contours are different when viewed from every point in the continuum.
That is you have as many different statements of 'now' as the are points in the continuum.

Worse you have no reason to accept any one of these as 'the rightone' or 'the best'.

 

This is the same chain of reasoning that leads to the idea that there is no absolute frame of reference.

[Strange]

17 minutes ago, studiot said:

One way of looking at simultaneity in the four dimensional continuum you mention is to plot isolines (contours) of constant time coordinate.
 

The problem is that these contours are different when viewed from every point in the continuum.
That is you have as many different statements of 'now' as the are points in the continuum.

Worse you have no reason to accept any one of these as 'the rightone' or 'the best'.

Thanks you. That is an image I had in my mind but wasn't sure how to put it into words....

[argo]

6 hours ago, Strange said:

One dimension of "now" doesn't mean there is a single "now" any more than the spatial dimensions mean there is a single "here".

Relativity says now is relative, there can only be one now at a particular time/dimension. Now can not be in two places at the same time any more than you can. Every point, here and now exists at a different time, this is what relativity is telling us. Your right if you use the old non-relativistic model but this is compartmentalization if we are referring to relativity.

 

6 hours ago, Strange said:

7 hours ago, argo said:

If you're saying now is being fused with every point in space then it is purely a time model of relativity, not a spacetime model with a four dimensional continuum but one point with one dimension at a time.

I am not saying that because it is incoherent gibberish. 

You quoted a blank then called it jibberish. (edit- look at the top of page 5, strange quoted me with an empty box but when i saved this came up, that's weird.)

Ok so you say every point is NOT fused with now, i disagree and so does relativity, happens with compartment thinking.

3 hours ago, Strange said:

  2 hours ago, studiot said:

One way of looking at simultaneity in the four dimensional continuum you mention is to plot isolines (contours) of constant time coordinate.

Pre 1905 we had non-relativistic classic 3+1 space and time, along comes Einstein with a completely new concept of space and time called relativity, but instead of  a completely new model for space and time that comes directly from the new concept we retrofit the old one. 

Relativity says now is relative and if you build the model from what relativity tells you every point must exist in it's own dimension/time. When the car came along we got rid of the horse and cart, spacetime is a horse pulling a car.

6 hours ago, Strange said:

Quote

it is purely a time model of relativity, not a spacetime model

Space-time IS the model of relativity.

Reported for trolling.

According to you a retrofitted spacetime model is the unquestionable truth and anyone who says different is a troll? 

The truth is relativity, the model of space and time must come from this source alone and not be retrofitted, fused or anything else. Now is relative, begin here without baggage.

Now is relative and this models a one dimensional realtime not a four dimensional spacetime.

Edited July 27, 2018 by argo
quoted box was empty when i replied

[beecee]

25 minutes ago, argo said:

Relativity says now is relative, there can only be one now at a particular time/dimension. Now can not be in two places at the same time any more than you can. Every point, here and now exists at a different time, this is what relativity is telling us. Your right if you use the old non-relativistic model but this is compartmentalization if we are referring to relativity.

No, you are contradicting yourself...There is no universal now, period. This is goverend and dictated by the universal maximum finite speed of light.

 

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Pre 1905 we had non-relativistic classic 3+1 space and time, along comes Einstein with a completely new concept of space and time called relativity, but instead of  a completely new model for space and time that comes directly from the new concept we retrofit the old one.

 yes, space and time [henceforth known as spacetime] is relative, that is not constant, not universal, but depended on other factors and frames of references governed by those factors.

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Relativity says now is relative and if you build the model from what relativity tells you every point must exist in it's own dimension/time. When the car came along we got rid of the horse and cart, spacetime is a horse pulling a car.

No. relativity says that space and time are relative, that is not fixed, not constant, not universal.

 

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According to you a retrofitted spacetime model is the unquestionable truth and anyone who says different is a troll? 

 perhaps some maybe getting trolling confused with ignorance.

 

 

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Now is relative and this models a one dimensional realtime not a four dimensional spacetime.

 Again, from where I sit, you appear to be contradicting yourself, and the standard accepted, observable and evidenced based model. 

[Markus Hanke]

7 hours ago, argo said:

Now is relative and this models a one dimensional realtime not a four dimensional spacetime.

What it models is 4-dimensional Minkowski spacetime, which is precisely - you guessed it - Special Relativity.
What are you hoping to achieve by denying the basics of one of the most studied and well-tested model in physics? This is standard undergrad stuff.

[Strange]

8 hours ago, argo said:

Relativity says now is relative, there can only be one now at a particular time/dimension. Now can not be in two places at the same time any more than you can. Every point, here and now exists at a different time, this is what relativity is telling us.

Relativity says nothing of the sort. Most of that makes no sense. 

You seem to be basing your argument on almost total ignorance of relativity. 

8 hours ago, argo said:

Ok so you say every point is NOT fused with now

I don’t even know what that means. Does it mean anything?

 

8 hours ago, argo said:

but instead of  a completely new model for space and time that comes directly from the new concept we retrofit the old one. 

Nonsense. The space time  model (ie relativity) is completely different from the old concept of space and separate absolute time. 

8 hours ago, argo said:

if you build the model from what relativity tells you every point must exist in it's own dimension/time.

Nonsense. This is just ignorant nonsense that you are inventing. 

8 hours ago, argo said:

According to you a retrofitted spacetime model is the unquestionable truth and anyone who says different is a troll? 

There is no truth in science. 

Your problem is that you just repeat the same empty baseless claims with no evidence. 

Either show us your alternative model or shut up. 

[swansont]

9 hours ago, argo said:

 Pre 1905 we had non-relativistic classic 3+1 space and time, along comes Einstein with a completely new concept of space and time called relativity, but instead of  a completely new model for space and time that comes directly from the new concept we retrofit the old one. 

Relativity reduces to Newtonian physics for low speeds (or low precision of measurement) so you are stuck with having to accommodate that. Since relativity works insanely well, the problem is...what, exactly?

9 hours ago, argo said:

 Now is relative and this models a one dimensional realtime not a four dimensional spacetime.

"Now" is a Newtonian concept. Why are you trying to retrofit it into relativity?

[geordief]

1 hour ago, swansont said:

 

"Now" is a Newtonian concept. Why are you trying to retrofit it into relativity?

Is a universal "now" more of a philosophical idea? How could it be defined in physical terms (as a devil's advocate)?

[Eise]

15 minutes ago, geordief said:

Is a universal "now" more of a philosophical idea?

No. It is a practical concept in daily use. Like 'here'. Both have no meaning without any context. Both are called 'indexicals' in linguistics and philosophy.

And, alas, there is nothing that corresponds with it in physics.

The idea of 'universal here' does not make sense already in classical physics. The idea of a a 'universal now' would mean that all watches in the universe agree on the time, and have the same pace. Since special relativity we know this idea does not make sense either.

Edited July 28, 2018 by Eise

[Markus Hanke]

13 minutes ago, geordief said:

Is a universal "now" more of a philosophical idea? How could it be defined in physical terms (as a devil's advocate)?

It can’t, because no such thing exists.
The best you could possibly do is use the notion as an approximation in a small local region, for slow speeds and low energies. For example, the inhabitants of Madrid and Barcelona could very roughly be said to share the same “now”, since they are close together and presumably are not in the habit of moving at relativistic speeds wrt to each other.

[Strange]

23 minutes ago, geordief said:

Is a universal "now" more of a philosophical idea? How could it be defined in physical terms (as a devil's advocate)?

It seems to me that there are two ways this could be interpreted in physics.

It could mean that one could define a standard time that is used throughout the universe such that when it is 5 o'clock in Guildford, it will also be 5 o'clock in Xrx!z in the Android galaxy (and everywhere else). We know this is not possible in the real (relativistic) universe.

The other is that every observer would agree about when events happened. So if Alice in New York thinks that A happened at the same time as B then Bob in the ISS would agree. We know this is not how the universe works either.

The fact that neither of these apply comes down to the same reason: the nature of space-time as described by relativity.

[geordief]

8 minutes ago, Eise said:

No. It is a practical concept in daily use. Like 'here'. Both have no meaning without any context. Both are called 'indexicals' in linguistics and philosophy.

And, alas, there is nothing that corresponds with it in physics.

The idea of 'universal here' does not make sense already in classical physics. The idea of a a 'universal now' would mean that all watches in the universe agree on the time, and have the same pace. Since special relativity we know this idea does not make sense either.

What if (erroneously) no account were taken of relative motion or gravitational  attraction?

 

In that unrealistic scenario all  synchronized clocks would agree for ever  ,wouldn't they? 

 

A universal now   could not be disproved then.....

[studiot]

33 minutes ago, geordief said:

Is a universal "now" more of a philosophical idea? How could it be defined in physical terms (as a devil's advocate)?

 

The whole point I was making, geordie, is not there there is a shortage of 'nows' or none, but that there are too many!

And they are all equally valid.

The same goes for 'heres'

23 minutes ago, Eise said:

No. It is a practical concept in daily use. Like 'here'. Both have no meaning without any context. Both are called 'indexicals' in linguistics and philosophy.

And, alas, there is nothing that corresponds with it in physics.

The idea of 'universal here' does not make sense already in classical physics. The idea of a a 'universal now' would mean that all watches in the universe agree on the time, and have the same pace. Since special relativity we know this idea does not make sense either.

Thank you for telling me this Eise, something I have learned today. +1

It also supports my oft contended statement that there is nothing you can say in mathematics you can't also say in English, but there are plenty of things the other way round.

[Eise]

50 minutes ago, geordief said:

In that unrealistic scenario all  synchronized clocks would agree for ever  ,wouldn't they? 

You mean if relativity were not true?

Well, if you take the finite speed of light into account, a 'universal now' would mean that all clocks show the same time for a local observer, but not for a remote one: if I could see a clock in the Andromeda nebula, I would see it running 2 Million years behind. But if I take the distance the light must travel into account (2 Million lightyears), I could conclude that it shows the same time as my clock. And that independent of the velocity of the Andromeda nebula. It would be impossible however, to set the clocks in such a way that everybody sees all clocks having the same time: when all the clocks show the same time for me, they do not for anybody else. So I cannot see a universal now, but I can conclude that a universal now exists.

But of course, relativity does away with this.

So yes, a universal now is disproved.

Edited July 28, 2018 by Eise

[geordief]

22 minutes ago, Eise said:

You mean if relativity were not true?

 

If we stripped Relativity's core predictions out of our expectations (a misguided  "thought thought" experiment,perhaps)...or in the heat death scenario perhaps

[dimreepr]

19 minutes ago, geordief said:

If we stripped Relativity's core predictions out of our expectations (a misguided  "thought thought" experiment,perhaps)...or in the heat death scenario perhaps

A universal now is a seductive concept it seems so real, but only if you could freeze spacetime. 

[swansont]

6 hours ago, geordief said:

Is a universal "now" more of a philosophical idea? How could it be defined in physical terms (as a devil's advocate)?

At best, it would have to be, since in science we are constrained by how nature behaves. It's similar to the circular orbits of the Bohr model.  You might use them as a stepping-stone to understanding, but they don't exist. We know the model is wrong.

[argo]

REALTIME

Spacetime says every point is a different point at the same time.

Realtime says every point is ITSELF at different times.

According to relativity now is relative, there can’t be two nows at the same time so relativity is saying now is ITSELF at different times.

 Quantum mechanics says things that exist now are both particle like and wave like.

At any one moment now is ALL that exists and particle like, but over any measured time it is ALL the points being measured.

 

[beecee]

50 minutes ago, argo said:

Spacetime says every point is a different point at the same time.

Relativity tells us that spacetime is a continious metric: The finite speed of light dictates that there is no universal now. Intervals of space and time vary depending on frames of references and associated properties such as speed and gravity and are not the same for different observers.

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 Realtime says every point is ITSELF at different times.

Every person/individual in any frame of reference, will always see his or her time pass at one second per second, period. And yes, that is real and valid time.

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At any one moment now is ALL that exists and particle like, but over any measured time it is ALL the points being measured.

Everyone has his or her own interpretation of NOW, but there is no universal now that can be applied to any other frame of reference.

[Markus Hanke]

6 hours ago, argo said:

Spacetime says every point is a different point at the same time.

Spacetime is the set of all points in space at all instances in time, along with the geometric relationships between these.

[Strange]

8 hours ago, argo said:

Spacetime says every point is a different point at the same time.

That makes no sense. 

8 hours ago, argo said:

Realtime says every point is ITSELF at different times.

That doesn't make much sense either. At different times, a point is itself? Huh?

8 hours ago, argo said:

According to relativity now is relative, there can’t be two nows at the same time so relativity is saying now is ITSELF at different times.

There can be two "nows", if by that you mean that two different observers can share the same frame of reference. 

Your language is so vague as to be meaningless. It is not clear what you are trying to propose. You need to provide a concrete, ideally mathematical, description. Not these ambiguous references to "points", "now", "itself", etc.

8 hours ago, argo said:

Quantum mechanics says things that exist now are both particle like and wave like.

I don't why "now" is in that sentence. Quantum mechanics describes things in terms of wave functions. They also have certain characteristics of particles. 

Note that quantum field theory is built on relativity, which, given the incredible accuracy of quantum theory, is yet more evidence that relativity is correct and you are wrong.

8 hours ago, argo said:

At any one moment now is ALL that exists

That may be true (it is not clear what it means) but that "now" can be different for different observers.

 

[geordief]

1 hour ago, Strange said:

 

That may be true (it is not clear what it means) but that "now" can be different for different observers.

 

Is it at all possible to talk about an observer at the origin of the creation of any system?

 

Admittedly we cannot say that there was a "point"  when our universe was created (although it seems a respectable theory that the universe naturally arose from "nothing"**) but if we posit that such a point (prior to the BB) did exist  could we in theory consider this point as the origin of a frame of reference?

 

Might the same logic be applied to any subsets of  this primordial system?So when  Archduke Ferdinand was assassinated can we set that occurrence  (see how  I skirted around calling it an "event") at that point in space and time to  be somehow privileged as a frame of reference for everything causally connected to it?

 

**respectable in that I have often heard it suggested ,even if I didn't myself understand why it might be so.

Edited July 31, 2018 by geordief

[studiot]

26 minutes ago, geordief said:

Is it at all possible to talk about an observer at the origin of the creation of any system?

A virtual observer 'looking/working backwards through the chain of events' perhaps.

Such an observer would not need to be at the point of the BB, so long as she could calculate correctly.

28 minutes ago, geordief said:

Admittedly we cannot say that there was a "point"  when our universe was created (although it seems a respectable theory that the universe naturally arose from "nothing"**) but if we posit that such a point (prior to the BB) did exist  could we in theory consider this point as the origin of a frame of reference?

No because we do not (can not) know the motion of that point relative to subsequent events.

29 minutes ago, geordief said:

Might the same logic be applied to any subsets of  this primordial system?So when  Archduke Ferdinand was assassinated can we set that occurrence  (see how  I skirted around calling it an "event") at that point in space and time be somehow privileged as a frame of reference for everything causally connected to it?

That is what light cones are all about.

Note that light cones only encompass points directly causally connected.

Each such point will have its own light cone, which may encompass points both within and outside the original cone so establishing a chain of events is tricky to say the least.
Perhaps Marcus may be able to offer more about that.

[geordief]

2 minutes ago, studiot said:

 

No because we do not (can not) know the motion of that point relative to subsequent events.

Yes I think I  see that. A  potentially privileged FOR but completely constrained  for the purposes of making any actual measurements?