Thread: The God's eye view

It has been pointed out to me several ties that there can be no God's-eye-view of science - principally the mechanics of Spacetime and Special Relativity.

I wonder where this point of view, this 'law' is derived from.

It seems strange to me for surely, the God's-eye-view, is precisely the one that one takes in investigating scientific theories?

Did the Big Bang Theory depend on where it was viewed from?

Can you explain what you mean by "God's eye view"?

In terms of relativity, I guess it could refer to an absolute or preferred frame of reference. For cosmology, looking at the universe from "outside". Is that the sort of thing you mean?

Or is it about the process of science itself? Expecting science to tell us The Truth, which (arguably) is not its purpose. Or just trying to be objective?

It is a term that was used in another thread: viz:

Originally Posted by SpeedFreek

There is no possible frame of reference from which the lightning strikes were both simultaneous on the train and simultaneous on the embankment. Or to go further, even if you find a highly convoluted frame of reference in which they are both simultaneous, there will be a third frame where they are not. You cannot find a frame of reference where the events are simultaneous in all other frames of reference, so there is no absolute simultaneity.

There is no "gods-eye view" of the experiment. All you are doing is mixing frames of reference.

So what I was wondering is whether this is some accepted principle that I was unaware of,or just one persons way of expressing themself?

I assume it is just SpeedFreek's analogy for the ability to see all frames of reference simultaneously (which obviously can't be done: "you cannot find a frame of reference where the events are simultaneous in all other frames of reference").

But isn't that just stating that events can't be simultaneous in all frames?

i.e. that time is not absolute?

Which leads me to question how can it not be absolute if it is a single dimension?

For a single dimension may be represented as a single line, straight or otherwise, yet each point on that line has a single value of displacement from the origin and, therefore, points in that dimension have a fixed order and a fixed displacement from any other point.
And no matter where or how they are viewed that order and those displacements can never change, so how is it not absolute?

Please note this is not another theory it is a request for an explanation of something I am trying to get my head round.

Originally Posted by space at the centre

But isn't that just stating that events can't be simultaneous in all frames?

i.e. that time is not absolute?

Which leads me to question how can it not be absolute if it is a single dimension?

For a single dimension may be represented as a single line, straight or otherwise, yet each point on that line has a single value of displacement from the origin and, therefore, points in that dimension have a fixed order and a fixed displacement from any other point.
And no matter where or how they are viewed that order and those displacements can never change, so how is it not absolute?

Please note this is not another theory it is a request for an explanation of something I am trying to get my head round.

Nice analogy - and using that same analogy it's easy to show that there can't be an absolute:
(This is just my take on it, so corrections are welcome).
If we have a single (finite) line - that we see the ends of - we know where the end points are and can use those as a reference, if the line is infinitely long (or as close to as makes no difference - i.e. we cannot define those end points in any way - "no centre" of the universe for example) then any point on that line is as valid as a reference point as any other.
You can't refer to end points because you don't know where they are (or if there actually are any), so you are automatically deprived of any absolute reference.

Originally Posted by space at the centre

But isn't that just stating that events can't be simultaneous in all frames?

Absolutely.

Which leads me to question how can it not be absolute if it is a single dimension?

(You appear to be in a state of quantum superposition where you both get this and don't get it at the same time!)

You gave a really nice description in another thread, in terms of rotation. As you rotate "between" the spatial and time dimension then they each change in apparent length. What you do when you observe one frame from another is effectively map their (rotated, from your PoV) dimensions on to yours; that is what the Lorentz transform describes. This is what causes the displacements between points on the line to be different between different observers.

The important point about this is there is no one frame you can say is "right" or "true". That is all that "no absolute time" means. Everyone will see their own single time dimension as being true and correct, and all other frames of reference dilated with respect to it. You can't step outside of all frames of reference and say, "aha, this is the "real" time dimension." (Which, I guess, is another way of expressing the God's-eye view metaphor.)

ETA: A similar question came up an another forum, where a poster wrote (I hope this isn't inappropriate):

Originally Posted by Buzi Blue

For most of my life my imagining of space-time has been hugely influenced by the brilliant Lewis Carrol-Epstein diagrams. I was fortunate enough to read this book from a local library, it is now very rare indeed. To picture our velocity through time (and space) very easily, look at this diagram:

http://www.relativity.li/en/epstein2/read/c0_en/c3_en/

Taken from this website, which explains most of Epstein's original ideas:
http://www.relativity.li/en/epstein2/read/

In essence, we always travel through space-time at velocity c. The only thing that ever changes is the direction, the more we deflect away from the time axis then the more we move along the spatial axis, with a consequently decrease in velocity through time (as seen from another frame). To us though, we always feel we are moving only through time (non-accelerating).

Incidentally, Epstein diagrams are the only ones I know of that illustrate how gravity bends space-time. Most of us are familiar with the rubber mat model, but that is only half the story. Gravity bends time, and it is so easy to picture this with no more than a paper cone. But that is another matter.

http://cosmoquest.org/forum/showthre...77#post2099777

Very interesting but what about proper time?

The time experienced or measured by a standard clock in its own Frame of reference, i.e. one that is not moving.

Time is changed, dilated (distorted?) when measured by a moving observer, when the relative velocity becomes a factor used in the formula for calculating time dilation.

All inertial Frames may be considered at rest, when viewed from their own native observers at rest in those said frames.

And does all scientific laws being the same in all inertial frames, not imply that proper time is the universal measurement, for all non moving frames? That time dilation is merely an effect found in the measurement of relative movement?

I too like the Epstein diagrams, yet it seems confusing that he talks of using only one space dimension viz: " We represent only one direction in space, the one in which the two reference systems move relative to each other"; yet then goes on to draw that one dimension as two lines that cross!

Can time have a different orientation in each of two relatively moving systems?
Does time have a direction? As points along a line are the moments in time, and that line can be any shape without affecting the single dimension, how can it have an orientation?

It seems to me that time must be orthogonal to all three spatial dimensions ye can have no direction itself.

I must emphasis that these are just the inferences that I perceive from what I read, from these di

Originally Posted by space at the centre

And does all scientific laws being the same in all inertial frames, not imply that proper time is the universal measurement, for all non moving frames?

There's the problem.
How do you determine which frame is non-moving?
There is no absolute rest, thus you can't say that any given frame is "actually" stationary.

Originally Posted by space at the centre

Very interesting but what about proper time?

The time experienced or measured by a standard clock in its own Frame of reference, i.e. one that is not moving.

Well, as everyone will measure proper time as "1 second per second" (if that even means anything) by definition, then I suppose you could consider that to be "real" time. But so what. No two frames of reference will agree on it (or on who is stationary) so what is the point of giving it that label.

Originally Posted by Dywyddyr

Originally Posted by space at the centre

And does all scientific laws being the same in all inertial frames, not imply that proper time is the universal measurement, for all non moving frames?

There's the problem.
How do you determine which frame is non-moving?
There is no absolute rest, thus you can't say that any given frame is "actually" stationary.

I refer you to Minkowski in his Time and Space where he states:
The substance existing at any world point can always be conceived to be at rest, if time and space are interpreted suitably.

I.e. any frame may be considered at rest, or moving depending on how (from where) it is viewed.

And as all basic scientific laws are the same in any inertial frame, then each inertial frames may be taken to be at rest and all others moving.

As you say no frame is actually stationary for without any determined framework, static point nor boundaries for Spacetime the concept of a frame being 'actually' stationary is meaningless; the state of 'rest' is a convenience for our consideration of Spacetime.

Any 'movement' can only be relative.

Originally Posted by Strange

Originally Posted by space at the centre

Very interesting but what about proper time?

The time experienced or measured by a standard clock in its own Frame of reference, i.e. one that is not moving.

Well, as everyone will measure proper time as "1 second per second" (if that even means anything) by definition, then I suppose you could consider that to be "real" time. But so what. No two frames of reference will agree on it (or on who is stationary) so what is the point of giving it that label.

(If all the basic scientific laws are the same- 1st Postulate - so must the conditions prevailing in every inertial frame )

And as noted by Einstein:

When two clocks arranged at rest in different places of a reference-body are set in such a manner that a particular position of the pointers of the one clock is simultaneous ... with the same position of the pointers of the other clock, then identical “settings” are always simultaneous ... .

Therefore standard clocks, all absolutely identical and under identical conditions, will keep identical time; therefore one second measured on one clock, will have exactly the same magnitude as one second, measured on any other identical clock.

(and if times are identical, so must lengths be identical between frames, each measured by observers at rest within each frame. Einstien's first postulate must apply to units of measurement as it does to all basic scientific laws.)

And is it not true therefore that observers, at rest within each inertial frame, viewing their frame to be at rest, will measure their own 'proper time', in seconds of identical magnitude?

These points seem to me to be simple logical deductions, which don't in any way change relativity, merely displacing some of the fog that surrounds aspects of it.

Originally Posted by space at the centre

Therefore standard clocks, all absolutely identical and under identical conditions, will keep identical time; therefore one second measured on one clock, will have exactly the same magnitude as one second, measured on any other identical clock.

(and if times are identical, so must lengths be identical between frames, each measured by observers at rest within each frame. Einstien's first postulate must apply to units of measurement as it does to all basic scientific laws.)

This seems to be where you have a tendency to slip from understanding proper time (or length) as being local to a frame of reference to giving it some sort of metaphysical "reality".

I get the impression that you understand and even accept relativity, but you can't get away from the idea that there must be some underlying "real" time, which then seems to lead you into misunderstanding or misinterpretation...

Originally Posted by space at the centre

Therefore standard clocks, all absolutely identical and under identical conditions, will keep identical time; therefore one second measured on one clock, will have exactly the same magnitude as one second, measured on any other identical clock.

Yep.
But, just because those clocks agree can you say that they are the "zero reference" or does it simply mean that they are co-moving (if that's a word).
If I have a billion clocks moving at 0.9c relative to us should we accept that our reference frame is "outnumbered" a billion to one and conclude that their reference frame (and time flow) is the "real" one?

Originally Posted by Strange

Originally Posted by space at the centre

Therefore standard clocks, all absolutely identical and under identical conditions, will keep identical time; therefore&nbsp;<em>one second measured on one clock, will have exactly the same magnitude as one second, measured on any other identical clock.<br></em><br>(and if times are identical, so must lengths be identical between frames, each measured by observers at rest within each frame. Einstien's first postulate&nbsp;<strong>must</strong>&nbsp;apply to units of measurement as it does to all basic scientific laws.)

<br><br>This seems to be where you have a tendency to slip from understanding proper time (or length) as being&nbsp;<strong>local to a frame of reference</strong>&nbsp;to giving it some sort of metaphysical "reality". &nbsp;

No, not 'reality' so much as 'commonality' in that measured under identical conditions they will be measured in units of the same magnitude.<br><br>

I get the impression that you understand and even accept relativity, but you can't get away from the idea that there must be some underlying "real" time, which then seems to lead you into misunderstanding or misinterpretation...

<br><br>

Originally Posted by Dywyddyr

Originally Posted by space at the centre

Therefore standard clocks, all absolutely identical and under identical conditions, will keep identical time; therefore <em>one second measured on one clock, will have exactly the same magnitude as one second, measured on any other identical clock.</em>

Yep.<br>
But, just because those clocks agree can you say that they are the "zero reference" or does it simply mean that they are co-moving (if that's a word).<br>
If I have a billion clocks moving at 0.9c relative to us should we accept that our reference frame is "outnumbered" a billion to one and conclude that their reference frame (and time flow) is the "real" one?

<br>
<br>
Nope, because what I am seeing is that the time measured locally (I want to say 'natively'?) in each frame by an observer at rest in that frame is the same as the time I measure in my frame. Their time is dilated to my measurement only because they are moving relative to me.<br>
<br>
And I am not by any means saying that time is 'real time' - it is no more than a common time, measured under identical conditions; i.e within an inertial frame.<br>
<br>
In Spacetime no frame is moving any more than any other frame. IF there is some absolute state of rest in Spacetime we have absolutely no way of determining what that state of rest is. All frames are equal as far as we are concerned. <br>
<br>
Every frame can make measurements of quantities that are at rest relative to it, or that are moving relative to it. Just those two states.<br>
<br>
So measurements are either Rest measurements or Moving measurements if Rest they are Proper Measurements and of equal magnitude to any other similarly measured proper units; whereas if moving they are Lorentz Transformed measurements that are a function of the Lorentz Factor.<br>
<br>
It seems to me there can only be those two classes of measurement; Rest or Moving; two sets of common measurements.

Originally Posted by space at the centre

No, not 'reality' so much as 'commonality' in that measured under identical conditions they will be measured in units of the same magnitude.

But, because they are in different frames of reference, you never test that "commonality" by putting the clocks next to each other. So the fact we think they tick "at the same" rate is actually meaningless. All you can do is observe relative values or rates of change (and apply the Lorentz transform).

But unless one can say that when measured from within a frame, measured natively, - as I put it - the units are the same, the Lorentz transforms mean nothing! How can you say that a time has been dilated by the Lorentz Factor unless you are using the same units? How can you determine that time or distance has been dilated/contracted if they are using units that don't relate? For in that case dilation/contraction becomes meaningless?

The fact - or conclusion - that there are different quantities of units means nothing unless the magnitude of those units is related.