Please Demonstrate
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25-11-2014, 02:44 PM (This post was last modified: 25-11-2014 02:48 PM by Free.)
RE: Please Demonstrate
(25-11-2014 02:28 PM)cjlr Wrote:  What I did explicitly state was that "age" does not mean what you think it means in a cosmological context. "Distance" does not mean what you think it means in a cosmological context. Naive human intuition is not useful at such scales. This is an extremely important thing to acknowledge, but you seem very reluctant to do so.

I am reluctant to do so because there has been no good example of an alternative view of age and distance for me to draw reference from. I have checked your link.

I can understand how space expansion can skew time and distance; I have no problem understanding this at all.

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25-11-2014, 02:59 PM
RE: Please Demonstrate
(25-11-2014 10:52 AM)Free Wrote:  
(25-11-2014 10:34 AM)cjlr Wrote:  First problem: nobody assumes the expansion happened at a uniform 10c.

So right away, this isn't speculating based on evidence, it's groundless hypothetical freewheeling...


See above. That is not what anyone supposes. If anyone did so suppose then they might - might - reach that conclusion. But they don't.


Due not only to metric expansion, but relativistic effects in general, to say the age or distance of objects on cosmological scales does not mean what you - on pure naive intuition - might think it does. Human intuition cannot describe phenomena on a cosmic scale.

We have two primary measures for distant objects (and that's distance in spacetime, not either/or). One is redshift, and the other is luminosity - simply put, the "farther" a ray of light has travelled, the dimmer it gets. Certain astronomical phenomena always occur at the same intensity at source, and so their relative apparent brightness is a very powerful measure.


That is what cosmological redshifting is.

If the space over which a ray travels is expanding then the ray must expand with it. This decreases its frequency - visible light moves towards the red end of the spectrum (hence, you know, redshifting). Most observation occurs at other wavelengths in any case, but the principle is the same.

But my point was that some scientists do theorize that expansion happened faster than the speed of light. The 10 X scenario was just for illustrative purposes to demonstrate that the observable universe may not be anywhere near the age it is theorized to be.

Yes, during the inflationary epoch which lasted a tiny fraction of a second.
"The inflationary epoch lasted from 10⁻³⁶ seconds after the Big Bang to sometime between 10⁻³³ and 10⁻³² seconds."

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25-11-2014, 03:18 PM
RE: Please Demonstrate
(25-11-2014 02:44 PM)Free Wrote:  
(25-11-2014 02:28 PM)cjlr Wrote:  What I did explicitly state was that "age" does not mean what you think it means in a cosmological context. "Distance" does not mean what you think it means in a cosmological context. Naive human intuition is not useful at such scales. This is an extremely important thing to acknowledge, but you seem very reluctant to do so.

I am reluctant to do so because there has been no good example of an alternative view of age and distance for me to draw reference from. I have checked your link.

... but that's just presuppositional. "I won't accept B instead of A because I don't accept B".

There are multiple ways to discuss "distance" (really: separation in spacetime) between cosmological objects, and precisely none of them correspond closely to the naive macroscopic personal experience of individual human beings.

It would be like asking "where" an electron is. It does not have a "position" as understood by your intuition. Period. End of story.

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25-11-2014, 04:30 PM (This post was last modified: 25-11-2014 04:55 PM by Free.)
RE: Please Demonstrate
(25-11-2014 03:18 PM)cjlr Wrote:  
(25-11-2014 02:44 PM)Free Wrote:  I am reluctant to do so because there has been no good example of an alternative view of age and distance for me to draw reference from. I have checked your link.

... but that's just presuppositional. "I won't accept B instead of A because I don't accept B".

Actually, I am reluctant to accept "theory A" because "theory A" has not been demonstrated.

In other words, if you are asking me to accept that- in the context of this cosmological discussion- distance and time cannot be understood by standard means, then I require the/an alternate example to draw a reference from. I need something- an example- which proves that conventional thinking absolutely cannot be applied.

Unless of course your meaning is still theoretical? If so, it demonstrates nothing.

Quote:There are multiple ways to discuss "distance" (really: separation in spacetime) between cosmological objects, and precisely none of them correspond closely to the naive macroscopic personal experience of individual human beings.

What is so difficult about understanding separation in spacetime? Depending on the rate of expansion in certain areas some objects (A & B) will separate from each other more quickly than others (C & D).

Unless I am missing something, I don't understand where the mystery is.

Quote:It would be like asking "where" an electron is. It does not have a "position" as understood by your intuition. Period. End of story.

Yet you can determine its trajectory and make a reasonable calculation as to where it will be at a given time, no? This allows us to calculate where it "was" at a certain point in time, but not where it actually is. But Heisenberg's Uncertainty Principle also comes into play, and I understand we cannot know everything about the electron at once, due to momentum and position.

But that is only the current state of our knowledge. In the future, i see no problem determining the exact position of an electron.

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26-11-2014, 10:54 AM
RE: Please Demonstrate
(25-11-2014 04:30 PM)Free Wrote:  
(25-11-2014 03:18 PM)cjlr Wrote:  ... but that's just presuppositional. "I won't accept B instead of A because I don't accept B".

Actually, I am reluctant to accept "theory A" because "theory A" has not been demonstrated.

In other words, if you are asking me to accept that- in the context of this cosmological discussion- distance and time cannot be understood by standard means, then I require the/an alternate example to draw a reference from. I need something- an example- which proves that conventional thinking absolutely cannot be applied.

The Global Positioning System - GPS.
The clocks on the satellites run more slowly than stationary clocks on earth. The times reported must be adjusted for the relativistic time dilation.

So, no, common sense notions of time and space are not true descriptions of reality.

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26-11-2014, 11:00 AM
RE: Please Demonstrate
(25-11-2014 04:30 PM)Free Wrote:  Yet you can determine its trajectory and make a reasonable calculation as to where it will be at a given time, no?

No. It does not have an orbit or trajectory in the sense you mean. It is validly viewed as a standing wave.

Quote:This allows us to calculate where it "was" at a certain point in time, but not where it actually is. But Heisenberg's Uncertainty Principle also comes into play, and I understand we cannot know everything about the electron at once, due to momentum and position.

No. Since we didn't know both its position and velocity then, we can't know it now.

Quote:But that is only the current state of our knowledge. In the future, i see no problem determining the exact position of an electron.

That paper says no such thing. It says electrons will be trapped as a plasma - we still can't know their position and velocity. Heisenberg still rules.

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26-11-2014, 01:17 PM
RE: Please Demonstrate
(25-11-2014 04:30 PM)Free Wrote:  
(25-11-2014 03:18 PM)cjlr Wrote:  ... but that's just presuppositional. "I won't accept B instead of A because I don't accept B".

Actually, I am reluctant to accept "theory A" because "theory A" has not been demonstrated.

And "theory A" here is relativity.

One of the best-attested and most fundamental physical theories we have ever proposed and tested.

Whether you accept it or not is of course your prerogative. There are those out there who choose not to accept evolution.

(25-11-2014 04:30 PM)Free Wrote:  In other words, if you are asking me to accept that- in the context of this cosmological discussion- distance and time cannot be understood by standard means, then I require the/an alternate example to draw a reference from. I need something- an example- which proves that conventional thinking absolutely cannot be applied.

Unless of course your meaning is still theoretical? If so, it demonstrates nothing.

The precepts of relativity are testable and have been tested. Many times. With great precision and accuracy and in great detail.

Chas has mentioned GPS satellites as an example. General relativity describes distortion of spacetime due to gravity; to be farther from a center of gravity (ie, the Earth) then affects relative flow of time between that frame of reference (ie, in orbit) and another (ie, on the surface). The two disagree.

And in fact we use atomic clocks to map the gravitational structure of the Earth itself, so senstitive are they.

(25-11-2014 04:30 PM)Free Wrote:  
Quote:There are multiple ways to discuss "distance" (really: separation in spacetime) between cosmological objects, and precisely none of them correspond closely to the naive macroscopic personal experience of individual human beings.

What is so difficult about understanding separation in spacetime?

I don't know; you're the one who seems determined not to?

(25-11-2014 04:30 PM)Free Wrote:  Depending on the rate of expansion in certain areas some objects (A & B) will separate from each other more quickly than others (C & D).

Unless I am missing something, I don't understand where the mystery is.

What do you mean by "separation"?

Do you mean instantaneous separation? Because that's meaningless - there's no such thing as instantaneity. Do you mean separation when the initial interaction occurred? Perhaps when light was emitted from a distant object? Do you mean separation when we receive that light? Do you mean how far the light has travelled? Do you mean how far the light has travelled if we neglect the cosmological metric expansion?

So no. The sort of "separation" as understood in "my desk is two metres away" is in no way comparable to the separation as contained in the sentence "a quasar is 8 billion light years away".

(25-11-2014 04:30 PM)Free Wrote:  
Quote:It would be like asking "where" an electron is. It does not have a "position" as understood by your intuition. Period. End of story.

Yet you can determine its trajectory and make a reasonable calculation as to where it will be at a given time, no?

Not as such. It does not have a classical trajectory either. That intuitive understanding of motion exists within the same inapplicable macroscopic understanding.

(25-11-2014 04:30 PM)Free Wrote:  This allows us to calculate where it "was" at a certain point in time, but not where it actually is. But Heisenberg's Uncertainty Principle also comes into play, and I understand we cannot know everything about the electron at once, due to momentum and position.

Indeed we cannot know everything; this is because fundamental excitations exist as probabilistic distributions and not pointlike objects.

To be somewhat simplistic, the fundamental uncertainty relation (between any two non-commuting quantum observables, not just the canonical position/momentum case) dictates that the uncertainty (which is not experimental uncertainty, but rather the fundamental "spread out" nature of the quantum distributions) is in a sense uncompressible. If one reduces the spread in one basis (position) then the spread in the conjugate basis (momentum) increases.

(25-11-2014 04:30 PM)Free Wrote:  But that is only the current state of our knowledge. In the future, i see no problem determining the exact position of an electron.

... but that article has nothing to do with the uncertainty principle?
(it's about high-intensity lasers - examining the radiation reaction energy at the relativistic limit; emitting high-energy radiation by conservation of momentum affects behaviour, and if the emission is counter the otherwise prevailing motion there's a net localising effect)

Trapping electrons is a thing, yes - it's essentially what any semiconductor does. They cannot be arbitrarily localised due to their quantum nature.

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26-11-2014, 01:27 PM
RE: Please Demonstrate
(26-11-2014 11:00 AM)Chas Wrote:  
(25-11-2014 04:30 PM)Free Wrote:  But that is only the current state of our knowledge. In the future, i see no problem determining the exact position of an electron.

That paper says no such thing. It says electrons will be trapped as a plasma - we still can't know their position and velocity. Heisenberg still rules.

But my point being that since they were trapped in a confined area, then we know for a certainty where they are; in the confined area.

Are they not in a measurable area when trapped in a confined space?

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26-11-2014, 01:45 PM
RE: Please Demonstrate
(26-11-2014 01:27 PM)Free Wrote:  But my point being that since they were trapped in a confined area, then we know for a certainty where they are; in the confined area.

Are they not in a measurable area when trapped in a confined space?

...

(26-11-2014 01:17 PM)cjlr Wrote:  Trapping electrons is a thing, yes - it's essentially what any semiconductor does. They cannot be arbitrarily localised due to their quantum nature.

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26-11-2014, 02:29 PM
RE: Please Demonstrate
(26-11-2014 10:54 AM)Chas Wrote:  
(25-11-2014 04:30 PM)Free Wrote:  Actually, I am reluctant to accept "theory A" because "theory A" has not been demonstrated.

In other words, if you are asking me to accept that- in the context of this cosmological discussion- distance and time cannot be understood by standard means, then I require the/an alternate example to draw a reference from. I need something- an example- which proves that conventional thinking absolutely cannot be applied.

The Global Positioning System - GPS.
The clocks on the satellites run more slowly than stationary clocks on earth. The times reported must be adjusted for the relativistic time dilation.

So, no, common sense notions of time and space are not true descriptions of reality.

Can the reason for the slower speed be explained via conventional thinking?

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