The Age of the Universe

[lpetrich]

A co-moving reference frame is what I'd tried to describe earlier. The age of the Universe is thus defined in terms of its co-moving-frame time. So it has a well-defined value.

[jamest]

You really need to get to grips with General Relativity theory if you are going to make sense of current observations. A co-moving frame of reference is sometimes referred to as a 'god's-eye view' of the observable universe. However, there is another frame of reference, from 1 dimension 'above' or 'beyond' the 'normal' 3-d of space + 1-d of time, from which the view is even clearer.

I'm hoping that you can explain this better to laymen, please.

[hackenslash]

Did you bother to read the linked Wiki? It explains it quite nicely. The idea of the comoving observer provides an objective inertial frame, because it places the observer in a neutral position with regard to a fixed reference, namely the isotropy (uniformity in all directions) of the CMB. Put simply, any observer that is in motion relative to the CMB will experience red-shift of the CMB in one direction and blue-shift in the other. By fixing the observer as static with reference to the isotropy of the CMB, a properly fixed frame of reference is obtainable. This makes a universal inertial frame, distinct from the relativistic idea that each observer has equal claim to being at rest.

As mentioned by newolder above, you really need to get to grips with general relativity if you want to have any hope of understanding this. Without the grounding in GR, the notion of a comoving observer is going to give you problems.

[jamest]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

[cowiz]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

Honestly? And remember, Jesus will cry if you're lying.

[jamest]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

Honestly? And remember, Jesus will cry if you're lying.

Dude, I'm not 'a Christian'. I'm trying to find answers to something that rationally puzzles me. And for that, I'm being hounded.

[cowiz]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

Honestly? And remember, Jesus will cry if you're lying.

Dude, I'm not 'a Christian'. I'm trying to find answers to something that rationally puzzles me. And for that, I'm being hounded.

No. you're being hounded for appearing disingenuous - you might want to work on that

[jamest]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

Honestly? And remember, Jesus will cry if you're lying.

Dude, I'm not 'a Christian'. I'm trying to find answers to something that rationally puzzles me. And for that, I'm being hounded.

No. you're being hounded for appearing disingenuous - you might want to work on that

You might want to work on your paranoia, too.

[cowiz]

Okay, but that's why I'm here, enquiring from those of you in the know, so as to improve my knowledge and try and find reasonable answers to my questions.

Honestly? And remember, Jesus will cry if you're lying.

Dude, I'm not 'a Christian'. I'm trying to find answers to something that rationally puzzles me. And for that, I'm being hounded.

No. you're being hounded for appearing disingenuous - you might want to work on that

You might want to work on your paranoia, too.

I think you mentioned "hounded" - you're not too good at this are you?

[newolder]

You really need to get to grips with General Relativity theory if you are going to make sense of current observations. A co-moving frame of reference is sometimes referred to as a 'god's-eye view' of the observable universe. However, there is another frame of reference, from 1 dimension 'above' or 'beyond' the 'normal' 3-d of space + 1-d of time, from which the view is even clearer.

I'm hoping that you can explain this better to laymen, please.

Do you have any specific questions related to the wiki link? The co-moving frame is very useful.

... If one divides a comoving distance by the present cosmological time (the age of the universe) and calls this a "velocity", then the resulting "velocities" of galaxies or quasars can be above the speed of light. This apparent superluminal expansion is not in conflict with special or general relativity, and is a consequence of the particular definitions used in cosmology. Note that the cosmological definitions used to define the velocities of distant objects are coordinate dependent - there is no general coordinate independent definition of velocity between distant objects in general relativity (Baez and Bunn, 2006). The issue of how to best describe and popularize the apparent superluminal expansion of the universe has caused a minor amount of controversy. One viewpoint is presented in (Davis and Lineweaver, 2003). ...

The other frame I mentioned is purely imaginary, so far, although it is grounded in a well-known, mathematical extension to relativity theory first proposed by Theodor Kaluza & related to the geometry of Oskar Klein in the early 20th century.

In physics, Kaluza–Klein theory (KK theory) is a model that seeks to unify the two fundamental forces of gravitation and electromagnetism. The theory was first published in 1921 and was proposed by the mathematician Theodor Kaluza who extended general relativity to a five-dimensional spacetime. ...

The idea of an extra, compact dimension of space helps one imagine our 3-d as an embedding therein (e.g. like Randall's 'drops on a shower curtain') – the notion of time from GR theory then helps one understand the dynamics in this larger realm. It's great fun but may be disproved as an aspect of observed reality in the days to come, who knows?