a peculiar diagram

[michel123456]

This a diagram from another thread

 

fig.2

 

(see the other threadfor explanation)

 

WARNING in the following diagram & explanations, there is a small intentional error. Just in order to enhance argumentation. The error will be corrected afterwards.

 

Now, for the sake of simplicity, let's forget for a while existing Theories, and say that we are living in a stable Universe where nothing moves & nothing expands. Let's pin all these stars & galaxies on a gigantic cardboard. Now, nothing can move. And let's wait till next year, the same epoch, to see what happened.

And here we are, a year has passed, and we look back at our cardboard. What do we see?

We see now the same Galaxies and stars that are 1billion year + 1 year away, because our point of vue moved in time one year.

Something like fig.a

 

Earth has moved from A to B in one year. It appears from Earth that the same stars & galaxies have moved in space only due to time. They moved from the black circle to the blue one. What happened? Did our cardboard expanded, did space expanded? Or is there a catch somewhere?

Of course there is a catch.

Edited December 15, 2010 by michel123456

[Sisyphus]

 

We see now the same Galaxies and stars

 

This is the error.

 

What is the purpose of this thread? A brain teaser?

[michel123456]

the error is that the whole cardboard didn't stay in place, it moved in time with us.

 

To see what happens, let's simplify the diagram and look at it from above.

It becomes something like fig.b

fig.b

 

a year has passed, we have moved in time from A to B. But time has passed for our cardboard as well. The cardboard in position 1 on which we have pinned circle 1 has moved in time and is now in position 2.

So we are looking at the same galaxies, they have not moved (in space) and nothing is expanding.

All right.

 

But imagine for a while that time for distant galaxy was not the same as time for us. That the 2 T's on the diagram were not exactly the same. Imagine that time was not regular, but exponantial, for example. What would have been our observation ?

Edited December 16, 2010 by michel123456

[Spyman]

Imagine that time was not regular, but exponantial, for example.

Now you have left the initial intention far behind and have started to speculate of other things...

[michel123456]

Sort of. It is the main reason I didn't post this in the other thread.

 

Shortly, my point is: when you play with Time, you inevitably play with Space.

Instead of stating "space is expanding" upon the assumption that Time is immuable, you could IMHO state that "time is expanding/shrinking" and get the same observational result.

[Spyman]

Shortly, my point is: when you play with Time, you inevitably play with Space.

Instead of stating "space is expanding" upon the assumption that Time is immuable, you could IMHO state that "time is expanding/shrinking" and get the same observational result.

But we would not get the same observational result. If it's the rate of time that is changing instead of scale of space then observable phenomenas would happen at differnet durations, as viewed by us, related to their distance to us. So it looks like you have a testable idea but it doesn't seem to match observation.

 

In astronomy 1a supernovas are used as standard candles to measure distances because they nearly constant follow a graph of afterglow luminosity as a function of time after the supernova ignition. The Phillips relationship are used to calculate 1a supernova peak magnitude from the speed of luminosity evolution and by comparing the luminosity with the observed brightness the distance can be calculated.

 

I think a cosmological time dilation influencing the rates of how fast supernova candles very far away decreases brightness compared to closer ones, would greatly alter the calculations and should likely have been discovered.

Edited December 17, 2010 by Spyman

[michel123456]

I think not.

A "Cosmological Time Dilation" as you said is already inside our models. Our unwritten assumption is that time don't change: in this case CTD is equal to unity.

 

Besides, we know that no universal time exist. Objects moving at large speed experience a time different than ours. Each observator has his own time, and following that principle, the Cosmological Time Dilation should not be seen as an actual property of the universe, but as an observational effect.

 

And I think yes.

If CTD exists, then indeed observable phenomenas would happen at different durations, and it would greatly alter our calculations. I estimate the dimension of the observable universe would be reduced, and density of matter should increase.