[guest39538]

It is important in  the understanding of simultaneity and simultaneous to completely understand time and to build a central or primary rule or principle on which time is based.  Time is the rudiment of existence, time is said to have begun of the big bang some what fourteen billion years ago.  Time is said to be the thing that stops things happening all at once.   Presently we refer to time as a measurement, the movement of the hands of a clock or the present use of Caesium clocks and it is said that  the  integral of the frequency is time,  9,192,631,770 hertz  being equal to one second of time measurement.  In ordinary terms , time is the mechanism that allows us to synchronise our everyday lives, synchronised in respect relative to  the inertial accelerating reference frame of the gravitational constant of the  Earth and relative velocity,  but not simultaneous relative  to other reference frames according to relativity. However it is important we do not overlook the mind experience and the observation of time,   all observers must agree on the observation of time  to be equal.

In thought let us imagine a spaceship that was going to make a journey from the Earth to the Moon.   On Earth Sam holds in his hand the modern technology of a camcorder, onboard the spaceship Sarah also holds an identical camcorder, finally on the Moon , Sid also holds an identical camcorder.

Sarah starts the engines on the spaceship and starts her journey from t=0 .

All three observers Sam, Sarah and Sid all synchronise their recording start  on the camcorders, starting to fill the internal storage with observed data in synchronisation with the light and time.   

It is not important we need to consider a forth observer or the speed of the journey or a time on a clock recording the journey.

Sarah arrives at the Moon to pick up Sid to return Sid to Earth, where Sarah , Sid and Sam compare the observation of the recordings.   
All observers agree they have recorded the exact equal amount of data, all observers agree that they experienced the  same amount of time in either location or in motion.  All observers agree the observation was simultaneous.

In this example we are defining time - ''Time is the synchronisation of observation'

Therefore I propose a rudiment principle  that is self evidently true.

Principle - All observers of time must agree that the observation of time is synchronous and constant.

Relative maths.

If we imagine a single Photon travelling from A → B and a single Photon travelling a parallel journey from B → A over a length of space-time X, we can calculate the net difference of time between the two photons journey times to reveal 0 net difference in time.

L=X
A_t=(+ve=c)
B_t=(-ve=c)
A_t - B_t = 0_t net difference.

Relativistic diagram

 [ Invalid Attachment ]

[guest39538]

No smarmy comments?

[Ethos_]

No smarmy comments?

The way you have drawn this v=c/v=c should give the answer of (1).

[jeffreyH]

Time can be summed up like this. If nothing changes then we cannot define time. When things are changing then time is defined as the device by which the rate of change is measured.

[Ethos_]

Time can be summed up like this. If nothing changes then we cannot define time. When things are changing then time is defined as the device by which the rate of change is measured.

Good answer Jeff. If Mr. Box would care to read my signature "The more things change, the more they remain the same." he might realize that; Because change is a constant reality in our universe, time is there for us to measure. And as long as we can measure time, our existence will remain the reality.

[guest39538]

No smarmy comments?

The way you have drawn this v=c/v=c should give the answer of (1).

Huh?  No, the diagram shows the parallel simultaneous journey in opposite directions as explained. The maths shows the net difference is 0.    If you don't understand the diagram  you should understand the maths, that is the beauty off of it. The big line of X is the axis, not a divide line lol.

[guest39538]

Time can be summed up like this. If nothing changes then we cannot define time. When things are changing then time is defined as the device by which the rate of change is measured.

But anything after 0 is instantaneous history, we can't measure time, we can only record the simultaneous of observation, things change whether we measure it or not, even 1 cycle on the Caesium clock is instant history, undeniable logic Jeff.

[guest39538]

Principle - All observers of time must agree that the observation of time is synchronous and constant.

Relative maths.

If we imagine a single Photon travelling from A → B and a single Photon travelling a parallel journey from B → A over a length of space-time X, we can calculate the net difference of time between the two photons journey times to reveal 0 net difference in time.

L=X
At=(+ve=c)
Bt=(-ve=c)
At - Bt = 0t net difference.



This remains ''true'', on the moon, on Earth or in any frame of reference, because all observers can measure the speed of light in a vacuum to be the same and constant.   

[jeffreyH]

Logic has run, screaming, from this thread and directly into the clutches of chaos absurdity.

[guest39538]

Logic has run, screaming, from this thread and directly into the clutches of chaos absurdity.

How do you conclude that? 

The logic is very good if I do say so myself, it is quite obvious that anything after 0 is history, even the smallest measurement you could possibly imagine.  Are you trying to suggest that if there was a vacuum on the moon and an equal length vacuum  on Earth , that the observer would not measure the speed of light to be the same?

Are you suggesting the very simple maths of net difference  is incorrect?

Are you suggesting that the camcorders will show a difference in time?