# Is There A Universal Now?

Discussion in 'Physics & Math' started by Cyperium, Jun 14, 2022.

1. ### phytiRegistered Senior Member

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Michael345;

The clock accumulates its cycles. If its a simple clock and the duration lasts more than a 24 hr day, you consult a calendar. In the light clock, the cycles are continuous and a detector counts the cycles, 9 billion+ equals 1 sec., the same as cesium based fountain clocks. Time accumulates, and we can know how long ago an event happened.

3. ### phytiRegistered Senior Member

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NOW believers;
The 'now' moment occurs when a sphere of images converge at the observer Al or a recording device. For simplicity we consider 180 deg of a circular slice of the sphere.
Because Al receives the images simultaneously, he thinks the composite image of A, B, etc. represents the current state of the universe.
That would require light propagation to be instantaneous, which is false as verified experimentally. Light propagation is finite as shown by the blue light cone.
If A is 50 ly distant, then it requires 50 yr transit time.
If B is 100 ly distant, then it requires 100 yr transit time.
Al is in reality seeing the objects as they were on the light cone, not as they are in his mind.

5. ### Neddy BateValued Senior Member

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That is what the observer sees by eye, but that is not what an intelligent observer would say is happening "now" because...

...the intelligent observer would say that "now" at A is 50 years ahead of what is seen by eye, and that "now" at B is 100 years ahead of what is seen by eye. The delay of distant observations caused by the finite speed of light is already factored out during Einstein's clock synchronisation process. The "now" of SR is very well defined, and does not suffer from unintelligent observers thinking that "now" is whatever they are currently seeing by eye. Come on, get real.

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7. ### Write4UValued Senior Member

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You don't need superpowers. It's all theory.
In theory we need no such device to "understand" the physics.
No I don't there is no contradiction.
I just try to avoid the subjective parts when describing "theoretical observation".

It always gets mixed up between "objective" Universal conditions and "subjective" Human experiences and symbolic codifications.
Objectively 1 + 1 = 2, regardless of how humans symbolize the actual "relational values"..

Last edited: Sep 7, 2022
8. ### Write4UValued Senior Member

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AI cannot be programmed to account for redshift? Is that not what AIs do in our observatories?

9. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Called THOUGHT EXPERIMENT

Humans create what they call time (There is no FUNDIMENTIAL TIME) by picking a natural process which has a regulatory process ie the second is defined as

The second (s or sec) is the International System of Units (SI) unit of time measurement. One second is the time that elapses during 9,192,631,770 (or 9.192631770 x 109 in decimal form) cycles of the radiation produced by the transition between two levels of the cesium-133 atom.

Purely arbitrary and I don't know what version this definition of the second is but there have been a few

Like all created measurement systems it is useful to have an agreed upon version

Not sure in which way

Last edited: Sep 7, 2022
10. ### BeaconatorValued Senior Member

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• Please do not post nonsense.
Pressure equals gravitational constant times acceleration over the area.

but how that relates to timeā¦ I have no idea.

11. ### phytiRegistered Senior Member

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Write4U;
NOW, chronology, and 14 billion years implies a period of 'time'. Humans and their concept of 'time' occurred the last few millenia of that period. There were no humans present to keep records of events. There were no NOWs.

12. ### phytiRegistered Senior Member

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Neddy;

The intelligent observer knows he is observing historical events, that happened 50 and 100 yrs ago, but only IF he knows the distances.
He has no idea of what is happening there 'now', simultaneously with his processing the images.
Einstein's clock synch method is for a ref. frame moving at constant velocity. It provides a constant 'now' for all observers in the frame where it is applied. It is based on the round trip transit time for light. The observer is coincident with the emission and detection of the light signal. He cannot be present at the reflection/reversal event.
Constant velocity allows the observer to assume a pseudo rest frame. In such a frame
the reflection occurs at (emission time + detection time)/2.

In the example of [A, B, ...] Albert only detects an inbound image, i.e. he doesn't have enough data to determine WHEN the image was formed. He has a local time of perception/awareness. The coordinate transformations were meant for that purpose if the relative velocity is known.

SR defines the time of occurrence of an event as that indicated by a clock in the proximity of the event. It would be impossible with present knowledge, to synchronize a local clock with random distant clocks.
The clock synch method is limited in its application. The Mars probes were autonomous for their landing procedures, since they couldn't wait ~15 min. for instructions.
The LOCAL GPS system needs constant corrections for useful service.

In the big picture, the objects within the dynamic universe do not remain at constant distances nor constant velocities. Imagine the logistical problems synchronizing a clock 100 ly distant!

13. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Humans not required

NOW (Singular) appears at the moment something appears

NOW remains singular until whatever appeared disappears

Last edited: Sep 10, 2022
14. ### Write4UValued Senior Member

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I agree with the posit.
But is the phrase "within the dynamic universe" not a limiting factor?

It is impossible to visualize the entire universe from "within". That construct can only be seen in its entirety from "without", no?

15. ### Write4UValued Senior Member

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But can anyone explain to me how a multi-nucleic single-celled slime mold can learn to anticipate timed intervals (future NOWS) without a clock?

Is this an early expression of chronobiology in a single-celled neuronless organism?

Last edited: Sep 11, 2022
16. ### Neddy BateValued Senior Member

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Yes, and fortunately he does know the distance. The intelligent observer can measure the distance by sending a light signal to the distant place, measuring the amount of time it takes for that signal to return to their eyes (reflecting off a mirror or bright surface, for example) then simply divide by 2. Just as you yourself stated is the Einstein synch convention. The intelligent observer would use a CLOCK to measure that. And during that process, both clocks would be synchronised, even the distant one.

Think about that word. Synchronized. That means, once that process is done, the intelligent observer knows that any two events happening at those locations can be compared according to the times on the synchronised clocks.

That is "now at a distance."

But it is not a "universal now," because other reference frames say those clocks are not synchronised.

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18. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Moot

Since there is only NOW - SINGULAR - in existence and the singular NOW applies to the Universe as a singular unit all the stuff you are trying to achieve with clocks and bouncing lasers off mirrors is MOOT

19. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Moot

Since there is only NOW - SINGULAR - in existence and the singular NOW applies to the Universe as a singular unit all the stuff you are trying to achieve with clocks and bouncing lasers off mirrors is MOOT

20. ### James RJust this guy, you know?Staff Member

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Write4U:

The universe does not have a singular timeline. Every particle in the universe has its own worldline through spacetime, so each particle has its own experience of time.

A better way to look at things is to consider that events in spacetime are constants. What happens, happens. All observers, in whatever frame of reference, must agree, ultimately, on what happens. That does not, however, mean they will all agree on when things happen(ed).

When it comes to the idea of "now" - a set of simultaneous events - that is very much observer-dependent. Similarly, past and future are observer-dependent.
Uniquely? Who or what do you imagine is in a superior position?
No. Observations we make happen when we make them. Of course, events that happened in the past can influence the observations we make now.
I have no idea what that sentence means. Sounds like a deepity.
The universe is not an observer.
"Age" is a measured time difference between identifiable events in spacetime. The "age" of anything will depend on the observer's frame of reference.
Where is your magical ONE clock located? What events is it measuring? How does it work?
No, I don't get it.

The 13.7 billion year figure is based on our measurements of the Hubble constant, which is a characteristic that describes the observed expansion of the universe. We make our observations from here, on Earth. We have no access to a magical universal ONE TRUE CLOCK.
Please outline a method by which I can find the "primary existential" chronological time at this instant. Dot points will be fine.

21. ### James RJust this guy, you know?Staff Member

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I think you're confusing the process of measuring a quantity with creating a quantity.

You appear to have the same confusion about distance. Possibly that confusion extends to other physical quantities as well.

If humans created time, what happened before there were humans on Earth? Or did Earth spring into existence at the instant the first human evolved?
The definition you quoted does not define time. It defines a unit of measurement: the second. I think you're probably confusing the two things.

22. ### James RJust this guy, you know?Staff Member

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Is that something that needs an explanation?

Do slime molds have no internal clocks?

How do you know they can anticipate timed intervals?

23. ### James RJust this guy, you know?Staff Member

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It follows that if "now" is defined as a particular set of simultaneous events, then different observers will also disagree about what "now" is.

In that context, it doesn't make any sense to talk about a "SINGULAR" (with large scary capitals) "NOW".

BTW, SHOUTING doesn't give your point any more credibility.

24. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Humans create what they call time

Sure the second is defined as time that elapses during 9,192,631,770 etc etc .... (a measurement (arbitrary))

The number of measurements are there, already in existence and happening

Humans label this particular measurement a second

Along with all the other arbitrary measurements (quantities (groupings)) is what humans call time

Hence time in that arbitrary context is a non-existent concept wholly within the thought processes, having no existent properties

A handy agreed upon reference frame but nothing more