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Requirement for two "nows" to grasp the idea of Simultaneity


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Einstein uses a lightning strike to establish the idea of simultaneity but fails to consider the distance of the two observers from the lightning strike.

My contention is that in order to understand simultaneity and discuss it and refer to the order of events and the appearance of time slowing and quickening and distances foreshortening and such, one needs to float the existence of two nows.  One where everything is happening in the entire universe right now at the same time, and one in reference to an observer in a location, moving at the speed of the frame of reference he or she inhabits.

It is true that NO other observer is in the same time as you are, because all events happening distavnt from you are experienced by you after they occur.  But there is a way to take a God's eye view and consider something happening in every location in the universe, right now.  Things happening 196000 miles away will be apparent in your personal now in a sec. But they actual happened a second ago when the happened at the same time as everything else that happened in the Universe a sec ago.

For instance, the Sun or a star is in your sky now if it is not cloudy.  It is immediate. The photons left the object 8 mins ago or 3 years ago, but they are arriving at the back of your eye now.  That star is shining now, in the God's eye view of things ,too.

My suggestion is to consider everything, every object, every event as happen now, existing now. 13.787±0.020 billion years after the big bang.

Then considering everything you see or experience as being old news about what happened earlier. 

The unfortunately is not an actual way to experience other star's nows.We have to just imagine what they might be doing the many years after what they appear to be doing now.  In that other now, the God's eye view now, where everything is currently happening.

One additional suggestion is to consider everyone on Earth existing in the same now, give or take several seconds.

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Einstein uses a lightning strike to establish the idea of simultaneity but fails to consider the distance of the two observers from the lightning strike.

My contention is that in order to understand simultaneity and discuss it and refer to the order of events and the appearance of time slowing and quickening and distances foreshortening and such, one needs to float the existence of two nows.  One where everything is happening in the entire universe right now at the same time, and one in reference to an observer in a location, moving at the speed of the frame of reference he or she inhabits.

It is true that NO other observer is in the same time as you are, because all events happening distavnt from you are experienced by you after they occur.  But there is a way to take a God's eye view and consider something happening in every location in the universe, right now.  Things happening 196000 miles away will be apparent in your personal now in a sec. But they actual happened a second ago when the happened at the same time as everything else that happened in the Universe a sec ago.

For instance, the Sun or a star is in your sky now if it is not cloudy.  It is immediate. The photons left the object 8 mins ago or 3 years ago, but they are arriving at the back of your eye now.  That star is shining now, in the God's eye view of things ,too.

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1 hour ago, tar said:

One where everything is happening in the entire universe right now at the same time

This 'now' does not exist, and is impossible.

 

1 hour ago, tar said:

One in reference to an observer in a location, moving at the speed of the frame of reference he or she inhabits

This 'now' is approximately possible in a local frame.

 

Time does not 'flow' equally all over the universe, but is dependent on relative speeds and gravitational potentials, making the concept of a universal 'now' non-sensical.

( I'm sure Markus will offer some explanation such as the regular foliation based on equal time co-ordinates in Minkowky space is not the only choice, any foliation where the simultaneities are spacelike hypersurfaces is valid, IOW different 'nows' for different observers )

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3 hours ago, tar said:

But there is a way to take a God's eye view and consider something happening in every location in the universe, right now.

I know it's been a while but I suspect you are going to get the same responses today as you've gotten in the past.

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No, you don't need two. You can have the two, but there's nothing that stops working or making sense with just the frame-dependent definition of simultaneity.

For order of events, causality is enough, and that doesn't depend on frames of reference or simultaneity. There is no "god's eye view" needed. You can add it in, but it doesn't explain any observations that can't be explained without it. Therefore it's likely more misleading than helpful for explaining. It would be like saying "To understand life and death, we have to first understand ghosts." Nothing requires that ghosts aren't real, but everything observed can be explained without ghosts.

For order of events, if two distant events are simultaneous, they're not causally linked (one doesn't cause the other). Their order is frame-dependent, and there's no problem with that because their order has no bearing on causality and on what other events are effected, and thus no bearing on what can be observed (since observations can be treated as a set of events). If the god's eye view is necessary, it's for something other than what's been observed or what's predicted to be, ie. metaphysical. The "universal now" is simply not needed for the universe to function.

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9 hours ago, tar said:

Einstein uses a lightning strike to establish the idea of simultaneity but fails to consider the distance of the two observers from the lightning strike.

 

That’s not true - relativity of simultaneity is explicitly about distant simultaneity, ie events and observers at different spatial coordinates. Within the mathematical treatment, this spatial separation as well as the finite propagation speed of light are explicitly accounted for within the necessary Lorentz transformation.

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10 hours ago, tar said:

Einstein uses a lightning strike to establish the idea of simultaneity but fails to consider the distance of the two observers from the lightning strike.

No, this is incorrect. He sets that distance to be the same (the observers are co-located), in order to simplify the problem. That way the only effect to consider is the speed. As Markus points out, different distances are accounted for in the math, should you choose to analyze a more complicated problem.

Quote

one needs to float the existence of two nows

Given the relative nature of time, "now" is not well-defined. We generally refer to a particular time according to a clock in one's reference frame.

!

Moderator Note

Duplicate topics merged

 
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On 10/25/2021 at 9:38 PM, MigL said:

This 'now' does not exist, and is impossible.

 

This 'now' is approximately possible in a local frame.

 

Time does not 'flow' equally all over the universe, but is dependent on relative speeds and gravitational potentials, making the concept of a universal 'now' non-sensical.

( I'm sure Markus will offer some explanation such as the regular foliation based on equal time co-ordinates in Minkowky space is not the only choice, any foliation where the simultaneities are spacelike hypersurfaces is valid, IOW different 'nows' for different observers )

MigL it absolutely does exist and it is not nonsense,

Let me prove it to you.

If you witness in your telescope a pulsar and it pulses at a rate of one cycle from highest amplitude to highest amplitude in one second and said pulsar is figured to be 150 light years from here, there HAS TO BE 28,840,000 sine waves in the space between the Pulsar and here, RIGHT NOW.

If not, you wouldn't see the peak that is 196,000 miles out, in a second and you do see it.

 

On 10/26/2021 at 2:05 AM, md65536 said:

No, you don't need two. You can have the two, but there's nothing that stops working or making sense with just the frame-dependent definition of simultaneity.

For order of events, causality is enough, and that doesn't depend on frames of reference or simultaneity. There is no "god's eye view" needed. You can add it in, but it doesn't explain any observations that can't be explained without it. Therefore it's likely more misleading than helpful for explaining. It would be like saying "To understand life and death, we have to first understand ghosts." Nothing requires that ghosts aren't real, but everything observed can be explained without ghosts.

For order of events, if two distant events are simultaneous, they're not causally linked (one doesn't cause the other). Their order is frame-dependent, and there's no problem with that because their order has no bearing on causality and on what other events are effected, and thus no bearing on what can be observed (since observations can be treated as a set of events). If the god's eye view is necessary, it's for something other than what's been observed or what's predicted to be, ie. metaphysical. The "universal now" is simply not needed for the universe to function.

Md65536,  the order of events isdifferent to three observers in the same frame of reference if for instance three observers in a triangle light a signal light when they see the lightning strike.  However the lightning strike occurred only once at a particular time and the  various signals occurred when the light from the strike reached each station.  They were causally connected because the light reaching each station caused the signal to be lit.

 

There used to be a ferry boat that served as the station at Port Imperial.  It is gone now,  But an observer with a powerful telescope on planet 25 ly from here would still see it sitting there on the shore of the Hudson across from Midtown Manhattan.

I need no relativity equations to know this.

Regards, TAR

On 10/26/2021 at 5:10 AM, Markus Hanke said:

That’s not true - relativity of simultaneity is explicitly about distant simultaneity, ie events and observers at different spatial coordinates. Within the mathematical treatment, this spatial separation as well as the finite propagation speed of light are explicitly accounted for within the necessary Lorentz transformation.

Mr. Hanke,

But if two events occur distant to two observers, lets say a light second away in opposite directions and the observers say they happened now, the events really happened a sec ago.  So there is the now they each witness the event at the same time and there is the now when the event actually happened.  That is it happened now, in the universal sense, a second ago.  An observer at the event would have witnessed it a sec ago.  The Mars Rover is doing something now that we won't see for 20 minutes.

So relativity says the twins will age differently and I say that is nonsense,

Anything that is true about how the traveling twin experiences the clocks at home and on the ship will be reversed on the trip back.  The flow of time is consistent everywhere, only appearances differ, and everything adds back correctly as neither twin ever leaves reality.

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So relativity says the twins will age differently and I say that is nonsense,

Anything that is true about how the traveling twin experiences the clocks at home and on the ship will be reversed on the trip back.  The flow of time is consistent everywhere, only appearances differ, and everything adds back correctly as neither twin ever leaves reality.

Both twins will experience the other in slow motion bhecause of the doppler red shift.  On the way back they will see each other's clocks blue shifted.  Clocks will be in sync when they reunite.

Actually if you want to add reality to the thought experiment, the traveling twin will be traveling so fast the the visible light waves coming from the direction she is going will be blue shifted so much that they will be experienced as high frequency high energy gamma waves and the ship will likely not survive.

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1 hour ago, tar said:

So relativity says the twins will age differently and I say that is nonsense,

Anything that is true about how the traveling twin experiences the clocks at home and on the ship will be reversed on the trip back.  The flow of time is consistent everywhere, only appearances differ, and everything adds back correctly as neither twin ever leaves reality.

Explain why clocks at different speeds, and/or gravitational potentials, are observed (as in, there is experimental evidence) to run at different rates.

 

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4 hours ago, tar said:

So relativity says the twins will age differently and I say that is nonsense,

Anything that is true about how the traveling twin experiences the clocks at home and on the ship will be reversed on the trip back.  The flow of time is consistent everywhere, only appearances differ, and everything adds back correctly as neither twin ever leaves reality.

Both twins will experience the other in slow motion bhecause of the doppler red shift.  On the way back they will see each other's clocks blue shifted.  Clocks will be in sync when they reunite.

Actually if you want to add reality to the thought experiment, the traveling twin will be traveling so fast the the visible light waves coming from the direction she is going will be blue shifted so much that they will be experienced as high frequency high energy gamma waves and the ship will likely not survive.

The changing of frame of reference is what causes the time dilation and length contraction. That's what breaks the mirror between the two.

A difference in total time elapsed remains.

Visualize seconds for one twin  spaced further apart. If counted you come up with a smaller total, meaning less time has passed.

IMO redshift, blueshift stuff should really just be ignored here. The one twin could stop halfway and still the effects of the time dilation experienced will persist.

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6 hours ago, tar said:

But if two events occur distant to two observers, lets say a light second away in opposite directions and the observers say they happened now, the events really happened a sec ago.  So there is the now they each witness the event at the same time and there is the now when the event actually happened. 

So relativity says the twins will age differently and I say that is nonsense,

I think what you have missed, is that in fact there is no universal now...your now is not my now, nor the now of my cousin on the planet orbiting Proxima Centauri...

You are certainly, definiely 100% wrong re the twins aging differently being nonsense. This fact has been varified amny many times.

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8 hours ago, tar said:

MigL it absolutely does exist and it is not nonsense,

Let me prove it to you.

If you witness in your telescope a pulsar and it pulses at a rate of one cycle from highest amplitude to highest amplitude in one second and said pulsar is figured to be 150 light years from here, there HAS TO BE 28,840,000 sine waves in the space between the Pulsar and here, RIGHT NOW.

If not, you wouldn't see the peak that is 196,000 miles out, in a second and you do see it.

And that is not true for any other, equally valid frame.
It is only approximately true even for the person on the telescope 1 meter behind you.

What makes your frame so special ???

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13 hours ago, tar said:

So relativity says the twins will age differently and I say that is nonsense,

This is not directly related to relativity of simultaneity, since in the twin experiment, the reason for differential ageing is that part of the travelling twin’s journey isn’t inertial, so the symmetry between frames breaks down. That’s a different mechanism.

You can see differential ageing in particle accelerators when using ion beams - fast beams spread slower (Coulomb forces) than slow beams, in the lab frame.

15 hours ago, tar said:

But if two events occur distant to two observers, lets say a light second away in opposite directions and the observers say they happened now, the events really happened a sec ago.

A second ago on the distant observer’s clock; at t=0 at the place of the event; maybe a year in the future for yet another observer.

That’s precisely the point - there is no universal time frame. It depends on the observer, and their relationships. Remember this is about simultaneity. And this is all correctly accounted for in the math, as pointed out.

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18 hours ago, swansont said:

Explain why clocks at different speeds, and/or gravitational potentials, are observed (as in, there is experimental evidence) to run at different rates.

 

I am working on that.  I need more information about the orientation of the clocks in the planes.  Atomic clocks work on counting the decaying particles of Cesium.  The detectors are in a certain direction from the emitting portions.  In a moving plane the detector is maybe moving toward or away fromnor the emitter.  Doppler shiftwise if you are moving toward a pulse you will count more pulses in a given time than if you are moving away.

The data from the various clocks show small variations of readouts from the moving clocks and the stationary clocks.  Some of the variations are explained in one direction by gravitation differences in terms of the altitude and distance from the center of the Earth and other differences are explained the motion.  The differences are small and not way far off normal error tolerances and there are motions and accelerations not taken into consideration, in terms of time of year and time of day during various takeoffs and landings.

One thing about electrons and photons and particles is they tend to move in a straight line but always in reference to the sum total of all the magnetic and gravitational fields it is moving through.  When you conduct an experiment on the Earth the Earthbound clocks do not know they are supposed to be stationary.  The Earth is rotating around its axis,  The Earth is revolving around the Sun. The Sun is rapidly revolving around a huge source of gravity and magnetic fields that are strongest toward Sagittarius. 

All in all the differences in the clocks are small and the data is wedged into gravitati.onal equations from relativity and motion equations from relativity to account for the small differences.  I submit that if I had two "stationary" cesium clocks, they would show differences to the same magnitude as the differences witnessed in the relativity experiment depending on how they were oriented.c 

One possible experiment to maybe see if my hypothesis is true is to take two identical  Cesium  clocks and mount one on a platform suspended within a structure that could rotate around four different axis through the center of a cube and its corners. 

the Axis could be oriented toward and away from the Great Attractor, the Center of the Milky Way. the Sun and the Center of the Earth.   I would be possible to program the platform to position the Cesium clock in the same orientations as if it were traveling around the Earth in that direction or this.

15 hours ago, Endy0816 said:

The changing of frame of reference is what causes the time dilation and length contraction. That's what breaks the mirror between the two.

A difference in total time elapsed remains.

Visualize seconds for one twin  spaced further apart. If counted you come up with a smaller total, meaning less time has passed.

IMO redshift, blueshift stuff should really just be ignored here. The one twin could stop halfway and still the effects of the time dilation experienced will persist.

Maybe, but I don't think so,  Consider this thought experiment.  Have two twins count the pulses from a pulsar and then send one travelinhe g fast toward the pulsar.  The traveling twin will be running into the waves and will see them blue shifted and will count more of them per minute than the twin on Earth.  The pulsar is only sending out one set of waves and traveling twin is counting the wave crests that have not yet reached the Earth.  On the way back the traveling twin will be traveling with the waves and will see the next wave coming to the ship as red shifted compared to how the Earth bound twin sees them and doubly red shifted in terms of how she saw them on  he way out.

Like if you were to count the waves on the way out to the oil platform and count the wave crests on the way back.  When you return your count of wave crests is exactly the same as the count the guy on shore counted.  

 

15 hours ago, beecee said:

I think what you have missed, is that in fact there is no universal now...your now is not my now, nor the now of my cousin on the planet orbiting Proxima Centauri...

You are certainly, definiely 100% wrong re the twins aging differently being nonsense. This fact has been varified amny many times.

 

47 minutes ago, tar said:

I am working on that.  I need more information about the orientation of the clocks in the planes.  Atomic clocks work on counting the decaying particles of Cesium.  The detectors are in a certain direction from the emitting portions.  In a moving plane the detector is maybe moving toward or away fromnor the emitter.  Doppler shiftwise if you are moving toward a pulse you will count more pulses in a given time than if you are moving away.

The data from the various clocks show small variations of readouts from the moving clocks and the stationary clocks.  Some of the variations are explained in one direction by gravitation differences in terms of the altitude and distance from the center of the Earth and other differences are explained the motion.  The differences are small and not way far off normal error tolerances and there are motions and accelerations not taken into consideration, in terms of time of year and time of day during various takeoffs and landings.

One thing about electrons and photons and particles is they tend to move in a straight line but always in reference to the sum total of all the magnetic and gravitational fields it is moving through.  When you conduct an experiment on the Earth the Earthbound clocks do not know they are supposed to be stationary.  The Earth is rotating around its axis,  The Earth is revolving around the Sun. The Sun is rapidly revolving around a huge source of gravity and magnetic fields that are strongest toward Sagittarius. 

All in all the differences in the clocks are small and the data is wedged into gravitati.onal equations from relativity and motion equations from relativity to account for the small differences.  I submit that if I had two "stationary" cesium clocks, they would show differences to the same magnitude as the differences witnessed in the relativity experiment depending on how they were oriented.c 

One possible experiment to maybe see if my hypothesis is true is to take two identical  Cesium  clocks and mount one on a platform suspended within a structure that could rotate around four different axis through the center of a cube and its corners. 

the Axis could be oriented toward and away from the Great Attractor, the Center of the Milky Way. the Sun and the Center of the Earth.   I would be possible to program the platform to position the Cesium clock in the same orientations as if it were traveling around the Earth in that direction or this.

Maybe, but I don't think so,  Consider this thought experiment.  Have two twins count the pulses from a pulsar and then send one travelinhe g fast toward the pulsar.  The traveling twin will be running into the waves and will see them blue shifted and will count more of them per minute than the twin on Earth.  The pulsar is only sending out one set of waves and traveling twin is counting the wave crests that have not yet reached the Earth.  On the way back the traveling twin will be traveling with the waves and will see the next wave coming to the ship as red shifted compared to how the Earth bound twin sees them and doubly red shifted in terms of how she saw them on  he way out.

Like if you were to count the waves on the way out to the oil platform and count the wave crests on way back.  When you return your count of wave crests is exactly the same as the count the guy on shore counted.  

beecee, I am aware that the equations of relativity have been found to be very descriptive of the events we witness, but reality does not conform to the equations, the equations conform to reality.  You say the moving twin ages differently than the stationary one and this has been experimentally proven.  I have seen many of these muon counts on platforms and such but always sense some fudging in the assumptions and set up and read outs because of frame shifting back and forth between one part of the experiment an another.  It take time for the signal at one end of the experiment to reach the other end and people flip from place to place in their mind at fasted than light speed.  This confounds the results.  I am not saying there IS a universal now, I am saying we assume one where things are happening now, before we witness them.  Proof being we say the light of a nearby star took three years to get to our eye.  This assumes the star is actually shining now and putting out photons we will see in our now in three years.  The universal now does exist.

 

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13 hours ago, MigL said:

And that is not true for any other, equally valid frame.
It is only approximately true even for the person on the telescope 1 meter behind you.

What makes your frame so special ???

I am making the Earthbound frame special because that is the one we all experience, give or take several seconds.

If the universe began at the big bang, then there is a T=0.

 

All objects and events happening now in the universe are the same age in reference to the big bang.

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1 hour ago, tar said:

I am working on that.  I need more information about the orientation of the clocks in the planes. 

AFAIK they were strapped into the seats, so the beam would be going perpendicular to the plane's motion. But that would have no measurable effect on the outcome according to SR.

1 hour ago, tar said:

Atomic clocks work on counting the decaying particles of Cesium. 

No radioactive decay is involved.

1 hour ago, tar said:

The detectors are in a certain direction from the emitting portions.  In a moving plane the detector is maybe moving toward or away fromnor the emitter.  Doppler shiftwise if you are moving toward a pulse you will count more pulses in a given time than if you are moving away.

It would be transverse in this case. But if you're thinking about some preferred frame, then you have to account for the fact that trips at one time of day would be in one direction, and trips 12 hours later would be in the opposite.

 

1 hour ago, tar said:

The data from the various clocks show small variations of readouts from the moving clocks and the stationary clocks.  Some of the variations are explained in one direction by gravitation differences in terms of the altitude and distance from the center of the Earth and other differences are explained the motion.  The differences are small and not way far off normal error tolerances and there are motions and accelerations not taken into consideration, in terms of time of year and time of day during various takeoffs and landings.

The time dilation was far larger than the measurement error from those clocks. 

If you think that the accelerations played a large part, that's one more thing that's up to you to demonstrate. From an relativistic point of view, the effect is minimal.

 

1 hour ago, tar said:

One thing about electrons and photons and particles is they tend to move in a straight line but always in reference to the sum total of all the magnetic and gravitational fields it is moving through. 

The gravitational drop in the several millisecond travel of a thermal cesium beam is quite small. External electric and magnetic fields are shielded; these would have a large effect on the clock's performance if they were not.

 

1 hour ago, tar said:

When you conduct an experiment on the Earth the Earthbound clocks do not know they are supposed to be stationary.  The Earth is rotating around its axis,  The Earth is revolving around the Sun.

Yes; the earth's rotation is taken into account in the analysis. The motion about the sun is not as the effect is (or was, for those clocks and such a short experiment) too small to measure

1 hour ago, tar said:

The Sun is rapidly revolving around a huge source of gravity and magnetic fields that are strongest toward Sagittarius. 

Can you calculate the angular speed of this to show that it's "rapid"? The gravity to show its hugeness?

(hint: how long does it take for us to compete 2*pi of a revolution?)

 

1 hour ago, tar said:

All in all the differences in the clocks are small and the data is wedged into gravitati.onal equations from relativity and motion equations from relativity to account for the small differences.  I submit that if I had two "stationary" cesium clocks, they would show differences to the same magnitude as the differences witnessed in the relativity experiment depending on how they were oriented.c 

Feel free to show this.

597247019_ScreenShot2021-10-28at12_22_44PM.thumb.png.7ab0b99d9a2f9f6bb4d7845ac30605ef.png

 

This is a graph from the Hafele-Keating results (Science, New Series, Vol. 177, No. 4044. (Jul. 14, 1972), pp. 168-170)

Fig 2 from p169. Seems to me the scatter in the timing signal is smaller than ∆t. (edit: and they cite the experimental error in their results)

 

1 hour ago, tar said:

One possible experiment to maybe see if my hypothesis is true is to take two identical  Cesium  clocks and mount one on a platform suspended within a structure that could rotate around four different axis through the center of a cube and its corners. 

the Axis could be oriented toward and away from the Great Attractor, the Center of the Milky Way. the Sun and the Center of the Earth.   I would be possible to program the platform to position the Cesium clock in the same orientations as if it were traveling around the Earth in that direction or this.

It's likely you would need to show some model demonstrating that you would expect a result before anyone does this experiment.

 

42 minutes ago, tar said:

All objects and events happening now in the universe are the same age in reference to the big bang.

Not if relativity is correct

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4 hours ago, tar said:

I am working on that. 

So have many scientists/physicists over a 100 years and more. 

3 hours ago, tar said:

If the universe began at the big bang, then there is a T=0.

The BB says nothing about how the universe began, only how it evolved from t+10-35th seconds or thereabouts. Secondly the BB applies to the observable universe.

Keep working on it.

3 hours ago, tar said:

All objects and events happening now in the universe are the same age in reference to the big bang.

There is no universal now, sorry.

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@tar

Are you really arguing about the results/methods of the Hafele-Keating experiments with a guy who designs/builds atomic clocks for a living ?
Surely you must realize you don't have enough firepower to win that battle 🙂 .

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32 minutes ago, MigL said:

@tar

Are you really arguing about the results/methods of the Hafele-Keating experiments with a guy who designs/builds atomic clocks for a living ?
Surely you must realize you don't have enough firepower to win that battle 🙂 .

Adherence to commonsense is the ailment.

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On 10/28/2021 at 12:28 PM, swansont said:

AFAIK they were strapped into the seats, so the beam would be going perpendicular to the plane's motion. But that would have no measurable effect on the outcome according to SR.

No radioactive decay is involved.

It would be transverse in this case. But if you're thinking about some preferred frame, then you have to account for the fact that trips at one time of day would be in one direction, and trips 12 hours later would be in the opposite.

 

The time dilation was far larger than the measurement error from those clocks. 

If you think that the accelerations played a large part, that's one more thing that's up to you to demonstrate. From an relativistic point of view, the effect is minimal.

 

The gravitational drop in the several millisecond travel of a thermal cesium beam is quite small. External electric and magnetic fields are shielded; these would have a large effect on the clock's performance if they were not.

 

Yes; the earth's rotation is taken into account in the analysis. The motion about the sun is not as the effect is (or was, for those clocks and such a short experiment) too small to measure

Can you calculate the angular speed of this to show that it's "rapid"? The gravity to show its hugeness?

(hint: how long does it take for us to compete 2*pi of a revolution?)

 

Feel free to show this.

597247019_ScreenShot2021-10-28at12_22_44PM.thumb.png.7ab0b99d9a2f9f6bb4d7845ac30605ef.png

 

This is a graph from the Hafele-Keating results (Science, New Series, Vol. 177, No. 4044. (Jul. 14, 1972), pp. 168-170)

Fig 2 from p169. Seems to me the scatter in the timing signal is smaller than ∆t. (edit: and they cite the experimental error in their results)'s

 

It's likely you would need to show some model demonstrating that you would expect a result before anyone does this experiment.

 

Not if relativity is correct

SwansonT,  In a way, the experiment has already been done, referencing your graphs. the magnetic field of the Earth is in one orientation when the  clocks are headed east and in the other orientation when the clocks are heading west.   In one direction magnetic north is to the beam's right.  In the other direction it is to the beams left.

On 10/28/2021 at 3:34 PM, beecee said:

So have many scientists/physicists over a 100 years and more. 

The BB says nothing about how the universe began, only how it evolved from t+10-35th seconds or thereabouts. Secondly the BB applies to the observable universe.

Keep working on it.

There is no universal now, sorry.

beecee,  You say there isn't when you use it all the time.  If the Mars rover is doing something now, yet we see what it did later, there are two nows.  One that is what is happening now, here, and one that is what is happening everywhere at the moment we are in here.

relativity equations work, but that does not mean they are correct and common sense is not.

there could be confirmation bias in the way the experiment is set up, and differences in results from expected results are often accounted for after the fact

relativity is real, but I believe it has to do with light travel time more than with gravity and velocity 

I am not thinking it is correct to apply angular velocity equations to huge spinning objects because you cannot see the whole thing at once and  the equation is immediate

The observable universe is all we have, and all we will ever be affected by.  If something not contained in the observable has an effect on the observable universe, and we detect that effect, than the thing we considered earlier not in the observable universe would be observable and hence within the observable universe, so talking as if there is something outside the observable universe is without purpose and value.

then not than

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35 minutes ago, tar said:

beecee,  You say there isn't when you use it all the time.  If the Mars rover is doing something now, yet we see what it did later, there are two nows.  One that is what is happening now, here, and one that is what is happening everywhere at the moment we are in here.

What I said is that there is no universal now...universal meaning a "now" for everyone in the universe including my cousin in Andromeda. The universal speed limit assures that everyone's "now" is different. You are actually agreeing with me with your Mars Rover example.

40 minutes ago, tar said:

relativity equations work, but that does not mean they are correct and common sense is not.

there could be confirmation bias in the way the experiment is set up, and differences in results from expected results are often accounted for after the fact

relativity is real, but I believe it has to do with light travel time more than with gravity and velocity 

I am not thinking it is correct to apply angular velocity equations to huge spinning objects because you cannot see the whole thing at once and  the equation is immediate

 SR/GR are probably the most tested theories of all time, and keep coming up trumps. The many examples of that, by many physicists around the world assures that we have no confirmation bias. It does not have to do with light travel per se, as it does with  it being a universal physical constant, at a universal finite speed we define as "c".

But hey! I'm only a poor old retired tradesman, that is echoing the many reputable books and the many irrefutable experiments that continually support the most complete theory of gravity that we have. (SR of course being a subset of GR)

On 10/26/2021 at 11:26 AM, tar said:

Einstein uses a lightning strike to establish the idea of simultaneity but fails to consider the distance of the two observers from the lightning strike.

The first order of business is for you to acknowledge your fundamental errors.

On 10/26/2021 at 8:10 PM, Markus Hanke said:

That’s not true - relativity of simultaneity is explicitly about distant simultaneity, ie events and observers at different spatial coordinates. Within the mathematical treatment, this spatial separation as well as the finite propagation speed of light are explicitly accounted for within the necessary Lorentz transformation.

 

On 10/26/2021 at 9:52 PM, swansont said:

No, this is incorrect. He sets that distance to be the same (the observers are co-located), in order to simplify the problem. That way the only effect to consider is the speed. As Markus points out, different distances are accounted for in the math, should you choose to analyze a more complicated problem.

 

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3 hours ago, tar said:

SwansonT,  In a way, the experiment has already been done, referencing your graphs. the magnetic field of the Earth is in one orientation when the  clocks are headed east and in the other orientation when the clocks are heading west.   In one direction magnetic north is to the beam's right.  In the other direction it is to the beams left.

The clocks use magnetic shielding to minimize any impact from external fields

3 hours ago, tar said:

relativity equations work, but that does not mean they are correct

Well, yes, that’s actually what that means.

 

3 hours ago, tar said:

and common sense is not.

Not an enforceable standard.

 

3 hours ago, tar said:

 

there could be confirmation bias in the way the experiment is set up, and differences in results from expected results are often accounted for after the fact

Well, then, identify these biases 

3 hours ago, tar said:

relativity is real, but I believe it has to do with light travel time more than with gravity and velocity 

Which is something that must be demonstrated, not asserted, as with all scientific discussion.

 

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On 11/2/2021 at 3:32 PM, beecee said:

What I said is that there is no universal now...universal meaning a "now" for everyone in the universe including my cousin in Andromeda. The universal speed limit assures that everyone's "now" is different. You are actually agreeing with me with your Mars Rover example.

 SR/GR are probably the most tested theories of all time, and keep coming up trumps. The many examples of that, by many physicists around the world assures that we have no confirmation bias. It does not have to do with light travel per se, as it does with  it being a universal physical constant, at a universal finite speed we define as "c".

But hey! I'm only a poor old retired tradesman, that is echoing the many reputable books and the many irrefutable experiments that continually support the most complete theory of gravity that we have. (SR of course being a subset of GR)

The first order of business is for you to acknowledge your fundamental errors.

 

 

beecee,  What I am arguing here is that the results from various experiments align with the equations of SR and GR but there are other ways to explain the results than to suggest that time dilates and distances shorten.   The mere idea of such things is counter the idea of c.   c is the distance light travels in a particular time.  You can't have c unless you have time remaining the same and distance remaining the same.  If the distance.shortens then light would cover the span in a quicker time.  This would invalidate the statement that light speed is invariant.   What I suggest is happening is that people do not switch properly between two frames of reference. You can for instance be in the same inertial frame but distant from another observer or from a part of the experiment.u

My example of the pulsar proves my argument.   You cannot have the next pulse in a second unless the light wave you are going to see in a sec is right now existing in space 186,000 miles from here.

The benefit of considering my proposal is that it corresponds to actual reality.  The universe is huge and longlived beyond comprehension.  It is incorrect to imagine the universe as being able to be seen all at once.  My universal now is not meant to be seen, as light is the media we experience and it will take what is happening now elsewhere time to get here.  However, there is something happening everywhere right now.  That is my argument. There are two nows.  One that sees the whole universe as photons coming in from a far, having been emitted a sec, or two or an hour or two or a year or two or a billion or two years ago. This is the actual way we see the universe all at once. 

The other now is real, things are actually happening outside our view, because the light has not reached us yet, but we know they have to be happening now because we see them later.  This other now is the universal now that for any one observer has to be imagined as happening now for an observer in those other locations.

But for any one location there is past, present and future.  It is a simple thing to imagine everything happening now, and determining what happened elsewhere when, nased on the image and the distance.

Experiments have to consider this other now.  Everything we see in space has already actually happened.  That is if we see a quasar filled with first generation stars we can know in our imaginations that right now, in that area of space, there is likely a galaxy like the Milky way, or Andromeda filled with third generation stars.

We of course will never see it because the light from the current situation is billions of years away. and we don't live that long, but that does not mean it is not what is happening now in that are of space where we see the quasar.

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1 hour ago, tar said:

beecee,  What I am arguing here is that the results from various experiments align with the equations of SR and GR but there are other ways to explain the results than to suggest that time dilates and distances shorten.   The mere idea of such things is counter the idea of c. 

It's because c is what it is that requires time to dilate and distances shorten the amount they do. The way you put it, the tail is wagging the dog...it seems to me.

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