Block universe vs two senses of now.

[Strange]

That is my idea. What part of my idea are you calling nonsense, when that is the basis of my idea, that there are two nows. The one that is actual, that we don't see, and the one we see that is actually an image of the distant event. (which is the way all observers in the universe, must see it, so it IS reality. The two senses of now.)

 

You can, of course, choose to define the word "now" in that way. It is, after all, a pretty vague term.

 

But that says nothing about there being a "universal now" (which there isn't - or at least, not a unique one). Nor does it show general relativity (which uses a static model of space-time) to be wrong.

[tar]

Strange,

 

Well, there does seem to be a difference in the claim of a static block universe, where all and every x.y,z,t coordinate exists concurrently in the same place, and the view I am trying to express, where the universe has not yet done, what it is going to do next.

 

Let me have you try this thought experiment. Put one end of a bundle of fiber optic strands in front of the readout of the atomic clock in Colorado and look at the readout from the other end of the fiber optic bundle, just a foot long. The read out will read the same as it reads from a foot away without the foot long bundle. Now look at the readout through a bundle that goes the 25,000 miles around the circumference of the Earth. There will be a difference of about 134 milliseconds between the two readouts of the same clock, standing in the same spot. You know the one is happening now, as surely as you know the other is happening now. You know what to do with the 134 millisecond discrepancy. When imagining a person standing on the other side of the Earth, spliced into your bundle, they must "currently" read the time as 67 milliseconds earlier than your circumference bundle reading, and 67 milliseconds later than your direct reading. If the observer on the other side of the Earth, had a second (heavily heat shielded) bundle that took the direct route, through the center of the Earth, just 8000 miles away, the clock would read .043 seconds later than your direct reading, and she would see a 24 millisecond difference between the clock she is looking at "directly" through the Earth, and the one she is looking at through the half circumference bundle. She can however know what time you must be seeing now, because she knows you are really 8 thousand miles away, and separated from her here and now, by 43 milliseconds of light travel time. As you are separated from her here and now, by 43 milliseconds of light travel time. You both experience life at the same "universal now", as does every other element of the universe, but you experience the rest of the universe later, when the light reaches you. Close stuff, within a moment. Solar system stuff, within an hour or two. Milkyway stuff within 100,000 years and distant universe stuff within 13.8 billion years, and then there might be stuff, we will never see. Does not mean it isn't happening now, for the first and only time it will happen, in the universal now, sense of the word.

 

Regards, TAR

Edited August 7, 2015 by tar

[Strange]

Well, there does seem to be a difference in the claim of a static block universe, where all and every x.y,z,t coordinate exists concurrently in the same place, and the view I am trying to express, where the universe has not yet done, what it is going to do next.

 

I guess that is just because you don't understand what the block universe model means.

 

For example, the word "concurrently" is meaningless in the sentence above. So is the phrase "in the same place". If two events were concurrent (according to some observer) then they would be in the same position on the t coordinate (as defined for that observer). If two events occur at the same place, then they will have the same x,y and z coordinates.

 

The path of the light from the sun to your eyes is represented by a line (a geodesic - the shortest path between the two events) in a similar way to representing your route on a map. If there is a line on a map showing your route from home to work it doesn't mean you were at every point on that line concurrently.

 

Better still if that line is a graph showing distance travelled against time. That is a 2D version of the block universe.

[MigL]

What is being 'sensed', can affect us and can be measured.

What is 'imagined' cannot affect us and cannot be measured.

 

The Sun, as it 'currently is' falls into the second catagory, similar to other universes,or multiverses. Or the part of the universe external to the observable universe, we know something must be there, but it can never affect us so it may as well be imaginary. Or the 'place' where you can look at the bock universe and 'see' every event concurrently in the same place. Where exactly in the universe, is this place which by definition, requires you to be outside space-time to have this 'God's eye' view ?

 

Don't try to pass off your imagination as science, or even philosophy.

Edited August 8, 2015 by MigL

[david345]

What is being 'sensed', can affect us and can be measured.

What is 'imagined' cannot affect us and cannot be measured.

 

The Sun, as it 'currently is' falls into the second catagory, similar to other universes,or multiverses. Or the part of the universe external to the observable universe, we know something must be there, but it can never affect us so it may as well be imaginary. Or the 'place' where you can look at the bock universe and 'see' every event concurrently in the same place. Where exactly in the universe, is this place which by definition, requires you to be outside space-time to have this 'God's eye' view ?

 

Don't try to pass off your imagination as science, or even philosophy.

In the block universe the human is represented as a "worm" which extends in the direction of time. Light from the sun can't hit us instantly. It will hit the "worm" at a later time. It will never effect us if we die the second it is released. A slice of the "worm" may lie outside the light cone. Other parts may lie inside the cone. One of the main purposes of physics is to make predictions. You seem to think physics should only talk about the past. Relativity is deterministic. We can have a good idea of how the sun will act many years from now. Even with quantum mechanics we can make certain predictions about the future. Knowledge of the laws allows us to predict what will happen before we see it. This is why we know what a machine will do before we build it. Edited August 8, 2015 by david345

[MigL]

I suggest you've mis-read my post.

And agree with everything you say, except the part where you analise what 'i seem to think'.

[tar]

david345,

 

Predict means you say something about what has not happened yet. You say it before it happens, then it happens and your prediction is right, or it doesn't happen and your prediction was wrong.

 

In a block universe, you say the past, present and future all exist together in a static way. That the worm's entire length is already fixed and certain...yet you cannot predict the length of the worm.

 

Why is that? Primarily because you cannot "get" to the place that can see the length of the worm. The reason for this is not a fault in your math. The reason for this, is because the length of the worm is absolutely NOT determined. Like the stock market, you can run all the metrics you like. Analyse the ups and downs and deviation from the mean. Predict it will follow a pattern and reverse its direction and wander only a certain amount of standard deviations off its mean and follow a certain stochastic pattern, in retrospect, for every size time period you wish to look at, but at the present, you cannot predict with 100% certainty the price point of every transaction, every buy and sell, that will take place tomorrow. This is because, the decision to buy or sell is based on the price to some extent, and the price is not set, until the next transaction takes place. The future has not happened yet, it is determined by what happened before, but it is determined by EVERYTHING that happened before, and everything, has not yet made it, to Earth. So what happens on Earth may be determined by what happened before and around a particular spacetime coordinate, but the intersection of reality, that exists at a space time coordinate is fresh and new, and has never occurred before. The price is not set, until the transaction that just happened, happens. Reality does not occur, until it does. A block universe says the future has already happened. It absolutely has not happened yet. That is the definition of future, that it has not happened yet. How can the block universe be right, if it contradicts such an a priori understanding?

 

Regards, TAR

[david345]

Tar, The future may be unknown but that is far from proof that it doesn't exist. You have failed to give a legitimate counter argument against the RietdijkPutnam argument. Your universal now is in disagreement with relativity. You say the future doesn't exist. Who's future? The future of the universal now we are all experiencing? You claim everything is the same age as the universe. How do you explain the twin paradox? One twin leaves on a space ship and returns younger. His cells and atoms are younger. You claim time flows at the speed of light. This answer is a joke. In your previous post you stated "The reason for this, is because the length of the worm is absolutely NOT determined". Later you stated "The future has not happened yet, it is determined by what happened before". Yet another example of your lies and hipocracy. You say I claimed the length of the worm is certain. Yet another lie. I said the worm exists. At certain times we may not know how long it is. This in no way proves that what you consider to be the future doesn't exist. If it is your opinion that the future doesn't exist then that is fine. Don't act like it is a proven fact. You have provided no evidence or contradictions. You have only told us what you don't know. You choose what is correct based off emotion. This is why I am tired of listening to you. It is clear you are on here to preach your own personal opinions and are willing to lie and flip flop to justify them.

Edited August 9, 2015 by david345

[tar]

David345,

 

It is important, when you parse a paradox, to consider your change in perspective and what you are considering true from each perspective.

 

Maybe I don't believe that the twin will be younger when she returns to Earth. You can't ask me to explain how that can happen, when I don't think it will. You have to explain to me, why you don't see a contradiction, in the fact that neither twin ever left the universe, the universe proceeded (aged) along with each twin, has to be the same age as each twin, and therefore the twins cannot be a different age, when they reunite.

 

In spacetime equations, there is a t and a t'. I am not sure, when these equations are concieved, as to what is being held stationary, what is proceeding, and from what perspective, each consideration is being made. In the twin paradox, it is mentioned that the universe and all physical processes proceed normally, for each twin. The one twin is moving in respect to the other twin, so relativitywise any acceleration the one has, away from the other, will be exactly the same acceleration the other has, away from the one. If you are claiming a difference for the Earthbound twin, because of his association with the Earth and Sun and their gravity, then that should be in the equation...and it is not a consideration...so there is no difference, conceptually, between me traveling at 98 percent the speed of light, relative to you, and you traveling 98 percent the speed of light, relative to me. If the traveling twin should age less than the stationary one, then the stationary one, should age less than the traveling one, as well. Since the twin paradox says the traveling one ages less, there must be a mistake, in the perspective switch somewhere to explain why the calculation would come up with an impossible result. The contradiction is in the claim of the twins being a different age. It does not jive with my definition of age. If a clock is moving away from you, it will tick slower, in your eyes, because it is moving away from you (red shift). This does not add up to the person, with the clock aging less than you. They are aging at the same rate, from a universal perspective, but are separated from you, by distance that it takes light to traverse. I am holding age constant from a god's eye perspective, that I can not have, just imagine, but it all adds back correctly. Just like the fact that the Sun is burning now, in two senses, is NOT a contradiction. While it IS a contradiction, to say that the Sun does not exist, really in the universal now sense of the idea of "exist" AND to claim that the Sun is currently burning 8 minutes prior the arrival of its photons. It HAS TO exist now it a god's eye view of now, in a universal now sense, inorder for it to appear in our sky, to exist in our sky, in 8 minutes. The fact that it will appear in our sky in 8 minutes is the prediction the assumption that it exists, burning right now, in a universal, god's eye, imagination of TAR, way, makes.

 

You say it cannot both exist now, in a universal now sense, AND exist now as a hot thing in our skies, because that would put it two places at once, and it cannot exist at just two places at once, and it has to exist at all its spacetime coordinates all the time. Our definitions contradict each others but I am not interested in explaining the contradictions in your definitions, I am interesting in showing where my definitions add up, and make sense, where your definitions result in contradictions.

 

Regards, TAR

Correction: I am not saying that the experiments showing a slowing of clocks at velocity, and a speeding of clocks at altitude are not correct. But general relativity and special relativity are hard to always consider together, as to what effects should be considered as being a result of being near a gravitational mass, and what effects should be considered as a result of a certain velocity obtained by being a certain distance from the center of a rotating frame of reference. Such difficulty is obvious from this line taken from the Wiki article on " Error analysis for the global positioning system".

 

"That is, the combination of Special and General effects make the net time dilation at the equator equal to that of the poles, which in turn are at rest relative to the center. Hence we use the center as a reference point to represent the entire surface."

 

It is difficult for someone like me, to understand why, for some considerations, the rotation of the Earth should be added or subtracted to velocity, and why sometimes it should be ignored. The center of the Earth is approximately the same distance from the equator or from the poles, at least in terms of altitude, the two points, that of a point on the equator and that of a point on a pole, are approximately the same altitude, and there should be no general relativity difference between the ticking of the one, and the ticking of the other. Whereas there should be a special relativity effect, as the point on the equator is rotating at a velocity, relative to the center of the Earth, whereas the point on the pole is on the axis of rotation and is not moving, relative to the center of the earth. So why would the relativistic effects of general relativity and those of special relativity cancel out when considering the clock at the pole, and the clock at the equator?

Edited August 10, 2015 by tar

[Endy0816]

 

In the twin paradox, it is mentioned that the universe and all physical processes proceed normally, for each twin. The one twin is moving in respect to the other twin, so relativitywise any acceleration the one has, away from the other, will be exactly the same acceleration the other has, away from the one. If you are claiming a difference for the Earthbound twin, because of his association with the Earth and Sun and their gravity, then that should be in the equation...and it is not a consideration...so there is no difference, conceptually, between me traveling at 98 percent the speed of light, relative to you, and you traveling 98 percent the speed of light, relative to me. If the traveling twin should age less than the stationary one, then the stationary one, should age less than the traveling one, as well.

 

Provided both are moving apart, this is absolutely true. Both will see the rate of time passing as slower for the other.

 

Up to this point the situations are symmetrical, but now how does the space traveling twin get back home?

 

Does the Earth based twin need to do anything special to meet up with his brother?

Edited August 10, 2015 by Endy0816

[Strange]

In the twin paradox, it is mentioned that the universe and all physical processes proceed normally, for each twin. The one twin is moving in respect to the other twin, so relativitywise any acceleration the one has, away from the other, will be exactly the same acceleration the other has, away from the one.

 

Sigh. No. (Again.)

 

Velocity is purely relative (you can never tell if you are stationary or moving, without reference to something else).

 

But acceleration is absolute: you can always tell if you are accelerating. You will feel a force pushing you back in your seat, for example. (OK. You can't tell if you are accelerating or in a gravitational field, but that is another matter.)

So why would the relativistic effects of general relativity and those of special relativity cancel out when considering the clock at the pole, and the clock at the equator?

 

That is explained in detail in the referenced paper: http://newt.phys.unsw.edu.au/einsteinlight/jw/2006AJP.pdf

 

(The Wikipedia page in question is: https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System#cite_ref-19)

Edited August 10, 2015 by Strange

[tar]

Strange,

 

Well thanks for the link. It sort of starts to answer...but then still confusion. If we were to launch a clock in a balloon on the North Pole, and put it 21kms up, it would be at the same distance from the center of the Earth, as a clock on the surface, at the equator, so General relativity concerns would be identical and only the velocity differences would be slowing the clock at the equator.

 

The launched clock at the pole would run faster than the surface clock at the pole, because it is further from the gravity of the Earth. The clock in the balloon at the pole would be running faster than the surface clock at the equator since the two surface clocks are running at the same pace, according to the figuring of equal potential.

 

On the equator, if we were to take a clock down into a hole 21 kms deep, to equalize the general relativity concerns as to distance from the center being equal to the surface clock at the pole, we would slow it down in velocity slightly, which would speed the clock up, but bringing it closer to the center, would slow the clock down. I am guessing, the clock in the hole at the equator would run slower than the clock at the surface at the equator. Similarly, if we were to launch a clock in a baloon at the equator, the altitude change would speed it up, but the velocity increase would slow it down. I am guessing that the clock in the baloon at the equator would run slower than the clock at the surface at the equator, according to special relativity.

 

So what must we do at the equator, with a clock, to speed it up? Lowering it slows it, as it gets closer to the center per general relativity and raising it slows it as its velocity increases, per special relativity.

 

Not so at the pole. Lowering it only has general relativity effects, and it slows. Raising it only has general relativity effects, and the pace of the ticking increases, as the pole is on the axis of rotation and no acceration due to rotation is present.

 

So the Earth provides rotational velocity, slowing the ticking per special relativity at the equator. No special relativity effects are present at the pole, at any altitude. So how can the special relativity effects cancel out the general relativity effects of a squished Earth, if there are NO special relativity effects at the axis of rotation?

 

Regards, TAR

[tar]

Endy0816,

 

I would think it reasonable to assume that since the clocks of each twin are slowed in the eyes of the other twin, as they separate in distance, that when they close the distance, the other's clock will appear to speed up. The red shift frequency shift as they separate will be exactly opposite the blue shift frequency shift as they get closer to each other.

 

The traveling twin is only younger, in terms of how she looks from earth. As Proxima Centauri looks 3 years younger than it is when we look at it from here, the traveling twin will look 3 years younger to us, as she passes Proxima Centauri. She will however be exactly as old as the rest of the universe, including her brother on Earth...who by the way, should look as if he didn't age 3 years that she knows have passed for her. This makes sense, when you add up the light waves that have hit her, coming from her brother on Earth as she has traveled. They hit her at exactly the speed of light, but the frequency of the waves is redshifted. Three years worth of images from her brother, are traveling through space, at the speed of light, carrying with them the information as to what the brother has done, and how he has aged in the last three years. As she slows to a stop, near Proxima Centauri the images from her brother are no longer red shifted, but appear normal speed. He is not moving and aging in slow motion any longer, he is moving and aging at normal speed, but is doing what he was doing 3 years ago. As she accelerates back to 98 percent the speed of light, on her way back, her brother appears to speed up and age quickly as she is "running into" the images that were on their way to Proxima Centauri. When she is 1 ly from Earth her brother should look only 1 year younger than her. When she gets back and stands next to him, everything looks exactly as it should. She never left the universe. It ticked along exactly as it would have, should she not have made the trip.

 

Regards, TAR

Thread,

 

Another aspect of the twin paradox trip, that is not considered, is what the other twin would "look like" to the other. At 98 percent the speed of light, the traveling twin would not "see" the Earth and her twin in wavelengths in the visable spectrum, as the visible wavelengths leaving her twin and coming toward her are stretched to microwave or radiowave length. Perhaps they should each carry a x-ray or gamma ray becon that would be "visable" to the other. On the way back, they should shift to some microwave or radio becon that the other can "see".

 

Regards, TAR

Edited August 12, 2015 by tar

[Janus]

Endy0816,

I would think it reasonable to assume that since the clocks of each twin are slowed in the eyes of the other twin, as they separate in distance, that when they close the distance, the other's clock will appear to speed up. The red shift frequency shift as they separate will be exactly opposite the blue shift frequency shift as they get closer to each other.

 

The traveling twin is only younger, in terms of how she looks from earth. As Proxima Centauri looks 3 years younger than it is when we look at it from here, the traveling twin will look 3 years younger to us, as she passes Proxima Centauri. She will however be exactly as old as the rest of the universe, including her brother on Earth...who by the way, should look as if he didn't age 3 years that she knows have passed for her. This makes sense, when you add up the light waves that have hit her, coming from her brother on Earth as she has traveled. They hit her at exactly the speed of light, but the frequency of the waves is redshifted. Three years worth of images from her brother, are traveling through space, at the speed of light, carrying with them the information as to what the brother has done, and how he has aged in the last three years. As she slows to a stop, near Proxima Centauri the images from her brother are no longer red shifted, but appear normal speed. He is not moving and aging in slow motion any longer, he is moving and aging at normal speed, but is doing what he was doing 3 years ago. As she accelerates back to 98 percent the speed of light, on her way back, her brother appears to speed up and age quickly as she is "running into" the images that were on their way to Proxima Centauri. When she is 1 ly from Earth her brother should look only 1 year younger than her. When she gets back and stands next to him, everything looks exactly as it should. She never left the universe. It ticked along exactly as it would have, should she not have made the trip.

Nope, for one thing, Proxima Centauri is 4.3 ly away, but we'll skip that and use your 3 ly figure.

The Doppler shift can be found with

sqrt((1+beta)/(1-beta))

where beta is equal to v/c and is positive if the source is approaching.

If v = 0.98c, then the factor is ~0.1005 for when they are separating and ~9.94987 when they are approaching.

Thus, according to our Earth observer, he sees his twin age at a rate of 0.1005 for the entire outward leg. It takes his twin 3/0.98= 3.06122 yrs to reach Proxima. However, since Proxima is 3 ly away, he doesn't see this happen until 6.06122 yrs have passed for him. Thus he sees his twin age at a rate of 0.1005 for 6.06122 years and the age he sees him as being 0.609176 yrs older upon arriving at Proxima. For comparison if we assume that there was a clock at Proxima which was sync to the the Earth observer clock, our Earth observer would see that clock as reading 3 years behind his, and upon the arrival of his twin, he would see this clock read 3.06122 yrs. (- 3 yrs + 6.06122 yrs). Seeing this, he can calculate that when his own clock read 3.06122 years, his twin had aged 0.609176 yrs.

The other thing to note is that since the Earth observer doesn't see his twin turn around until 6.06122 years have passed, his twin, having turned around after 3.06122 yrs is already most the way back to Earth when the Earth observer sees him reach Proxima. The entire trip by the Earth observer's clock takes 6.12245 yrs. so he only sees his twin approaching for .061225 yrs, during which time he see him age at a rate of 9.94987 or ~0.60917 years for a total of 1.21836 yrs of aging for the entire trip. The time dilation factor for 0.98c is ~.198997 and 6.12 x .198997 = 1.21836. What the Earth observer sees agrees with what time dilation predicts.

 

The traveling twin sees the following:

On the outbound leg he sees the Earth clock run at a rate of 0.1005. The distance between Earth and Proxima is ~0.596992 light years ( Promixa and Earth are moving at 0.98c relative to him and thus they and the distance between them is length contracted). At ).98c it takes 0.609176 yrs to cross 0.596992ly, so his clock will read 0.609176 yrs when he and Proxima meet.( note that this is exactly what the Earth observer sees as his age upon reaching Proxima) Meanwhile, he sees the Earth age 0.061224 years due to Doppler shift. He then fire his engines so that the velocity between Earth-Proxima and himself reverse direction. At this time he sees the Doppler shift from Earth shift from 0.1005 to 9.94987. (while the Earth observer had to wait 3 years to see this shift, he doesn't. The Earth observer was three ly away from the event of his changing velocity, while he is at the event and sees the results instantly.)

It takes another 0.609176 years before he and Earth meet up again, during which time he see the Earth age 6.06122 years. This added to the .061224 from the outbound leg equals 6.12245 yr, The same time the Earth observer measured for the trip. He himself has experienced 1.21836 years during the whole scenario

 

Both twins agree that the Earth twin aged 6.12245 yrs while his brother aged only 1.21836 yrs. between the time they separated and rejoined.

Edited August 12, 2015 by Janus

[tar]

Janus,

 

Doesn't this statement require there be two nows? One where the traveler is already most of the way back to Earth, and one where the Earthbound twin is looking at what time the clock reads on Proxima Centauri?

 

"The other thing to note is that since the Earth observer doesn't see his twin turn around until 6.06122 years have passed, his twin, having turned around after 3.06122 yrs is already most the way back to Earth when the Earth observer sees him reach Proxima."

 

The Earthbound twin must be able to watch the traveling twin, from turnaround until she is home. There is only one instance of his sister. In your figuring you jumped from the one now to the other inappropriately. You figured the 9.9 factor for only the small fraction of the trip that was left after the twin had already traveled most of the way home, based on the fact that the turn around had happened 3 years before it was seen to happen along with a clock that was 3 years retarded, figuring that just now, the traveler is almost home. But "just now" the clock on Proxima Centauri has ticked off the 3.06122 yrs it took her to get back, and she separated herself from the clock at such a rate, as it appeared to hardly move at all. Since she is always in view, she must look as if she is sped up considerably more than 9.9 times. She appears to make a 3 lyr trip in .061125 yrs. She would have to appear to be aging at 50x the normal rate during the whole time after the turn around is seen, 'til she was standing next to her twin. Which means she aged the three years it took her, to make the trip. No time dilation or length contraction required. Just a view of her, coming back like a fast forward movie, viewed in the high ultraviolet near x-ray, band.

 

Regards, TAR

Janus,

 

If both twins watch a outside clock, like a pulsar, during the trip, wouldn't they have to count the same total pulses from separation, until they were reunited? Wouldn't they have to both age the same amount of time as pulses of the pulsar? If the pulsar was in the direction of, and behind Alpha Centauri, she would see it pulse faster than normal on the way out, and slower than normal on the way back, but her total count, would have to be the same as her brother's, once they were together again. Neither ever left the universe, nor left the view of the pulsar.

 

Regards, TAR

[tar]

Janus,

 

So when you say we have synced the clock on Proxima Centauri and the clock on Earth, what do you mean?

 

The clocks are separated by 3 years of light travel time. They are by definition, out of sync. There is not a faster than light method we have to see both clocks at once, as to what tick they are currently on. There is my universal now consideration, where both the clocks are on their 13.8 billionth yearly tick, but that seems to be under question here, so we have to agree as to whether we are allowed to know a clock is on a tick we will not see for 3 years, or not. In the experiment, there are four perspectives that can be taken, and what "time" it is from each perspective has to add back fully to what time it is from the other 3 perspectives, at any particular moment a particular event is occuring, for the observer observing it. The switch from one perspective to the other, can not be made willy nilly, but must be made completely, with everything adding up in terms of what is seen and what is imagined actually being the case, from each perspective. To fully watch the whole scene unfold from any one perspective, you have you follow it, from all four, simultaneously, putting what needs to be imagined in the actual or apparent, or "has to be" category, depending on what must be the case, for everything to add up. You can't shift from apparent to figured, to actual, and claim you are viewing the event from "the same time" because you are not.

 

You have not explained why the traveling twin disappears on the way back, and exists in an invisible imaginary state, "almost home", when the turnaround is viewed.

 

At any stage of the trip, it is a time on Earth, a different time on the ship, and a different time on Proxima Centauri. The only time that connects the three is the imaginary universal now, that is the actual time each observer (or the environment they are in) has aged since the beginning of the universe 13.8 billion years ago. That and the local now that the twins share on departure and on reuniting, and the local Proxima Centauri time the Proxima Centauri observer shares with the traveler, when she is in the local area of Proxima Centauri.

 

If we can't have a universal now as an imagined reference, you wind up having to dilate time, and contract length. Both operations are highly imaginative, and physically impossible, and difficult to "add back" in terms of what each observer should see of the others during the trip. You wind up with difficult situations, and difficult questions, like "does light travel faster than light, when it transverses a contracted distance?" If time is dilated and distance is contracted, how can 186,000 miles per second, have a meaning?

 

Regards, TAR

[Janus]

Janus,

 

So when you say we have synced the clock on Proxima Centauri and the clock on Earth, what do you mean?

 

The clocks are separated by 3 years of light travel time. They are by definition, out of sync. There is not a faster than light method we have to see both clocks at once, as to what tick they are currently on. There is my universal now consideration, where both the clocks are on their 13.8 billionth yearly tick, but that seems to be under question here, so we have to agree as to whether we are allowed to know a clock is on a tick we will not see for 3 years, or not. In the experiment, there are four perspectives that can be taken, and what "time" it is from each perspective has to add back fully to what time it is from the other 3 perspectives, at any particular moment a particular event is occuring, for the observer observing it. The switch from one perspective to the other, can not be made willy nilly, but must be made completely, with everything adding up in terms of what is seen and what is imagined actually being the case, from each perspective. To fully watch the whole scene unfold from any one perspective, you have you follow it, from all four, simultaneously, putting what needs to be imagined in the actual or apparent, or "has to be" category, depending on what must be the case, for everything to add up. You can't shift from apparent to figured, to actual, and claim you are viewing the event from "the same time" because you are not.

Send a light signal from the Earth to Proxima with the information that the Earth clock read 0 when the light left. The clock at Proxima is stopped but already reading 3 yrs. Upon arrival of the light signal from Earth it starts. Since the light took three years to reach Proxima the two clocks read the same at the same time. Or you place a light source halfway between Earth and Proxima and have it send a flash to both. When it arrives, both clocks start. Either method ends up with the clocks being in sync in the Earth-Proxima frame.

I don't know where you set the idea that just because the two clocks don't physically see the same time on each other means that they are out of sync. You are using a different definition for " synchronized" than what is accepted in Relativity. There is no requirement for there to be a faster than light method to synchronize two clocks in the same frame.

 

 

You have not explained why the traveling twin disappears on the way back, and exists in an invisible imaginary state, "almost home", when the turnaround is viewed.

The traveling twin does not disappear. The Earth observer sees him during the whole trip back, he just sees the trip compressed in time. The light that left Proxima when the traveling twin starts on his trip back takes 3 years to reach Earth. The traveler himself takes 3.061224 years to make the trip. Thus the light arrives just 0.061224 years ahead of the ship. All the images of the ship between the it leaving Proxima and arriving at Earth will arrive in sequence within this 0.061224 yr period. This will make it visually appear to the Earth observer that the ship traveled from Proxima to Earth at greater than c speeds, but that is just an optical illusion caused by the fact that the ship is following its own light so closely.

It is important to distinguish what the Earth observer "sees" in terms of light arriving from the ship at any given moment from what is actually state of the ship at that moment according to the Earth observer. He may "See" the ship 3 light years away, But the ship at that moment is actually only 0.06 ly away, and he'll "see" the light from the ship in this position 0.06 yrs later.

You might be confused by the how the word "see" is used in Relativity discussions at times It is common to say that a stationary observer "sees" a moving observer as being time dilated. But what is meant here by "see" is not meant to mean what he physically sees by visible light, but by what is left over after accounting for Doppler effect and light propagation delay caused by distance.

 

At any stage of the trip, it is a time on Earth, a different time on the ship, and a different time on Proxima Centauri.

Again, since Earth and Proxima are at rest with respect to each other, it is the same time on Earth as it is Proxima in the Proxima-Earth rest frame. The light propagation delay between the two does not effect the time measurement between the two.

The only time that connects the three is the imaginary universal now, that is the actual time each observer (or the environment they are in) has aged since the beginning of the universe 13.8 billion years ago. That and the local now that the twins share on departure and on reuniting, and the local Proxima Centauri time the Proxima Centauri observer shares with the traveler, when she is in the local area of Proxima Centauri.

 

If we can't have a universal now as an imagined reference, you wind up having to dilate time, and contract length. Both operations are highly imaginative, and physically impossible, and difficult to "add back" in terms of what each observer should see of the others during the trip. You wind up with difficult situations, and difficult questions, like "does light travel faster than light, when it transverses a contracted distance?" If time is dilated and distance is contracted, how can 186,000 miles per second, have a meaning?

 

Regards, TAR

 

It seems to me that you are placing yourself in the same type of position as those that used to argue that the World couldn't be round because the people on the underside would fall off. These people thought of the direction "down" as being universal and this was the "natural state of things.

A round world would then naturally have a "top" and "bottom" and people would only be able to stand on the top. The idea that "down" could be towards the center of the round world was rejected because that would mean that "down" could be be in many different directions at once, and down "naturally" could only have one direction.

 

I think you are doing the same thing with Relativity. You have formed a view of time and space that seems "natural" to you, and Relativity runs counter to this view. It says that two observers in relative motion with respect to each other will both consider time as running slow for the other. You don't see how this can be as it runs counter to your notion of the nature of time. But just like the round Earth model rewrote the concept of "down", Relativity forces us to rethink our notions about time and space.

So you have two choices you can either accept and try and learn this new model for time and space, or you can rail against them in favor of your own. But be warned, if you choose the second course you should be aware that a good bit of modern technology is based on the idea that the Relativistic view of the universe is the correct one. Arguing against it is much like arguing for a flat Earth in an age where we have orbital satellites.

[tar]

Janus,

 

How is asking for sensibility equate to railing against relativity.

 

I am assuming that there is no "preferred" time, and that every here and now is on their own clock. However, as you allow a clock 3 lyrs away to be in sync with a distant clock in its reference frame, so do I. In fact that is the basis of my argument. The clock on Proxima Centauri is ticking presently its 13.8billionth year tick, as is the clock on Earth, as is the clock on the planet that has formed several star generations after the quasar we are looking at, in deep space. But my imagination requires that every clock, everywhere is equally synced and is ticking its current tick for the first and only time it will tick that tick.

 

Where I have adjusted my thinking is in the sense that I cannot "see" or know or contain the happenings further away than the moon or so, because the stuff I see currently happening at those distances, is the real current existence of the thing, whereas any further than a moment away, the thing I see is more an image of the actual event, then the actual event. That is the thing I see happening on Proxima, happened three years ago, not a moment ago. As the ship gets closer, on its return trip, its position becomes closer and closer to being within a moment of me. It changes character from being image, to being actual, and that which I have to figure, becomes eventually that which is actually happening the moment I see it. In the mean time, as I watch my blue shifted twin getting closer to the Earth she is watching the Alpha Centuari clock get further and further out of sync, with her clock. She can know the clock is actually in sync and only the light travel time is the difference between image and actual, or actual and image, but she cannot maintain this understanding if her clock is not ticking at the same rate. As she watches the Proxima Centauri clock separate from her's in the same manner as the Earth's clock separated from her on the way out, the way the Proxima clock acted on the way there, is the same way the Earth clock will act now that she is on the return trip. If there is no time dilation or length contraction used to account for the differences noted from each perspective, her clock can tick along exactly at the pace of both the Earth bound clock and the Proxima clock and she can still, because of light time delay, see the Earth bound clock as ticking slow on the way out and ticking fast on the way back, and the Proxima Clock as ticking fast on the way out and ticking slow on the way back, and nobody's clock is ever out of sync with anybody elses.

 

Regards, TAR

In the quantum domain it is considered that a particle's position and momentum can not both be known. However in retrospect, one can assume the particle had to be within the distance a particle can travel in the time it took light to get from the spot of detection to the detector. That is, that probability cannot say that the particle was on Proxima Centauri 4 nano seconds ago. It had to be within 4 nanosecond light travel time from the spot it was detected 4 nanoseconds before it was at the location it was detected at.

 

In science, there is a classical assumption about certain things that puts certain limits at infinity, when the speed of light actually sets a distance limit, an impulse, or field or particle can displace within a time period. And then in modern figuring the speed of light is often reduced to unity. I take a middle ground, where infinity makes no sense, because the speed of light is finite, and unity makes no sense because the speed of light is an actual physical reality, that means something in terms of distance and time. The universe is actually immense enough that 186,000 miles per second is a crawl when the grain size is that of a galaxy. What can happen in a model, or in a mind, can happen in a moment, when the actual thing happening will take 100,000 years. So the relativity model, that models the whole universe as one thing where every x,y,z,t coordinate is equally accounted for, is not possible or realistic or like the universe, at all. That is, the block universe fails, when it is obvious to the both of us, that we need to allow the clock on Proxima to tick currently, even though we won't see the tick for 3 (4.8) years.

 

Regards, TAR

Edited August 13, 2015 by tar

[tar]

Thread,

 

In imagining the Earth and its rotation, and its revolution around the Sun, and the Sun's trek around the center of the Milky Way, and the Milky Way's trek toward the great attractor, and an unknow movement of the great attractor around or toward some other point, there are a lot of velocities and gravities to consider. It is very hard to imagine an equation that takes all the motions and gravities into account, applying special relativity formulae properly at the right moment and general relativity formulae at the right moment, and knowing whether to consider the Sun deep in the Galaxy's gravity well, or far from its center...etc. When ever we write an equation, it is usually an approximation, letting certain terms fall to zero and be ignored, and others approach limits, that may or may not be correct, when assuming a differently sized system. The light travel time from one corner of a sugar cube, to the other, for instance is not 0, while for certain considerations it can be taken as such. While the light travel time from here to the center of the Milky Way, is considerable, it can niether be taken as 0 or as infinity or as 1, because the light travel time is different than the time it takes light to get from one corner of a sugar cube to it's far corner. It is a particular number, in both cases, and for certain consideration the one number should be used, and for other considerations the other should be used, but if ever dropped to 0 or taken to infinity, or to unity, in the one case, it ruins the import of the figure in the other case.

 

Different things can be said about the universe. Predictions can be made, based on measurements and prior readings as to what will happen again, or is likely to happen next. But most of the universe is happening, more than a moment away, but, since nothing we know of happens without a context, the context is important to consider. The imagined burning of the Sun, at the moment, 8 light minutes away forces what is sensed to be delayed information about what actually occurred in the past, that we will see and sense in 8 minutes to be a constant condition. A constant context that is always the case. The Sun has nuclear reactions going on now, in the universal sense of the word now, that will get here in 8 minutes. The photons we see now were released 8 minutes ago, and were halfway here 4 minutes ago, and the image of the Sun we will see in 4 minutes is currently "residing" in space, halfway between here and the Sun. If an observer there, now, were to look at the Sun, they would see photons that were released from the Sun, 4 minutes ago. Each spot in space can be likewise figured, base on two conceptions. Here and now, happening now for the first time ever. And here and now, also happening everywhere else, for the first and only time, ever, right now.

 

Regards, TAR

In the twin paradox, a number very close to the speed of light is used to show how time dilation, and length contraction must occur, for other things to remain true. I wonder sometimes how many other things would actually have to be different though, to get a twin and her ship, to 98 percent the speed of light. It would not be instantaneous, so a geometrical track of her progressive acceleration would have to be laid out, and what was happening to time, in terms of which here and now, she was in, at each moment, would have to be taken into consideration, and the track of the Sun around the Milky Way, and such, and what "time" it was, at each point in the journey, at that point in space, regarless of the fact that the traveling twin, is in that spot. She could be traveling fast or slow, left or right, up or down, excellerating or decellerating, and the spot she was in, in space would still have the exact relationship to every other spot in the universe, as it did before she got there, and as it would, after she left. It is a certain time in that spot, regardless of her presence. It is 13.8 billion years after the big bang, everywhere, now.

 

And the other problem with the twin paradox is the immense amount of energy it would take to get her traveling that fast. She can't take the fuel with her, because she would have to take along the mass required to turn to energy to accelerate to that speed and what happens to the gravity of a mass, and its inertia when it is changed to energy, along with the E=MCsquared formulae? Too many things are changing during the thought experiment, that have to be held constant to make a simple formulae. I don't think the universe operates in such a way as complex connected systems can be simplified to isolated systems, and have the predictions be realistic and meaningful. Imagining a block universe, ignores the actual one.

 

Regards, TAR

[Endy0816]

Time dilation and length contraction are what keeps things consistent not the other way atound.

Edited August 14, 2015 by Endy0816

[tar]

Endy0816,

 

Well I understand. For the definitions of Hilbert Space and dynamical systems and such it is possible to make time a dot above a symbol and basically drop it from consideration of some eigenvalue taken in some higher dimension or whatever...but these are analogies and manuveurs and functions taken in the mind of a mathematician, not actual "things" going on in reality.

 

The universe already fits together flawlessly, it does not have to respond to, or fit into an equation. There are many equations that work very much like reality does, especially in geometry and three dimensional cartesian coordinates but there are areas where analogies and transforms and "pure" systems act as a decent model of the place, but do not result in making the place do what it does.

 

You say that time dilation and length contraction keep things consistent, not the other way around. This seems backward to me. You could be right, and time dilation and length contraction actually occur, but it could also be the case that they are just a result of the way we look at things, and define things and have established a mental model of the place, that goes by certain rules, that "works out" nicely, if you stick to the definitions and the rules, and make the right transforms and the right time, drop the right terms, add the right terms and apply the right sensible adjustments at the right time and so forth. My contention is not that physicist and mathematicians don't know what they are talking about, but that what they are saying about reality does not compare in strength and sureness with what reality already does. That is, that if the reality of situation is that lengths contract, and time dilates, then C has no meaning, because the speed of light is defined as the time it takes light to travel a certain distance. If neither time or distance is fixed, then the speed of light is not fixed. I think the speed of light is absolutely fixed, as the universe itself only operates by its own rules. It cannot do anything wrong, it has to always do the fitting thing, that relates flawlessly to everything else. Regardless of what is in our model of it.

 

Regards, TAR

[Strange]

In the twin paradox, a number very close to the speed of light is used to show how time dilation, and length contraction must occur, for other things to remain true.

 

 

Speeds close to the speed of light are used in examples, simply to give "impressive" numbers. No one would be very interested in a more realistic description involving real spacecraft where one person is a few picoseconds older than their twin. I think most people would just shrug and say, "so what".

 

I wonder sometimes how many other things would actually have to be different though, to get a twin and her ship, to 98 percent the speed of light. It would not be instantaneous, so a geometrical track of her progressive acceleration would have to be laid out, and what was happening to time, in terms of which here and now, she was in, at each moment, would have to be taken into consideration, and the track of the Sun around the Milky Way, and such, and what "time" it was, at each point in the journey, at that point in space, regarless of the fact that the traveling twin, is in that spot. She could be traveling fast or slow, left or right, up or down, excellerating or decellerating, and the spot she was in, in space would still have the exact relationship to every other spot in the universe, as it did before she got there, and as it would, after she left.

 

All of those things could be taken into account, if you just wanted to make the calculations more complicated. You would end still end up with a different total elapsed time.

 

It is 13.8 billion years after the big bang, everywhere, now.

 

No it isn't.

 

And the other problem with the twin paradox is the immense amount of energy it would take to get her traveling that fast.

 

That is why it is a thought experiment. Of course, when the experiment was really done, the speeds were nowhere near the speed of light.

 

I don't think the universe operates in such a way as complex connected systems can be simplified to isolated systems, and have the predictions be realistic and meaningful.

 

I think you are wrong. I have working science on my side. You have a vague (and incorrect) belief.

The universe already fits together flawlessly, it does not have to respond to, or fit into an equation.

 

But, amazingly, it does.

 

You could be right, and time dilation and length contraction actually occur

 

They do. We have measured them, directly and indirectly. On the "indirectly" side, if it weren't for these, your computer would not work, systems which depend on GPS for time keeping and distance measurement would not work, and so on.

 

My contention is not that physicist and mathematicians don't know what they are talking about, but that what they are saying about reality does not compare in strength and sureness with what reality already does.

 

Then you should be able to provide some evidence of what reality does that is different from our current theories. Can you do that?

 

That is, that if the reality of situation is that lengths contract, and time dilates, then C has no meaning, because the speed of light is defined as the time it takes light to travel a certain distance. If neither time or distance is fixed, then the speed of light is not fixed.

 

You are talking nonsense. Length contraction and time dilation are inevitable (and fairly simple) consequence of the constant speed of light (as described by Maxwell's equations - which were based on experimental evidence and have been repeatedly tested since).

 

I think the speed of light is absolutely fixed, as the universe itself only operates by its own rules. It cannot do anything wrong, it has to always do the fitting thing, that relates flawlessly to everything else. Regardless of what is in our model of it.

 

And that is why we test out models against reality. To show that they match.

[tar]

Strange,

 

I already have predicted that the Sun is currently putting out photons that we will see in 8 minutes, based on the fact that we see some photons now, that we know had to have been released 8 minutes ago, because of the distance between the Earth and Sun and the speed of light. It seems an obvious fact to me, about how the universe must work, and you say I am talking nonsense.

 

I don't know why you consider the stating of such obvious truth, as being heretical to science.

 

Regards, TAR

Strange,

 

And I certainly don't understand why I deserve a neg rep for saying that the universe is more complete and sure and accurate then any model of it we can formulate.

 

Do you think the model is better than the thing it is modeling?

 

I suppose the problem is here, that I am trying to share an insight, and I am being told the insight is incorrect. Yet it seems "forced" to me, and I can't unsee it.

 

I'll stop, but its not because I think I am wrong, but because I am obviously not being helpful.

 

Regards, TAR

[Strange]

I already have predicted that the Sun is currently putting out photons that we will see in 8 minutes, based on the fact that we see some photons now, that we know had to have been released 8 minutes ago, because of the distance between the Earth and Sun and the speed of light. It seems an obvious fact to me, about how the universe must work, and you say I am talking nonsense.

 

No one disagrees with this. Why do you keep pretending that they do?

 

 

I suppose the problem is here, that I am trying to share an insight, and I am being told the insight is incorrect. Yet it seems "forced" to me, and I can't unsee it.

 

And that is why science doesn't rely on "insights", beliefs, common sense or popularity. What seems "obvious" to you is shown to be wrong by observation and experimental evidence.

 

The fact that you cannot get over your intuition in favour of a more accurate model doesn't make you correct. It just makes you misguided.

[tar]

Strange,

 

My model has two nows that are actual.

 

Does the block universe have two nows that are actual, or not.

 

If no one disagrees with my take, then which part of it, is nonsense?

 

For the Sun to be burning in our sky, at the moment, and for it to be burning in my imagination and your imagination, right now, 8 light seconds away, requires there to be either two instances of the Sun, which makes no sense, or one instance of the sun that requires it informs the rest of the universe of its presence at the speed of light. The reciprical arrangement is such that the Earth informs the rest of the universe of its presence, also at the speed of light. Since the Sun sees the Earth, presently, it is an 8 second ago Earth that it sees and vice a versa. The Earth sees an 8 second ago Earth NOW and the Earth sees an eight second ago Sun NOW.

 

If you agree with this statement of fact, and everybody agrees with this statement of fact, then NOW can be taken in two senses. One in which both the Sun and the Earth see the other as 8 seconds old, having done what they appear to be doing, 8 seconds ago, which means that what is seen is representative of actual occurances which have already happened. There must therefore exist a reality in which events are occurring now, which will be withnessed by both Earth observers as Sun happenings, and Sun observers as Earth happenings 8 seconds from NOW.

 

These two nows are obviously separated by a distance. The distance is exactly the time it takes light to get from the one place to the other. For the Earth observer the Sun actual exists only once and does its existing at a distance of 8 seconds. Same for the Sun observer, the Earth exists only once, at a distance of 8 seconds. But, right now, when we look in the Sky, the Sun is there. So the Sun exists in two senses. The one we see, and the one we imagine. It is in our sky NOW and it is in the actual universe from a godlike, imaginary, instantaneous perspective, NOW, as well.

 

Which part of this, is nonsense to you, if all parts are actual fact that everybody agrees with?

 

Regards, TAR