tar

Has this been tried? Match 12 lasers as closely as you can to be outputting the same frequency and power. Place them facing in 12 different directions from a center point, at each end of 6 different axis, (same configuration as twelve ping pong balls would fit around a center ping pong ball) Place a CCD a meter from the business end of each laser, and measure and record the output of each CCD as precisely as you can. Have the whole arrangement housed in an approximately 2 meter diameter sphere. Rotate the sphere to various positions (ie turn one of the axis end for end) and record any change in reading of any of the voltage outputs of any of the twelve CCD, of course recording the "up" position of the sphere in reference to the Earth, the latitude and longitude of the experiment, the time of day, date, year and so forth so you know the attitude of each laser in each of the recorded trials. If a pattern emerged, where a certain "direction" got higher readings and the opposite direction got lower...it might tell us which way we are headed.

P.S. to Cap'n, Wait, the return trip from the mirrors would need a couple more diagrams. After the bounce of the right wall, the laser is "chasing" the me, and will have to travel a longer distance than it did to hit the wall in the first place, and the laser that hit the left wall, although it traveled more than five meters to reach the left moving wall will have to travel less than 5 meters to get back to the me. The me will NOT measure the bounce off the right wall as shorter than the bounce off the left wall. The me will measure them the same. Off the right wall he/she will measure 10 units (4 plus 6) and off the left wall he/she will measure 10 (6 plus 4.) The me's only conclusion is his/her room is standing still! (although the me is incorrect.) P.P.S. cross posted Cap'n, Although, if the mirrors had energy sensors, or sensed the wavelengths of the laser, the right mirror would say that the laser was blueshifted to a higher energy or frequency, since the wavelengths were shorter, and the left wall mirror/sensor would say that the laser was of a lower energy, since the wavelengths were longer. The me would get back the same energy he/she put out since the return trip of each of lasers would be the reciprocal of respective trips to the wall, the blue shifted laser the right wall sees, redshifted on the way back to the me, and vice a versa to the left wall. Regards, TAR2 the me may still have some ways to discover the room is moving to the left Perhaps Michelson-Morley found no motion through the ether 'cause the upwind and downwind paths canceled each other out. In addition to measuring the fringes that found the wavelengths back in sync on return, they should have measured the energy hitting the upwind and downwind mirrors.

Cap'n, Is the speed of light constant, or is the measured speed of light constant? I am trying to understand the implications of your diagram. The diagram seems to be saying to me that it will take longer for the light to hit the left wall than it takes to hit the right wall. It will not hit both walls simultaneously but indeed will hit the right wall first, and later will hit the left wall. The distance the light has to travel to reach the right wall is shorter than that which it has to travel to hit the left, since the right wall moved to the left, toward the point of firing, and the left wall moved to the left away from the point of firing. This proves to me only that if the me was to measure the time it took light to reach each wall, by timing its return from mirrors on each wall he/she would find that it took a longer time to return from the left wall, than from the right wall. Already knowing the distance between himself and each wall, and already knowing that light travels one unit per second, his/her only conclusion could be that his/her room is moving in the direction of the left wall. Regards, TAR Schrödinger's hat, I'll take here and now as the preferred frame of reference. I'll take distance from here, in any direction to be the separation from here to there in meters. I'll take time from now, in either direction to be the separation from now to then in seconds. The things that are happening now everywhere will not be real to me until their effects reach me, which will take at least some amount of time, equal to or greater than the time it takes light, traveling at 300,000 meters/sec. to reach here from there. Which or course will be another now, 'cause it will take some time, and will be another here, because I will have moved by then. Regards, TAR2

Schrodinger's hat, (sorry, not sure how to get the umlaut) I guess my thought experiment was designed to establish one FOR that both the buoys and the double ended flashlight were operating within. All clocks, buoys and recording devices were to be brought back to the lab and studied to see what actually did happen, and "when" and "where" events actually occured, in the lab's reference frame, in retrospect. It seems to me, that in this scenario, the flashlight never leaves the lab's reference frame, and the conclusion would be that since length can not be (in the flashlight's FOR) both expanded in the rearward direction, and contracted in forward direction, or contracted in the rearward direction and expanded in the forward, that indeed the laws of physics themselves need to be assessed from just one frame. 'Cause clocks cannot slow unless they slow in reference to "normal", and if the flashlight's clock slows in reference to the "lab" which included the whole local group of galaxies, AND the clocks of the whole local group of galaxies slow in reference to the "normal" of the flashlight, then the whole shooting match should grind to a halt. Which it does not. So the flashlight does not redefine the universe and cause it all to move at .5C around it. It moves through the universe at .5C. The foward photons cannot reach the 187th and the first buoy at the same timestamp in the "galaxy lab" perspective, AND be figured by the flashlight to have to arrive at anything other than the "proper" time. So the flashlight does not see the universe as homogenous. It sees the one direction, in which it is traveling, as extremely blueshifted, and where it has been, as extremely redshifted. The flashlight "knows" it is traveling at .5C through the "galaxy lab". Regards, TAR2 P.S. And the flashlight "sees" the "fixed galaxies" that are perpendicular to its direction of motion, in normal light.

Cap'n, Well here is probably where I cannot understand what is meant. Why would he feel he needed to measure equal distances between his flashlight and a receding photon, and his flashlight and a photon he is chasing? He KNOWS he and his flash light are traveling at 93,000 miles per second because he is passing the stategically placed syncronized photon detectors, at that clip. These detectors have been placed on space bouys that are star powered and keep their position based on holding the angular position of a set of 12 "close" stars, 12 distant stars, and 12 "fixed" galaxies, precisely constant to the configuration existing when they where placed. The clocks on them where synchronized on Earth, flown each to their numbered buoy and back at a known speed and distance, any differences found were logged, so that when doing the final tally descrepencies could be subtracted or added as required. A recording device on each buoy would be hooked to its clock and detector which would timestamp every photon detection. We positioned 187 of these buoys each 1000 miles apart and tested, recorded and brought the records back to compare on Earth the results of a bevy of methods and facilities used to position and reposition the buoys (precisely tensioned thousand mile strand of fiberoptic cable, light flashes, radar, survey triangulation and all sorts of tests and measurement) until we were sure that the buoys WHERE indeed spaced in a straight line, 1000 miles apart. Then we run our test and our .5C flashlight flashes forward and backward as it passes the 94th bouy. My contention is, that the 1st bouy will timestamp the passing of the flashlight 12:00:00, the 94th 12:00:01 and the 187th 12:00:02 and the 1st will timestamp the flash 12:00:01.5, the 94th 12:00:01 and the 187th 12:00:01.5. Where am I going wrong? Owl, Why can the universe not be both subjectively real and objectively ideal? Regards, TAR2

Cap'n, OK, can we go over a few definitions and assumptions? "There is a distance between two objects." Does this imply that this distance is invariant? For instance, the traveling holder of the flashlight is "assuming" that the photon is 300,000 miles away from its launch position after one second, based on the constant speed of light, the invariance of seconds, and the invariance of miles. After one second, neither the holder of the flashlight or the photon is at the launch position of the photon. The holder is 150,000miles away, and the photon is 300,000miles. The observer sees neither the flashlight or the photon in his/her present time until some time after the events occurred, depending on his/her distance(real invariant distance) from the events in question. Or put another way. If the holder of the flashlight where to launch a photon forward (in the same direction as his/her .5C travel, and launch one backward at the same moment, after one second would not the forward launched photon be 150,000 miles from the flashlight, and the rearward launched one 450,000 miles from the flashlight, according to both the expectations of the .5C holder and the observer? Regards, TAR2 P.S. Again, I think we only have two ways to take "is". One being our actual here and now, and one being the metaphysical "universal now" we figure to be the case.

Iggy, If our ship is 300,000 meters long, there is a second's difference in the now of the forward portion and the now of the aft. You have to pick your t0 to be either the fore or the aft and figure the now of the other from there. What I take objection to is the thought that you can take both postions as happening similtaneously, in an objectively real way. This, I think, is what this thread is about. There is an objective reality that we can only parse by considering it, from one place (here) and one time (now). We have the ability to put ourselves, our here and now, in the shoes of another here and now, and calculate the differences in time and space by shifting our frame of reference from the one to the other, and seeing that everything adds back perfectly. If I am 240 miles from you, you are 240 miles from me. If I am writing this 3hrs. before you read it, you are reading it 3hrs. after I write it. What should we consider now? When I write this, or when you read this? Fact is, we both know how to switch back and forth, and know exactly what the other was refering to, or will be refering to. This requires both a subjective experience of here and now, and a metaphysical understanding of a collection of here and nows, that all are connected in a regular, specific way that fit together flawlessy. You cannot "see" all this objective reality from any one place and time, but the place and time you are at. And you cannot "know" all this objective reality from any places and times but the ones you have either experienced or put yourself in the shoes of. There is a suggestion that people make, that there is an objective reality, that is "greater" than the subjective reality that we experience and metaphysically understand. I do not believe that this makes any sense, and do not think that this is the way it has to be. We are of and in this objective reality. We sense it, and we know it. We experience it one time and place at a time. We have no other way to experience it. And by piecing together the various times and places, we can hold a working model, metaphysically, in our collective minds and libraries that lead us to believe correctly, that it is enormous in both size and duration, beyond our comprehension. The "way" it works is certainly also complex and intricate, beyond our comprehension, but it can only be experienced from our perspective, and can only be understood from our perspective. If there are things in reality that have had no effect on our reality, are having no effect on our reality, and will never have any effect on our reality, then they are of no importance or consequence. There is a "feeling" that people get, that they can contain it all, by understanding exactly how it works. I have a feeling that we already understand what contains who, and who contains what. Religious people have called it God. Physicists have called it Math. Some call it Nature, or the Universe, or Reality or simply "the way it is." No amount of figuring will put us in a position where we are greater than it. We will always be in and of it. Just a matter of sharing the experience, and making it possible for others to do the same. Iggy, I am very interested in understanding "how" everything works and fits together. And perhaps I will agree that classical mechanics cannot cover it. But I cannot discard a notion till I have the insight that naturally discards it. There is not a point of view that can check what is happening at both the front and the back of the ship at the same time, except a point at the middle of the ship. And this point can only know 1/2 a second later. It can not know what is happening "now" at both ends, except in retrospect. Regards, TAR2

Iggy, I am not sure why the frequency of the light observed, would not resolve any "differences". It is well known that objects (stars) moving toward each other appear blueshifted. For instance, if Alpha Centuri is 4.5 light years distant and now at the Sun is ts0 and now at Alpha Centuri is ta0, then the light we see coming from Alpha Centuri is a ta-4.5 year old image. If we were to head off toward Alpha Centuri at C (say we are riding a photon) it would take us 4.5 years to make the trip. When we got there, the time would be ta4.5 years. During the trip we would have experienced 9 years worth of Alpha Centuri images. As we journeyed, life on Alpha Centuri would appear to be moving at double time, at twice the frequency. When we got there, it would be ts4.5 and ta4.5. But as we look back at the Sun in our rear view mirror, time is standing still, the photons from the Sun completely red shifted to something with a wavelength 4.5 lightyears long. As we park on Alpha Centuri and continue watching the Sun, we see it proceed normally at normal wavelengths, starting at ts0. We make the return trip and we see the Sun in double time, at twice the normal frequencies, and get home 9 years from when we left (ts9) and look back at Alpha Centuri and although it is at ta9, we look back and see it as it was at ta4.5. Regards, TAR2

Iggy, Sorry for the long delay in response. Irene left us without power for 48hrs. and we just got internet back this afternoon. I had difficulties with the red line, because the trail end of it followed the moving planet. The trail end of it should have stayed at the starting point. But you tell me it was to show the distance between the moving planet and the photon. This is fine, except how does the scientist on the moving planet determine how far away from the ship the photon has gotten? We need the third "god's eye view" to make this determination. The moving planet's scientist cannot "see" the photon get to the other planet. I return to my simutaneity question. If the moving scientist knows the distance at the start is 1 light year, the photon will get there in a year and the moving planet,(I forget its speed, say .9C) will get there in 1.11... years. Whose perspective, or whose "now" is violated by this reality? Is the objective reality that relativity describes based on the now of the moving planet, the now of the stationary planet, or the now of a "God's eye" view that can see all events happening at once? Regards, TAR2

Iggy, In you diagram with the green planet and the blue planet the red line, at least the lead arrow represents only the position of the lead photon, which was emitted when the blue planet was at its starting point. At every point of its motion a new red arrow should go out to the green planet. According to my conception a photon emitted from the blue planet will travel the same speed and distance as there is between the blue and green planet, regardless of whether the blue planet is following it fast, standing still or going the other way. The second photon emitted by the blue planet would do the same. It would have a slightly smaller distance to travel, and would hence make the trip in a slightly smaller amount of time, but would still cover 186,000 miles per second. If a yellow planet at the midpoint, sent a signal to the green planet, when it saw the blue planet start moving toward the green, the signal would reach the green planet at the same moment the red arrow reaches it. If the yellow planet at the midpoint, sent a signal to the green planet, when it saw the blue planet pass by, the green planet would recieve the signal, at the same moment that it recieved the photons put out by the blue planet as it passed the midpoint. The "difference" between the signal from the yellow planet, and the signal from the blue planet, as seen by the green planet would be the "frequency" of the signal. If the same signal was sent by both the yellow planet and the blue planet, as the blue planet passed the yellow, the green planet would see the blue planet's signal "blueshifted", in comparison to the yellow's signal. Perhaps this conception requires an "ether" which Michelson/Morley did not find. But I don't think it does. What it requires only is an objective "medium" built by the magnetic and electric fields of the photon, which are subject to the characteristics of the electric and magnetic fields which the photon finds itself among. Subjective experience of any given signal requires that the signal was generated at a distant point at a past time. Only an objective gathering of the evidence, can however determine this. If one is to imagine an objective universe, it should be one that fits together, and exists in its entirety, irregardless of which parts of it are experienced here and now. In fact, most of it is "unreachable", being that it is happening "now" and is too far away for us to sense in our lifetimes or even in a million years. Does relativity describe the reality that exists "now", that we will never experience? Or does it describe the reality that we experience? Regards, TAR2

Schrödinger's hat, There are several issues I have with "understanding" what you are talking about. I have been told to dispose of certain notions I have of reality, which do not agree with the math that describes reality "better" than my notions of it. I am somewhat bewildered by this. I am not certain how one is supposed to imagine anything without making an analogy to something "already" understood. If we are "aware" of reality, it is because we know what space is, and our position in it, and we know what time is, and our position in it. If we are to assume (assumption number 1) that the speed of light is a constant thing, when measured from an inertial reference frame, then we have to PREsume that there is a constant thing that measures space and a constant thing that measures time. How can you have a constant of 186 thousand miles per second, if you are not prepared to hold either miles constant or seconds constant? The whole idea of constancy loses its meaning. All the SI units are interrelated. Each defined in reference to the others. If meters are shorter than meters and seconds are longer than seconds to make C an integer, namely 1, in your formula, then you just changed the meaning of every other scientific unit in the book. How the laws of physics can hold under these circumstances appears more like a shell game, than a description of reality that I should yield to, instead of holding on to a sensible notion. I never did understand the difference between a "real" force and a "ficticous" one. If it throws me off the merri-go-round, it is sufficiently real for my consumption. There are "ways" that we sense, remember and predict reality. We have analogies we draw, maps we make, things we discover and share, names we give to stuff we collectively experience. We are not gods, we cannot see Alpha Centuri and our hand pointing at it, at "the same time" except in the manner that it actually happens. Our existence at a particular place and time, allows us to put everything else in perspective, and measure the "distance" things are from us. But that assumes the speed of light is a constant 186,000 miles per second. And a mile stays a mile, and a second stays a second. Otherwise, what exactly is it that you are holding constant? Regards, TAR2

Owl, I don't wish to interfere with your discussions. I thought I might be augmenting. Perhaps not, but I am enjoying this thread none-the-less. I am still hung up on time being the same type of thing as space as Schrödinger's hat points out in 177. I lean in your direction on this Owl, and think it something else that exists along with, or because of, or as a result of 3-D space. What seems to be always swept under the rug, is the fact that this moment is different than the one that just past, and the one that is about to happen. It is this difference that is time. A stationary room, say Point A, will feel the effects of it, even if it doesn't move at all. All the physical processes going on inside the room will continue to happen. Things will grow and die, be built and fall apart, within the room, given the interplay between the components of the room. Even the vacuum of space inside a void between strings of galaxies will have the rest of the universe "going on" around it, and the photons of an immense number of "events" passing through any given volume, "all the time", or "at any given time." One of the things I have "figured out" in the last couple years, is that space, in its enormity, "loses" important characteristics, if thought of, all together, "at one time". It simply does not exist this way...ever. That "now" where Alpha Centuri exists and we will "see" it in 4.5 years CANNOT be seen together with "this" now, except at a midway point in 2.25 years. And there is no actual way to coordinate the experiences together as "one thing". And the "event" that is occurring "now" on Alpha Centuri, does not actually "end". It continues through the midpoint in 2.25 years, through the Solar System in 4.5 years, and right on past to the environs behind us (as we face Alpha Centuri). Every event, everywhere has this "ripple" effect through the rest of the universe, and every point in the universe is continually buffeted by the continual ripples sent out from every other point in the universe. In an important sense there IS only one perceiver, because if not at the particular place "here", and the particular time "now", there is no place or time to be. Regards, TAR2 'Cept all those "other" places and times we can consider in reference to "this one."

Owl, You say that "one perceiver" is clearly theistic, but I don't think it has to be taken that way. It is you that are the perceiver, or me, or whoever, but this one perceiver, who perceives the world at a particular time, and at a particular place, is not "other than" the world which he/she/it perceives. "The perceiver is one with that which is perceived." I don't think this requires an Anthropomorphic being, to be true. I think it simply is true. There is no place or time, other than reality from which a perceiver can evolve. By definition we must be both of and in reality. My feel, (or thought) is that our brains hold an analog representation, or model of reality, that we constantly "check" against that which is "happening". We improve our model by "discovering" or "learning" what is going on. (this normally aids in our survival, and our ability to predict and modify and "use" what is going on, to our benefit, and avoid what would be harmful) And we have the ability to "put ourselves in someone else shoes." Here is where the "frame of reference" comes in, in my book. We HAVE the ability to consider the world from more than one. We can consider that the world fits together well, and ANY frame of reference will "add back" to ours, flawlessly. Thus establishing both a subjective reality AND an objective reality that exists for us to have evolved from, and to exist in, and to perceive. I do not think that this way of looking at it denies either science or religion. But I do not know which camp these thoughts would put me in, in regards to this thread. I personally look for the ways that "everybody" is "correct". And figure that most difficulties are "in the translation". Regards, TAR2

Cap'n Refsmmat, How can time be unrelated to movement from point to point, if movement from point to point, takes it (time)? It takes a collection of matter (entity C) "time" to make the trip between collection of matter A, and collection of matter B. In addition, since A and B are separated by this distance that it take "time" for C to transit, it take "time" for even light to make the trip between A and B. Thus there is the "time" it takes matter to make the trip, AND there is the "time" it takes light to make the trip. I think the distance between A and B can be defined as either the time it takes matter to make the trip, or the time it takes light to make the trip, and that these "distances" will equate. There is a problem with considering "real", the idea that point A and point B are "no distance" from each other. If relativity requires that point A and point B be at the same point, in any dimension, that dimension must be hypothetical or "without" dimension. Regards, TAR2

Oblate spheroid folks, If from a stationary point, along the path of the high speed flyby guy, the Earth is a circle, and from the next point, the Earth is a circle, and from the next point the Earth is a circle, at what point is it not a circle? I would think that the Earth could not be seen at all, unless there was light reflecting off of it. And the "shape" of the Earth would always be a result of the amount of the "sky" of the observer that was "filled" by the Earth. Arclength wise, this would be always be the diameter of the Earth whether horizontally considered, or vertically, or diagonally or any diameter direction you wish to consider. There is not a stationary vantage point from where the Earth would not be this circle shape. Why would it matter how fast one changed their observation point? The Earth would always be a circle. At no one point would it ever have a reason to fill a different shape. Would it? Regards, TAR2

Iggy, I don't think that is true. You cannot outrace light. Regards, TAR2

SwansonT, No reference frame that represents reality? Not quite sure what that means. We have the Earth, we have human size scales of space and time. That is what we know. Why would any reference frame, that could not be mapped back to this one, have any meaning at all to us. For instance, if something happens "now" on Alpha Centuri, it will not be "real" for us for another 4.5 years. And any reference frame that is not "like" ours, were we "know" a particular place and time as here and now, is not a very useful frame, or very useful thing to consider "real". If it doesn't map back to our reference frame, why should we even know or care about it, much less consider it "real"? Regards, TAR2

Owl, Perhaps, but my mind is concerned with the fact that what we know to be the case, is an imagined condition, based on past "actual" experience, that we predict will be the case in the future. So what we have "learned" is applied to our "predictions". Subjectivity and Objectivity are interwoven in this consideration of "now" as deeply as it is for the "shape of the Earth". Perhaps, since its your thread, I should listen to you. But I believe, that if you consider it a piece of the investigation of subjectivity and objectivity, you might entertain it here. Regards, TAR2

So if what we see happening on Alpha Centuri, now, is our past light cone, and what is happening "now" on Alpha Centuri is happening in our present instant, what of the 4.5 years worth of "events" that are currently in transit? What does relativity call those moments? Regards, TAR2

Iggy, I understand the concept that Einstein was talking about with similtaneity, and the important role that light speed plays in the determination of "distance" in both space and time. I go by it. But there is a "reference" point, a viewer we use, to concieve of the observer "inbetween" that sees the two simultaneous moments, and this "viewer", that "sees" the inbetween observer IS NOT CONSTRAINED BY THE SPEED OF LIGHT. This viewer can be at both ends and in the middle, AT THE SAME TIME. This is not "possible", it can only be imagined, and only "proved out" by repeated experimentation, and memory of what was the case, before. This is why I am leaning in the direction of there being two types of NOWs. One actual, and the other imagined. Both however, real, in that the "imagined" one will indeed prove out to be the case. More than likely Einstein and the other geniuses that have been cogitating on this for the last century, have indeed "figured" it out, put it down in writing and formulae, and tested it all out, to indeed "be the case". What I object to is calling the view of this viewer, that sees both ends and the middle at the same time, the "real" objective truth. When this view, is actually the "imagined" one. Regards, TAR2

Kturbo, I was raised Christian, I said my prayers, I had long talks with God, I have no problem with anybody having a "personal" relationship with the universe/reality/nature/God, or whatever or however you want to call it. I cannot have "your" relationship with the world. You cannot have mine. It is not appropriate in my way of thinking, that anyone should think that "their" way is the only way it should be done. That simply is not correct, or logically possible. It is much more sensible to figure that EVERYBODY is doing it correctly. There is no doubt in my mind, that we are all of, and in reality, with approximately the same "access" to it. I don't have to use your key to open any lock. The door is standing wide open already. Regards, TAR2

Iggy, Thanks again for #109. I read it through a few time. Get hung up around the same time each time. Will have to read through it again a few times. I don't like the "now" line at tzero. That looks too much like the universal now we have been talking about. That is not an empirically observable moment, from ANY reference frame. And it takes a God's eye, or at least an imaginary eye that "sees" instantly, events separated by lightseconds of distance "at the same time". If this imaginary view of "now" is to be considered "real", it can only be sensibly understood as what will be "real" seconds later. And I am left with the same question. Which "now" are we talking about? There are a number of ways one can look at a moment, in both duration and in size. After all, from the point of view of an epiphany I had 30 years ago "life on Earth, from the first organic molecule till an evolved forest of Oak, and Maple and Pine, is but a fleeting instant in the vastness of time and space". I wonder sometimes about how "scale" effects this discussion. We have no problem considering something we can hold between our hands, being in one place, at one time. But there is some fraction of a lightnanosecond's distance between our right and left hands. At any grain size, from a quark to a universe, we can consider the whole thing contained in one thought (properly scaled). Existing at a properly sized "here" and a properly sized "now". Not empirically proper to consider ANY two separated events "simultaneous". By definition they are separated. Either by time, or by the time light takes to go the distance. Regards, TAR2

Iggy, I am still reading #109. Thank you for doing that. I have had problems with my computer that I usually use, so I am not keeping up. Will "respond" after catching up with the thread. Regards, TAR2

Iggy, Still working on what "understandings" we can have, without relating one thing to another. And how much "time" it takes to make the comparison. Such an investigation is one of the reasons I am on this board, and particularly on this thread. Critical to the discussion though, is the fact that "time marches on" with or without us. And this progression is something that we are subject to, along with everything around us, and by extention, a "thing" that is happening everywhere, all the time, and has been going on since the beginning of the universe, and will continue to go on for a very long time, since we have no good evidence that it has any reason to stop. Regards, TAR2

Iggy, Oh. I understand. But there is the historical knowledge, of having sent something between A and B that "gives" us a knowledge of the distance. And then, we are in a position to predict the results, of repeating the experiment. As much about reality, there is what has happened before, that "structures" the situation. That makes it real. Time, in this regard, in my estimation, is something that we experience continually, and "measure" in retrospect. Spacetime then is not something handily "present". That is, it does not appear to be something you can step out of and take a look at. There is no actual way to get out of it, or any platform available (other than here and now), where you can take a look at it. There is however an "understanding" of it, that we already have. An analog model of the world, built in the synapses and connections and layout of our brains, that places actual items in the real world at various "distances" from us in space, and various events, in their proper "place" in time. Time is an actual constituent of reality. One that we have already, as Kant would say, an intuition of. Space is Kant's other "pure" intuition. Between the two, we have spacetime, if you will. But simultaneity needs some heavy agreement on some rather deep "thoughts". Perhaps the manifolds and equations lay out exactly what it is that I already have an intuition of. Perhaps they make of it, something that it is not. There are easy misunderstandings in "what is meant". And perhaps subtle misapplications, where an analogy is taken too far, or into a domain, where it does not belong. It seems reasonable to me, that if the universe is a certain age, then ALL of it is that age. That makes it hard to figure what somebody could possibly mean by time slowing down or speeding up. Every piece of the universe, should have had the same time to evolve to where and how it is, in relationship to the rest, and should be at the point where the next moment, for it, has never before occurred. Each peice, at whatever grain size you choose, should have a past history, a present state, and a future state. And there is no way to get to another place in the universe, without taking some time to get there, not actually. But we can mentally take the trip, in "no time". I think it important to note, the distinctions between, (as Owl put it), the map and the territory. Regards, TAR2