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Everything posted by AbstractDreamer

  1. Its made up in the same way that we assume time is constant over time. Any observations or experimental evidence that is itself "trapped" in time can neither support or disprove either that time is constant or non-constant. And yet we are happy, without evidence or measurement, to assume it is constant; and draw as a useful conclusion, the FLRW metric to describe a Universe that changes over time - it "looks different at different moments in time". Is this not in contradiction with its OWN premise of homogeneity of the Universe?
  2. If spacetime is a continuum, and space has been observed to expand, why is it not described as time contraction? Why must the constancy and consistency of time be preserved? What makes the immutability of time more sacred than space?
  3. While this is a sensible statement rooted in logic, it's not a universal law or principle afaik. Is there any way to test Hawking Radiation at the event horizon on the black hole? Does it have a measurable effect? Is there any way to test space expansion at the edge of our observable universe? Does it have a measureable effect?
  4. Ha! I honestly struggle making sense of it myself, definitions in words is very difficult, and my maths is school boy level so I cant model anything. But I think overall we are grasping at the same concept. Let's say that this notion of "time over time" is NON-constant. What I mean by this is that the "rate that time propagates" is different at two different values of time, relative to a theoretical frame of reference that is "outside" or "independent" of time. Now clearly there is no such frame of reference in reality. Everything in our spacetime is intrinsically bound within time. Hence it is a theoretical, or imaginary frame of reference. But that the frame is suitably "static" relative to both events in time. So let's say that one second, today at time t=13.8B years, is defined by caesium frequency of caesium atoms that exist at time t=13.8B years. Let's imagine at time t=1 year that caesium atoms exist, and 1 second is again defined by caesium frequency of caesium atoms that exist at time t=1 year. So then you measure the speed of light in units of "distance per caesium frequency". Assuming distance is constant (this is another problem), then both today and at t=1 year, both measurements would arrive at the same result - relative to the caesium frequency of that time. But if somehow you compared the two caesium frequencies, using a measure and a frame of reference independent of both time today and time 1 year, then a "non-constant time over time" would allow the two frequences to differ - and yet nothing need be violated for either of the two events, within their respective time. I'm really not sure how to respond to those three points and how they might relate and where I might disagree. Those three points are total valid, but there are practical limitations implied within them. Point 2 is about measuring time. My point accepts that measuring is currently experimentally impossible. Point 3 is about using the clock as its own frame of reference. This is different to a frame of reference independent of time.
  5. Thank you for such precise answers to my questions! I shall digest them thoroughly. My biggest enlightenment was learning that a Schwarzschild BH have very exact requirements... can I argue it is a physically improbable in our real universe - to have a black hole that exists in perfectly flat, albeit possibly hyperbolic, spacetime? Is it also true that flat Minkowski space is similarly improbable in our real universe?
  6. How would you test for constant time?
  7. There is no evidence that "non-constant function of time over time" doesn't work. GR, experimentally, works with "non-constant function of time over time" too. Would you agree with the above statements?
  8. So "Schwarzschild spacetime is entirely empty vacuum everywhere", but Schwarzschild spacetime is not necessarily uniform or symmetrical? For example a source of significant curvature on one side, external of the blackhole would create asymmetry of the spacetime beneath the EH? So in a circumstance when spacetime is significantly asymmetric under the EH around the singularity, and when spacetime is significantly asymmetric above the EH around the black hole; would a non-rotating Schwarzschild blackhole still appear perfectly spherical?
  9. Because is it possible that a "non-constant time function over time" could model observed space expansion? It would remain experimentally untestable, unless your experiment spanned a volume of space time that contained such expansion, yet somehow remained unaffected by the expansion. I cant really grasp the scale that expansion works on, but I would wildly guess that it appears to me to break homogeneity at least on a scale reasonable local to expansion. Of course the argument for homogeneity is to choose a larger scale. If spacetime is a continuum, then homogeneity in space is also homogeneity in time. How do we can reconcile homogeneity in time, when we have a universe that apparently expands locally or globally, or at least inflated globally? It's appearance and properties shortly after t=0 is much different that today. In the same way that GR has no evidence to support that time is constant over time? Not sure how this relates at all. What is the principle in GR that assumes time is constant over time? I don't think there is one. Indeed it doesn't need one... experimentally. However it does assume this, right? On a similar notion, what evidence do we have that any unit is constant over itself? Take distance for example. At a large enough scale that experiences significant expansion, something that measures D units using measurements within that expansion, might measure D+E relative to observations from without that expansion. What is the principle of realism that states non-theoretical units are uniform from zero to infinity?
  10. So anything crossing into the EH joins/shares its charge, mass, angular momentum with the single entire entity of the blackhole? Does a black hole experience gravitation from objects outside its EH? If some nearby spacetime is curved by some other object, does this curvature extend beyond the EH? As a graviton wave crosses into the EH, does the black hole grow in energy? Which if any of its properties will change? If the black hole was of sufficient "volume? surface area?" where the external curvature at one location was significantly different from the other "side?", and taking the blackhole as a single non-quantisable entity, would this cause one part of the black hole to "move" in a different direction to another part of the black hole? Would this cause pressure or stress within the black hole?
  11. I don't think you could tell experimentally. But my question is really: If we assume that time is constant over time, WHY do we assume that? What evidence is there? I'm guessing there is no evidence, hence my questions here. As physics is based on evidence, why is this one assumption exempt? What are the theories in the scientific community that considers time over time as non constant? I'll posit again that motion or potential changing the experience of time is missing the point. In a thought experiment, take two volumes of spacetime, both identical in motion and gravitation potential, and identical all other properties EXCEPT in the property of time. One volume is close to t=0, and the other volume is close to t=infinity. Theoretically or mathematically, but not experimentally, comparing the progress of time in each volume relative to the other volume, why do we assume they are the same?
  12. Thank you for this, but I'm not talking about motion or potential. Or either of them changing over time.
  13. The first question was whether GR is premised on time being constant The second question was if there is any basis that time is constant. Both questions are about time being constant over time, which I believe you have either misunderstood or ignored, hence your answer about time being dependent on your motion relative to another observer, and on your gravitational potential. With respect, you are repeatedly selecting only some of my questions, and then providing answers that do not relate to those questions.
  14. So you are saying categorically it (time) cannot depend on anything else, such as for example a function of itself? Which of my questions is "no" the answer to? How do the equations in GR allow for Proper Time that has a world line that spans two manifolds between which have observed space expansion?
  15. So do the equations of General Relativity premise on the propagation of time being constant since the Big Bang? That is, the premise that the axes of time are uniform between t=0 and t=infinity. Is there any logical or reasonable basis upon which to assume that the propagation of time is a constant since the Big Bang? If we accept that the spacetime continuum experiences a stretching of its axes when observing space expansion, why should we assume that its only the axes of space that is stretched, and that the axes of time remain uniform?
  16. I have read that Blackholes have properties Mass, Charge and Angular Momentum, and that the Event Horizon is the boundary between where spacetime is curved so much that all paths converge, and between where there are some paths that could diverge. Putting aside Hawking Radiation, apparently "nothing?" can leave the EH. As far as I understand, the "nothing" refers to anything with mass and any form of electromagnetism such as light, and perhaps categories of other things. So if electromagnetic waves cannot exit the EH, how does the charge of the Blackhole create the electromagnetic effect that propagates around the black hole due to that charge? Likewise with mass and curvature, how does the density of the mass "inside" the black hole's EH manage to curve the space time outside the EH, if the EH is a boundary where all paths converge? If you were a bit mass under the EH, and you tried to emit your gravitational wave through the EH, that wave would have a geodesic that remains within the EH. If that wave never exits the EH, and if ALL waves never exit the EH, what is causing the gravitational effect of the blackhole as experienced by objects outside the EH?
  17. It didn't think it does matter. That's why I'm asking questions. If learned minds can also agree it doesn't matter, I'll take it as a reasonable basis to continue using it as a premise to my end question about dark energy. It's meaningless perhaps today from anything directly measurable within spacetime. But theoretically, would you agree there if there is a conceptual idea of the rate of change of time, that there is no basis to assume it is constant at different moments/periods in time? Something is seemingly stretching the axes of spacetime. With a leap of faith, it is possible this entity is outside of time? What if this entity was not directly measurable, but its effect on the measurable universe CAN be observed. We can observe space expansion occurring in the measurable universe, it is possible that we cannot directly measure what is causing it? Can we directly measure a singularity? I don't think so. A singularity exists outside of spacetime as its gravitational potential is undefined. Can we observe the effects of a singularity? Maybe not. What exactly does a singularity do? Perhaps we cant measure dark energy directly. Perhaps dark energy is outside of spacetime as it's motion is undefined. Perhaps its effect can be observed through spacetime expansion. Is it possible that singularities are the source of dark energy?
  18. Right, we can't notice it! We are all "trapped" in the same rate of change of time. The unit of time could be doubling, halving, exponential, logarithmic. We would not be able to observe it, and it would have not consequence to anything within our spacetime. If there is no theoretical or experimental evidence that this is the case, then why should there be theoretical or experimental evidence that this isn't the case? What basis do we have to assume the rate of time is constant? So it doesn't really break any theories to consider the rate of time as non-constant, as it is not measurable. So why not pick an arbitrary function of this rate of time and tie it into dark energy with undefined motion, to explain space expansion? What are the main arguments that oppose this approach?
  19. Yes, I think that is my question. And no, I don't think it matters at all to the standard model. Which is why I'm asking the question... if it doesn't matter, what are the theories that follow if the "unit" of time does or does not change, as time progresses. And can dark energy exist outside of time. And in the possibility that dark energy can exist outside of time, could it cause or be caused by time accelerating? I accept that the passing of time is relative, and therefore it changes. That is, time dilates. But this argument does not refute my question. My question is more: For a situation where the effect of time dilation due to relative motion is zero, is there no possibility that the rate of change of time is variable - specifically, a rate that has a denominator value "outside" of time. Undefined motion akin to gravitational potential at a singularity. Do singularities have undefined gravitational potential? Would this mean singularities exist "outside" of time? Black holes will eventually decay, but what happens to the singularity? My choice of the word "speed" is poor. I should have said "rate of change per something else". Density is mass/volume. If mass increases, it is denser. Speed is distance/time. If distance increases, it is faster. "rate of change of time per Gap" is time/Gap. If time increase, it is more "rate of change of time per Gap" But I don't think it needs to be another clock. It just needs to be another unit, measureable or not. But for conceptual purposes, lets call it Imaginary Time or iT, where iT is orthogonal to T. It relates via my wildly speculative question about variable rate of time and space expansion - that is, whether it is possible that the unit of time changes over time with respect to a unit of something else outside of time. And, if there are entities that exist outside of time (such as an imaginary entity with undefined motion), could they be linked to dark energy somehow. And ultimately, could something like a variable rate of time be the cause or the effect of space expansion.
  20. Well I deliberately avoided any precision in its definition because I really don't know myself. I have an idea that time propagates. And if this propagation is with respect to something else, then we can define the rate of propagation (relative to that something else). Of course, if we cant find anything else, we cant define the rate of propagation. But that doesn't mean the propagation is constant, it just means it is undefined (possibly meaningless but also possibly meaningful). If we create a theoretical unit of something, lets just say its called Gap, which is a measurement of time but from outside of time. We can calibrate Time and Gap arbitrarily, so we can take any moment in time and any period of time as equal to 1 Gap. So lets take right now as the moment, and a period of 1 hour = 1 Gap. So we can ask will 1 hour=1 Gap tomorrow, next year, next 13 billion years, 13 billions years ago? (Lets define 1 hour as something which exists unchanging in all time moments, like some probability of emission decay of some particle.) We might never be able to empirically show that the speed of time is constant or changing (it might be meaningless). Whether it is variable or not, it wont ever affect any experimentation as everything we do is "trapped" in the same time and subject to the same changes in the speed of time. So does it break anything if we assume or not that time has a speed and that this speed is variable? What if space expansion today, and the inflation model 13 billion years was a manifestation of this? Could dark energy exist outside of time? Do singularities have infinite or undefined gravitational potential? Would this mean singularities exist "outside" of time? Black holes will eventually decay, but what happens to the singularity? Is there anything (theoretical or otherwise) that has undefined motion relative to another observer? Space expansion/dark energy? Would something with undefined motion necessarily exist "outside" of time? Would that thing need to have undefined motion relative to ALL observers concurrently at one moment in time, or is it enough to be undefined relative to just one observer? If a thing has undefined motion at one moment in time, will it always have undefined motion?
  21. Whether Time is linear or cyclical or something else, is the speed of time constant? What basis do we have to extrapolate time back to t=0 (or very close to 0) and assume it's speed is the same as it today? I read descriptions of the early universe describing things like "A few millionths of a second (after the big bang), quarks aggregated to produce protons and neutrons" https://home.cern/science/physics/early-universe How would an observer in the early universe measure time when there are only quarks, protons and neutrons? Is it possible the speed of time is variable? Could 1 millionth of a second in the early universe be equivalent to a few million years today, relative to that early universe? If time is accelerating universally, would this not affect any empirical evidence of any experiments performed to date, unless we can time travel? If time is accelerating, could that explain dark energy and space expansion?
  22. If you zoom OUT far enough, and assuming you zoom out at the same rate for the X and Y axes, then y=x^2 approaches a straight line. Does this mean anything? Is it possible that eventually that no global curvature can be measured from the equation? How is it a global curvature if its not truly global and only local? What does it mean if you zoom IN at different rates? What if this rate itself was not a constant but another function of something. Is it possible it may not look flatter? Is there a loose analogy between the zoom-ratio of axes and tensors?
  23. If you had two or more clones that were absolutely identical in that there was no way to practically (not theoretically) identify one from another, how do you know you have two or more clones to begin with? The identification of multiple clones confirms they were not identical. The absence of identification of multiple clones, suggests you only had one clone to begin with. You either have only one clone until you identify another, or you have many clones that are not identical. And anything that you do not know only exists as a probability, subjectively.
  24. Thanks for the visuals. So Simultaneity is just subjective. But what about concurrency? Lets presume both you and I exist. Is the star shining concurrently for you and me, or sequentially? That is, my detection of photons are registered sequentially by me, and your detection of photons are registered sequentially by you. But are our combined detection of photons registered collectively sequentially, or could some be registered concurrently?
  25. Not a single unexpected macro event that violates GR in this universe, other than singularties. Is that not rather odd, considering all the random branches of possibilities that MIGHT occur with every quantum observation everywhere since the beginning. If the fundamental essence of the universe is random, chaotic, unpredictable, then surely there cannot be any fundamental laws or principles or constants. Conversely if the essence of the universe is determinate, ordered, and predictable, then surely there must be a fundamental laws/principles/constants.
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