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Author | Topic: General Relativity. | |||||||||||||||||||||||
crashfrog Member (Idle past 1467 days) Posts: 19762 From: Silver Spring, MD Joined: |
Those with imperfect knowledge should stick to what they know, and not get to preaching alternate creation. "Alternate creation"? As far as I'm concerned, pal, you're the one with the alternate creation fable.
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sidelined Member (Idle past 5908 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
14gipper
If there was a whole lot more than the physical universe, and we hardly have a grip on what's going on here, that would be comparitively clueless. Why do you always reference to something other than the physical universe as though that had any meaning? What does you mean by not physical my friend?
If not, and the unknowns that abound are really just around the corner, if we follow the carrot on the stick, then, it is true, we have some good clues now, after all. But which of these best applies, we really don't know, and indeed, in that respect are clueless indeed. Science operates in the region between known and unknown and has found physical explanations for all the questions of how the world operates when we can properly use experiments to test the models from which we learn. That we have different possible scenarios for further study of leading edge physics is not as result of being clueless but because of the difficulty of producing the conditions necessary to test the modles we do have. However, without the different models we cannot have any idea about which direction to put effort to best secure further study. But I realize now that these people were not in science; they didn’t understand it. They didn’t understand technology; they didn’t understand their time.
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simple  Inactive Member |
Alternate to something appearing for no apparent reason, or creator involved, yes.(though some might suppose God meant eden as a fable and the singularity magic act was really where it's at).
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simple  Inactive Member |
quote:Not all. Not what was before the big bang, or what caused the somethin from nothin. Not where life from nonlife appeared. Not for sure whether this physical universe is infinite or finite. Not whether there are ghosts or not. I would expect there would be 'physical explanations' for things in a physical universe, but not beyond. Beyond doesn't just mean far away, but long ago, or in the future. quote:This is important, in other words we have definite limits. quote:I understand, make the best with what you do have, and the limits under which you must do this.
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madeofstarstuff Member (Idle past 5929 days) Posts: 47 Joined: |
Cavediver:
Thus you can still have A and B appearing at 90 degrees and at the declared distances, but the line AB will certainly not be the pythagorean distance, nor the angles OAB and OBA the expected trignometric values. So how do you distinguish between the pythagorean and the nonpythagorean distance? If you look out and are justified in seeing the pythagorean distance and have no reason to believe otherwise, with respect to what is there more than the pythagorean distance? It seems as though there is some standard of distance in a certain inertial frame of reference as long as you have no knowledge of the increased density of space. This "extra" space is seemingly packed into an apparent pythagorean amount of space, so why would you need to know the curvature was there to accurately render your environment? Why should it not be apparent?
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
You will measure the real distance. You can measue the distance to A from O and B from O. But travel to A and measure AB, you will find it not equal to sqrt(OA^2 + OB^2). By taking enough measurements like this, you can build up a picture of the local curvature.
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madeofstarstuff Member (Idle past 5929 days) Posts: 47 Joined: |
OK, thats what I thought, that is strange. So if I were standing at O and saw something traveling at constant v toward AB, what would their motion look like from O as they progressed (continually from their perspective at v) from A to B?
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sidelined Member (Idle past 5908 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
simple
Not all. Not what was before the big bang, or what caused the somethin from nothin. Not where life from nonlife appeared. Not for sure whether this physical universe is infinite or finite. Not whether there are ghosts or not. I would expect there would be 'physical explanations' for things in a physical universe, but not beyond. Beyond doesn't just mean far away, but long ago, or in the future. First off before the big bang is a wrong question since "before" is a temporal term and has no meaning when there is no spacetime in which a before can have logical placement.That something came from nothing is not the likely case either.The universe most likely has existence at a level that is not consistent with the universe we experience since we are constituents of the universe as it is in spacetime.The background vacuum energy which is a consequence of the principle of uncertainty allows for the "existence" of particles that constantly fluctuate with energy as long as they vanish within a brief enough time period that they do not violate conservation of energy in the universe. Infinite or finite is far more difficult because a vast enough finite universe is,for all practical purposes, indistinguishable from a truly infinite one. As for ghosts we can say with pretty good confidence that they are not at all likely.
This is important, in other words we have definite limits. These are limits imposed by nature as to what is possible given what we already know about the universe
I understand, make the best with what you do have, and the limits under which you must do this I am not sure you do. The limits are a consequence of the structure that we study not a limit on what we can discover. It is true that there are things we can also never know about the universe since properties such as the speed of light limit prevent any information from reaching us from certain places in the universe.That does not mean that we fill the gap with anything that takes our fancy since if we do not know about those regions we cannot say anything at all about them for any idea is just as valid as another. But I realize now that these people were not in science; they didn’t understand it. They didn’t understand technology; they didn’t understand their time.
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
You would just see them accelerate (in direction as well as speed), then decelerate but would not discern any force exerted.
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madeofstarstuff Member (Idle past 5929 days) Posts: 47 Joined: |
Is that because the time dilation is more prominent than the spatial "contraction"?
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madeofstarstuff Member (Idle past 5929 days) Posts: 47 Joined: |
I tried to get a new thread on this but it was denied, but I'm also not sure whether its relevant to a GR thread, so I will ask anyway because I am curious. When something, anything, changes from one instant to the next (strictly QED), is this due solely to the exchange of a photon from one electron to the other? I assume that these events, photon exchanges, occur instantaneously. If a body of mass (which is mostly affected by EM radiation) changes in some way (be it momentum or velocity), is this due to an exchange of a photon? Can anything noticeable happen without this exchange? Is absorbing a photon the only way to "realize" anything happened? Lastly, does this indicate that time is discrete in its progression from one "instant" to the next, or has it been shown to be analogous?
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simple  Inactive Member |
quote:Same can be said of the merge idea, and who knows what else. Space time as we know it only applies to this universe after it came into being, whether created, of from the tiny universe you suggest. quote:Well, since you really don't know, we could say that, or something else for that matter! quote:This is what people who propose another non physical dimension would say also, but there, you would likely sceam for evidence? quote:So there may be a part of the universe we don't really see, or are uncertain about, but when it comes to vanishing and appearing things, like ghosts, your theorries as to the real explanation are only as good as your imagination. quote:Speculation. You don't know the limits we can discover. quote:These unknowns also may affect the knowns, and there is no way we can say, then, that there may this other dimension beyond these admitted limits. quote:This is a good description of what is being attempted with having things like a microscopic universe just appear on the scene, or life from non life.
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crashfrog Member (Idle past 1467 days) Posts: 19762 From: Silver Spring, MD Joined: |
This is a good description of what is being attempted with having things like a microscopic universe just appear on the scene, or life from non life. No, those are conclusions based on observation. The difference should be apparent.
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cavediver Member (Idle past 3643 days) Posts: 4129 From: UK Joined: |
A bit too busy at the moment to address this, but I will come back to it. Good "question" though, and it does have an important connection to GR so it is not too out of place here. A quick point though... it's not just photon exchange but also graviton exchange. The others we can effectively ignore for your discussion.
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madeofstarstuff Member (Idle past 5929 days) Posts: 47 Joined: |
quote: I understand. I appreciate the time you have given me so far. I had also replied to your revealing to me the motion of a thing through a curved space being perceived as acceleration without force. I had wondered if this was due to the time dilation being more prominent than the spatial contraction. Take your time, I don't plan on having my death event anytime soon, and once again thanks for your time and patience.
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