BaalChatzaf Posted February 22, 2011 Share Posted February 22, 2011 It is not clear to me what Rand means here. My understanding is that many attempts were made to discover the ether and all failed. So it was not some "epistemological" process that lead scientists to deny the existence of the ether - it was experiments. Then, faced with no medium for light waves to travel in, physicists had to come up with some other explanation that accounted for the facts, ie. special relativity.Indeed, Rand's remark doesn't make any sense, she doesn't understand what she's talking about. From the definition of the ether (as a medium for the transmission of light) you can derive certain properties, for example the movement of the Earth with respect to the ether. Experiments (notably the Michelson-Morley experiment) couldn't detect any movement however, and attempts to save the ether notion (like the dragging theory) were also falsified. Only Lorentz came up with a rather contrived solution, including length contraction and time dilation, where he in fact discovered the equations of special relativity (which therefore also bear his name as Lorentz transformations). Einstein however then came up with the simple solution of the principle of relativity and the constance of the speed of light, which solved in one stroke all the problems and which didn't need the ether hypothesis. This was sufficient reason to conclude that the ether didn't exist. Compare the argument with the argument against the existence of a personal God who interferes with the lives of people:1. There hasn't been any empirical evidence for the existence of the ether, all the experiments for detecting the ether led to contradictions with the definition of that ether.2. Phenomena for which the concept of a luminiferous ether was hypothesized to explain them, can be explained by a simple and elegant theory, without any reference to an ether.Conclusion: the ether doesn't exist.The same argument can be used mutatis mutandis against the existence of a personal God, and in that case Rand didn't say "You cannot arbitrarily restrict the facts of nature to your current level of knowledge", implying that you cannot rule out the possibility that God in fact does exist. She was definitely not an agnostic in that regard. Peikoff didn't improve her reputation by publishing that passage.Ignorant speculation:What is the relationship of light and energy (or heat)? Call the source of light "X." It can be the sun. The further you get from X the less energy you experience, not because the energy is dissipated but because the energy is stretched so you are exposed to less of it. I differentiate between dissipated and stretched because the former is only commonsensical for energy isn't destroyed--right?--only transformed. The 14 billion year-old light our astronomers see with their instruments is a tremendously stretched expression of energy. (If we assume 14-15 billion years represents the beginning of time--i.e., of the universe--but we can see this no matter which direction we look, then could we actually be looking at the center of the universe ripped apart by the curvature of space and that the complete universe is twice that distance in the opposite direction--the other side--but unobservable? This would mean twice as big as what can be observed and we are at the center only of the observable universe as are all other beings therein?) Now, when we talk about the speed of light we are talking about the speed of energy expressed by light. Through nothing the speed of light must be instantaneous for there is nothing to resist it. What is there in the known universe that might resist the natural speed of light? Background radiation. Now, if this is correct--!!!???--the radiation must not only resist the propagation of energy as light it must over incomprehensible distances slow it down too. If so, the observable universe in terms of actual distance as opposed to a time expression is smaller than we think it is. Background radiation isn't going to slow planet rotation enough to make any difference in that.--Brantboy geniusThis is the old "tired light" notion for which there is not an iota of laboratory evidence.Ba'al Chatzaf Link to comment Share on other sites More sharing options...
Brant Gaede Posted February 22, 2011 Share Posted February 22, 2011 It is not clear to me what Rand means here. My understanding is that many attempts were made to discover the ether and all failed. So it was not some "epistemological" process that lead scientists to deny the existence of the ether - it was experiments. Then, faced with no medium for light waves to travel in, physicists had to come up with some other explanation that accounted for the facts, ie. special relativity.Indeed, Rand's remark doesn't make any sense, she doesn't understand what she's talking about. From the definition of the ether (as a medium for the transmission of light) you can derive certain properties, for example the movement of the Earth with respect to the ether. Experiments (notably the Michelson-Morley experiment) couldn't detect any movement however, and attempts to save the ether notion (like the dragging theory) were also falsified. Only Lorentz came up with a rather contrived solution, including length contraction and time dilation, where he in fact discovered the equations of special relativity (which therefore also bear his name as Lorentz transformations). Einstein however then came up with the simple solution of the principle of relativity and the constance of the speed of light, which solved in one stroke all the problems and which didn't need the ether hypothesis. This was sufficient reason to conclude that the ether didn't exist. Compare the argument with the argument against the existence of a personal God who interferes with the lives of people:1. There hasn't been any empirical evidence for the existence of the ether, all the experiments for detecting the ether led to contradictions with the definition of that ether.2. Phenomena for which the concept of a luminiferous ether was hypothesized to explain them, can be explained by a simple and elegant theory, without any reference to an ether.Conclusion: the ether doesn't exist.The same argument can be used mutatis mutandis against the existence of a personal God, and in that case Rand didn't say "You cannot arbitrarily restrict the facts of nature to your current level of knowledge", implying that you cannot rule out the possibility that God in fact does exist. She was definitely not an agnostic in that regard. Peikoff didn't improve her reputation by publishing that passage.Ignorant speculation:What is the relationship of light and energy (or heat)? Call the source of light "X." It can be the sun. The further you get from X the less energy you experience, not because the energy is dissipated but because the energy is stretched so you are exposed to less of it. I differentiate between dissipated and stretched because the former is only commonsensical for energy isn't destroyed--right?--only transformed. The 14 billion year-old light our astronomers see with their instruments is a tremendously stretched expression of energy. (If we assume 14-15 billion years represents the beginning of time--i.e., of the universe--but we can see this no matter which direction we look, then could we actually be looking at the center of the universe ripped apart by the curvature of space and that the complete universe is twice that distance in the opposite direction--the other side--but unobservable? This would mean twice as big as what can be observed and we are at the center only of the observable universe as are all other beings therein?) Now, when we talk about the speed of light we are talking about the speed of energy expressed by light. Through nothing the speed of light must be instantaneous for there is nothing to resist it. What is there in the known universe that might resist the natural speed of light? Background radiation. Now, if this is correct--!!!???--the radiation must not only resist the propagation of energy as light it must over incomprehensible distances slow it down too. If so, the observable universe in terms of actual distance as opposed to a time expression is smaller than we think it is. Background radiation isn't going to slow planet rotation enough to make any difference in that.--Brantboy geniusThis is the old "tired light" notion for which there is not an iota of laboratory evidence.Ba'al Chatzaf I don't see how there ever could be any direct, lab evidence; the distances needed for any effective measurement are simply too great.--Brantso much for "boy genius"not even a boy Link to comment Share on other sites More sharing options...
BaalChatzaf Posted February 22, 2011 Share Posted February 22, 2011 (edited) I don't see how there ever could be any direct, lab evidence; the distances needed for any effective measurement are simply too great.There is not even indirect corroboration of the "tired light" thesis. Since there is no support for it, it is not employed in currently physical theories. The evidence currently supports Einstein's theories. Photons do not lose energy over time. They may collide with other particles and re-emit at lesser frequencies (hence lesser energy). For example the Compton Effect. Or the gravitational red-shift. Light going through a strong gravitational field is red-shifted. Ba'al Chatzaf Edited February 22, 2011 by BaalChatzaf Link to comment Share on other sites More sharing options...
kiaer.ts Posted February 22, 2011 Share Posted February 22, 2011 What is the relationship of light and energy (or heat)? Call the source of light "X." It can be the sun. The further you get from X the less energy you experience, not because the energy is dissipated but because the energy is stretched so you are exposed to less of it. I differentiate between dissipated and stretched because the former is only commonsensical for energy isn't destroyed--right?--only transformed. The 14 billion year-old light our astronomers see with their instruments is a tremendously stretched expression of energy. (If we assume 14-15 billion years represents the beginning of time--i.e., of the universe--but we can see this no matter which direction we look, then could we actually be looking at the center of the universe ripped apart by the curvature of space and that the complete universe is twice that distance in the opposite direction--the other side--but unobservable? This would mean twice as big as what can be observed and we are at the center only of the observable universe as are all other beings therein?) Now, when we talk about the speed of light we are talking about the speed of energy expressed by light. Through nothing the speed of light must be instantaneous for there is nothing to resist it. What is there in the known universe that might resist the natural speed of light? Background radiation. Now, if this is correct--!!!???--the radiation must not only resist the propagation of energy as light it must over incomprehensible distances slow it down too. If so, the observable universe in terms of actual distance as opposed to a time expression is smaller than we think it is. Background radiation isn't going to slow planet rotation enough to make any difference in that.--Brantboy geniusI am not exactly sure what you mean by "stretched" in this context, but if you mean stretched over the direction of travel, as if a spiders thread were to stretch as it climbs down it, rather than spread out, like buckshot spreading out as it leavs the barrel of the gun, then you are mistaken.The inverse square law, which applies for most phenomena spreading out from a point source, explains why you feel less heat as you move further away from a heat source. The energy doesn't stretch in length, rather the front expands, spreading out as it gets farther from the source. Inverse-square lawFrom Wikipedia, the free encyclopediaIn physics, an inverse-square law is any physical law stating that a specified physical quantity or strength is inversely proportional to the square of the distancefrom the source of that physical quantity. The lines represent the flux emanating from the source. The total number of flux lines depends on the strength of the source and is constant with increasing distance. A greater density of flux lines (lines per unit area) means a stronger field. The density of flux lines is inversely proportional to the square of the distance from the source because the surface area of a sphere increases with the square of the radius. Thus the strength of the field is inversely proportional to the square of the distance from the source. Link to comment Share on other sites More sharing options...
Brant Gaede Posted February 22, 2011 Share Posted February 22, 2011 Thanks, Ted. Nice explanation for me, the layman.--Branthumiliated once again on OL by the OL out-to-get-me cabaljust because you're paranoid doesn't mean they aren't out to getchatear off their heads and s___--wait a minute!--that's Bob K! Link to comment Share on other sites More sharing options...
Guyau Posted July 24, 2011 Share Posted July 24, 2011 .A recent experimental result concerning the speed of light is reported here:Single Photons Cannot Exceed the Speed of LightOptical Precursor of a Single Photon The experiment supports the proposition that information cannot be conveyed optically faster than ceven were the information conveyed by using single photons. This could not be tested until now.~~~~~~~~~~~~~~~~~~SR Kinematics (or V2N6) Link to comment Share on other sites More sharing options...
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