rrw4rusty Posted October 17, 2009 Share Posted October 17, 2009 Hi, I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around. Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow. Got all of that (know where this is going?)? Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured? Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning. Something knows if the rod is turning or, the barrow is turning. What is this something? Thanks, Rusty Link to comment Share on other sites More sharing options...
dr.syntax Posted October 18, 2009 Share Posted October 18, 2009 Hi, I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around. Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow. Got all of that (know where this is going?)? Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured? Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning. Something knows if the rod is turning or, the barrow is turning. What is this something? Thanks, Rusty REPLY: Electromagnetic waves create the medium they move through as they move through it. Go to : http:http://www.bookrags.com/research/waves-wop/ . This is nothing new. There is no aether. ...Dr.Syntax Link to comment Share on other sites More sharing options...
swansont Posted October 18, 2009 Share Posted October 18, 2009 (edited) A person rotating in such a fashion would feel like they were standing in a gravitational field. Do you notice that you are standing in a gravitational field, rather than floating weightless? Given other equipment, there are other ways one could tell that one was rotating. Your scenario is reminiscent of some ideas related to Mach's conjecture http://en.wikipedia.org/wiki/Mach's_principle Edited October 18, 2009 by swansont grammar Link to comment Share on other sites More sharing options...
Moontanman Posted October 18, 2009 Share Posted October 18, 2009 Spin a coin, a spinning coin will not act properly if you spin it inside an object rotating for the effect of gravity. A spinning coin will not stand up on it's axis in side a space craft spinning for gravity. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted October 20, 2009 Share Posted October 20, 2009 A person rotating in such a fashion would feel like they were standing in a gravitational field. Do you notice that you are standing in a gravitational field, rather than floating weightless? Given other equipment, there are other ways one could tell that one was rotating. Your scenario is reminiscent of some ideas related to Mach's conjecture http://en.wikipedia.org/wiki/Mach's_principle I think that is rusty's point though (rusty, correct me if I am wrong) While there is no non-relativistic ether, space is not "nothing". Something (somehow) is doing the accounting. 1 Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 20, 2009 Author Share Posted October 20, 2009 I think that is rusty's point though (rusty, correct me if I am wrong) While there is no non-relativistic ether, space is not "nothing". Something (somehow) is doing the accounting. That's it exactly... someone must know (and there is a post above that needs research on my part that probably explains it). This is basically relativity in rotation-- what says one thing is rotating and one thing is not? Well the item swinging around in a circle is going against the curve of space/time... that's why the item 'wants' to go straight and it takes energy to make it swing... but what is space/time, where is it, what does it look like and despite what anyone says, isn't this an ether that all things move through? I know I'm sounding stupid here... I just need to understand. Rusty Link to comment Share on other sites More sharing options...
toastywombel Posted October 20, 2009 Share Posted October 20, 2009 That's it exactly... someone must know (and there is a post above that needs research on my part). So whatever invisible something is there... I want to know what its doing as far as the expansion of the universe is concerned. This is basically relativity in rotation-- what says one thing is rotating and one thing is not? Well the item swinging around in a circle is going against the curve of space/time... that's why the item 'wants' to go straight and it takes energy to make it swing... but what is space/time, where is it, what does it look like and despite what anyone says, isn't this an ether that all things move through? I know I'm sounding stupid here... I just need to understand. Actually, according to some theories in quantum mechanics there is no such thing as nothing. Link to comment Share on other sites More sharing options...
Spyman Posted October 20, 2009 Share Posted October 20, 2009 isn't this an ether that all things move through? "Aether and general relativity "Aether and the theory of relativity" was a title used by Einstein in a lecture on general relativity and aether theory. Einstein said that according to general relativity space is endowed with physical properties (the metric field), and one could use the word "ether", if one wished, to refer to this metric field, although he acknowledged that this meaning of the word "differs widely from that of the ether of the mechanical undulatory theory of light". In particular, the metric field of spacetime has no mechanical properties at all, not even a state of motion or rest. Its parts cannot be tracked over time. The general attitude to this amongst physicists today is that although it is purely a matter of semantics, Einstein's comments stretch the word "aether" too far: it is argued that an "aether" with no mechanical properties doesn't correspond to the historical idea of aether, and so it is potentially misleading to apply this name to the spacetime field of general relativity." http://en.wikipedia.org/wiki/Aether_theories Link to comment Share on other sites More sharing options...
Klaynos Posted October 20, 2009 Share Posted October 20, 2009 I think the concept we need here is angular momentum... Link to comment Share on other sites More sharing options...
swansont Posted October 20, 2009 Share Posted October 20, 2009 I think that is rusty's point though (rusty, correct me if I am wrong) While there is no non-relativistic ether, space is not "nothing". Something (somehow) is doing the accounting. "Something must know" is an example of the pathetic fallacy. Link to comment Share on other sites More sharing options...
dr.syntax Posted October 20, 2009 Share Posted October 20, 2009 (edited) Hi, I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around. Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow. Got all of that (know where this is going?)? Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured? Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning. Something knows if the rod is turning or, the barrow is turning. What is this something? Thanks, Rusty REPLY: This explains it " electromagnetic waves disturb electric and magnetic fields instead of particles. These waves include light,micro waves and radio waves" . Information quoted from bookrags.com. The link I used previously typed in NOW will not work. For working link scroll up to previous Dr.Syntax posting #2 in this thread . ...Dr.Syntax Edited October 20, 2009 by dr.syntax Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 20, 2009 Author Share Posted October 20, 2009 REPLY: Electromagnetic waves create the medium they move through as they move through it. Go to : http:http://www.bookrags.com/research/waves-wop/ . This is nothing new. There is no aether. ...Dr.Syntax Dr. Syntax, Yes, this is what I must research -- maybe today. The question that pops to mind is: how do electromagnetic waves know whether an object is spinning or the unseen universe is spinning around the object? They have to be keying off of something. Thank you so much for your help! Rusty Link to comment Share on other sites More sharing options...
dr.syntax Posted October 20, 2009 Share Posted October 20, 2009 Dr. Syntax,Yes, this is what I must research -- maybe today. The question that pops to mind is: how do electromagnetic waves know whether an object is spinning or the unseen universe is spinning around the object? They have to be keying off of something. Thank you so much for your help! Rusty REPLY: Hello Rusty, I appreciate your thanking me. My instantaneous reaction to your question was that it had something to do with the fact that these electromagnetic waves are 2 fields: electric field and the magnetic field moving at right angles to each other. I`m not saying I know the answer to your question. It`s just that when something just pops into my mind like that without me even consciously thinking about it, it means my subconscious mind sees and understands something my conscious mind is unaware of. It does not mean I know I am right or know the answer. Just maybe that may help you come to the answer you are seeking. Take Care, Dr.Syntax Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 20, 2009 Author Share Posted October 20, 2009 REPLY: This explains it " electromagnetic waves disturb electric and magnetic fields instead of particles. These waves include light,micro waves and radio waves" . Information quoted from bookrags.com. The link I used previously typed in NOW will not work. For working link scroll up to previous Dr.Syntax posting #2 in this thread . ...Dr.Syntax If I'm readding this correctly then "electric and magnetic fields" fill space and guide electromagnetic waves. Electric and magnetic fields are my 'ether''. Link to comment Share on other sites More sharing options...
dr.syntax Posted October 20, 2009 Share Posted October 20, 2009 If I'm readding this correctly then "electric and magnetic fields" fill space and guide electromagnetic waves. Electric and magnetic fields are my 'ether''. REPLY: I think you answered your own question. Well done Rusty. ...Dr.Syntax Link to comment Share on other sites More sharing options...
swansont Posted October 20, 2009 Share Posted October 20, 2009 If I'm readding this correctly then "electric and magnetic fields" fill space and guide electromagnetic waves. Electric and magnetic fields are my 'ether''. In the absence of EM radiation (and other sources of fields, like charges and currents), there are no fields. Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 20, 2009 Author Share Posted October 20, 2009 In the absence of EM radiation (and other sources of fields, like charges and currents), there are no fields. In this case, what would guide electromagnetic waves (i.e. know if the rod is turning or, the barrow is turning -- see original post)? Something that comes to mind that has not been mentioned is gravity... I believe that gravity would be everywhere in the universe. There was another item mentioned that I have yet to look into: angular momentum. Someone out there must know the answer -- I can't believe that I've come up with something that's never before been considered. Rusty Link to comment Share on other sites More sharing options...
swansont Posted October 20, 2009 Share Posted October 20, 2009 In this case, what would guide electromagnetic waves (i.e. know if the rod is turning or, the barrow is turning -- see original post)? You'll have to explain why you think there is a connection here. The OP said nothing about EM waves. Something that comes to mind that has not been mentioned is gravity... I believe that gravity would be everywhere in the universe. There was another item mentioned that I have yet to look into: angular momentum. Someone out there must know the answer -- I can't believe that I've come up with something that's never before been considered. Rusty I think these have been addressed. You can tell if you are in a non-inertial frame. Perhaps you need to reformulate the question. Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 20, 2009 Author Share Posted October 20, 2009 I'm sorry if it seems I've run this thread into the ground. If my OP was answered I really didn't catch it, I'll re-read everything. I do need to research several posts that might be the answer. As for... You'll have to explain why you think there is a connection here. The OP said nothing about EM waves. EM waves was a possible answer and comes from here: REPLY: Electromagnetic waves create the medium they move through as they move through it. Go to : http:http://www.bookrags.com/research/waves-wop/ . This is nothing new. There is no aether. ...Dr.Syntax REPLY: This explains it " electromagnetic waves disturb electric and magnetic fields instead of particles. These waves include light,micro waves and radio waves" ...Dr.Syntax REPLY: I think you answered your own question. Well done Rusty. ...Dr.Syntax And this seemingly shot down that answer: In the absence of EM radiation (and other sources of fields, like charges and currents), there are no fields. As for... I think these have been addressed. You can tell if you are in a non-inertial frame. Perhaps you need to reformulate the question. I'm confused at the moment -- too much multi-tasking, lol. Those items have been mentioned but I don't yet see an answer (to the OP) in them... but I'm still looking 'non-inertial frame'?? I need to refresh myself on 'non-inertial frame' -- I didn't think it applied. I'll let this thread rest for a while... while I do some home work. I certainly do not wish to abuse anything... this forum has been an enormous help to me. r Link to comment Share on other sites More sharing options...
swansont Posted October 20, 2009 Share Posted October 20, 2009 An inertial frame has no acceleration. You can tell if you are accelerating, not if you are moving with constant velocity. Link to comment Share on other sites More sharing options...
dr.syntax Posted October 21, 2009 Share Posted October 21, 2009 Hi, I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around. Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow. Got all of that (know where this is going?)? Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured? Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning. Something knows if the rod is turning or, the barrow is turning. What is this something? Thanks, Rusty REPLY: I do not truly understand the question. But, unless everything component of this scenario is at absolute zero degrees Kelvin. and nothing is moving, which is not the case in this scenario, some amount of kinetic energy is being generated however small that amount may be. Therefore some amount of electromagnetic waves are being generated from the spinning rod or the spinning barrel. This would seem to me to provide some frame of reference though I don`t see how this answers your question any more than I can see how the existence of an aether answers it. But if the existence of an aether answers your question the existence of these electromagnetic waves would serve the same purpose or so it would seem to me. ...Dr.Syntax Link to comment Share on other sites More sharing options...
ydoaPs Posted October 21, 2009 Share Posted October 21, 2009 Hi, I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around. Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow. Got all of that (know where this is going?)? Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured? Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning. Something knows if the rod is turning or, the barrow is turning. What is this something? Thanks, Rusty The barrow is a composite object(it is made of atoms). Since there is no absolutely rigid material(see spinning an infinately long rod), there would be a pressure wave through the material composing the barrow when the motion is initiated. One atom moves with respect to the others which then moves the adjacent atom et al until the entire object is spinning. Link to comment Share on other sites More sharing options...
moth Posted October 21, 2009 Share Posted October 21, 2009 one point that is easy to overlook, even when you spin at a constant rate you still experience acceleration because you change the direction you are moving as you go around(mass likes to move in straight lines) , and you can measure that acceleration. so if the guy inside feels a force towards the sides of the barrow he knows the barrow is spinning not the bar. Link to comment Share on other sites More sharing options...
Spyman Posted October 21, 2009 Share Posted October 21, 2009 If my OP was answered I really didn't catch it Something knows if the rod is turning or, the barrow is turning. What is this something? If an object is spinning, the parts of the objects are constantly changing the direction and thus the Inertia of the parts tries to resist the change. The parts know they are turning because they want to continue in a straight line, but gets accelerated into a new direction. "Inertia is the resistance of any physical object, to a change in its state of motion. <snip> In even simpler terms, inertia means that an object will always continue moving at its current speed and in its current direction until some force causes its speed or direction to change." http://en.wikipedia.org/wiki/Inertia Link to comment Share on other sites More sharing options...
rrw4rusty Posted October 21, 2009 Author Share Posted October 21, 2009 If an object is spinning, the parts of the objects are constantly changing the direction and thus the Inertia of the parts tries to resist the change. The parts know they are turning because they want to continue in a straight line, but gets accelerated into a new direction. "Inertia is the resistance of any physical object, to a change in its state of motion. <snip> In even simpler terms, inertia means that an object will always continue moving at its current speed and in its current direction until some force causes its speed or direction to change." http://en.wikipedia.org/wiki/Inertia Thanks for replying! This I completely understand -- so then, in a universe with no external references what defines this 'straight line'? That's the point. Returning to the normal universe, the distant stars determine everything -- even if you hide them. They determine a straight line, acceleration and rotation. How can they do that? The question I'm trying to resolve can be found here: http://en.wikipedia.org/wiki/Mach%27s_principle From what I've read so far, it seems to be complex and may have no easy answers (or maybe there is an easy answer and I just haven't got to it yet). Rusty Merged post follows: Consecutive posts mergedone point that is easy to overlook, even when you spin at a constant rate you still experience acceleration because you change the direction you are moving as you go around(mass likes to move in straight lines) , and you can measure that acceleration.so if the guy inside feels a force towards the sides of the barrow he knows the barrow is spinning not the bar. This is excellent! I never thought of this but I can sure see it. But again, its like you are moving though something that establishes what is normal, what is 'constant' what's a straight line and what is or is not rotating. Again http://en.wikipedia.org/wiki/Mach%27s_principle is the unresolved dilema. Rusty Merged post follows: Consecutive posts mergedThe barrow is a composite object(it is made of atoms). Since there is no absolutely rigid material(see spinning an infinately long rod), there would be a pressure wave through the material composing the barrow when the motion is initiated. One atom moves with respect to the others which then moves the adjacent atom et al until the entire object is spinning. This is also really really good. I'll have to think about this one. I think this works as the rotation is started but once something is moving at a constant speed this breaks down. What tells the atoms that this is straight and going off this path is turning? Link to comment Share on other sites More sharing options...
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