Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Sverre Vigander on 10/04/2011 18:30:03
-
Sverre Vigander asked the Naked Scientists:
Have the alledged anomalies of acceleration been observed on Pioneer only, or on Voyager as well?
Any theroetical work to explain anomalies in Pioneer would surely also have to be consistent with the Voyager flights.
If there are no anomalies associated with these, that would seem to me to indicate that the explanation is something mission-specific rather than new physics...
Thanks,
Sverre
What do you think?
-
Hi Sverre,
This is my take on the anomaly, I don't believe it is mission specific or involves new physics. In fact it has been predicted by relativity but apparently ignored.
The Pioneer anomaly is due to time dilation that is caused by the gravity of the Solar
System. As pioneer leaves the solar System the rate of flow of time increases causing a
doppler blue shift relative to our perspective. This blue shift reduces the expected red
shift so the red shift is not as far red shifted as expected. The craft is where it is supposed
to be, it just appears to be closer to us than it is.
Full article here http://vixra.org/abs/1103.0103
Mike
-
There is another, more mundane explanation, (http://www.newscientist.com/article/mg21028073.700-mundane-explanation-for-bizarre-pioneer-anomaly.html) that slowly seems to gain acceptance. Here are some other alternative explanations. (http://www.space-time.info/pioneer/pioanomlit.html)
-
Hi,
Thanks for the links. I've read most of the other explanations and most of them are just complicated or unlikely or both. I am not a mathematician so have not done the mathematics but surely the simplest answer (so long as it agrees with known facts) is most likely to be correct?
Gravitational time dilation also explains other anomalies
Galaxy rotation anomaly
http://vixra.org/abs/1104.0041
The Discrepancy in Redshift Between Associated Galaxies and Quasars
http://vixra.org/abs/1103.0113
I suspect it is also the cause of the spacecraft flyby anomalies as well but have not studied that.
Mike
-
Maybe. I don't know Mike. Myself I think there will be several causes building up to the deviation.
"The Pioneer 10 and 11 deep space probes were launched in 1972 and 1973, visiting Jupiter and Saturn before pushing on toward interplanetary space, into the unknown. The Pioneer program really lived up to its name, pioneering deep space exploration. But a few years on, as the probes passed the through the 20-70 AU mark, something strange happened… not suddenly, but gradually. Ten years ago Pioneer scientists noticed that something was wrong; the probes were slightly off course. Not by much, but both were experiencing a slight but constant sunward acceleration. The Pioneer probes had been measured some 240,000 miles (386,000 km) closer to the Sun than predicted. This might sound like a long way, but in astronomical terms it’s miniscule. 240,000 miles is a tiny deviation after 6.5 billion miles (10.5 billion km) of travel (it would take light 10 hours to cover this distance), but it’s a deviation all the same and physicists are having a very hard time trying to work out what the problem is.
That is until NASA physicist Slava Turyshev, co-discoverer of the anomaly, rescued a number of Pioneer magnetic data storage disks from being thrown out in 2006. These disks contain telemetric data, temperature and power readings that both Pioneer probes had transmitted back to mission control up to 2003 (when Pioneer 10 lost contact with Earth). From this, Turyshev and his colleagues teamed up with Viktor Toth, a computer programmer in Ottawa, Ontario, to design a new code designed to extract the vast quantity of raw binary code (1s and 0s), revealing the temperature and power readings from the crafts instruments. It sounds as if the search for the culprit of the Pioneer anomaly required a bit of forensic science.
Now the researchers have a valuable tool at their disposal. Turyshev and 50 other scientists are trying to match this raw data with modelled data in an effort to reconstruct the heat and electricity flow around the craft’s instrumentation. Electricity was supplied by the on-board plutonium generator, but this is only a small portion of the energy generated; the rest was converted to heat, lost to space and warmed up the probe’s bodywork. Heat lost to space and warming of the probe’s instruments are both thought to have a part to play in altering spacecraft momentum. So could this be the answer?
Tests are ongoing, and only a select few simulations have been run. However, early results indicate that around 30% of the Pioneer anomaly is down to the on-board heat distribution. The rest, it seems, still cannot be explained by probe dynamics alone. The team are currently processing a total of 50 years of telemetry data (from both Pioneer 10 and 11), so more simulations on the rich supply of transmissions from the probes may still uncover some surprises."
The Pioneer anomaly by Slava Turyshev from 2010. (http://www.emis.de/journals/LRG/Articles/lrr-2010-4/download/lrr-2010-4Color.pdf)
It seems as a extensive research.
-
yor_on
Thanks for your reply.
As I understand it much of the research into a gravitational solution is based on Newtonian gravity. However, my limited research tells me that the result would not be much different for a relativistic solution. If that is the case then there must quite obviously be something wrong. To the best of my knowledge, Newtonian gravity totally ignores relativistic time dilation due to gravity.
I cannot help feeling that if the gravity of the Solar system is strong enough to stop it from all flying off into space then it is strong enough to marginally dilate time within the Solar System, which is predicted by relativity and is exactly what we see.
In my research into the anomaly, I have not come across anyone else suggesting the anomaly is due to time dilation within the solar System and yet it seems to me that it is the most likely answer.
As I said before I am not a mathematician and at 67 I am not about to start but I have a very strong feeling that either I or all of the scientific community who have looked at this problem are missing something and I really believe it is them. I really feel like I am missing something…?
To my mind, the Pioneer anomalies are quite obviously due to gravitational time dilation within the Solar System. Would I be right in thinking that the Voyager spacecraft may be experiencing something similar? To my mind all craft leaving the Solar System should experience the same Doppler blue shift.
If anyone can prove to me for certain that the anomaly is not due to time dilation in the Solar System I would be delighted to hear from them.
Mike
-
Well, let me reason around it a little and see what we can agree on Mike? First of all, talking about gravitational time dilation. The greater the invariant mass the larger the time dilation relative some observer being 'at rest' outside that gravity well, right? But Pioneer was on its way out of the 'Solar system'¨as it started to deviate so the gravitational attraction should become increasingly weaker, do you agree?
Then we come to the blue-shift. I'm not entirely sure how you expect a object going away from the observer to be blue-shifted? Think of it as a rope that we arranged as a wave in space. Tie one end to the ship, the other you hold, now let the ship move away. The rope will tighten up right? All troughs and crest we had made will now 'smoothen' out into a 'straight line'. The same can be said for any wave-like radiation it creates, as its telemetry, if anything I would expect it to become red-shifted relative us? Maybe you are thinking that as it gets out of the solar systems gravitational field everything on that ship 'speeds up' in some way?
Maybe I will see your point better after sleeping :)
Let us discuss it tomorrow Mike.
-
"Maybe you are thinking that as it gets out of the solar systems gravitational field everything on that ship 'speeds up' in some way?"
Yes exactly, time passes slower in the Solar system because of gravitational time dilation, so it must flow faster outside the solar system. So relative to us it is blue shifted. This blue shift reduces the expected red shift.
"But Pioneer was on its way out of the 'Solar system'¨as it started to deviate so the gravitational attraction should become increasingly weaker, do you agree?"
Again yes, as the gravity becomes weaker so the rate of the flow of time increases relative to us. The signal is blue shifted relative to our perspective which results in an overall decrease in the expected red shift.
"Think of it as a rope that we arranged as a wave in space. Tie one end to the ship, the other you hold, now let the ship move away. The rope will tighten up right? All troughs and crest we had made will now 'smoothen' out into a 'straight line'. The same can be said for any wave-like radiation it creates, as its telemetry, if anything I would expect it to become red-shifted relative us?"
I don't know much about waves but if the rate of flow of time is faster outside the Solar System then the wave length must get shorter, not longer?
Thanks for your input, I find this a fascinating subject.
Mike
-
This is just to hopefully clarify the situation.
Nasa speaks of the Voyager spacecraft making an anomalous acceleration towards the sun. This is gobbledegook for meaning the spacecraft are slowing down.
Using the same logic, a decrease in red shift can be seen as a blue shift. (or an anomalous acceleration towards the sun)
If this theory of time dilation within the solar System is correct then everything we observe from outside of the Solar System is slightly gravitationally red shifted. I believe the effect is so small as to be insignificant for anything other than craft we are tracking leaving the Solar System.
All clear?
Mike
-
Sorry that should read Pioneer not Voyager.
-
What you are suggesting then is that due to a lesser gravity the Pioneer's red-shift, as observed relative earth, will be decreased? That as the gravity-well the light 'climbs' out of will diminish, the further that spacecraft moves from us? It's a cool idea :)
Now let us turn that around. We use red-shift to define astronomical objects, from those red-shifts and other types of triangulations we set their 'distances' relative us. Assume that with different gravity this red-shift will change relative us observing those suns etc. If you would be right you not only found a explanation to the Pioneer anomaly, but also invalidated all definitions we have of redshift, as we then also would need to know the specific 'gravity' involved at their source for defining their speed etc relative us.
I don't know Mike, to me a light quanta/photon will be of a defined energy. If we now translate that into a wave then it follows that this wave also have a 'defined' energy. What the light quanta does, when 'climbing' a gravity well like you sending a beam up from earth into the sky, is following the same path as it takes anywhere in the universe. That means that it does not expend any 'energy'. You need to remember that a photon never lose 'energy'. If it did we could expect all photons/waves to die at some point traveling towards us, but as far as I know they don't.
But when that light climbs the 'gravity well', assuming that we have an astronaut observing it, it will to him seem 'red shifted' meaning that it somehow have 'lost' energy. But as we already have defined it hasn't, not 'really' :). The redshift seen is a effect between the observer and the 'source' and that same 'light quanta' if instead observed outside that gravity well will now be found to be back to normal and no longer red shifted.
And if we assume that the beam is directed at some planet in another solar system, the observer on 'Earth Two' instead will see it as a 'blue-shift' as it 'accelerates' into that 'gravity well'. But from another light-quanta/photon/wave traveling beside our first, always at rest relative it, that light-quanta/photon/wave never changed its 'energy'.
That's how I see gravity's influence on relative red and blue shift. Then we come to relative motion. If you have two flash-lights, their beams pointing at each other and both equipped with detectors of that same beams, we can by setting them into motion towards or from each other get a similar effect. When you let them move apart their 'light-waves' will seem to 'stretch' relative each other, as with that rope I talked about and as long as they are moving apart this 'red-shift' will be true. The opposite, moving towards each other, will produce a blue-shift, relative each other.
Why I keep using 'relative each other' is because this effect seen is 'relative'. Remember that our light quanta/photon/wave have one 'invariant' energy, not many. But depending on whom sees that light, moving towards it or apart from it it will express a different 'energy'. That energy is a true measure of the energy, but only relative the one measuring it.
It takes some thinking around corners to see what I mean here but it falls back on, again as I see it, that lights speed in a (perfect) vacuum only can be of one 'speed'. The only way a 'light quanta' can express relative 'speeds' (motion relative a observer) is by red or blue-shifting where a blue-shift will be two objects moving towards each other, and a red-shift will be the same objects moving apart.
The red-shift seen is primary a Doppler red-shift, same as listening to that ambulances horn, sounding shrilly as it comes towards you, only to change to a deeper 'slower' bass as it later moves away from you, a little part but raising with velocity is the so called Lorentz-contraction that comes into play, noticeably around 0.5 'c' if I remember right and raises to become insurmountable near 'c' contracting the spacecraft in its motion.
Hope I didn't bore you to death here, but to see my points you need to see my premises.
And they are some :) and growing..
1. light is massless
2. light is time less
3. light has no inertia
4. a light-quanta will, from source to sink, be of one same 'energy', until its annihilation.
5. light has only 'one same speed' from, and in, any 'frame of reference' observed
6. The only way you can translate a 'acceleration/deceleration' for light, is in its relative blue or red shift. And that is a relation between the observer and the 'light-quanta/photon/wave'
7. When discussing the 'recoil' of a photon, as observed in some experiments. It has nothing to do with a acceleration. Assuming that the 'system' (source/photon) are at 'rest' before the excitation. The recoil will be a response to the 'demand' that the the final 'total momentum' of the source/photon interaction must equal zero. If we assume a photon to have a certain momentum, then the recoil have to exist to 'counteract/equalize' it. It's a question of the symmetry of our universe, and so make a very weird sense, just as lights 'speed' in a vacuum makes a weird sense.
In a way there are two ways to look at the laws of our universe. From inside where we discus forces and fields. From 'outside' where we talk about 'symmetries'. It's a really confusing place, SpaceTime :)
So the red/blue shift defined relative a gravity well is a 'short range' effect, only existing inside the gravity well. Whereas 'relative motions', moving towards or apart, is 'long range' effects, as I see it. This one is disputable and a sort of hand waving :) But I use it to emphasize a point. Invariant mass and 'gravity' is 'short range effects' as I thinks of it, the gravity-wells strength diminishing rapidly as it's a law squared, as you double the distance you have to quarter the gravity, or expressed differently Gravity Force Coupling Constant. (http://hyperphysics.phy-astr.gsu.edu/hbase/forces/couple.html)
Those seven goes into each other, defining a very weird 'constant' regulating all life and our whole universe. Light never change its 'speed'.Frozen into a Bose Einstein condensate it will still have the property of 'c', although now in a state, relative us observing, that makes us describe it as being 'still'. As soon at we 'release it' we will find it 'moving at c', no acceleration involved. And what really happened there is that we enforced a new state on the condensate, storing the 'idea' of a photon in it, or if you like, added a energy to it that it couldn't express under those 'chilled' conditions.
Well, that's how I see it. And, as always, I will need to look at it later to see if it makes sense. Coffee usually helps there:) In a way you can see it as 'hand waving' as we only discuss it, not using any math. But I'm pretty sure that I have the idea of it right here. So, getting back to Pioneer, I don't think it is possible myself, although I'm not a hundred percent. Any red-shift expressed (versus us observing from Earth) will be relative its motion apart as I think, and what blue-shift we can expect will be the exact same blue-shift as for all light coming at us astronomically. But I still need to look at it again and see if I made any sense. So bear with me huh :) And let me get my coffee..
Light is so weird.
==
Told you I needed to look at it again :)
I'm the master of rewriting ::))
Ah well :)
But coffee helps, I just need some more..
==
Well, it worked, the coffee that is.
I hope I've corrected most of my misspellings, etc, now?
If I haven't, even coffee has a limit :)
-
“What you are suggesting then is that due to a lesser gravity the Pioneer's red-shift, as observed relative earth, will be decreased? That as the gravity-well the light 'climbs' out of will diminish, the further that spacecraft moves from us? It's a cool idea :)”
Yes, it’s a cool idea but as I understand it, it was Einsteins. All I have attempted to do is apply the logic of relativity, without the math to the problem.
”Now let us turn that around. We use red-shift to define astronomical objects, from those red-shifts and other types of triangulations we set their 'distances' relative us. Assume that with different gravity this red-shift will change relative us observing those suns etc. If you would be right you not only found a explanation to the Pioneer anomaly, but also invalidated all definitions we have of redshift, as we then also would need to know the specific 'gravity' involved at their source for defining their speed etc relative us.”
The speed of light is a constant in a vacuum (away from anything that upsets it). As I said everything that we see from outside the Solar System is marginally red shifted. Light leaving any source that is big or massive enough for us to be able to see is being affected by a gravitational red or blue shift at source. That’s why the quasar in a galaxy quasar pair always seems to be far red shifted in relation to the galaxy. The quasar is far blue shifted at source. Why is it blue shifted you might well ask? Quasars only appear in the early universe, the first 20% of its age. Quasars are what built the universe. They are white holes in our universe; time reversed black holes in the previous antimatter cycle. However, I digress into another even more fascinating subject.
I am a bit pushed for time at the moment so will keep this short for now.
This is the main thing to remember and people quote it frequently but I suspect seldom stop to really think about it.
“Relativity allows mass to gravitationally dilate time” (not stated but equally valid it allows for negative mass to contract time. I do not know whether it states this or not but a very large local input of energy can also contract time locally.)
This is probably the main thing we need to remember.
The speed of light in a vacuum is allowed to be a constant because the rate of flow of time is a variable.
This affects all other constants of nature in a way that makes it impossible for us to tell any difference in the rate of flow of time. One minute to us in our universe could to a hyperthetical observer outside the universe represent one minute or a million years.
So yes, the speed of light is invariant but the rate of flow of time isn’t.
Time flows slower near to the Earth. Time flows slower in the Solar System. Time flows slower in the Milky Way galaxy. Time flows slower in our local cluster and so on and so forth right up to intergalactic voids where gravity is at a minimum. So you can see the one thing that the rate of flow of time isn’t, it isn’t constant. Now there is good reason to believe that Einstein was correct when he declared the speed of light to be invariant. However you can see from above that if we decided that the rate of flow of time was invariant then the speed of light would be a variable and variable all over the place.
Clear?
Mike
-
Well Mike, we have a divergence there. Time has the same 'rate' everywhere you go as I see it. If you go spacefaring or settle down on a neutron star doesn't matter for that. Time as such do not slow down on any of those places. The time dilation we see is a phenomena between 'frames of reference' not any observable for you. The only way to prove it is to make a so called twin experiment, and only as the traveling twin come home to roost will it be shown.
Imagine yourself having a super telescope following that traveling twin. At no 'time' will you lose sight of him and at no time will you find your 'time' to act funny watching him, and neither will you find his spacecraft slow down as it 'speeds up' relative you. What gravity does is influencing 'time' but in no way perceptible for you. Assume that each human have one million heartbeats before he dies, then that is our measured life span. And it will be so wherever you go, and whatever you do. That the universe dies as you travel near light doesn't matter for this. Your time will be the same, as mine, and as everyone else's. The mistake people make is to assume that as a time dilation exist time isn't of one duration. That's wrong, time is of only one duration, but when comparing between frames of reference we will find discrepancy's. But without a twin experiment you will have a he* of a problem defining how your 'time' fares relative anything else. Time is on your personal plane of only one duration, but on the conceptual plane 'fluid'. You have to see the difference there because that one is important for understanding why there are no pockets of 'slower time' in the universe.
In reality you will never find a place where time change duration.
-
Ok good now we are making progress.
Well Mike, we have a divergence there. Time has the same 'rate' everywhere you go as I see it. If you go spacefaring or settle down on a neutron star doesn't matter for that. Time as such do not slow down on any of those places.
Relativity tells us that the rate of flow of time can vary. Where is our divergence, do you not believe in Relativity? Relativity proposes time dilation by massive objects right? We know this to be correct as it has been shown that atomic clocks in orbit where gravity is less run faster than on Earth. Also time dilation has to be taken into account for satellite navigation systems. Time dilation caused by the Earth is minute but is the scheme of things the Earth is only small. Do you agree so far?
Time dilation is very real.
Lets go back to the Pioneer anomaly again. The anomaly was signals from the spacecraft were observed to be blue shifted. This was interpreted as meaning that the spacecraft were slowing down. The anomaly only became apparent when the spacecraft were leaving the Solar System. These I think you will agree are known facts.
Relativity states that massive objects can gravitationally dilate time (slow it down). Still with me? The pioneer spacecraft outside the Solar System transmit their signal home. That signal as it enters the Solar System becomes red shifted due to gravity, which is exactly what we see. From our perspective we see the signal as relatively blue shifted. As I have said before the red shift is not as far red shifted as predicted. The spacecraft are where they are supposed to be they just appear to be closer to us than they are. What is it about this that you either don't agree with or don't understand?
At no 'time' will you lose sight of him and at no time will you find your 'time' to act funny watching him, and neither will you find his spacecraft slow down as it 'speeds up' relative you.
Consider he flies too close to a large black hole and just manages not to get caught. We would observe him to slow down whilst he was near the event horizon but he would still consider himself travelling at the same speed. There is a discrepancy in the rate of flow of time between the two twins.
You have to see the difference there because that one is important for understanding why there are no pockets of 'slower time' in the universe.
That's not true we live in one. If we lived in orbit at the edge of a black hole event horizon we would be living in a very large one.
In reality you will never find a place where time change duration.
The only way you can make a statement like that is if you don't believe in gravity causing a relativistic time dilation. I guess you don't have to believe in it but it has been proven to be true. Personally I don't believe in quantum gravity. However, I suspect you do believe in relativistic time dilation by gravity, in which case I'm not sure what it is we disagree upon?
One of us must have got it wrong. I don't think it is me and I know I am out on a limb but If you can prove me wrong then fair enough. Hopefully, we will eventually reach a mutual agreement that will entail an increase in knowledge and understanding.
Mike
-
No Mike :)
I think I'm right there, and I have no trouble believing in 'time dilation'. It's just that there exist no corners of this universe that will make your time go any 'slower'. As I said, time dilation is a comparison between 'frames of reference', not 'time' slowing down for you.
==
Thinking of it, maybe that 'spaceship' moving apart will 'hang' too? :)
Yep, I think it will. But it doesn't invalidate what I say.
=
You also need to realize that, from the viewpoint of those people inside the spacecraft, their 'time' is as always. They will in a 'time' oversee-able by them pass what we define as the EV and plunge into the singularity. And that 'time' they experience will to them be no different than the 'time' they experienced at home. As I see it :)
I'm not proselyting Mike, this is the opinion I have. You're welcome to yours however. I don't expect you to change your mind here though, so let us merely accept that we have two interpretations of the same phenomena.
-
You know, I really need to consider that definition of it 'hanging' there. First I explained as the light being 'delayed' but I took that away as you then would assume that your interpretation of different pockets of 'local time' being true. My explanation was correct but not 'clear'. It is a result of the room time geometry around a black hole. As the spacecraft falls toward the event horizon the 'room time geometry' around that ship warps with the increasing gravity and the photons bouncing of that spacecraft will red shift relative the observer outside the gravity well, as well as take more 'time' to reach him. So it's not photons slowing down as they bounce back from the event horizon, but rather a effect of the room time geometry around it. But it is easy to see that there is no such pockets of 'slow time' if we turn it around. Assuming you to be right you would now find that the speed of light in a vacuum no longer can be called a 'constant' as it then would have to 'slow down' in those 'time pockets'. Quite a nice name btw :)
Hope this one makes better sense :)
==
If you accept that the speed of light is a 'constant' the same everywhere in SpaceTime, then any explanation talking about 'delayed light', propagating inside a vacuum (space) only has one solution. Namely the room time geometry being warped for the light propagating. I use 'room time geometry' instead of 'frame of reference' for defining a 'SpaceTime' as seen from 'first perspective', the one we experience first handedly. 'Frames of reference' is very much about comparisons between frames conceptually, but I find the 'first perspective' to be more of a immediate 'reality' as that is the one we experience ourselves, constantly, until we die.
-
Ok, let me try to summarize. Please correct me if I am wrong.
This is part of what I wrote in my last post and it is in essence what we are disagreeing about:-
"Lets go back to the Pioneer anomaly again. The anomaly was signals from the spacecraft were observed to be blue shifted. This was interpreted as meaning that the spacecraft were slowing down. The anomaly only became apparent when the spacecraft were leaving the Solar System. These I think you will agree are known facts.
Relativity states that massive objects can gravitationally dilate time (slow it down). Still with me? The pioneer spacecraft outside the Solar System transmit their signal home. That signal as it enters the Solar System becomes red shifted due to gravity, which is exactly what we see. From our perspective we see the signal as relatively blue shifted. As I have said before the red shift is not as far red shifted as predicted. The spacecraft are where they are supposed to be they just appear to be closer to us than they are. What is it about this that you either don't agree with or don't understand?”
Although you didn’t directly answer the above questions, as I understand it whilst saying that you have no trouble in believing in ‘time dilation’ between ‘frames of reference’ you don’t actually believe in time dilation as being a very real and observable property of the universe, is that correct?
My take on the Pioneer anomaly is it is a real and observable example of time dilation. Time dilation means that the passage or rate of flow of time is variable. For the speed of light to be a constant, the rate of flow of time must be a variable.
To summarize my view, the speed of light is a constant because the rate of flow of time in the universe is a variable. The universe has an average rate of flow of time, however on any local scale there can be deviations from the average.
To me the idea of the rate of flow of time being variable is perfectly reasonable. It is predicted by relativity, has been proven to be true and is a real and observable phenomenon. It explains the Pioneer anomaly in very simple terms.
As you say we can agree to disagree because we have two interpretations of the same phenomena. There probably is only one truth on the subject and it would be good to agree.
You said in a previous post:-
“What you are suggesting then is that due to a lesser gravity the Pioneer's red-shift, as observed relative earth, will be decreased? That as the gravity-well the light 'climbs' out of will diminish, the further that spacecraft moves from us? It's a cool idea :)”
Yes, that’s it exactly, you initially seemed to like the idea until you thought about it and realized that it implied gravitational time dilation.
Although you say you believe in time dilation, it seems to me you only believe in it in an abstract frames of reference sense. Why is it so difficult to believe in time dilation as being real and observable as in the Pioneer anomaly?
I do not want to labor the point but where you say:-
“But it is easy to see that there is no such pockets of 'slow time' if we turn it around. Assuming you to be right you would now find that the speed of light in a vacuum no longer can be called a 'constant' as it then would have to 'slow down' in those 'time pockets'.”
If we analize what you are actually saying.
the speed of light in a vacuum no longer can be called a 'constant' as it then would have to 'slow down' in those 'time pockets'.”
What you are missing here is the speed of light in a vacuum is a constant precisely because the rate of flow of time is a variable.
Mike
-
In your last post you said:-
“If you accept that the speed of light is a 'constant' the same everywhere in SpaceTime, then any explanation talking about 'delayed light', propagating inside a vacuum (space) only has one solution. Namely the room time geometry being warped for the light propagating.”
Or another way of putting this is:-
“If you accept that the speed of light is a 'constant' the same everywhere in SpaceTime, then any explanation talking about 'delayed light', propagating inside a vacuum (space) only has one solution. Namely the room time geometry being warped for the light propagating.”
"For room time geometry being warped for the light propagating.”
Read, space time geometry being warped by mass for the light propagating.
For space to be warped, something has to cause it to warp. In this case, we are talking about mass.
Another way of putting this is mass cause’s space-time to dilate (warp).
Another way of putting this is mass causes the rate of flow of time to slow down.
You seem to be in full agreement with me. Surely, this cannot be?
Mike
-
Time is a really weird phenomena Mike, just as 'frames of reference'. Take a look here and see how it is explained in the wiki Relativity of simultaneity. (http://en.wikipedia.org/wiki/Relativity_of_simultaneity) . It's as they say 'counterintuitive' and makes no real sense, well, as we're used to think of it. It's like 'times arrow' as such always is following you keeping the same steady rate, but when comparing between frames we find the opposite being true. There we need to apply mathematical transformations, translating their 'SpaceTime coordinates' to ours before they start to make sense.
You might see it as if 'light' is what gives you the 'whole seamless SpaceTime' whilst 'motion' and 'mass' is what creates the different frames of reference, that's how I see it myself for now. But there is one thing I'm quite sure of and that is that you will find nowhere in the universe where light will slow down, or speed up, in a vacuum. And if you was right then those places should exist relative the observer outside the gravity well. And as far I know they don't. It's a cool idea, 'time-pockets' as I call them but I don't expect them to exist myself. That 'times arrow' differs when comparing is a direct result of the SpaceTime geometry. And as I said, when discussing it from the 'first person' view then I like to call that your 'room time geometry'. And that definition is solely mine :)
-
"But there is one thing I'm quite sure of and that is that you will find nowhere in the universe where light will slow down, or speed up, in a vacuum."
I agree entirely light never slows down or speeds up. It does not have to, the rate of flow of time changes to accommodate it. As I have been saying all along, the speed of light is a constant because the rate of flow of time is a variable.
Mike
-
How Mike?
How does time adapt?
And why would it adapt to a constant?
-
A constant is by definition unchanging. You can't have it both unchanging and changing Mike, if you use such a definition then we're not talking about a constant any longer. When we speak about the room time geometry inside a black hole we can define it, depending on whose math we trust and 'mass' as 'infinite'. That doesn't state that time changed its 'speed' to adapt so that we will find the speed of light in a vacuum to fit. It state that the room time geometry is different, the reason why we use room time is because you can't have a 'room' without time and neither can you have a 'time' by itself. But the direct effect for us being inside will be that the room in fact become infinite, not that light as such change speed.
In one way this whole discussion is meaningless as 'speed' is a very shaky definition. The only thing that always seem to have one exact 'duration' when measured by us, invariant in/from all frames, is lights speed in a vacuum. And that goes from anywhere you choose to measure it, inside that black hole or outside it. You can measure it from any frame you like, against any other frame, moving near the speed of light measuring that event horizon for example. You will still find it to have one single 'speed'. But you can have an observer at the same exact 'location' as where you do your measurement, but contrary to you being still relative that black hole. He will be doing the exact same measurement on the same light. And you will both find the speed to be the same, namely 'c'.
The speed of light in a vacuum is invariant. Time does not slow down to adapt the light speed, as shown by our two observers, to fool us. To me it's a question of the geometry of SpaceTime, and it is coupled to mass, motion, and possibly energy?
==
As it seems to me )
In your world everything gets invincible forcefields of 'time' adapting itself so that we won't notice lights speed 'differing' if I understand you right? Whilst in mine there is only one thing that is constant, namely lights speed in a vacuum. I go out from that definition and from there I find the geometry of 'SpaceTime' to change. That also fits with all observation I know of your personal time never differing, no matter if you're at the EV of a black hole, speeding away near light, or just comfortably reclining in your sofa.
Using your definition it becomes trickier it seems. When it comes to uniform motion you can exchange any motion measured. For example, 'A' will say it moves close to lights speed relative 'B' being still, but, you can as easily exchange that to it being 'B' moving near lights speed relative 'A' being still, or give them both any speeds in between as long as they add up to the number measured relative each other.
In Relativity both statements are true when it comes to uniform motion, and it builds on the equivalence of them, as observed and tested in a 'black box scenario'. If all experiments you can do inside that black box, on each of the ships, gives you the exact same results, then all uniform speeds are the same from that point of view and so speed becomes a meaningless definition. (ignoring tidal forces here)
But it seems to me that if you was right then we would have a way to prove that only one of them was 'moving'. And that would redefine the equivalence principle and theory of relativity to me :) And as I see it, for Einstein too if he was here.
-
You can, if using my definition, think of time as measured out by lights invariant propagation. Then it will with relative motion (and mass) be found to have different 'distances' to reach. If you're uniformly moving away from the light it will take longer to reach you than if you were moving towards it. That can in a way be translated into time. The geometry you move in is dependent on those light signals, they are the watch that 'ticks', and they 'tick' differently for you moving than for you being still. And they will be normal to you as all 'light ticks' only can have one constant invariant speed, but to the observer being still they will describe another duration as they propagate trough space, moving with you.
And as light is the only true constant, that and the fact that your personal time never changes, then the effect you see in a time dilation suddenly will be found to be placed in the relation between you and the observer. In SpaceTime all time is a definition from lights propagation, and the geometry changes with it too. To you the light clock you have with you always bounce the same amount of 'distance'. But to the observer at rest relative your origin (Earth) that same 'light corn' will bounce a different (longer) path through SpaceTime. And yet you both observe the same light-clock, although it to him will be found to take a longer path through space as you move, but for you, being at rest with it comoving, it will be found to take the exact same path as on Earth.
There is two ways to look at that phenomena, that light will be found to have a 'longer path' from Earth than as what you perceive traveling aside it. Either you define it as the light clock 'slowing down' as observed by the observer on Earth, now saying that light goes 'slower' inside that ship, and that seems to be your interpretation of it, or you define it as light having one invariant speed and the effect you observe being a result of 'different' room time geometries, the observers and yours, aka 'frames of reference'. But as I also see their 'times arrow' as unchanging in both scenarios, which is my interpretation of it :) I state that it is the room time geometry that is different for them. And stating that I define the room time geometry as their 'SpaceTimes' being different. Which in a way make me even more heretic than you as I now define them each one to have a unique, different, SpaceTime :) And that's kind'a weird :) The only thing that I see binding those SpaceTime's together is 'light'. Radiation is what makes this universe seem seamless to us, that and mass, motion, and possibly 'energy'. It both is what shows us that we're in reality 'divided' at the same time as it 'joins us' :) And now I'm afraid we soon will have to move us both to 'New Theories'.
Ahem..
And that's why your personal time always is the same, unchanging, and that's why the observer and you will disagree on the 'time taken'. And that's why a time dilation exist. But it weirder than that :) Because as I said, you can define any uniform motion as being at rest, weightlessly 'drifting', no gravity existent. And that is true, there is no way you will find any gravity inside that black box. And if you measure a light coming from the stern to the aft, it will not 'blue shift' no matter what speed you believe yourself to have relative Earth. Also you can redefine our planetary gravity (Earth) as a constant 'uniform' acceleration at one gravity. And that is the direct equivalence to your spacecraft starting to accelerate a constant one gravity. And if you now watch that light in-falling from the stern you will find it to blue shift, same as on Earth. So it's a tricky business, where it's very easy to get lost in its definitions. But it's a nice idea, although I see it differently.
-
Let's try an experiment.
I'm zipping along in my very fast spaceship. So fast in fact that time will be dilated relative to time on Earth. On my spaceship, I happen to have an evacuated tube and a light source that allows me to measure the speed of light in a vacuum. It's really quite a simple setup.
If I understand how this all works, despite any shortening of the tube and local time dilation, the value that I measure in my spaceship will be exactly the same as the value I measure using the same equipment on Earth.
Do we all agree with that, or have I got it wrong somewhere?
-
As long as you're uniformly moving that should be correct as I see it :) It will 'zip away' or 'tick' heh :) the same as on Earth.
==
Maybe you are thinking of what will happen if you turn it around? In the direction of the motion '|' as for putting it horizontal '-' to the motion. The Lorentz contraction will equalize the difference as I see it. and so the 'ticks' will be found, from a thought up observer on Earth, to be the same when measured, all of the same duration. And for you being inside the ship, you will be at rest with your equipment and so notice no difference at all.
In a acceleration it becomes trickier for me as there will be a constant accelerating displacement relative the lights path, with a respective red and blue shift noticeable. But as lights speed in a vacuum is a constant, it shouldn't matter for the 'ticks'. Ah, that is for you being inside, at rest with the light source. For our observer at Earth the acceleration will change the durations measured, well as I think. Acceleration is indeed trickier, and very weird to me.
==
Think of bouncing a tennis ball on the floor of a aircraft at 900 km/h. The ball won't care, it will go straight down on the floor and up. But if the floor was made of glass and someone standing on earth could watch that ball bounce he would swear to it taking a curved path down and then a curved path up. Exchange the ball for light, and define it as a constant, always of the same exact 'speed' in a vacuum. Then try to define the shortest durations we can measure. That will be by that same invariant light, won't it? Radiation is the best 'clock' we have.
-
Ah! Good. So, what might we conclude?
Well, I think we can say that the speed of light is constant for any observer within their frame of reference. Speed is correct in that sense because it really is the distance travelled in time.
Here's where it might get ugly. We know that the two clocks (the one on the spaceship and the one on earth) are not in agreement. Also, we know that the two vacuum tubes are not really the same length while they have a great difference in relative speed. Soooooo, if you could measure the speed of light on the spaceship using the the Earth clock and the Earth vacuum tube, you would measure a value for c that was different from the official c.
-
The thing is that all measurements you can do by using the earth's clock and tube will be corrected by the speed of light relating you to the earth...
By the way, i agree with Mike about the blueshift, but i suppose it has already been taking in account and it should be quite small. It may be only a drifting of electronics components... They surely cannot measure it...
-
The thing is that all measurements you can do by using the earth's clock and tube will be corrected by the speed of light relating you to the earth...
Actually, they won't [:D]
If the spaceship was orbiting the Earth, you could send it a signal during every orbit so that the spaceship's clock was continuously synchronized with Earth time. Then you would measure a different value for c on the spaceship.
But that does not violate relativity because, in that situation, you would not be measuring the speed of light using the time within the frame of reference of the observer.
-
You're cheating, you forgot the tube... [;)]
-
It would seem that I can't stress this enough:-
The speed of light is a constant, is a constant is a constant.
But
The speed of light is a constant because the rate of flow of time is a variable.
Without wishing to get into what time is it has two components, direction and rate of flow. Obviously time is a product of the universe and its rate of flow must be connected to some particular qualities of the universe, say its a relationship between energy and mass, energy divided by mass. This ratio is not constant in the universe, nor is it constant on any local volume of space that contains mass.
There is very good reason, known and understood why the speed of light is a constant. There is nothing that says the rate of flow of time is a constant. It isn't. General Relativity states that the passage of time (the rate of flow of time) is relative. Traveling near to the speed of light or being in a gravity well dilate time. These are not abstract frame of reference ideas that can't be seen or measured. Time dilation is real and observable and has been proven to be correct.
"Gravitational time dilation is the effect of time passing at different rates in regions of different gravitational potential; the lower the gravitational potential, the more slowly time passes. Albert Einstein originally predicted this effect in his theory of relativity and it has since been confirmed by tests of general relativity.
This has been demonstrated by noting that atomic clocks at differing altitudes (and thus different gravitational potential) will eventually show different times. The effects detected in such experiments are extremely small, with differences being measured in nanoseconds." http://en.wikipedia.org/wiki/Gravitational_time_dilation
Gravitational time dilation is minute on the Earth because the Earth in cosmological terms contains little mass.
ArkAngel
It would seem reasonable to assume the blue shift has been taken into account as it is predicted by relativity but honestly, I don't believe it has.
Mike
-
Further to comment from ArkAngel:-
As I understand it Newtonian Gravity was used as the model when analysing the Pioneer anomaly. Newtonian Gravity is obviously lacking for this scenario as it does not take into account gravitational time dilation by our solar system.
Mike
-
Further to comment from ArkAngel:-
As I understand it Newtonian Gravity was used as the model when analysing the Pioneer anomaly. Newtonian Gravity is obviously lacking for this scenario as it does not take into account gravitational time dilation by our solar system.
Mike
It would be extremely embarrassing to physicists if the anomaly was as simple as them not using general relativity to do the calculations. Interestingly, I can't find any description of the model of gravity used in the original papers on it. See this one, for example: http://arxiv.org/PS_cache/gr-qc/pdf/9808/9808081v2.pdf
However, some of the attempted explanations involve using general relativity and assuming dark matter/dark energy http://arxiv.org/PS_cache/gr-qc/pdf/0407/0407023v1.pdf, so I assume the effect has been checked with general relativity. It would be odd to check the anomaly using general relativity with added dark matter/energy and not notice that general relativity without these additions explains the anomaly.
At any rate, I agree with ArkAngel on this one. Surely they've checked if GR alone predicts the effect, even if I can't find someone explicitly stating that in an article.
-
I agree, it would seem odd if they hadn't considered general relativity. Einstein, when he came up with these theories based much of his work on thought experiments. I don't know how he would have translated thought experiments into specific as opposed to general mathematical solutions. Perhaps relativity needs tweaking.
Apart from the Pioneer anomaly there exists the galaxy and associated quasar red shift anomaly and the galaxy rotation anomaly. I am sure that these anomalies are also based around relativity. Personally I do not believe in dark matter or dark energy.
Anybody care to comment on the speed of light being a constant because the rate of flow of time is a variable. I think this is what relativity is telling us and I believe my interpretation of this is correct. However perhaps you know better?
Mike
-
"ANOMALOUS GRAVITATIONAL FORCE
A discussion of this phenomenon appears in the 4 October 1999 issue of Newsweek magazine (See also the December 1998 issue of Scientific American.) The mystery of the tiny acceleration towards the sun in the motion of the Pioneer 10, Pioneer 11 and Ulysses spacecraft remains unexplained as of 2006. A team of planetary scientists and physicists led by John Anderson (Pioneer 10 Principal Investigator for Celestial Mechanics) has identified a tiny unexplained acceleration towards the sun in the motion of the Pioneer 10, Pioneer 11, and Ulysses spacecraft. The anomalous acceleration - about 10 billion times smaller than the acceleration we feel from Earth's gravitational pull - was identified after detailed analyses of radio data from the spacecraft. A variety of possible causes were considered including: perturbations from the gravitational attraction of planets and smaller bodies in the solar system; radiation pressure, the tiny transfer of momentum when photons impact the spacecraft; general relativity; interactions between the solar wind and the spacecraft; possible corruption to the radio Doppler data; wobbles and other changes in Earth's rotation; outgassing or thermal radiation from the spacecraft; and the possible influence of non-ordinary or dark matter. After exhausting the list of explanations deemed most plausible, the researchers examined possible modification to the force of gravity as explained by Newton's law with the sun being the dominant gravitational force. "Clearly, more analysis, observation, and theoretical work are called for," the researchers concluded. The scientists expect the explanation when found will involve conventional physics. An article in http://www.space.com/scienceastronomy/mystery_monday_041018.html discusses the current thinking on the acceleration anomaly."
http://www.nasa.gov/centers/ames/missions/archive/pioneer.html
Although it mentions general relativity, it talks about modification to Newtons law. We are now talking about three spacecraft with the same anomaly. One of which is a different design. It's a very small but consistent anomaly.
I am absolutely certain that my original explanation is correct. Either they haven't used general relativity, or they have done the sums wrong or general relativity needs tweaking.
Mike
-
Iv'e just sent an e.mail to Slava Turyshev at NASA's Jet Propulsion Laboratory who is handling the enquiry. If I get a rely I will post.
Mike
-
I am absolutely certain that my original explanation is correct. Either they haven't used general relativity, or they have done the sums wrong or general relativity needs tweaking.
Absolute certainty is a huge leap of faith. Is it backed up by science? What evidence makes you so certain that your explanation is right?
I do happen to agree with you that the idea that GR might need tweaking is a very interesting possibility. I don't think there's any reason to be certain that it does, though.
By the way, as yor_on posted there was a recent paper claiming that the anomaly could be explained by thermal radiation off an antenna. It hasn't been double checked.
------------------
As for the speed of light being constant because time is variable, it's usually put the other way. The speed of light is constant for all observers. This is from experimental evidence. In order for that to be correct, the geometry of space-time has to depend on the velocity of observers which means that clocks and measuring sticks moving at different speeds don't match up.
You could come at it the other way, I think. That clocks and measuring sticks of moving observers don't agree and from measuring exactly how they disagree you could come to the conclusion that the speed of light is constant.
It's harder to motivate GR that way, though, since you'd have to take a lot of measurements of clocks and measuring sticks in different gravitational situations to construct the theory.
-
In the Naked Astronomy podcast (or possible another sci-cast) they mentioned that the recent ideas about a(nother) directional source of thermal radiation causing the anomaly would cause problems for those who were using the anomaly to tweak GR in their own special way - if they were modifying GR I think you can be certain that they were using GR/SR in their initial calcs. The JPL orbital calculational engine definitely takes into account some relativistic effects.
Mike - can you actually DO the sums required? If so, do them and show they are wrong - ie for a start what is the time dilation caused by the gravitational potential of the sun at the position of the earth's orbit, mars', jupiter's etc. This would at least give you an idea if you were talking in the right magnitude
edit here is a quote giving a rough idea of the methodology used
The ephemeris programs use equations for point-mass relativistic gravitational accelerations. They are derived from the variation of a time-dependent, Lagrangian action integral that is referenced to a non-rotating, solarsystem, barycentric, coordinate frame. In addition to modeling point-mass interactions, the ephemeris programs contain equations of motion that model terrestrial and lunar figure effects, Earth tides, and lunar physical librations . The programs treat the Sun, the Moon, and the nine planets as point masses in the isotropic, parameterized post-Newtonian, N-body metric with Newtonian gravitational perturbations from large, main-belt asteroid
This is from this paper produced by JPL and others http://arxiv.org/PS_cache/gr-qc/pdf/0104/0104064v5.pdf I think even this snippet makes it clear that the calculations are not based on solely Newtonian physics.
-
JP. I agree, there is nothing scientific about being absolutely certain but it is still how I feel.
The explanation that I gave, is, the simplest explanation, requires no assumptions, does not require anything new and is the one predicted by general relativity.
"As for the speed of light being constant because time is variable, it's usually put the other way. The speed of light is constant for all observers. This is from experimental evidence. In order for that to be correct, the geometry of space-time has to depend on the velocity of observers which means that clocks and measuring sticks moving at different speeds don't match up"
Yes, I agree but in this instance we are considering gravitational time dilation which is predicted by general relativity and is a proven fact. Gravity slows down the rate of flow of time. Or to put it another way the speed of light is a constant because the rate of flow of time is a variable.
I have just found this:-
This is an extract from a paper about the pioneer anomaly written by Slava G. Turyshev, Viktor T. Toth
Slava G. Turyshev is the person investigating the anomaly at JPL Pasadena.
"This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained."
"While most of the modern experiments in the solar system do not show disagreements with
general relativity, there are puzzles that require further investigation. One such puzzle was presented by the Pioneer 10 and 11 spacecraft. The radiometric tracking data received from these
spacecraft while they were at heliocentric distances of 20 – 70 astronomical units (AU) have consistently indicated the presence of a small, anomalous, Doppler frequency drift. The drift was
interpreted as a constant sunward acceleration of aP = (8.74 ± 1.33) × 10
−10 m/s
2
experienced by
both spacecraft [15, 18, 391]. This apparent violation of the inverse-square law has become known
as the Pioneer anomaly; the nature of this anomaly remains unexplained."
"Before Pioneer 10 and 11, Newtonian gravity was not measured with great precision over great
distances and was therefore never confirmed. The unique “built-in” navigation capabilities of the
two Pioneers allowed them to reach the levels of ∼ 10
−10 m/s
2
in acceleration sensitivity. Such an
exceptional sensitivity allowed researchers to use Pioneer 10 and 11 to test the gravitational inverse
square law in the largest-scale gravity experiment ever conducted. However, the experiment failed
to confirm the validity of this fundamental law of Newtonian gravity in the outer regions of the
solar system. Thus, the nagging question remains: Just how well do we know gravity?"
"One can demonstrate that beyond 15 AU the difference between the predictions of Newton
and Einstein are negligible. So, at the moment, two forces seem to be at play in deep space:
Newton’s law of gravity and the Pioneer anomaly. Until the anomaly is thoroughly accounted
3for by conventional causes, and can therefore be eliminated from consideration, the validity of
Newton’s laws in the outer solar system will remain in doubt. This fact justifies the importance
of the investigation of the nature of the Pioneer anomaly"
http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.3686v2.pdf
It would appear that the problem has been analysed from the standpoint of Newtonian gravity and surprise, surprise ..."the validity of Newton’s laws in the outer solar system will remain in doubt." Let's face it they haven't taken into account gravitational time dilation by mass have they?
Mike
-
"One can demonstrate that beyond 15 AU the difference between the predictions of Newton
and Einstein are negligible. So, at the moment, two forces seem to be at play in deep space:
Newton’s law of gravity and the Pioneer anomaly. Until the anomaly is thoroughly accounted
3for by conventional causes, and can therefore be eliminated from consideration, the validity of
Newton’s laws in the outer solar system will remain in doubt. This fact justifies the importance
of the investigation of the nature of the Pioneer anomaly"
http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.3686v2.pdf
It would appear that the problem has been analysed from the standpoint of Newtonian gravity and surprise, surprise ..."the validity of Newton’s laws in the outer solar system will remain in doubt." Let's face it they haven't taken into account gravitational time dilation by mass have they?
Actually, if you read the bolded part above, they did account for general relativity, and noted that the differences from Newtonian gravity is negligible at those distances. So they ignored time dilation because they considered it and found that it isn't important here.
-
imatfaal,
No, I can’t do the maths I wish I could.
Mathematics is just another language, the one mostly used by the scientific community. It is frequently used to prove some theory or another. There are countless theories on just about everything that can be represented by mathematics, most of them wrong. Whilst mathematics are capable of telling ultimate truths they are just as capable of deceit, unwitting or otherwise.
I am always reminded of this quote.
“Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction”.
Albert Einstein
I don’t need to do the maths to know that I am “talking in the right magnitude”. The anomaly is extremely small but real, just the kind of adjustment that gravitational time dilation should predict.
These are quotes from the paper you mention
“It is also possible to infer the position in the sky of a spacecraft from the Doppler data. This is accomplished by examining the diurnal variation imparted to the Doppler shift by the Earth’s rotation. As the ground station rotates underneath a spacecraft, the Doppler shift is modulated by a sinusoid. The sinusoid’s amplitude depends on the declination angle of the spacecraft and its phase depends upon the right ascension. These angles can therefore be estimated from a record of the Doppler shift that is (at least) of several days duration. This allows for a determination of the distance to the spacecraft through the dynamics of spacecraft motion using standard orbit theory contained in the orbit determination programs”
http://arxiv.org/PS_cache/gr-qc/pdf/0104/0104064v5.pdf
The above programs were written obviously for spacecraft in orbit within the solar system. It is highly probable that when they were written they did not take into account that they would be used on spacecraft leaving the solar System
“Is there any evidence that some kind of “time acceleration”
http://arxiv.org/PS_cache/gr-qc/pdf/0104/0104064v5.pdf
Although “time acceleration” is mentioned in, the above paper and various methods proposed and discounted. I could not find any reference to relativistic, gravitational time dilation being seriously considered.
Although the anomaly being discussed is about Pioneers 10 & 11 it seems there may be a total of four that are “probably” affected in the same manner, possibly more. The anomaly only becomes apparent when spacecraft are leaving the Solar System. Most explanations have been proposed and discounted. Gravitational time dilation of photons entering the Solar System remains the simplest and most likely explanation.
JP wrote.
"One can demonstrate that beyond 15 AU the difference between the predictions of Newton
and Einstein are negligible. So, at the moment, two forces seem to be at play in deep space:
Newton’s law of gravity and the Pioneer anomaly. Until the anomaly is thoroughly accounted
3for by conventional causes, and can therefore be eliminated from consideration, the validity of
Newton’s laws in the outer solar system will remain in doubt. This fact justifies the importance
of the investigation of the nature of the Pioneer anomaly"
http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.3686v2.pdf
"One can demonstrate that beyond 15 AU the difference between the predictions of Newton and Einstein are negligible.
In other word below 15AU they are significant right? The photons from 20AU are being gradually red shifted the closer they get to Earth.
“Actually, if you read the bolded part above, they did account for general relativity, and noted that the differences from Newtonian gravity is negligible at those distances. So they ignored time dilation because they considered it and found that it isn't important here.”
“So they ignored time dilation because they considered it and found that it isn't important here.”
This should read:-
“So they ignored time dilation because they didn’t understand it. See Above
Mike
-
I don’t need to do the maths to know that I am “talking in the right magnitude”. The anomaly is extremely small but real, just the kind of adjustment that gravitational time dilation should predict.
Actually, you do have to do math to know that you're talking about the right order of magnitude. Orders of magnitude are quantitative. How do you know you're not of by a factor of 10, 100 or 1000 if you haven't done the math?
-
I don’t need to do the maths to know that I am “talking in the right magnitude”. The anomaly is extremely small but real, just the kind of adjustment that gravitational time dilation should predict.
JP quote
"Actually, you do have to do math to know that you're talking about the right order of magnitude. Orders of magnitude are quantitative. How do you know you're not of by a factor of 10, 100 or 1000 if you haven't done the math?"
Point taken. Let me substitute "ball park" for magnitude.
The fact remains as I said before The anomaly is extremely small but real, just the kind of adjustment that gravitational time dilation should predict.
Mike
-
The fact remains as I said before The anomaly is extremely small but real, just the kind of adjustment that gravitational time dilation should predict.
But if the real observations are on the order of 10-9 m/s2, and time dilation ends up being 10-11 m/s2, then it isn't responsible for most of the anomaly. Can you give any justification that they're on the same order of magnitude other than the fact that time dilation should be "small"?
I doubt you'll change your mind, even faced with these facts. It is also technically possible that the physicists working on this problem have all made a very basic mistake and that you caught it. However, it seems a bit extreme to post with absolute certainty you have the answer to the Pioneer anomaly that everyone else missed when you can't provide any numbers to show that the effect you're citing is even the right order of magnitude.
-
" During the past 30 years, 2.1 GHz maser signals have been transmitted to the Pioneer 10 and Pioneer 1 spacecraft and coherently transponded back to earth, the frequency shift of the received signal being used to determine the recessional velocity of the spacecraft for the purposes of navigation. However, Anderson et al. report that when the computed velocity is compared to the velocity predicted by orbital models, a discrepancy is found, even after adjustments are made for all known forces that might act on the spacecraft. They find a frequency blueshift residual that increases linearly with time, or in direct proportion to the increase in the line-of-sight distance the spacecraft. If interpreted as a Doppler effect, this residual implies the presence of an anomalous force accelerating the craft toward the Sun, which Anderson et al. calculate to be (8.7 ± 1.3) × 10 ^–8 cm/s^2 .
When the propulsive effects of onboard thermal radiation sources are taken into account, this decreases to a residual acceleration of (6.85 ± 1.3) × 10^-8 cm/s
If interpreted as an anomalous acceleration, the effect is perplexing since most plausible forces, such as gravity, decrease rapidly with distance whereas the Pioneer apparent acceleration remains relatively constant with time. Moreover, an anomalous acceleration of similar magnitude does not appear to be acting on the planets, given that their orbital periods experience no similar secular change within the accuracy of current determinations."
You know Mike, there seems to be a mountain of theoretical frameworks discussing the underlying physics out on the net :) But to define a new 'physics' on one spacecrafts anomaly seems somewhat drastic. I've seen so many weird explanations now, everything from expecting photons to 'naturally' blue shift (Subquantum kinetics) to the tired light explanation where they 'die out' which in a way seems incorporated in the aforementioned explanation too. And you know what :) They all have tons of math supporting their definitions. Then you have some calling it a redshift instead of a blue shift, finding Andersons et al. definitions and proofs questionable in themselves etc etc.
Let's put a end to this debate. We're not here to judge the best explanation of the Pioneer anomaly and we would need more experiments done to find what it really was/is. The antenna used wasn't that specific (narrowed down) and NASA could neither say with certainty when it was 'closed down' not working, as I understands it. There are so many uncertainties in this material, although I can understand that mathematically inclined physicists threw themselves at the result of the Anderson et all. investigation and started to theorize around it.
And i still have to see how they can define a object moving away from the detector as blue shifted. There has to be an explanation to that idea, I've seen some id* mumbling about accelerating away as explaining it but that one is them mixing the idea of potential energy with red and blue shift.
Take anything moving away, emitting a light, relative you 'standing still'. here is you X and here is the object -- 0 -- when it is still relative you. the '-' is a measure of the lights frequency, the shorter the more energetic/blue shifted here.
Now it starts to move relative you X ---0- And as you can see :) it will be blue-shifted relative its direction of motion -> and red shifted relative you <--- being 'still'. It's a very simple phenomena basicly. If I assume the Pioneer to have moved apart from us then the blue shift should be in the direction it moved and any red shift should be relative us. To that you can add that any gravitational field will blue shift a incoming photon, as gravity seem to act as an 'accelerator' of energy.
You might assume that the same should be true for a single photon, but it's not. If we assume it to be blue-shifted it will be so, as I see it, from any vector 'observed'. But it will be combined effect of your motion/mass relative the vector/momentum of that photon. Macroscopic objects express a blue and red-shift through their motion relative you, in their waves/photons. But a single photon I believe to have the same 'energy', always. As I see it that is mainly due to two things, We don't see them until they interact, and assuming a 'propagation' any 'photon' will have a direction, and a momentum, (vector=magnitude and direction) directed into what vector they are 'propagating'. That momentum, expressed, and actually created in the 'interaction' with whatever it 'hits', is what will define its final 'energy', not too unlike a ball moving. This does not contradict the idea of a photon having a intrinsic invariant energy though. Just as little as the balls velocity as it smash into you is contradicted by its 'invariant mass', both will have a relevance to the impact. The other reason is that a photon is a 'point particle', not existing inside our SpaceTime other that as a '(wave) packet of energy'.
As photons does not take any 'place', and does not exist until its interaction we can't really say what a photon does in the immediate 'duration' it 'propagates'. One really need to consider the difference between a object of invariant mass (e.g a ball), and also consider it macroscopically to realize that there is a major difference between the idea of a 'photons propagation', as compared to that ball coming at you in the air. the balls trajectory is 'there' for you, you see it before it hits you, translated by the same 'photons' that only exist in their interactions.
To not admit to what is true is one of the worst mistakes one can do. To generalize a propagation of light is well documented and follow laws of physics that allows us to give light a 'invariant speed', but I prefer to look at that as pure constant myself. And as I said, that lights speed is a 'invariant', a 'constant'. That was what Einstein built his theory on relativity on, not 'time pockets' and gravitational 'field' having their own 'time density'. Although I can see how you can think of it that way. 'motion' and 'distance' is relative in Einsteins universe, not light. Light has one same 'speed' in all frames, and as measured from any frame possible. That's actually what makes light unique. Well, there are more things too it, as always. Ask JP :) but that's what he built his theory of relativity on.
==
Had to clear it up some :)
-
JP.
Yes, I said “I am absolutely certain that my original explanation is correct.”
This is just my feeling on the subject. I have already admitted that it is not a scientific approach. It was never meant to be. My purpose was to put forth an idea and hope that it would stimulate debate. The only real debate it seems to have stimulated so far is over my own feelings on the subject and whether I can do the maths. I have already retracted “magnitude and substituted “ball park”. Whilst I do not want to trivialize the scientific approach, I believe you are “nit picking” and trying to trivialize a much more important issue. I have already admitted I do not understand the math’s but presumably some amongst you will. This is an important debate and there is nothing to stop any of you from mathematically investigating the anomaly.
yor_on
Quotes
“If interpreted as an anomalous acceleration, the effect is perplexing since most plausible forces, such as gravity, decrease rapidly with distance whereas the Pioneer apparent acceleration remains relatively constant with time. Moreover, an anomalous acceleration of similar magnitude does not appear to be acting on the planets, given that their orbital periods experience no similar secular change within the accuracy of current determinations."
"Pioneer apparent acceleration remains relatively constant with time."
EXPLANATION This is because the wavelength of photons emitted by the spacecraft are continually being dilated by gravity as they enter the Solar System. The dilation is progressive, the further the spacecraft, the more the dilation. Once the spacecraft is ‘effectively’ outside the gravity of the solar system, the dilation will no longer be progressive but constant.
"Moreover, an anomalous acceleration of similar magnitude does not appear to be acting on the planets, given that their orbital periods experience no similar secular change within the accuracy of current determinations."
EXPLANATION Of course, it does not affect the planets or anything else within the Solar System as the strength of gravity within the Solar System remains fairly constant
“You know Mike, there seems to be a mountain of theoretical frameworks discussing the underlying physics out on the net :) But to define a new 'physics' on one spacecrafts anomaly seems somewhat drastic. I've seen so many weird explanations now, everything from expecting photons to 'naturally' blue shift (Subquantum kinetics) to the tired light explanation where they 'die out' which in a way seems incorporated in the aforementioned explanation too. And you know what :) They all have tons of math supporting their definitions. Then you have some calling it a redshift instead of a blue shift, finding Andersons et al. definitions and proofs questionable in themselves etc etc.”
"But to define a new 'physics' on one spacecrafts anomaly seems somewhat drastic."
CORRECTION It’s at least three very similar spacecraft anomalies, could be four or more. Possibly enough to be statistically significant but this is not the point.
CORRECTION I never mentioned anything about new ‘physics’ nor was it my intention so to do. Throughout this debate, I have continuously referred to General Relativity gravitational time dilation as being the cause of the anomaly. This is not new ‘physics’. This idea was originally suggested, as it seemed the most obvious answer to the question. If you have read the above then you will have seen that when analyzing the problem gravitational time dilation was ignored. As I pointed out, it seems they choose to ignore General Relativity because they thought it irrelevant but they were wrong.
"They all have tons of math supporting their definitions"
As I have already mentioned maths supporting conflicting theories just shows how unreliable maths can be.
“And i still have to see how they can define a object moving away from the detector as blue shifted. There has to be an explanation to that idea, I've seen some id* mumbling about accelerating away as explaining it but that one is them mixing the idea of potential energy with red and blue shift.”
This was my original post and it contains the complete explanation.
“The Pioneer anomaly is due to time dilation that is caused by the gravity of the SolarSystem. As pioneer leaves the solar System the rate of flow of time increases causing a doppler blue shift relative to our perspective. This blue shift reduces the expected red shift so the red shift is not as far red shifted as expected. The craft is where it is supposed to be, it just appears to be closer to us than it is.”
Another way of putting this is:-
The wavelength of photons emitted by the spacecraft are gravitationally red shifted as they enter the Solar System.
What I said was:-
As pioneer leaves the solar System the rate of flow of time increases causing a
doppler blue shift relative to our perspective.
CORRECTION I never said light was blue shifted only that it appears blue shifted from our perspective. (Actually, thinking about it, yes it is blue shifted. The blue shift reduces the expected red shift. The red shift is not as far red shifted as expected.)
“To not admit to what is true is one of the worst mistakes one can do. To generalize a propagation of light is well documented and follow laws of physics that allows us to give light a 'invariant speed', but I prefer to look at that as pure constant myself. And as I said, that lights speed is a 'invariant', a 'constant'. That was what Einstein built his theory on relativity on, not 'time pockets' and gravitational 'field' having their own 'time density'. Although I can see how you can think of it that way. 'motion' and 'distance' is relative in Einsteins universe, not light. Light has one same 'speed' in all frames, and as measured from any frame possible. That's actually what makes light unique. Well, there are more things too it, as always. Ask JP :) but that's what he built his theory of relativity on.”
“To not admit to what is true is one of the worst mistakes one can do.
The implication being that I am knowingly refusing to admit to what is true.
There is nothing true that you or the scientific community have said that I have refuted. On the other hand you have almost continually refuted, distorted and misquoted most of what I have said. This is a fact documented by this thread.[/color]
“And as I said, that lights speed is a 'invariant', a 'constant'. That was what Einstein built his theory on relativity on, not 'time pockets' and gravitational 'field' having their own 'time density'”.
I have never mentioned ‘Time Pockets’ or ‘time density’, they are your inventions.
What I have mentioned and is consistent with General Relativity is gravitational time dilation. If you accept gravitational time dilation as a very real, observable and quantifiable effect, which it has proved to be then you must accept that as the strength of gravity varies in the universe on a local scale so must the rate of flow of time. In other words the speed of light is a constant because the rate of flow of time is a variable. It is built into General Relativity. It’s not my idea, I am not proposing anything new.
All the explanations above I have given before, I have to keep repeating the same facts.
I add this so there is no mistake on what I have proposed. The Pioneer anomalies can and should have been explained by General Relativity. No new physics are required
As I mentioned a few posts ago, I have e.mailed JPL with the above suggestion. If and when I receive a reply I will post it here, assuming the thread to still be open of course.
Mike
-
I have just noticed this from my last post:-
"As I pointed out, it seems they choose to ignore General Relativity because they thought it irrelevant but they were wrong.
"They all have tons of math supporting their definitions"
As I have already mentioned maths supporting conflicting theories just shows how unreliable maths can be."
If I am correct in thinking that there is no anomaly, it is just an artifact of using the wrong math then it shows just how unreliable mathematics can be when applied by the Human mind.
Mike
-
Perhaps this will help to put things into context.
I have just done an online search, phrased in different ways, to find online gravity calculators.
There is an abundance of calculators for Newtonian gravity, likewise an abundance for relatavistic calculators as regards speed.
I haven't found one that can calculate time dilation due to gravity. It's obviously something that people just don't consider.
That might make me the world expert! [;)]
Mike
-
Mike - you are starting to sound like a crackpot. I can absolutely guarantee that time dilation due to both relative velocities and due to gravitational potentials are taken into account within the calculations for orbital positions of satellites.
You seem to be failing to grasp how maths and science is inter-twined, and the power of falsification; maths can support many ideas at the same time - but it can also rule out absolutely an idea that doesn't agree. As a very simple example
- you are given an unknown function y=f(x)
- and told if x=2 then y=4
- the speculations abound ie y=2x or y=x^x or y=4 or y=x^2
- all are potentially valid
- but y=x^3 is not valid
- you are then given additional info if x=1 y=1; two of the above are ruled out and two remain
etc...
The maths behind the theory is an essential part of the physics - without engagement with the maths all we have is pipedreams
-
Mike - you are starting to sound like a crackpot. I can absolutely guarantee that time dilation due to both relative velocities and due to gravitational potentials are taken into account within the calculations for orbital positions of satellites.
You seem to be failing to grasp how maths and science is inter-twined, and the power of falsification; maths can support many ideas at the same time - but it can also rule out absolutely an idea that doesn't agree. As a very simple example
- you are given an unknown function y=f(x)
- and told if x=2 then y=4
- the speculations abound ie y=2x or y=x^x or y=4 or y=x^2
- all are potentially valid
- but y=x^3 is not valid
- you are then given additional info if x=1 y=1; two of the above are ruled out and two remain
etc...
The maths behind the theory is an essential part of the physics - without engagement with the maths all we have is pipedreams
Iv'e already said in an earlier post that general relativity is used in calculations relating to gps satelites. So what we are not talking about satelites. We are talking about craft exiting the solar system and the specific method used to analyse signals from them. If you,ve read my earlier posts you will see that JPS have admitted that they did not use general relativity in their calculations.
You seem to be totally missing the point. I am not proposing anything new. The maths that should have been used to analyse the pioneer data was general relativity but it wasn't used. If I am wrong then it is easy to prove do the math.
If I am right and had done the math and confirmed the 'anomaly' was due to JPL not using General relativity then I could have contacted them myself, end of story. I thought the idea of a science forum was for debate.
The first of my last three consequtive posts was mainly in answer to clear up a load of miss quotes. There is a lot of things in there that you could query or disagree with. Stick to what I have said and if you disagree say why. I really do not understand your attitude all I have ever said is that the Pioneer anomaly can be understood through the mathematics of General Relativity. Jps have themselves admitted that they have not used General relativity in their calculations. And your calling me a crackpot. If there is anything appertaining to the pioneer anomaly that I have said that you disagree with then please tell me.
Mike
-
Stick to what I have said and if you disagree say why.
Mike, what I disagree with is that this is a science Q&A forum and your response to the initial question is based entirely on an unscientific guess. Your defense of your original answer isn't based on science either, it's based on your intuition. Why post this on a science forum if you aren't willing to engage with other posters using the scientific method of offering quantitative and falsifiable results?
-
I do agree on "gravitational time dilation as a very real, observable and quantifiable effect." Mike, as described when measuring between frames of reference. To really show it you need a 'twin-experiment' though. And this is because only then will you be able to measure a quantitative difference between the twins, the traveling twin being younger biologically. What i don't like is the idea of it existing places where 'time' goes slower, and where as I understood you to put it before, time do so to to adapt to lights 'constant speed'.
As I see it, when you do so you redefine light as having different speeds but with 'time' now adapting itself to, more or less, fool us :) That's not how Einstein saw it, and it's not how I see it either. Light is the foremost constant I know, it has only one 'speed' and doesn't care about where it comes from. It can come from a black hole, a torch light in your hand, or a speeding rocket and hit your eye simultaneously, all three will have the same speed. And if you go those to three places you will find your own time durations, as measured by you, to be 'as always'. So, according to you, there will be nowhere that 'time' slows down, that is, you will not by any experiment made prove that idea. This does not mean that time on earth has the same 'durations'. There has been experiments done with extremely sensitive 'radiative clocks', where you by placing one on the floor and the other on a table being able to show a difference in their measure of temporal durations. But you do not , whether you stand up or lay down change anything about the duration that is measured for you. Your life expectancy will not become any longer by laying on the floor.
So your time will always be the same, but durations between positional systems in SpaceTime will differ when compared. And why they do it is because light only have one speed in a vacuum. And so the idea of gravitational time dilation becomes one where you only can get it confirmed by a twin-experiment, where there is a comparison done between two human 'systems' having a 'exact same' biological clock and a same temporal origin, being 'twins', one leaving to then come back again. But, none of those twins will ever have noticed time 'moving differently'. There's a difference.
-
“Mike, what I disagree with is that this is a science Q&A forum and your response to the initial question is based entirely on an unscientific guess.”
Rubbish, my initial answer was based on firm scientific proven fact.
General Relativity states that mass dilates time but that was not taken into account, hence the anomaly
“Your defense of your original answer isn't based on science either; it's based on your intuition.”
Rubbish, my intuition has told me to base it on known facts. If you dispute this, tell me what I have said that is wrong.
“Why post this on a science forum if you aren't willing to engage with other posters using the scientific method of offering quantitative and falsifiable results?”
Rubbish, I am and have been more than willing, as evidenced by my posts in this thread, to engage with other posters. Have any of them answered any of my points, ever?
I have not proposed a new theory or new physics therefore there is absolutely no reason whatsoever to offer quantitative and falsifiable results.
What I have maintained is that the physics to explain the anomaly already exist but have been ignored. This has so far been confirmed to be correct. Virtually all of the points that I have posted have been ignored, not debated. I have been continually miss-quoted by you, which I have mentioned before but none of that has been addressed
You accuse me of bad science but really you need to look at a lot of what you have written, it’s mostly ideas and waffle and wrong
I have just written this before reading your last post which is mostly a load of rubbish.
-
Well, Mike, I give up on trying to explain where you and the scientific method don't agree. It's clear you have your own opinion and aren't willing to hear others. It's a shame, because your point about time dilation was interesting, but the certainty with which you present along with your dismissal of the need for mathematics leads to a host of scientific problems with the idea and have bogged down any useful discussion.
-
Mike, don't take our views to hard. You have what we might call a hypothesis. To prove it you need to create some proofs. That's what the math is for, I tried to look for your question and although I found, especially some Russian scientists that seemed to wonder in a similar fashion I found none asking the exact same. As you say, no matter how you and me argue, you base it on what you see as the theory of relativity which in a way is quite palatable to me :) I'm a avid fan of the theory of relativity myself, and you want to have it proved or disproved.
Well, then you need to do the math I think, because then you will have the definition laid out for us to look at. And your and mine discussion might or might not come in there, but I think we will agree on what math there is needed. Don't get all angry, Imatfaal is a very knowledgeable young man, and JP even more so. You need to remember that without any mathematical definitions it's awfully hard to 'count on it' and see if it will make sense. And you can't expect us to do the math for you, it's your theory and your math that should define it, not ours.
There are three different 'red shifts' in astronomy, Doppler, gravitational and cosmological (space expanding), and then above 0,4-5 'c' we find the Lorentz contraction expressing itself too. And all 'normal' photons you see are expected to come from exited atoms. Law of Energy Conservation and the Doppler Effect. (http://www.relativitycalculator.com/energy_doppler.shtml) It's a lot of math in that one but this one may be more palatable to start with Redshift components. (http://arijmaki.wordpress.com/2009/06/20/redshift-components/) And for those wanting a overview(?)
I guess some may want that, listening to the arguments. I find this one a very nice description of Doppler relative Lorentz contraction, making good sense to help one see the basic differences. C-ship: The Doppler Shift (http://www.fourmilab.ch/cship/doppler.html) And JP I expect to know exactly what he talks about, when he doesn't he will tell you.
-
JP,
I think it is a shame, none of you give any encouragement only criticism. I have not had any positive feedback at all. Yes I am confident that I have identified the source of the anomaly, but that's how I feel and I will have to deal with it if I am wrong.
I have never criticised the scientific method, it's essential in science. I'm a firm believer in maths, as I said in a previous post but maths isn't the answer to everything. I didn't think and I still don't think that maths is required to suggest what the reason is to explain what I consider to be obvious. I sincerely believe that my explanation of the anomaly is the first thing that should have been considered to see if it explains the mystery. The idea, it could be argued has little to do with science but a lot to do with common sense. I have already reiterated on numerous occasions that I wish I understood the maths but I don't. According to your reasoning that gives me no right to make any suggestions. The world would be a much poorer place if everyone shared those views. If you look back through all of the posts you will see there never was the start of any useful discussion. There was never any feedback on the content and quality of what I suggested just a continuous stream of repeated attacks.
One question:-
It is known that gravitational time dilation is real and observable. So it is known that any craft that leaves the Solar System will be affected by it. What should have been the first suggestion to explain the anomaly?
-
Mike,
I think it is necessary to quantify effects in science and, unfortunately, the only way to do that is mathematically. Also, math provides a common language that promotes common understanding in a way that spoken languages never do. Without some math to sort out the significant from the insignificant, we are liable to descend into acrimonious debates, QED this thread.
Perhaps we should lock this topic before matters deteriorate any further.
-
"If anyone can prove to me for certain that the anomaly is not due to time dilation in the Solar System I would be delighted to hear from them." &
"I am absolutely certain that my original explanation is correct."
Mike
Would that I have such certainty!
I have been thrilled and astounded for a very long time now with the progress of science. If I have learned anything it is this:
As in love and war, and politics and life, so it is that nothing is certain in physics, astronomy and cosmology. [:)]
-
Mike - firstly keep it civil or one of the mods will lock the thread (btw prefixing every paragraph of a reply with rubbish is not imo civil).
I have just reread one of the papers by the JPL incl Turyshev - it details the methods that JPL use. I can quite understand that it is difficult to grasp - but the calculation regarding gravity used various Parameterised Post-Newtonian Formalisms. PPN is a method that directly engages with GR (as well as many other metrics) in situations where all speeds are significantly sub-luminal and the gravitational field is weak. The measurement of the the light that you worried was not taking into account the gravitational potential time dilation/gravitational red-shift is calculated using the correct relativistic equations and comparisons with ephmeris time / barycentric coordinate time ie all times and rates are adjusted in terms of a clock outside the gravity well and is accurate to one part in 10^17.
That Turyshev says that the difference between Newtonian calcs and GR are negligable is due to the fact that both were calculated and the difference was negligible.
These calcs are summarised at around pages 55-60 of the latest Tuyrshev article. If you wish to continue the debate please engage with the previous paragraphs as they confirm to my mind that you have been misunderstanding Turyshevs comments. A repeating of the line that Turyshev said GR wasn't used will not be responded to.
-
First of all, hello peeps. I had a similar thought to yours mike and after a bit of searching, i was directed here.
I have to say, having read through the thread several times i feel that you've been treated unfair. All your posts made total sense to myself and used terminology that I'm familiar with. The OP however repeatedly misquoted you and often coined his own phase's.
Maybe we're (well, i am) just of a lesser intellect and dint understand the big picture, lol.
Like yourself the maths of this is way over my head, I had a hunch and decided to research it. Don't all theories start off that way? obviously at some point they need backed up with hard facts, but i guess since we cant do that, maybe we should keep quiet.
Afterall someone may do the maths, write a paper on it and win a nobel prize or something.
-
Mattyh, one don't has to like it, but one do need to know the 'mainstream' definition, Einsteins own actually, first. As for needing the math? Oh yes, you will need to learn it, and as you do you also will need to redefine Einstein's definitions to fit this idea of 'variable light'.
Myself I don't find it possible.
-
Mattyh,
My sincere thanks, that's the only bit of encouragement I have received on this site.Mattyh, one don't has to like it, but one do need to know the 'mainstream' definition, Einsteins own actually, first. As for needing the math? Oh yes, you will need to learn it, and as you do you also will need to redefine Einstein's definitions to fit this idea of 'variable light'.
Isn't it amazing how people try to turn things around. My ideas are to the best of my knowledge completely in keeping with Relativity as expressed in my previous posts. I assume the above is another missquote like the rest you mention. The same can not be said about about yor_on who while telling me I had got relativity wrong quite obviously did not understand gravitational time dilation himself. Having said that I note from his latter posts that his attitude towards gravitationa time dilation is now falling more inline.
If you are interested in gravitational time dilation you may be interested in my articles on Time and Gravity in the New Theories section. They do contain the maths but no replies. You just can't win.
Thanks again
-
I should have added by way of update. I have e.mailed Nasa once and Jpl twice in the last seven weeks on the Pioneer anomalies and am still awaiting replies.
If I were definitely wrong then I would have expected a reply by now.
-
Mike - please stop asserting in the Physics forum that your ideas are mainstream, they simply are not.
I have explained here why your points about JPL not using any GR in their calcs are simply wrong.
http://www.thenakedscientists.com/forum/index.php?topic=38611.msg353958#msg353958
I will take the time to have a look at your thread in New Theories - but as you have already posted that
the maths to calculate the effect of GR time dilation on the above probe is beyond then there is no way that you can validly approximate your theories to mainstream views. The complexities of GR are formidable and beyond all unless they are willing to dedicate time and effort to it.
Lastly please do not criticise another member of the forum or question their knowledge apart from within the context of a debate with that member and addressed to that member.
matthew
-
I'd like to apologise for flaring things up, that was by no means my intention here. (Late night, a few beers, then a boat load of coffee).
On a final note I'd like to say, If everyone had the same views, used the same proven science and no one took that 'leap of faith', would science (hell, even the World) be better off? I don't think so, it needs people who think outside the box to move forward. Diversity is the key, much like in evolution.
Kind regards Matt
-
Think nothing of it Matt - if we didn't relish a little cut-n-thrust we wouldn't be here!
I don't think there is a single scientist, amateur or professional, lay or academic, who would disagree with you; but science moves on with new ideas that are challenged, shown to be consistent with evidence, and build upon or overthrow the current thinking. What science does not do is envisage an idea and insist it must be correct because it 'feels right' or it fits an internal logic; merely providing an alternative heuristic is no good whatsoever if the new underlying theory does not corectly explain and predict experimental results. Many of the great ideas of science seem to be simple isolated logical plans backed up by easily understood thought experiments - however, they are in fact also founded upon amounts of data, maths, and interconnecting logic. There will no doubt be another great leap forward in our understanding, which after the fact will seem simple, and which may be pilloried at first; but the vast majority of science is hard work and slow grind.
-
Mike, I believe the way I look at light here as being the way Einstein looked at it too :) And that's just a simple truth.
-
you_on
That's exactly the way I look at it.
If you look back through your posts you could not accept that there are 'pockets' of varying time which are necessary for time to be constant.
-
you_on
That's exactly the way I look at it.
If you look back through your posts you could not accept that there are 'pockets' of varying time which are necessary for time to be constant.
Sorry, should read
If you look back through your posts you could not accept that there are 'pockets' of varying time which are necessary for the speed of light to be constant.
-
Well, that is where we differ. As I said, you can possibly? See it that way. Although it would wreck havoc on the idea of light as a 'constant' and redefine what a constant should be seen as. It would make this universe a lot more complicated though. Going out from the light constant we have a simple way of explaining how 'frames of reference' will produce a time dilation as it comes naturally from that definition. Using your definition it becomes a definition of light not being a constant, more of the room time geometry as a whole being one, with each 'frame of reference' then representing a different island, and as you need to remember, all of them able to be created at a instant, depending on your acceleration. And as I said, neither Einstein nor me have this impression, at least as I understands it.
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
You have previously referred to this as 'pockets of time' and denied that they can exist. Furthermore, you have said that both you and Einstein are on agreement on this. You are not. Pockets (your word) of varying passage of time do exist. This is in full accord with what Einstein said.
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
-
Yep that's true, I keep forgetting to add this 'inertial' definition. What that mean is just that light is defined as moving at 'c' anyway we measure it in a inertial frame as Earth. But the same will hold true for an accelerating frame too. He defined that one in SR 1905. He used this definition to define how two inertial 'frames of reference' could 'tick' at the same rate while still being defined as measuring all light at 'c'. Why i keep forgetting to add that one is that there are two effects of this definition. One is that all 'local time' will be the same, and that one must be true. That is, your own 'time' as measured by you will alway have the same duration and there will be no way for you to lengthen that time, except relative another frame of reference. The other is that 'c' will hold for accelerating frames too. There is no way I know of to measure light as other than propagating at 'c' in a vacuum.
When I think of the definition of 'inertial frames' I automatically connect it to 'time' as described above.
==
But you're not the only one having this idea of a variable time. I've seen the people using a train analogy with 'light clocks'¨ticking finding it to prove that 'time' is variable. That's wrong, room time is a variable, but only as compared between frames. If time was variable, why would there would be a synchronization when the 'twins' meet up? The mere idea that they will find a time dilation builds on their 'local time' being the same, as long as they share the approximate same 'frame of reference', as on Earth. So your (always) local time, combined with lights invariant speed in a vacuum defines the frames you measure.
-
What that mean is just that light is defined as moving at 'c' anyway we measure it in a inertial frame as Earth. But the same will hold true for an accelerating frame too.
Actually, I do have a slight mistake in what I said above. The speed of light is constant globally in inertial reference frames.
It is constant locally in non-inertial reference frames.
Geometrically, this amounts to the speed of light being constant if measured over flat regions of space-time.
If you're in curved space-time, you need to look at a very tiny chunk of it which appears to be flat (just like your backyard looks flat compared to the curvature of the earth), so you say it is locally flat--which means that locally the speed of light is constant.
-
Yep :) but don't mess up my beautiful explanation here please.
We can discuss gravity as only able to be defined by 'point particles' too :)
There is no way you ever will measure light in a vacuum other than at 'c'. And all points might be called 'flat' :) But yeah, that definition is worthy of a thread of its own I think JP. Why did Einstein find it necessary to define it this way?
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
It's not different at all
E=mc2 says exactly that. For the speed of light in a vacuum to remain a constant then either length or the'passage of time' have to be variable. As we use the speed of light to define the length of a meter then 'time' itself is the variable. In which case "the speed of light in a vacuum is a constant because the 'passage of time' is variable", is a perfectly reasonable statement.
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
It's not different at all
E=mc2 says exactly that. For the speed of light in a vacuum to remain a constant then either length or the'passage of time' have to be variable. As we use the speed of light to define the length of a meter then 'time' itself is the variable. In which case "the speed of light in a vacuum is a constant because the 'passage of time' is variable", is a perfectly reasonable statement.
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light. Distance contracts AND time dilates - they do so that in a non-accelerating frame the speed of light will be measured as a constant.
Your continual use of misleading terminology is very confusing and will stop many taking anything you say seriously. If you mean time dilation then use the term that people know. If it is an entirely new (or with different equations) then also say so. By the way the time dilation side of einstein's theory has been tested to amazing exactness - AND it requires a length contraction to maintain speed of light constancy. If you are maintaining that no distance contraction occurs then you need to explain how light speed constancy remains when the time dilation is the sole effect and we know experimentally that time dilation follows the equations einstein used.
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
It's not different at all
E=mc2 says exactly that. For the speed of light in a vacuum to remain a constant then either length or the'passage of time' have to be variable. As we use the speed of light to define the length of a meter then 'time' itself is the variable. In which case "the speed of light in a vacuum is a constant because the 'passage of time' is variable", is a perfectly reasonable statement.
(1)Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light. (2)Distance contracts AND time dilates - they do so that in a non-accelerating frame the speed of light will be measured as a constant.
(3)Your continual use of misleading terminology is very confusing and will stop many taking anything you say seriously. If you mean time dilation then use the term that people know. If it is an entirely new (or with different equations) then also say so. By the way the time dilation side of einstein's theory has been tested to amazing exactness - (4)AND it requires a length contraction to maintain speed of light constancy. If you are maintaining that no distance contraction occurs then you need to explain how light speed constancy remains when the time dilation is the sole effect and we know experimentally that time dilation follows the equations einstein used.
(1) The speed of light (meaning speed of light in vacuum), usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time.
http://en.wikipedia.org/wiki/Speed_of_light
It seems to me that distance is precisely defined as a function of the speed of light (and vice-versa).
(2) I thought the speed of light(in a vacuum)was constant in any inertial frame.
(3)Your continual use of misleading terminology is very confusing and will stop many taking anything you say seriously.
‘Passage of time’ Einstein, sometimes used the word passage. 'Passage of time', I believe is self descriptive and would be understood by everyone. Time dilation only refers to time slowing down not speeding up so is imprecise as a term to explain time being variable. The problem is the inadequacies of language, as we have already established dt/dt makes little sense.
(4)AND it requires a length contraction to maintain speed of light constancy. If you are maintaining that no distance contraction occurs then you need to explain how light speed constancy remains when the time dilation is the sole effect and we know experimentally that time dilation follows the equations einstein used.
As I understand it, distance contraction only applies to objects traveling at relativistic speed. Gravitational time dilation is not accompanied by an associated length contraction. Therefore, length contraction is not required to maintain speed of light constancy.
Speed is distance divided by time. As long as the arbitrary units defining length and time remain the same (299,792,458 metres per second) the speed of light will remain a constant. However, the ‘length’ of a second and a meter can both change within that constraint.
-
No - a metre is defined in terms of the speed of light - there is a difference. we have found that many measurements can be linked - ie they can be independently measured to a high degree of accuracy AND they can be calculated from other measurements taken from completely different experiments. to make life easy we set constants in one and only one way - and that means that some measurements are done in terms of other things. velocity is a function of distance - but the speed of light is so central to out physics that when it comes to measurement we use the speed of light to define the standard metre rule.
On your point on contraction - if you say distance contraction doesn't happen you must explain how relative velocity contraction/dolation works, not just find a circumstance in which it doesnt apply.
-
No - a metre is defined in terms of the speed of light - there is a difference. we have found that many measurements can be linked - ie they can be independently measured to a high degree of accuracy AND they can be calculated from other measurements taken from completely different experiments. to make life easy we set constants in one and only one way - and that means that some measurements are done in terms of other things. velocity is a function of distance - but the speed of light is so central to out physics that when it comes to measurement we use the speed of light to define the standard metre rule.
Yes. This is an important point. The meter wasn't always defined in terms of the speed of light. It was defined in terms of the size of the earth at one point. The speed of light was experimentally found to be constant under this old definition. As a result of this experimental evidence, the meter was redefined since the speed of light was apparently a universal constant.
-
quote from imatfaal
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light.
quote from MikeS
The speed of light (meaning speed of light in vacuum), usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time.
http://en.wikipedia.org/wiki/Speed_of_light
It seems to me that distance is precisely defined as a function of the speed of light (and vice-versa).
quote from imatfaal
No - a metre is defined in terms of the speed of light - there is a difference.
In your first quote above you say that distance isn't a function of the speed of light.
In your second quote above you say that distance is a function of the speed of light.
They can't both be correct.
quote imatfaal
By the way the time dilation side of einstein's theory has been tested to amazing exactness - AND it requires a length contraction to maintain speed of light constancy.
I was merely pointing out that in general relativity, gravitational time dilation does not require a length contraction. Therefore, length contraction cannot be a pre-requisite for the speed of light to be constant. I am not proposing anything new.
quote from imatfaal
velocity is a function of distance - but the speed of light is so central to out physics that when it comes to measurement we use the speed of light to define the standard metre rule.
Velocity is a function of distance and time. As we use the speed of light to define the 'length' of the meter and length (distance) is a function of speed then it's a circular argument. So when I said that "It seems to me that distance is precisely defined as a function of the speed of light (and vice-versa)." was reasonable. To measure velocity (speed) we have to use distance but distance is defined from speed which means its a circular argument.
-
Mike you would be better off reading some physics than flogging this dead horse. That a unit of measurement is defined by reference to a physical constant does not mean that one is a function of the other. You must learn that the metre and distance are not synonyms.
-
Let me see if I understand this, you say "that distance is a function of the speed of light" but that the meter which is a unit of distance isn't. Is that correct?
-
Let me see if I understand this, you say "that distance is a function of the speed of light" but that the meter which is a unit of distance isn't. Is that correct?
Mike - are you being deliberately obtuse? Here is what I said:
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light.
but the speed of light is so central to out physics that when it comes to measurement we use the speed of light to define the standard metre rule.
That a unit of measurement is defined by reference to a physical constant does not mean that one is a function of the other.
To take a phrase out of my post and quote it but remove the words "does not mean" and completely reverse the import of my post is completely out of line. Which of the above quotes could possibly lead you to think that I had said what you have posted?
-
Correct me if I am wrong but I have always maintained that the speed of light in a vacuum is a constant because the 'passage of time' is variable. That is in full agreement with Einstein.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
It's not different at all
E=mc2 says exactly that. For the speed of light in a vacuum to remain a constant then either length or the'passage of time' have to be variable. As we use the speed of light to define the length of a meter then 'time' itself is the variable. In which case "the speed of light in a vacuum is a constant because the 'passage of time' is variable", is a perfectly reasonable statement.
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light. Distance contracts AND time dilates - they do so that in a non-accelerating frame the speed of light will be measured as a constant.
Actually, what Einstein would have claimed is that the speed of light is locally constant in an inertial reference frame in vacuum. Therefore, observers in different reference frames do not agree when they compare lengths and time intervals.
This is quite a bit different from your claims that "the speed of light in a vacuum is a constant because the 'passage of time' is variable."
I really don't see the difference.
"the speed of light in a vacuum is a constant because the 'passage of time' is variable."
I could have added
"Therefore, observers in different reference frames do not agree when they compare lengths and time intervals."
Let me see if I understand this, you say "that distance is a function of the speed of light" but that the meter which is a unit of distance isn't. Is that correct?
Mike - are you being deliberately obtuse? Here is what I said:
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light.
but the speed of light is so central to out physics that when it comes to measurement we use the speed of light to define the standard metre rule.
That a unit of measurement is defined by reference to a physical constant does not mean that one is a function of the other.
To take a phrase out of my post and quote it but remove the words "does not mean" and completely reverse the import of my post is completely out of line. Which of the above quotes could possibly lead you to think that I had said what you have posted?
Sorry I got it the wrong way around, please accept my apologies.
I have only just realised what I think is leading to the confusion.
Previously I wrote
"It seems to me that distance is precisely defined as a function of the speed of light".
Perhaps i should have said
"It seems to me that 'the meter as a unit of' distance is precisely defined as a function of the speed of light".
quote imatfaal
Mike just because the metre is now set by reference to the speed of light does not mean that distance is a function of the speed of light. Distance contracts AND time dilates - they do so that in a non-accelerating frame the speed of light will be measured as a constant.
If I am reading this correctly I think you are saying that 'distance' (the concept) is not a function of the speed of light. If that's the case I agree.
But I still don't see what made you take issue with me when I said
"the speed of light in a vacuum is a constant because the 'passage of time' is variable."
Would it have been acceptable to you if I had added
"the speed of light in a vacuum is a constant because the 'passage of time' 'in any reference frame" is variable."?
-
Sorry I got it the wrong way around, please accept my apologies.
No worries - Thanks.
"It seems to me that 'the meter as a unit of' distance is precisely defined as a function of the speed of light".
Yes - i would say "in terms of" rather than "as a function of" because any function no matter how complex of a constant is pretty boring. Even the most natural unit of the length - the planck length has the speed of light in its definition - but then so does the planck time, mass, temperature and charge!
on the "passage of time" usage - it is non-standard; this is a highly non-intuitive and recondite area of physics and we cling to standard definitions and usage. Why use a term that needs explanation when time dilation is easily used; passage of time (for me at least) brings in metaphysical questions. Philosophers since Augustine (and probably before) have pondered the passage and perception of time - it is important to remove experimental physics from abstract philosophy.
-
And the meter is defined in terms of the speed of light precisely because the speed of light was found to be constant back when the meter was defined in terms of the size of the earth.