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Post by speakertoanimals on Oct 14, 2010 15:28:16 GMT 1
Except that we were not talking about the gravitational field strength as a whole (of course, if you scale up the whole field, the potential rises accordingly), but about the field strength AT A POINT where you had the potential.
So, I could increase the field strength in the region between the two points A and B, hence increase the potential difference, yet leave the field strength at A and at B unchanged. The strength at a point is the gradient of the potential, doesn't matter how you try and play with words, the mathematical nature of that relationship won't change. All you can do is try and redefine strength..........
Think instead of electric potential, measured in volts. you can have a region of high (but constant) potential, and they'll be no electric field there. True, there will be an electric field somewhere else, but that wasn't what we mean by field strength AT A POINT, since I'm interested in the point I'm at (where it's zero), not what it does elsewhere.
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Post by Progenitor A on Oct 14, 2010 15:31:29 GMT 1
Well, the thing to remember, I think naymissus, is that science arbitrarily classifies different ideas as if they were really separate 'things in themselves' when in fact it's all really a unified whole. For example, it used to be thought that energy and mass were distinct aspects of matter yet we now know that these are simply different sides of the same coin and so are intimately related, so in that way you could be said to be correct. Mathematics insists that things be broken up into 'packets' of information that can be mathematically manipulated, which is why we have the confusion about the gravitational field and gravitation potential. I agree We are measuring the same phenomenon in different ways
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Post by Progenitor A on Oct 14, 2010 16:13:46 GMT 1
Except that we were not talking about the gravitational field strength as a whole (of course, if you scale up the whole field, the potential rises accordingly), but about the field strength AT A POINT where you had the potential. So, I could increase the field strength in the region between the two points A and B, hence increase the potential difference, yet leave the field strength at A and at B unchanged. The strength at a point is the gradient of the potential, doesn't matter how you try and play with words, the mathematical nature of that relationship won't change. All you can do is try and redefine strength.......... Think instead of electric potential, measured in volts. you can have a region of high (but constant) potential, and they'll be no electric field there. True, there will be an electric field somewhere else, but that wasn't what we mean by field strength AT A POINT, since I'm interested in the point I'm at (where it's zero), not what it does elsewhere. Work done against what? Will there be more work done if the gravitational field is stronger?
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Post by speakertoanimals on Oct 14, 2010 18:30:16 GMT 1
Can't you bloody READ!
Work done is DIFFERENCE of potential, hence if that increases it tells us about the increase of gravitational field strength SOMEWHERE over the path between the two points.
It DOESN'T tell us that the gravitational field strength has increased at our end point, hence measuring the potential at that point DOESN'T tell us specifically about the gravitational field strength AT THAT POINT.
Problem is, just saying gravitational field is stronger is not SPECIFIC enough -- okay, it may have increased over there, but if my feet here still press on the floor in the same way, do I care? Does it effect the time dilation, and if so, where, here or over there where the strength DID increase? It's not as simple as some WUMs would like to pretend, which leads people to the WRONG answer, that the more my feet press on the floor, the greater the time dilation. In some cases, yes, in other cases no, hence the wrong answer..................
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Post by Progenitor A on Oct 14, 2010 19:53:39 GMT 1
Can't you bloody READ! Work done is DIFFERENCE of potential, hence if that increases it tells us about the increase of gravitational field strength SOMEWHERE over the path between the two points. I wonder why you are getting so excited? The work done is against the force of the gravitational field (of course) We agree, you see, it tells us something obout the strength of the gravitational potential field Take two points and get the graviational potential strengths there and you can then calculate the gravitational force field strength. The gravitational force field can be derived from measurements of the gravitational potential field strength. Two alternative ways of describing and measuring the gravitational field
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Post by buckleymanor1 on Oct 15, 2010 10:55:24 GMT 1
Why do you have to go all round the houses, STA? Why can't you simply say that gravitational time dilation is a result of being in differing regions of a gravitational field? This business of gravitational potential is confusing people because you have yet to make it clear that what it refers to is the amount of opposition to gravity an object presents by sustaining a position away from the surface of the earth, thereby resisting its total acceleration. In other words, people standing on the surface of the earth are experiencing the earth's full gravitational acceleration (I won't talk about the actual centre of the earth), but somebody suspended a mile above the earth is resisting the earth's total gravitational acceleration by virtue of storing some of it as potential energy, which is why a clock on the ground is accelerating more than one a mile above it and running slower. Hence, we have time dilation. I'm not sure I would employ you as an instructor, STA, because you have a way of totally obscuring what should be fairly straightforward ideas. Absolutely A gross case of obfuscation and obscurantism. This person STA will never be trusted again! Interesting ideas though there does seem to be a contradiction going on between the three of you or I don't understand. Yuo see carnyx replies with this after comments made by abacus and naymissus . Now is abacus saying the clock on the ground is running slower. naymisses is agreeing. While carnyx is saying the clock on the ground is running faster. Carnyx hypothesis states that clocks higher in a gravitational feild(on the mountain) weigh less and run slower. Abacus and naymissus both agree that the opposite is true but they allso agree with carnyx. It cannot be all ways either carnyx is right and they are wrong or vice versa.
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Post by speakertoanimals on Oct 15, 2010 13:08:37 GMT 1
Just try thinking for a moment. I'm not disagreeing for one moment with the totally obvious statement that force field and potential field are just different descriptions of the same thing, or that by making various measurements of one, you can derive the other.
What the point is is about whether measuring or knowing the gravitational potential AT A POINT is some sort of measure of the strength of the field at that point.
I'm not talking about knowing it over some area, I'm just saying you know it at a point (well actually two since we have the reference point where it is defined as zero as well).
As I've already said, just knowing the difference to reference tells you nothing about the strength of the gravitational field AT THAT POINT. SO if large is says there may be zero gravitational field where you are, but a really strong bit somewhere else. Or the gravitational field may be constant along the path between the two points. You don't know if all you know is the potential AT A POINT.
To know the strength at a point, the potential isn't enough, you need the gradient of the potential, which means you need the potential over some region, not at a point.
Hence we have potential at a point ISN'T a measure of field strength AT THAT POINT, or anywhere else, frankly.
The point here is there is a difference between what provides a complete description of the field (the potential or the gravitational force), and what quantity derived from that provides a measure of something else -- like the strength of the field.
Look at it this way, where potential is height, field strength is slope of the ground. If I am at a height of 1000m and someone else is at 0m, this doesn't tell me that I am on the slopes of a mountain, and the slopes are steep. I could be on a plateau, flat as a pancake. Hence just knowing my height tells me nothing about the slope. Knowing someone else is at 0m says there is a slope somewhere, but doesn't say if it is steep, or shallow -- and it is the steepness or shallowness that is the 'strength' in this case.
SO, coming back to gravitational time dilation, many people are mistakenly of the opinion that it is the field strength (the slope) that effects clocks (first poster included) -- which is wrong. It is just the height/potential that does it.
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Post by buckleymanor1 on Oct 16, 2010 10:37:45 GMT 1
The first poster gets it the wrong way round. If gravity acted in the way he proposes on all clocks. Then twin clocks would read the opposite of what he is saying. The clock brought down from the mountain "height" will show less time recorded than the one on the ground. When what actualy happens is the opposite. The one on the ground being near a massive object "the Earth"shows less time, this clock runs slower not the other. The only conclusion must be that the poster imagines gravity to be a repulsive force.
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Post by carnyx on Oct 16, 2010 18:43:23 GMT 1
I hope to clear up this local argument, so we can get on with the argument posed by Post 1
A clock on the surface of the earth will experience a force of one 'g' ( e.g. an acceleration of 9.81m/s^2 equivalent to the force equal to its mass)
An indentical clock at 50 miles up will experience a slightly smaller force, or less than one 'g' .
The difference in force .. and so in acceleration, can be found by changing the 'D' value in the relationship 1/d^2, from ~ 4000 miles to 4050 miles
And so the difference in the potential and in the kinetic energy between the two bricks is not directly due to h, but a function of it.
And so ALL mappings of gravitation relatioships with geo-distance are based on the 1/d^2 mass-attraction relationship.
But in our simpe case, rate-changes between the two clocks of the same mass but weighing slightly differently, ought to have an alternative explanation based on internal changes.
Bending the time and space terms in the equations to suit the actualité, is a necessary practice of simulation engineering, and some Climate scientists ... and IMO is not real, or physics come to that. So, can anybody come up with plausible ideas as to how varing 'g' forces could affect counting processes at the atomic level?
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Post by carnyx on Oct 16, 2010 19:25:29 GMT 1
@sta#261
Assuming that your whole schtick boils down to;
"The higher you go the less you weigh.. in an inverse square kinda way, like wot Netwon said "
... then at last you are coming round to the question;
Here it is again in simple anglo-saxon;
- Identical clocks
- One clock one foot higher that the other goes slower.
- It also weighs less.
- Any pair of identical clocks, of any type, produces the same results
- What is happening inside the clocks? (PS ... try not to say that the words Mass, Length, or Time have somehow magically taken on new meanings, as it will offend olmy. ... especially Time, because he believes that it has an independent existence as physical, independent, universal, and immutable as Mass )
PPS do you ski?
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Post by buckleymanor1 on Oct 17, 2010 0:26:09 GMT 1
Yes but it is not the way you propose.
It won't go slower if 'g' forces have any effect on the counting process. It should go faster. Imagine that you hit a golf ball on the earth with a certain force. Now hit the same golf ball with the same force but this time on the moon. Which one travells furthest. The one on the moon travells further so it must gain a greater velocity. Same applies to clocks less 'g' more velocity.
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Post by carnyx on Oct 17, 2010 8:52:33 GMT 1
buckleymanor#265
You are right ... It was in the correct sense in Post 1 , and I must have transposed it at some time during the thread. Apologies if it has confused the argument, and thanks for correcting it. However, it does not change the the basics of the argument. Clock rates change with changes in 'g' force.
And while I am at it, I suspect that STA was similarly confused by my use of the term gravitational field rather than gravity force field.
So, stripped of examples and redundant comments, and using the correct sense, here is the Post 1 question again;
"Time is relative, in the sense that it can only be measured as a number of successive events in a sequence, that are counted between two successive events in a separate sequence.
And, as any device ( i.e. clock or timer ) for the physical determination of an event involves the movement of mass, then all such devices are ineluctably affected by changes in the local force of gravity
And this effect of changes in the local force of gravity on mass can be expanded to include ALL sensible 'clock' processes of any description; physical, chemical and biological. The rates of all processes ( aka sequences of events, or 'clocks' ) are affected by changes in the local 'g' force.
And so 'measured time' or the 't' in the physics equations, is a relative count between two processes that are affected by their local 'g' .
In other words the 't' time in those physics and mathematical formulae, is not physical.
As the 't' of the equations is relative and not physical (as opposed to L and M) then modification of the 't' term and the L term in the equations to get then to match the actualité .... is also not physical.
So the explanation based on corrections to the equations to get them to work, projected back to claim that Space and Time are distorted too, are not entirely convincing. There may be an alternative and more satisfactory explanation of why all clock-processes are affected by changes in acceleration ... and this might be found at the atomic level.
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Post by buckleymanor1 on Oct 17, 2010 23:45:18 GMT 1
That is the crux of the matter if clock rates change due to gravity pulling down on them when they are near a massive body like the earth, and when they are accelerated like on board a spacecraft. In both cases time should slow down if your premis is correct. They do slow down but this is due to time dilation. To prove conclusively that it is due to gravity acting on the clock like say a magnet which will stop certain clocks if it gets too near one and not time dilation. Is unlikely, as clocks which measure time dilation are likely to take into account 'g' forces. Occilating horizontal springs are able to ignore the horizontal component of gravity because basicaly there is not one, when a clock is accelerating or near the earth. It is all verticle. Similar machines and methods are used to weigh people and objects in space. You could imagine though that a powerfull gravitational force like a black hole would stop any clock whatever method was used if it got too close.
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