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Post by Mr Red on Feb 17, 2011 13:48:09 GMT 1
 Greg insists that the time dilation with space (satellites eg) is due to gravity. I say speed. Probably both have an effect - but which is causing the most clock drift with GPS and Comms satellites. ?? 
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Post by speakertoanimals on Feb 22, 2011 15:50:08 GMT 1
Effects act in opposition. So, speed alone makes clocks in sateliites run slow, whilst height in gravitationalo field makes then run faster.
7 microseconds a day for speed effect, 45 microseconds a day the other way for gravitational effect, hence net effect of about 38 microseconds a day faster than ground-based clocks.
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Post by abacus9900 on Feb 28, 2011 21:58:54 GMT 1
Effects act in opposition. So, speed alone makes clocks in sateliites run slow, whilst height in gravitationalo field makes then run faster. So we can see here that time is relative to speed and gravitational fields. |
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Post by speakertoanimals on Mar 1, 2011 0:35:14 GMT 1
not quite, else that kind of implies that speed is absolute, whereas it is relative.
And its not gravitational fields per se, its gravitational potential, not quite the same thing! you can be higher than someone else, in a region where the gravitational field is ZERO, but its the potential difference that matters, NOT whether or not there is a non-zero gravitational field at one or both points.
So, to draw an analogy with electrostatics, you can have ZERO electric field inside a conducting sphere,and ZERO inside another sphere, yet have an enormous potential difference/vltage between the two. Its the voltage difference that matters, not whether or not there is an electric field locally.
By analogy, similar thing with gravitational field ( although you shouldn't confuse the details, since electric fields can be cancelled, and repel or attract,whereas gravitational fields can't).
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Post by abacus9900 on Mar 1, 2011 13:34:06 GMT 1
Of course speed is not absolute, that's so blindingly obvious it's hardly worth saying.
Why you say it's not gravitational fields per se, but gravitational potential that causes increases in mass is meaningless because without gravitational fields there can be no gravitational potential. You are making distinctions which don't really exist.
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Post by speakertoanimals on Mar 1, 2011 13:52:50 GMT 1
Any idiot can see that there is a difference between potential difference, and electric fields. Similarly, any idiot should be able to see that there is a difference between differences in height and differences in gravitational field strength. One is a scalar, the other is the gradient of a scalar. They are different, and claiming that the distinction doesn't exist is just mind-bogglingly stupid.
So, more of the usual utter bollocks from abacus, and even worse, exactly the SAMe bollocks he has come out with time and time again.
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Post by abacus9900 on Mar 1, 2011 14:06:48 GMT 1
Any idiot can see that there is a difference between potential difference, and electric fields. Similarly, any idiot should be able to see that there is a difference between differences in height and differences in gravitational field strength. One is a scalar, the other is the gradient of a scalar. They are different, and claiming that the distinction doesn't exist is just mind-bogglingly stupid. So, more of the usual utter bollocks from abacus, and even worse, exactly the SAMe bollocks he has come out with time and time again. No, actually, because when a physicist tells a non-expert that mass increases when a) in the presence of a gravitational field or b) with an increase in velocity, this is basically correct. What you seem to want to do is pretend that a gravitational field has nothing to do with gravitational potential which is bollocks (your term) since it is the gravitational potential that arises from it! It's like saying an electrical potential field has nothing to do with electricity! Come off it luv. Perhaps a nursing career would have been a better choice, STA, what do you think? |
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Post by speakertoanimals on Mar 1, 2011 14:30:03 GMT 1
Except Mass doesn't increase in the presence of a gravitational field, we were talking about time, do try harder! Or perhaps you meant weight?
I NEVER said that gravitational potential had NOTHING to do with a gravitational field, I just keep repeating (as you know bloody well, you're just repeating the SAME total bollocks you did before you had your celebrated 'rest'), just that height and gradient are DIFFERENT aspects of the same thing. Just as you can't get higher on a hill without there being a slope sOMEWHERE, but also recognisingb that there is a DIFFERENCE between an effect that depends on two people being at different HEIGHTS (time dilation), and an effect that depends on people being at twom places with different slopes (differing weights).
So, you CAN have two people with SAME weight (same local slope of the hill), but different heights (gravitatioanl potential difference), hence same weight but time dilation. You can also have people at the SAME height (gravitational potential) but different weight (slope of hill).
Which now makes it laughably easy -- we have TWO physical effects, weight difference and time dilation, and it is found that weight difference depends solely on the difference in slope, in the hill analogy, whereas time dilation depends solely on difference in height. SOME people get it wrong, and think that time dilationn depends on difference in weight, which is wrong.
And others CLAIM that drawing a distinction between height and slope is stupid, whereas any idiot can see that they are two different things, that you can locally vary one without varying the other. Hence two possible causes of physical effects.
For the hard of thought, I'm using a hill and height as a map of gravitational potential, whilst the SLOPE of the terrain is the gravitational field strength. You can't have height difference without a slope somewhere, but that doesn't mean the slope HAs to be at the points where our two people are.
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Post by Progenitor A on Mar 1, 2011 14:35:11 GMT 1
Any idiot can see that there is a difference between potential difference, and electric fields. Similarly, any idiot should be able to see that there is a difference between differences in height and differences in gravitational field strength. One is a scalar, the other is the gradient of a scalar. They are different, and claiming that the distinction doesn't exist is just mind-bogglingly stupid. So, more of the usual utter bollocks from abacus, and even worse, exactly the SAMe bollocks he has come out with time and time again. No, actually, because when a physicist tells a non-expert that mass increases when a) in the presence of a gravitational field or b) with an increase in velocity, this is basically correct. What you seem to want to do is pretend that a gravitational field has nothing to do with gravitational potential which is bollocks (your term) since it is the gravitational potential that arises from it! It's like saying an electrical potential field has nothing to do with electricity! Come off it luv. Perhaps a nursing career would have been a better choice, STA, what do you think? Oh Jeez Abacus! Don't get the lunatic raving once more! |
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Post by speakertoanimals on Mar 1, 2011 15:07:43 GMT 1
Note that Nay doesn't say anything about abacus attempts to needle me (AND disparage nurses in the process BTW), instead just admonishes him for rattling may cage. Shows all too clearly that neither of them gives a tinkers cuss about the supposed rudeness that they constantly try and admonish me for..................
Lunatic and raving, need I say more about NM's supposed good-behaviour credentials.......................Or abacus claims to be polite and a perfect gentlemen........................
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Post by abacus9900 on Mar 1, 2011 15:10:11 GMT 1
Sorry naymissus but I'm testing her under pressure to see if she really has learnt her lesson. Sigh, so far the signs are not good. |
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Post by abacus9900 on Mar 1, 2011 15:18:46 GMT 1
STA, the point is that you always seem to want to say a basic scientific statement is wrong when in point of fact it is not wrong but a basic description, a generalisation for non-experts. This is why it is virtually impossible to carry on a sensible dialogue with you about scientific ideas because something that somebody has read somewhere about this or that scientific concept, which is basically correct, gets rejected by you as being wrong. This is very discouraging for people wishing to engage you in a discussion since you are putting them down from the very beginning by implying they have completely misunderstood what they have read. This is a terrible way of trying get people to understand more advanced aspects of a subject because they feel they don't have the ability to grasp it.
What you keep doing is dealing with more detailed aspects of a theory straight off the bat, instead of stating the fundamental concepts and them moving on from there when appropriate. Kids at high school don't start off studying calculus, do they? No, they have to equip themselves with preparatory ideas first.
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Post by speakertoanimals on Mar 1, 2011 17:57:08 GMT 1
Nope, what you come out with is just plain WRONG (or bollocks if you prefer). It's not a generalisation when the error is tantamount to misusing white to mean black.
Plus potential and force AREN'T that difficult, even for non-experts, so why keep talking as if the difference is trivial, or needless nit-picking.
You can have either a wishy-washy basic description for idiots, or you can have a scientific statement, don't confuse the two. ANd if you don't point out the glaring errors in some of the formerm you'll never learn the latter. Yet when I do that, you accuse me of being needlessly pedantic. ANyone would think you weren't actually interested in learning anything..................
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Post by Progenitor A on Mar 1, 2011 18:09:07 GMT 1
Sorry naymissus but I'm testing her under pressure to see if she really has learnt her lesson. Sigh, so far the signs are not good. She has already been tested to destruction and has happily destroyed herself (or at least destroyed her pretensions at being a 'physicist') |
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Post by speakertoanimals on Mar 1, 2011 20:34:40 GMT 1
More empty noises from NM.
You wouldn't know a physicist or a correct explanation if you came across one, just as it turned out you didn't understand the basics of information theory.
Keep churning out the crap, why don't you, since it seems your sole aim is to fill up these boards with misleading nonsense and pointless one-line questions that any fool could look-up for themselves in a minute or less...................
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