Summations Only

This is just a general thanks to the likes of NoNukes, Onifre and Son Goku.Having these concepts explained like this is very helpful for someone like me to read. I appreciate the time and effort you're putting into your posts and I just wanted to say thanks for spelling it out. Sometimes the strict science-threads get a bit over-technical and these basic ideas are "assumed to be known."I, for one, appreciate going over these basic concepts. I mean, I knew they were valid concepts, but I didn't really understand why (or perhaps I had just forgotten...), and these basic descriptions are helping me get a firmer grasp of the subject. I may not be the designated specific audience... but when you exlain why certain questions don't make sense, or how to correct the simple errors in some basic incorrect assumptions... it is helpful for my understanding of the subject matter.Just wanted to say that your efforts are appreciated...And no, I'm not a pansy. I just play one on the internets

I think you are the intended audience.

dbl postEdited by onifre, : No reason given.

Add yourself to the list too. I'm brushing up as we go along also and by no means have the knowledge NoNukes has in this subject, let alone Son Goku. So I appreciate it much in the same way you do.I hope ICANT does too - Oni

As I mentioned, and NoNukes has since provided more references and detail, experimental tests have been performed on the effects of gravity on atoms and subatomic particles.The effects have been shown to be negligible. Atomic energy levels are altered by gravity to a very small degree and hence this physical effect on the atomic structure of the clock could not be the cause of the disagreement between the satellite and Earth clocks.However General Relativity predicts it is a combination of the distortion of time itself (a physical dimension) and one other effect that causes the disagreements between the clocks. The amount of disagreement between the clocks agrees exactly with that predicted by General Relativity.There are two separate effects in General Relativity which change the rate of the clocks.
First of all there is the distortion of time itself caused by gravity. This causes clocks near the Earth to be slower compared to satellite clocks.Secondly, there is the effect of how different observers moving at different speeds split up our universe into the three-dimensions of space and the one dimension of time. Our universe is simply a four dimensional object/shape/manifold and there is no unique direction on this shape that you can definitively say is the time direction. The disagreement between how objects on the satellite and objects on the Earth parse time and space, means that a section of Earth time corresponds to less Satellite time. Hence satellite clocks run slower.
This effect is solely due to how objects divide up space and time and would be present even if spacetime were not distorted. It is called relative velocity time dilation.So the two effects:Relative Velocity time dilation:
How spacetime is split up into space and time is not unique and different observers will disagree. Happens even when spacetime is not curved and so even occurs in Special Relativity.Gravitational time dilation:
Due to the physical distortion of spacetime because of the presence of mass. This distortion also causes in the effect we call gravity, the tendency of massive objects to approach one and other.

Hi No, Does General Relativity predicts that clocks in a stronger gravitational field will tick at a slower rate? Yes/NoDoes Special Relativity predict that moving clocks will tick at a faster rate? Yes/NoAt orbit heights does a atomic clock oscillations oscillate faster than an identical clock on earth at sea level? Yes/NoMaybe I should put that last question a little different.Does GR predict that the oscillations of a atomic clock in a GPS satellite will be about 45,900 ns/day because they are in a weaker gravitational field than atomic clocks on Earth's surface? Yes/NoDoes Special Relativity predict that the oscillations of a atomic clock in a GPS satellite which is in motion will be about 7,200 ns/day than atomic clocks on Earth's surface? Yes/NoMaybe you are right and I am mixing them up if so please straighten me out. SRGod Bless,

Hi Son, So gravity does effect the oscillations of atoms. Then why was General Relativity used to figure out that the atomic clock on the GPS satellite would produce 45,900 ns/day more than an atomic clock on the Earth's surface?Then Special Relativity was used to determined that due to the motion of the satellite the clock would lose 7,200 ns/day relative to an atomic clock on the Earth's surface.So then they decided the offset should be for a 38,700 ns/day variation between the clock on the satellite and the clock on Earth. I can't find where the makers of the clocks say anythiing about the distortations of time being used in the caculations.What kind of an object is time that it could be distorted as you are talking about? Gravity and what else?Special Relativity effects the rate of the clocks.The Sagnac effect, effects the rate of the clocks.That is all I can find. I find where it is said General Relativity predicts that clocks in a stronger gravitational field will tick at a slower rate.I don't find where this is cause by a distortion of time. Then time is not a dimension of the universe. Actually according to the math the clock on the satellite is 38,700 ns per day faster than a clock on the Earth's surface. Unless we change the definition of a day. What kind of an object is time that it can be dilated? Are you saying the decrease by 7,200 ns/day motion predicted by Special Relativity is time being shrunk? Are you saying the increased of 45,700 ns/day predicted by General Relativity is the streaching of time.So how do you streach time if it is not an object?If it is an object, what is it?Time is a method mankind has devised to measure duration between events in existence.God Bless,

Hi oni, Yes, according to Special Relativity the clock on the satellite will run 7,200 ns/day slower than the clock at the Earth's surface due to its motion.But General Relativity says the clock on the satellite will run 45,900 ns/day faster than the clock at the Earth's surface due to being in a weaker gravatational field.That means the clock on the satellite is running 38,700 ns/day faster than the clock on the Earth's surface.God Bless,

I am going to answer your question after I patch it up a bit.For one thing the 45,900 ns/day refers to a differential number of seconds per day and not to a number of oscillations as your question implies.Second, General Relativity includes everything that Special Relativity predicts plus more. Special Relativity does not address gravity, so I will distinguish on that basis.Special relativity predicts a time dilation effect of about 7200 nseconds/day due to the velocity of GPS compared to the ground. Since the time signals of the GPS clock are transmitted to the ground, the ground observer observe the satellite clock to be running slow by this amount.On the other hand, the difference in gravitational potential (and not the difference in the strengths of gravity at the two locations) causes the satellite clock to run slowly as compared to an identical ground clock. The amount for GPS satellites in about 45900 nanoseconds per day.The total difference in the clock rates is 45,900 - 7200 nsec/day or 38,700 nsec/day. Excellent.So how does SR produce that effect? You believe that gravity squeezes atoms to produce the 45000 ns/day. So how does SR produce the opposing 7000 ns//day. After all, we know from direct measurement that a correction of 38000 ns/day is what was needed.

This has been explained to you four different times. I do not think you are ever going to appreciate the issue.Gravity affects time. The clocks on the satellite tick at the same rate as measured on the satellite at all times, but because the rate of time is different, and observer in a different location will see a different clock rate if we can find some way of transmitting the time information from the satellite to that observer.If the only effect where gravity directly affecting atoms, there would be a negligible effect on clock rates.Perhaps the obstacle to your understand of what Son is saying is your disbelief in time dilation. But the time dilation explanation is completely consistent, and you should be able to appreciate that even if you don't agree with it.

Where have you looked? Have you ever read even a single paragraph of any text on General Relativity? How about the wikipedia article on Gravitational Time Dilation?

quote:

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Gravitational time dilation is the effect of time passing at different rates in regions of different gravitational potential; the faster the gravitational potential (the closer the clock is to the source of gravitation), the more slowly time passes. Albert Einstein originally predicted this effect in his theory of relativity[1] 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.

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Gravitational time dilation was first described by Albert Einstein in 1907[2] as a consequence of special relativity in accelerated frames of reference. In general relativity, it is considered to be a difference in the passage of proper time at different positions as described by a metric tensor of spacetime. The existence of gravitational time dilation was first confirmed directly by the Pound—Rebka experiment.

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Hi No, According to your statements and numbers there would be a -53,100 ns/day difference in the clock on the ground and the one in the satellite.SR predicts -7200 ns/day.
GR predicts -45,900 ns/day according to you.But GR predicts that the clock on the satellite will run 45,900 ns/day faster than the clock on the Earth's surface.Which is it? The satellite in which the clock resides is moving. Your assumption is wrong.I believe that the lower in the gravatational field the clock is the slower the oscillations will be. That would mean that the higher in the gravatational field the oscillations would be faster as gravity would not have as much effect on them the higher the clock was above sea level of the Earth at the Earthbound clock.There is also the Sagnac effect caused by the Earth's rotation on which the Earthbound clock resides. So both clocks are moving.God Bless,

Hi No, I have read several books and many papers on GR, SR, and Time Dilation.wikipedia noGod Bless,Edited by ICANT, : No reason given.

Hi No, How?What kind of an object is time that gravity can have an effect on it? Yes.That amounts to 38,700 ns/per day faster than the clock on Earth's surface according to the prediction of General Relativity.God Bless,

You have made a math error. The 7000ns/day due to relative motion is in the opposite direction from the 45000 ns/day caused by gravitational time delay.What book did you read about general relativity?Edited by NoNukes, : No reason given.