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ralfcis

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No, no help at all except for one bit of info I didn't know. He stated GPS satellites orbit the earth at 8000 mph but do they actually orbit because I thought they were geostationary which means they shouldn't be moving in relation to spots on earth. Yes as the earth turns they have to trace out a larger arc to remain geostationary but in the end they should still have no relative velocity towards you the observer as they never approach or recede from you. I don't know the answer to this and I've asked this many times and never got an answer. Maybe they're not geostationary at all or relative velocity along an arc doesn't need to approach or recede from you? Yeah, that's probably the reason as reciprocal time dilation from relative velocity is not dependent on direction.

 

Now I've been wrestling with trying to understand this bombshell revelation that it's gravity-like non-inertial acceleration that is the true cause of age difference. I've only heard this twice before and my former mentor for 10 yrs, who I completely believed, scoffed at this idea even in the book he wrote. But now this new guy has pointed out two important mistakes my former mentor made and this could be the biggest.

 

I kept forgetting that SR doesn't apply when gravity is around. So my example of Alice taking off from Bob on earth is wrong unless Bob is orbiting earth in microgravity and Alice flys by and doesn't take off from the space station because her non-inertial acceleration would be equivalent to gravity. However, I believe her acceleration in relative proximity to Bob would not cause as much age difference as when she's farther away and does a turnaround. This is supported when you do the analysis on a spacetime diagram (STD). If non-inertial acceleration/gravity is the only cause of age difference, as measured when they re-unite at the end of the spacetime path, then we can ignore the parts of the path that are inertial constant relative velocity where only reciprocal time dilation is experienced. (In the case of the GPS satellites, the relative velocity is a factor in time dilation but not in permanent age difference because there is no turnaround involved unless they do indeed orbit the earth.) 

 

If Bob had been on the surface of the earth, the force of gravity could cause him to be permanently younger than Alice at the end if the gravity she experiences from her turnaround is less than Bob's over time. If Alice hadn't experienced any acceleration and just handed off her clock info to Charlie returning to earth, then Bob should definitely have aged less than the clock reading Charlie was returning with. Even if Bob was on the space station the whole time, there would have been no acceleration in the entire scenario and hence there should have been no age difference between Bob's clock and the clock info Charlie was bringing back. This is definitely a contradiction to relativity.  If this interpretation turns out to be true, then everything else I've heard about relativity isn't.  So I don't know what the right answer is and these are specific questions that it's almost impossible to get specific answers to because people who know the truth don't share it willingly for fear it will blow your mind. I'm sure KJW on thescienceforum would eventually answer these questions but that bridge is permanently burnt unless someone else can get this message to him and not mention it's from me.

 

P.S. I saw your profile, your from winterpeg. Have you ever seen the show Dragons' Den? I've been on it 4 times.

Edited by ralfcis
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No, no help at all except for one bit of info I didn't know. He stated GPS satellites orbit the earth at 8000 mph but do they actually orbit because I thought they were geostationary which means they shouldn't be moving in relation to spots on earth. Yes as the earth turns they have to trace out a larger arc to remain geostationary but in the end they should still have no relative velocity towards you the observer as they never approach or recede from you. I don't know the answer to this and I've asked this many times and never got an answer. Maybe they're not geostationary at all or relative velocity along an arc doesn't need to approach or recede from you? Yeah, that's probably the reason as reciprocal time dilation from relative velocity is not dependent on direction.

 

 

 

 

The gps system does not use geosats.

 

There are six low earth orbits with 4 satellites in each orbit (not including spares)

 

The constellation looks like this

 

ConstellationGPS.gif

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The reason it can't be determined during the path is that the age of each participant is subject to perspective when separated. All perspectives are valid so there is no universal answer on how age difference unfurls from all perspectives except during co-location of the parties.

 

 

 

This is a philosophical (metaphysical, epistemological) postulate of quite dubious validity, Ralf.  You strike me as being quite sincere, but it seems you have been trapped into accepting unwarranted premises which then create insoluble difficulties.  Back in a minute with a citation....

 

Here ya go:

 

http://www.scienceforums.com/topic/34636-physics-based-on-einsteins-errors/page-3?do=findComment&comment=367041

 

That link didn't work out quite right.  I was trying to direct it to post #42 in that thread, although other posts may also be relevant.

Edited by Moronium
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This ->

The reason it can't be determined during the path is that the age of each participant is subject to perspective when separated. All perspectives are valid so there is no universal answer on how age difference unfurls from all perspectives except during co-location of the parties.

 

I find it strange that for a theory that is supposedly settled science, I can't find any agreement on what it actually says amongst the experts. So far the only 2 experts I've found don't agree but I'm not sure because I can't even get confirmation from an expert of what he just said. They even admit the story changes based on what level  they're teaching it at. To me this latest theory, that age difference happens during the non-inertial acceleration phase but can't be revealed until the end of the spacetime path when perspective no longer comes into play, sounds good because it's tied very closely to GR but still has holes that need to be addressed. I don't know for sure what the answer is and won't know until I get some confirmation from an expert. If someone pulls out a wiki article that confirms this, I will definitely read it but I'm not going to read every wiki article that has the word relativity in it.

Edited by ralfcis
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This ->

The reason it can't be determined during the path is that the age of each participant is subject to perspective when separated. All perspectives are valid so there is no universal answer on how age difference unfurls from all perspectives except during co-location of the parties.

 

I find it strange that for a theory that is supposedly settled science, I can't find any agreement on what it actually says amongst the experts. So far the only 2 experts I've found don't agree but I'm not sure because I can't even get confirmation from an expert of what he just said. They even admit the story changes based on what level  they're teaching it at. To me this latest theory, that age difference happens during the non-inertial acceleration phase but can't be revealed until the end of the spacetime path when perspective no longer comes into play, sounds good because it's tied very closely to GR but still has holes that need to be addressed. I don't know for sure what the answer is and won't know until I get some confirmation from an expert. If someone pulls out a wiki article that confirms this, I will definitely read it but I'm not going to read every wiki article that has the word relativity in it.

 

Well, if I'm reading you right, Ralf, the issue of the effect of acceleration on time dilation has long been settled as both an empirical and theoretical matter (by Einstein, from the outset).  I really don't know why any "expert" would claim otherwise.

 

The clock postulate says that the rate of an accelerated clock doesn't depend on its acceleration.  But note: the clock postulate does not say that the rate of timing of a moving clock is unaffected by its acceleration....Although the clock postulate is just that, a postulate, it has been verified experimentally up to extraordinarily high accelerations, as much as 10 18 g in fact (see the FAQ What is the experimental basis of Special Relativity?)

 

 

http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html

 

But that's not the issue I was raising, really.  Why would anyone assume that  "all perspectives are valid," or that there is no theoretical answer to questions we can't directly verify at the moment?

Edited by Moronium
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Here's a little more on the clock hypothesis (which has been called the "third postulate of relativity") from wiki, if you're interested in more confirmation:

The clock hypothesis is the assumption that the rate at which a clock is affected by time dilation does not depend on its acceleration but only on its instantaneous velocity....The clock hypothesis was implicitly (but not explicitly) included in Einstein's original 1905 formulation of special relativity. Since then, it has become a standard assumption and is usually included in the axioms of special relativity, especially in the light of experimental verification up to very high accelerations in particle accelerators.

 

 

https://en.wikipedia.org/wiki/Time_dilation#Clock_hypothesis

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I'm disengaging. The statement is nonsense because it doesn't define clock rate relative to what? Relative to the observing frame or relative to the observer inside the frame being accelerated. As far as I know, proper time (observed by an  observer inside the frame being accelerated) is not affected by acceleration and there's no time dilation due to the external relative  velocity (instantaneous or not) inside the frame from this perspective either.

Edited by ralfcis
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Why to which part? The article is mixing up a whole bunch of terms.

 

I was asking why you were "disengaging."  I have no idea of what "article" you're referring to right now, or in what way it is "mixing up a whole bunch of terms."  Care to clarify?

 

Edit:  I now notice that you have added to your original post.  Let me read it...

Edited by Moronium
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The wiki article you posted. I'll just jump to the chase. When you're driving your car are you moving. If you're stepping on the gas, are you moving. These questions are incomplete. Are you moving inside your car from your perspective? And outside your car, what relative velocity would people see you moving at. Would they all agree? If you drop off your friend and take off, what's his relative velocity as you view him in your rear view mirror?

Edited by ralfcis
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Your supplemented post:

 

I'm disengaging. The statement is nonsense because it doesn't define clock rate relative to what? Relative to the observing frame or relative to the observer inside the frame being accelerated. As far as I know, proper time (observed by an  observer inside the frame being accelerated) is not affected by acceleration and there's no time dilation due to the external relative  velocity (instantaneous or not) inside the frame from this perspective either.

 

I believe the clock hypothesis applies to any and all frames.

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The wiki article you posted. I'll just jump to the chase. When you're driving your car are you moving. If you're stepping on the gas, are you moving. These questions are incomplete.

 

Is this supposed to be a trick question?  Of course you're moving.  In relation to what?  Well, to the surface of the earth, for one.  Relative to the motion you had before you got in the car, for another.

 

As for the effect of acceleration when you're "stepping on the gas," even in the context of SR theory, this is deemed to be "absolute" motion, not relative motion.  In other words it is not "frame dependent."

Edited by Moronium
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