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GPS and Relativity Misconceptions 1

Posted October 24, 2011 2:17 PM by Jorrie
Pathfinder Tags: GPS relativity

Ronald R. Hatch of NavCom Technology has published a number of controversial relativity articles, mostly in 'fringe' publications and forums. One example is titled Relativity and GPS. Here I will only discuss one of the several issues I have with that article: the misinterpretation of a scholarly article by Prof. Neil Ashby of the University of Colorado in Boulder, titled Relativity and the Global Positioning System.(a)

Hatch wrote: "Ashby, in the opening paragraph of his abstract, states:
Important relativistic effects arise from relative motions of GPS satellites and users, ...
And Ashby also states, at the start of a section on time dilation:
First, clocks in relative motion suffer (relativistic) time dilation, ...
"

Taking these quotes out of context, Hatch then laboriously "shows", through an example of two satellites in identical, but counter rotating orbits, how the satellites of the GPS should suffer velocity time dilation relative to each other. Since it is common knowledge that the GPS satellites do not suffer velocity time dilation relative to each other,(b) Hatch then wrongly claims that Ashby - and hence special relativity theory - must be in error.

This is obviously not the case, because the GPS satellites are not moving relative to each other in the chosen non-rotating earth centered inertial (ECI) reference frame. Even Hatch's counter-orbiting satellites have the same relativistic clock rates in the ECI frame, special relativity (SR) tells us. No need to call on Lorentz Ether Theory (LET) to rescue SR.(c) Both clocks tick slower than an identical clock, stationary in the ECI frame, though. This is compensated for in GPS satellites.

I think the confusion comes from the fact that in the inertial frame of each counter-orbiting satellite their relative speeds do play a role. This is a much more difficult relativistic problem to solve numerically, but SR unequivocally says that their clock readings will be the same on every subsequent passing of one another. They will stay in sync, despite their obvious relative speed.(d)

In the rotating earth-centered, earth-fixed, (ECEF) reference frame of a stationary ground receiver, counter-orbiting clocks do not stay in sync, of course. Earth's rotation makes them pass overhead at different times and hence their clocks appear to be out of sync with each other. What's more, they will both appear to be out of sync with a ground receiver clock. Of course, counter-rotating satellites are not applicable to GPS.

The standard GPS orbiting clocks stay in sync with each other, but un-compensated orbiting clocks will get increasingly out of sync with ground clocks. IMO, this is the context of Prof. Ashby's statements, quoted and misinterpreted by Ron Hatch. This type of misinterpretation is not uncommon amongst people with 'absolute frame' mindsets.

Jorrie

(a) I did not have full access to Ashby article in GPS World, but found a later (2002) version on Physics Today.org: http://www.ipgp.fr/~tarantola/Files/Professional/GPS/Neil_Ashby_Relativity_GPS.pdf.

(b) Apart from minor corrections for orbital parameters and the uneven gravity of earth, GPS satellite clocks run in sync with each other. A broader, more advanced and regularly updated GPS paper by Ashby is available at https://link.springer.com/article/10.12942/lrr-2003-1. Prof. Ashby really knows his relativity and his GPS.

(c) Contrary to some of Hash's claims, LET and SR are not distinguishable by means of experiment. They are just different philosophies for explaining special relativistic effects. LET has a few problems when it comes to accelerated frames and GR, of course. In his Modified LET (MLET) Ron Hatch attempted to add gravity to LET. AFAIK, the GPB results refuted MLET experimentally. http://cr4.globalspec.com/comment/787587/Re-Universal-Time

(d) The simplest argument for two identically counter-rotating satellites is that for every possible inertial frame of reference, the spacetime paths of the two satellites are equivalent. Consider them as first sitting statically at the same altitude in the ECI frame. Their clocks will remain in sync. Now accelerate them horizontally and identically for a short time, but in opposite directions and then let them coast inertially. The satellites are still equivalent in terms of spacetime paths and their clocks will remain in sync. Because they have traveled a longer spatial route and hence 'traveled' less in time, the clocks will however both lose time relative to a theoretical ECI frame clock. It is a consequence of the invariance of the spacetime interval in Minkowski spacetime and the Tartaglia paper mentioned below confirms this mathematically.

Due to the dragging of inertial frames by earth's rotation (gravitomagnetism), there are some gravitational effects that differ for the counter-orbiting clocks, which will then very slowly desynchronize. See technical detail in http://polito.academia.edu/AngeloTartaglia/Papers/769566/Gravitomagnetic_effects, around equation (43). These differences are orders of magnitude smaller than what is needed for GPS work (calculated as a few pico-seconds per orbit). In any case, we are ignoring all gravitational effects for this discussion and counter-rotating satellites are not applicable to GPS. Gravitomagnetic effects are the same for all GPS satellites.

-J

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#1

Re: GPS and Relativity Misconceptions 1

10/24/2011 4:07 PM

Then if two orbiting GPS satellites in opposite orbits will stay in synch regardless of thier speeds, then why would two clocks in opposite travel around the earth in airplanes vary in time? Are you saying that what applies for one does not apply for the other? That somehow GPS satellites are immune from the same affects on clocks on airplanes?

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#2
In reply to #1

Re: GPS and Relativity Misconceptions 1

10/24/2011 10:26 PM

"That somehow GPS satellites are immune from the same affects on clocks on airplanes?"

Yes, in the sense that the satellites are independent from earth's rotation. Please read again what I wrote about the frames of reference, e.g.:

"In the rotating earth-centered, earth-fixed (ECEF) reference frame of a stationary ground receiver, counter-orbiting clocks do not stay in sync, ..."

It is only in the ECI reference frame that they remain in sync. Please read again and then think carefully. The two satellites travel different distances in the ECEF frame, while they travel the same distance in the ECI frame.

-J

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#4
In reply to #2

Re: GPS and Relativity Misconceptions 1

10/24/2011 11:51 PM

So you actually want me to believe that a clock on board a satellite rotating counter to the earth's rotation is any different from an airplane flying counter to the earth's rotation, or with it for that matter? You really need to think of a better excuse than that, truly. So these satellites orbit the Earth how? Since an airplane apparently travels independently of the earth's rotation as well as one may fly any direction independently of the earth's rotation. GPS satellites work just as well in the Sun centered reference frame, since they are orbiting the Sun with the earth are they as well independent of the Sun's reference frame or perhaps tied into the Suns frame by the Earth's orbit around the Sun?

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#6
In reply to #4

Re: GPS and Relativity Misconceptions 1

10/25/2011 12:47 AM

"So you actually want me to believe that a clock on board a satellite rotating counter to the earth's rotation is any different from an airplane flying counter to the earth's rotation, ..."

Yep.

You obviously realize that a 747 flying from NY to LA is actually going predominantly west-east in the non-rotating ECI frame. The return flight from LA to NY is also going west-east in that frame, just quite a bit faster.

As an exercise in the two different frames (ECI and ECEF), can you work out approximately how far the 747 has traveled in each frame? Take rough distances and angles and any nominal value for ground speed that you like. Ignore relativity and wind.

-J

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#8
In reply to #6

Re: GPS and Relativity Misconceptions 1

10/25/2011 2:13 AM

And yet a satellite on a path from LA to NY and one from NY to LA would experience the same time flight differences as the earth revolved underneath them as the two planes, discounting relativity and wind as you said. There is no difference. Use any nominal ground speed you like and calculate how far each has traveled.

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#10
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:07 AM

SJW, were you still awake? It seems that you did not notice I tried to guide you into realizing that we are talking about two different frames of reference for aircraft and satellites.

I can also quote from my Blog article, which is the purpose of this thread (and which you should have read carefully :-)

"Hatch then wrongly claims that Ashby - and hence special relativity theory - must be in error. This is obviously not the case, because the GPS satellites are not moving relative to each other in the chosen non-rotating earth centered inertial (ECI) reference frame.", and:

"In the rotating earth-centered, earth-fixed, (ECEF) reference frame of a stationary ground receiver, counter-orbiting clocks do not stay in sync, of course. Earth's rotation makes them pass overhead at different times and hence their clocks appear to be out of sync with each other."

It seems like you are ignoring the difference frames of reference. Unless you accept the above as correct, or present the calculation that I fairly asked for, there is no point in discussing this further with you. It has reach a stage now where you must put up....

-J

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#12
In reply to #10

Re: GPS and Relativity Misconceptions 1

10/25/2011 11:12 AM

You may of course try to "guide" someone all you like, but answer the distance question you asked, then use the same same speed and answer the distance question I asked and let me know the answers will you. You want to separate two events which have the exact same occurrence. The earth spins under both the satellite and the airplane, one must always travel further relative to the other direction. You may try to dodge this fact by trying to confuse your readers with frames of reference, but in either frame airplane or satellite must travel further when traveling with the rotation of the earth. The only difference is the satellite travels faster while in orbit to cover the same amount of ground as an airplane as it has a larger circumference to traverse. Don't try to throw your readers off with misdirection, answer the two questions since you seem to be the math expert.

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#13
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Re: GPS and Relativity Misconceptions 1

10/25/2011 1:09 PM

If (and that is a big if) I understand this correctly, please allow me a question:

Let us suppose the airliner makes a trip from the south pole to the north pole. Then, a return trip from north pole to south. What will be the difference in time of travel (in hours) and distance traveled between these two trips be?

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#15
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:02 PM

True North or Magnetic North?

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#17
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:14 PM

Times and distances will be identical for the two trips, I think. There will be Coriolis effects that will tend to make the aircraft veer off course, but as long as the pilot or autopilot steers due geographical north or south, I can see no difference.

-J

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#20
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:24 PM

The times would be identical if you ignore the atmospheric effects of winds, humidity, and air pressure.

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#18
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:16 PM

There will be no time difference nor distance difference, provided it is as anonymous pointed out true north and not magnetic north, as the magnetic pole drifts from true north.

So then you must ask why there would be time differences traveling east and west if it is just velocity that causes clocks to shift time. It is because one is going with the magnetic force of the earth and one is going against the magnetic force of the earth. it can not be gravitational as gravity pulls equally no matter the rotation of an object.

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#22
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:43 PM

So, if the reference point for viewing the pole-to-pole trips is the center of the earth, both will have the appearance of 180° travel, if airspeed is constant, autopilot... all things being equal.

Now, a similar theoretical trip following the equator, from two selected points 180° around the world from each other. From the same point of view (center of the earth) one trip will appear to be over 180°, and one under by the same amount. This amount will depend on airspeed.

Are these planes of reference, from the same point of reference...

Ooops I'm losing my train of thought. This is why I don't comment on Jorrie's threads too often. Can one of you pick up on this? Or is this so far off it has nothing to do with this thread?

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#14
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Re: GPS and Relativity Misconceptions 1

10/25/2011 2:40 PM

SJW: "... but answer the distance question you asked, then use the same same speed and answer the distance question I asked and let me know the answers will you."

Honestly, I still cannot quite figure out what question you asked. Since you did not answer mine, I must assume that you also could not make out what I asked. When it comes to reference frames, hand waving arguments provide few answers. Like your "The earth spins under both the satellite and the airplane, one must always travel further relative to the other direction. You may try to dodge this fact by trying to confuse your readers with frames of reference, but in either frame airplane or satellite must travel further when traveling with the rotation of the earth."

Travel further, by the same distance? Obviously not, but can you see what I'm getting at? Words are very dubious in this case. To know what's going on requires some simple calculations. In order not the leave this open-ended or going in circles, I will show my calculations, so that any reader can check it for errors.

In the rotating ECEF frame, it is obvious that a 747 will travel roughly the 4000 km distance between NY and LA in each direction and that's that.

For the non-rotating ECI frame, assume a fast 747 ground speed of 900 km/h, so it will fly for 4.44 hours in either direction, take-off and landing obviously excluded. Due to earth's rotation, the speed of LA and NY is around 1350 km/h eastward in ECI frame, so in 4.44 hours they move some 6000 km to the east.

Hence, the LA-bound 747 travels around -4000+6000 = 2000 km to the east, while the NY-bound 747 travels around 4000+6000 = 10000 km to the east, both in ECI coordinates. No math required, really, provided that we are prepared to work in different frames.

Now for two GPS-like satellites, identically, but counter-orbiting, both hypothetically overflying LA and NY (GPS satellites don't of course, and it is rather impossible to achieve with any two satellites).

In the non-rotating ECI frame, the distance between LA and NY is still roughly 4000 km. The ground projection of these satellites' positions move some 40000 km in 11h 58m, or 3345 km/h in the ECI frame - not relative to the ground, where the east and west speeds differ. So they will both cover 4000 km in 1.2 hours, but in this time, LA and NY have moved some 1620 km to the east in the ECI frame.

Hence, the LA-bound satellite travels around 4000-1620 = 2380 km to the west, while the the NY-bound satellite travels around 4000+1620 = 5620 km to the east.

-J

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#16
In reply to #14

Re: GPS and Relativity Misconceptions 1

10/25/2011 3:03 PM

"In the rotating ECEF frame, it is obvious that a 747 will travel roughly the 4000 km distance between NY and LA in each direction and that's that."

No it is not. As it travels from East to West NY to LA The earth rotates underneath the plane, and it actually has a shorter distance to travel, this is why international flights to Europe take more time that flights from Europe, the distance one way is actually shorter than the other. Likewise when traveling from LA to NY the earth spins with the plane and it has more distance to travel. Only in a car would the distance be the same either direction.

It doesn't matter if I am viewing this distance from the planes or from the ground, the results are identical in both cases.

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#19
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:22 PM

Ah, ha! You are not thinking in the right inertial reference plane and that is your problem with the logic you are proposing. For one thing you are mixing the two reference planes and you can't do that.

The distance between the two cities is always the same (discounting California sliding away in an earthquake). That's the way the world is. Directly flying, or driving on the ground, or going by camel, it makes no distance. If you use the same route and altitude in each direction the distance is always the same - referenced to ECEF.

In the real world the real reason that flights take different times there and back is because (for one thing) they actually do not fly the same exact route and (for another reason) you have to account for head winds and tail winds at altitude. Those winds are significant. I know because I am a pilot.

However, your argument about increased distance in one direction over the opposite direction would make a great (if not amusing) argument at the airline service desk trying to get extra frequent flyer miles!

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#23
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:49 PM

You were faster than me - is it because my internet signal had to go against the spin of earth for quite some distance?

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#28
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Re: GPS and Relativity Misconceptions 1

10/25/2011 5:07 PM

Probably has to make a stop at the NSA, too.

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#24
In reply to #19

Re: GPS and Relativity Misconceptions 1

10/25/2011 4:14 PM

First we were assuming no wind or relativity affects. If the plane never gained or lost distance relative to the earth's rotation it would remain stationary. A geosynchronous orbit. If you put thought into it a plane traveling West actually requires more thrust and fuel to overcome the natural tendency to rotate with the earth, yet it arrives faster even though it is still rotating with the earth. Likewise a plane traveling with the earth's rotation requires less thrust and fuel for the same distance, and arrives later even though it is traveling faster than the earth rotates, else it wold not gain ground. Check travel prices, the price of a ticket from NY to LA is not the same as a ticket from LA to NY. Yes, I am sure you can provide many links showing the distance is the same, but the fact remains if you were not moving relative to the Earth's rotation you would be in geosynchronous orbit even if you had to apply constant thrust to maintain that position.

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#21
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Re: GPS and Relativity Misconceptions 1

10/25/2011 3:43 PM

Ah! Gotha! You apparently still refuse to consider frames of reference and hence you blundered badly here.

Time and distance in the ECEF (rotating) frame are identical for east and west (relativity and weather ignored). Aircraft uses this frame for navigation. You are now confusing it with the ECI non-rotating frame, where the distances do differ, as I laboriously calculated for you.

It is more likely that you think about the jet stream in the tropopause. It may cause significant time differences between eastbound and westbound flights, if the wind is right at the altitude. But note, the jet stream works in the opposite direction to what you said - flights from the US to Europe are usually shorter, not longer than the return flights.

-J

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#25
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Re: GPS and Relativity Misconceptions 1

10/25/2011 4:16 PM

Well we were discussing no wind or relativity, but since you brought that up a plane traveling with the rotation of the earth has the wind blowing with it, while one traveling against has a headwind, yet the one traveling against the wind arrives first. funny how that works in direct opposition to the theory the earth's spin makes no difference.

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#26
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Re: GPS and Relativity Misconceptions 1

10/25/2011 4:54 PM

What flight is that? Now you must be pulling that one out from where the sun does not shine.

I just looked up direct flights from Philadelphia to London and the return trip is much longer.

Add to that you need to consider the actual flight path fro each trip, which will most likely be different depending on how they are routed. Aircraft fly the Great Circle routes.

Anyway, I want to see your data on this one.

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#27
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Re: GPS and Relativity Misconceptions 1

10/25/2011 4:54 PM

You could be correct I may have mixed up time flight directions, no one is perfect :). But I also admit when I may be wrong. But let me ask one question, why would east or west make a difference to clocks, but not north or south? The only difference is direction against or with the spin of the earth, yes? Not counting the slight equatorial bulge and higher gravitational potential there, as north/south crosses it both ways and one east/west on the equator would never leave it, so gravity can not be the answer to that problem. The simple solution is direction in the electromagnetic field, but why is that never considered as a solution? If both planes retain the same velocity, then velocity cannot answer that question either, since as you have pointed out velocity relative to the earth's rotation makes no difference to distance.

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#31
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Re: GPS and Relativity Misconceptions 1

10/25/2011 11:45 PM

"But let me ask one question, why would east or west make a difference to clocks, but not north or south? The only difference is direction against or with the spin of the earth, yes?"

Yes.

"The simple solution is direction in the electromagnetic field, but why is that never considered as a solution?"

Because nobody else (with the exception of perhaps Ron Hatch) thinks it has the effect on clocks that has been found over and over in practice.

Besides that, Einstein's theory predicts the observed effect with extreme accuracy...

-J

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#29
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Re: GPS and Relativity Misconceptions 1

10/25/2011 10:23 PM

flights from the US to Europe are usually shorter, not longer than the return flights

You may be right, but my wife just returned from a trip to Germany. Her flight time to Frankfurt was 11 hours, and return trip to Denver was 9 hours. Both were non-stop, but I don't know the routes. I agree that the flight times are different (if same length) because of wind speed relative to the ground.

In the case of the GPS satellites, are you saying that because the clocks are staying in sync, that there are no relativistic differences to consider?

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#30
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Re: GPS and Relativity Misconceptions 1

10/25/2011 11:30 PM

"In the case of the GPS satellites, are you saying that because the clocks are staying in sync, that there are no relativistic differences to consider?"

Only relativistic time differences between satellite clocks and ground receiver clocks are considered and compensated for in the setup of the satellite clocks, so that they essentially run in sync with receiver clocks. Once a day, they are also resynchronized, compensating for orbital perturbations and irregular gravitational potential of earth.

Aircraft clocks do however suffer relativistic time dilation on east-west flights in any direction, because they do not fly at the same speed relative to the ECI frame of the GPS, but it is so small that only the military needs to consider it.

-J

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#32
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Re: GPS and Relativity Misconceptions 1

10/26/2011 12:43 AM

"Aircraft clocks do however suffer relativistic time dilation on east-west flights in any direction, because they do not fly at the same speed relative to the ECI frame of the GPS, but it is so small that only the military needs to consider it."

Interestingly, the SR-71 spy plane could actually have beaten a GPS satellite in effective ground speed, even westbound. The air force did not say, but they probably considered the relativistic effects.

For SJW's benefit, the SR-71 would have lost time against UTC when flying LA-NY and gained time against UTC when flying NY-LA. How much can be calculated, but I haven't done so.

-J

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#33
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Re: GPS and Relativity Misconceptions 1

10/26/2011 7:59 PM

That's not the point, the point is that if I choose one of the GPS satellites as my frame of reference, then all other GPS satellites should run slow, but they do not. Your claim that it is do to ECI frames is not considered in his theory, all frames are relative. I do not doubt something is affecting clocks on board aircraft more than satellite clocks, but it can not be velocity, else North/South would cause the same affects, likewise it cannot be gravity (beyond distance from the gravitational source). That only leaves one major force unspoken for.

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#34
In reply to #33

Re: GPS and Relativity Misconceptions 1

10/26/2011 9:23 PM

You wrote, "I do not doubt something is affecting clocks on board aircraft more than satellite clocks..."

I believe that statement is incorrect. GPS clocks require more compensation than aircraft when referenced to ECEF. Where did you get information that states otherwise?

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#35
In reply to #34

Re: GPS and Relativity Misconceptions 1

10/26/2011 11:23 PM

No because according to you two gps satelites stay in sync while two clocks on airplanes dont, so which is it? You simply dont adjust the clocks on airplanes for their landings and takeoffs, while u do adjust gps for perigee and apogee. Because you choose not to do the same for airplanes dont complain to me gps require more adjustment. They are also higher above the earth and travel faster.

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#39
In reply to #35

Re: GPS and Relativity Misconceptions 1

10/27/2011 6:49 AM

This would be a whole lot easier if you sat down and tried to at least understand the damn theory you are trying to poke holes in first.

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#37
In reply to #33

Re: GPS and Relativity Misconceptions 1

10/27/2011 12:39 AM

SJW: "... the point is that if I choose one of the GPS satellites as my frame of reference, then all other GPS satellites should run slow, but they do not."

You misunderstand relativity. You can only use the simple γ = √(1-v2/c2) SR time dilation principle if the satellites were moving in a gravity-free environment in a straight line, i.e. Minkowski spacetime. GPS satellites in the same orbital plane do not move relative to each other anyway, but GPS satellites in different orbital planes do. One needs the more general principle of the invariance of the spacetime interval in Minkowski spacetime.

I essentially covered this in end note (e) of my OP article. Or, of course, one can use the full GR equations and show the same thing. Many people would not follow such a treatment, but for reference, I quoted http://polito.academia.edu/AngeloTartaglia/Papers/769566/Gravitomagnetic_effects before.

SJW: "... else North/South would cause the same affects".

You are making up effects. Between neither GP satellites, nor satellites in polar orbits, there are any such effects. As you yourself wrote before: "But let me ask one question, why would east or west make a difference to clocks, but not north or south? The only difference is direction against or with the spin of the earth, yes?"

There is definitely a difference between all satellite clocks and aircraft clocks (or with ground clocks, for that matter). And that effect is precisely as predicted by GR. Why do we need another theory?

-J

PS: because it seems that lay people typically have problems with this very misconception, I am busy with calculations based on an approximation of GR. It might be more easily understood then the 'full Monty'. Will post that later.

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#3

Re: GPS and Relativity Misconceptions 1

10/24/2011 11:37 PM

Sounds like Mr Hatch is another one who would rather spend a year trying to prove everyone wrong, than a week to actually understanding what's being said.

The attitude is not uncommon, but the question is why do people do it.

I suspect it enables the holder to feel clever but also gives a reason why no one takes them seriously. So it's a case of "I'm just as smart as Albert Epstein, but my ideas are being suppressed by the establishment".

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#5
In reply to #3

Re: GPS and Relativity Misconceptions 1

10/25/2011 12:16 AM

Because we see the holes in the explanations and refuse to close our eyes to blatant untruths and mathematical fudges. You may happily choose to go through life with a theory that has contradicting explanations, math that requires fudging at every turn to make it work, undetectable particles and when all else fails resorting to virtual particles that act when needed but otherwise affect nothing. Some of us prefer real science, where questions are raised and valid answers brought forth, not science that attempts to misdirect to save a theory for no other reason than it's accepted. I really do not care what theory you use as long as your explanations make sense and do not try to misdirect or try to tell me that I have to believe that nothing can be something or that 96% of the universe is something that can't be detected. It has been for over 100 years, you just refuse to accept it as it might challenge your religious beliefs, as that is exactly what they are, beliefs. Every new data set that comes in the words "we were surprised" almost invariably accompany the discovery. Why? Your search for gravitational waves has failed, your search for the Higgs Bosun has failed, your search for Cold Dark Matter has failed, but did you once think to look at the underlying theory to see where it may be wrong instead of making up new things to look for instead? Instead you would prefer to devise more exotic impossibilities to try to rescue the theory instead of perhaps revising it. Science today is in a rut of its own making because new ideas are excluded if they do not fit into the mold, while any theory no matter how impossible it might be is readily excepted as long as it does not question current cosmology. You find a huge hole in the CMB data, could the theory perhaps need revising, nah, it's because there's a parallel universe there, that's all. I would laugh here but my heart is too sick at the state of science to do so.

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#7
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Re: GPS and Relativity Misconceptions 1

10/25/2011 12:59 AM

".. Some of us prefer real science ..." That's good to hear.

Of course, if you really want to be " where questions are raised and valid answers brought forth" then you need to actually understand what has already been done. The science we already have does a fantastically good job of explaining what we see in the world.

I'll take a wild guess; does your "science" have a deity at the center?

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#9
In reply to #7

Re: GPS and Relativity Misconceptions 1

10/25/2011 2:19 AM

Not at all, I follow science, not mysticism. It only works because of fudges, plain and simple. We cant even explain the basics yet and you want to move on to exotic formula and delve into the mathematical world when we have yet to understand the basic mechanical principles behind 99% of the science you proclaim is correct. What causes gravity, it don't matter the math works. What causes electricity, it don't matter the math works. What is space and how is it bent or expanded if it is composed of nothing, it don't matter the math works. the math works because you fudged it to get the results you wanted to match the data.

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#11
In reply to #9

Re: GPS and Relativity Misconceptions 1

10/25/2011 3:13 AM

Pardon for intruding, but I get the distinct feeling sjw40364 will do better on a philosophy forum than on a science/engineering forum.

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#36

Re: GPS and Relativity Misconceptions 1

10/27/2011 12:00 AM

I do have one simple question about clocks:

According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates, i.e. one works more slowly than the other. But the theory also requires that you cannot distinguish which clock is the 'moving' one; it is equally true to say that A rests while B moves and that B rests while A moves. The question therefore arises: how does one determine, consistently with the theory, which clock works the more slowly? Unless this question is answerable, the theory unavoidably requires that A works more slowly than B and B more slowly than A.

So which clock works more slowly, A or B?

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#38
In reply to #36

Re: GPS and Relativity Misconceptions 1

10/27/2011 5:24 AM

SJW: "According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates, i.e. one works more slowly than the other."

No, this is not what the SR theory says, if you take everything in context. You must move clocks away from each other and then bring them back together again. Only then can you predict and measure which clock 'works more slowly'. This is the essence of the 'twins paradox' and it does not work 'one-way' only. I know that there are people trying to 'prove' that it also works 'one-way', but it is simply not valid.

If you accelerate clocks, you change their ratios of space:time in their spacetime intervals. If you create different ratios for clocks by means of acceleration, they will measure the time interval and hence also the space interval differently. But, the only way of observing that is by starting and ending with them in the same place. Then you can 'see' which one lost time.

If you start them together and then accelerate both of them identically, but in different directions, they still have identical space:time ratios (or rather equivalent spacetime paths) for the 'test'. If the accelerations are so that they come together once again, even just for an instant, you can verify that they have ticked at the same rate.

This is what happen with GPS satellites in equivalent orbits. If you accelerate only one of the two, they will of course have different space:time ratios and you can then work out which one will work more slowly. I have described this effect somewhat in end-note (e) in the OP.

I have also described it a bit more fully and in 'engineering-like' terms in chapter 1 of my eBook. A pdf of the chapter sits here. Minor math in there, but the parable of Pam and Jim on pages 19/20 is an easy read. However, without the context of the prior part of that chapter, it may be rather difficult to understand.

-J

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#40
In reply to #38

Re: GPS and Relativity Misconceptions 1

10/27/2011 11:46 AM

Ok, but are there or are there not no privileged reference frames? Can I or can I not assume A is at rest while B travels out and back and can I or can I not also consider B at rest while A travels out and back? Not being sarcastic, looking for a real answer.

One other question: What was the name of Einstein's famous paper?

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#41
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Re: GPS and Relativity Misconceptions 1

10/27/2011 11:50 AM

The answer is YES! That is what inertial frame of references are all about. You are right, there are no privileged frames of reference.

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#42
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Re: GPS and Relativity Misconceptions 1

10/27/2011 12:06 PM

Then it is also a valid conclusion that A is slow to B and B is slow to A, so both clocks are slow regardless of which moves and which is stationary. So in order for one clock to be slow to another clock one must indeed choose a privileged reference frame or no valid result can be obtained.

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#43
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Re: GPS and Relativity Misconceptions 1

10/27/2011 1:28 PM

There are no 'privileged' frames, but there is a big difference between inertial frames and non-inertial frames. Whoever goes "out and "back" is not in an inertial frame and will record less elapsed time than the "stay at home" inertial observer.

Did you digest what I wrote in replies 37 and 38?

Which Einstein paper do you refer to? He published many famous papers.

J

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#44
In reply to #43

Re: GPS and Relativity Misconceptions 1

10/27/2011 2:21 PM

The 1905 paper that started it all.

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#45
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Re: GPS and Relativity Misconceptions 1

10/27/2011 2:25 PM
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#46
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Re: GPS and Relativity Misconceptions 1

10/27/2011 3:01 PM

Why isn't relativity relative?

How can a body which is moving at a relative velocity of 95% of c be contracted 70%, while the time on such body is only dilated or slowed down by about 3%? These values are not reciprocal, and your concepts are neither logically nor mathematically consistent. How do you explain these inconsistencies?

http://www.relativityoflight.com/images/E-M_12.jpg

http://www.relativityoflight.com/images/E-M_13.jpg

The paper I am referring to is "On the Electrodynamics of Moving Bodies." So why are you ignoring the electrodynamics in every single description of astrophysics?

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#47
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Re: GPS and Relativity Misconceptions 1

10/27/2011 3:28 PM

http://www.relativityoflight.com/

Anyone else here reads such utter nonsense?

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#49
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Re: GPS and Relativity Misconceptions 1

10/27/2011 5:08 PM

This is the back side of the sword of the internet.

From science to politics, there is so much misinformation that it will make your head spin. It doesn't stop there, religion, hate, witchcraft, you name it.

All claim to hold the truth, which is the first sign that you should run, not walk, from it.

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#48
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Re: GPS and Relativity Misconceptions 1

10/27/2011 4:45 PM

SJS: "So why are you ignoring the electrodynamics in every single description of astrophysics?"

This is what we do every time we discuss Einsteins special relativity. Electrodynamics classically means the interaction between light and matter and it does not include gravity.

Classical electrodynamics has been superseded by quantum electrodynamics, but we still do not have a consistent theory of quantum gravity.

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#50
In reply to #48

Re: GPS and Relativity Misconceptions 1

10/27/2011 5:55 PM

Yet I am not the one needing to insist that frames of reference are not prefered, then explain a clock's behavior only by that frame, when theory requires that any frame is equivalent to any other frame for observation. A or B may be considered at rest or neither, yet in order for you to show one clock is slower than another you MUST choose one frame over the other, else you get conflicting results. So you may talk about no preferred frames all you like, but the reality is that you must choose a preferred frame or both A and B are slow equally at the same time.

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#51
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Re: GPS and Relativity Misconceptions 1

10/27/2011 11:22 PM

SJS, do you read anything we write properly?

I rest my case.

Anyway, if you want to discuss alternative theories to relativity, please post a new thread on CR4, because this Blog is not the place.

If you can come up with pertinent questions on standard relativity (not already answered), you are welcome to continue here.

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#53
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Re: GPS and Relativity Misconceptions 1

10/27/2011 11:56 PM

You fail to consider that one clock is accelerated and one is not. In my understanding that's the difference between the special theory and the general theory. Only the clock with no acceleration can be considered at rest. If both are accelerated equally, then they will agree on the time when returned to the starting point (neither will be slow compared to the other). Jorrie may not agree with the "method" but I think he will agree with the outcome.

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#54
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Re: GPS and Relativity Misconceptions 1

10/28/2011 12:38 AM

And yet theory says I can consider either to be at rest or either to be moving, that their are no privilaged frames, so when you make up your mind about that then one can have a logical conversation, until then you are just throwing out random words that mean nothing. Either I can consider A at rest and B moving and likewise B at rest and A moving or I can't, which is it? If I can't then you might as well throw out all of relativity because that's one of the basic tenets of it. So A says B is slow, B says A is slow, so both are slow and only by choosing one as the preferred frame can you overcome this contradiction, but then that contradicts relativity, no matter how you might like to twist the words to say different. And frankly it doesn't matter which frame you choose, the other frame runs slow. Look at B from A, B is slow, immediately switch to B, A is slow, you just go right ahead and follow that logic.

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#55
In reply to #54

Re: GPS and Relativity Misconceptions 1

10/28/2011 1:05 AM

Frankly I don't care if you want to say A is moving and B is at rest from the point of view of A what does B's clock read, slow or fast?

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#56
In reply to #53

Re: GPS and Relativity Misconceptions 1

10/28/2011 1:45 AM

Hi S, no problem with the method, just a minor correction. The "special theory", being just a special case of the general theory for when gravity is absent, is quite capable of handling accelerated frames. One can view acceleration as just a succession of infinitesimal inertial frame changes (dealt with by Lorentz transformations).

Another way to look at it is that accelerated frames are equivalent to frames in a hypothetical "uniform gravity field", i.e. with no spatial curvature, just 'time curvature' (time dilation). In GR, you cannot have the one without the other, as Einstein discovered during the trial and error period of his development of GR. Hence, acceleration in flat space is only approximately compatible with GR.

One is free to choose even an accelerating frame in flat space as your reference, but that makes life very complicated analytically. You do however get the same answers, at least approximately.

I think SJW's misunderstanding is that he can choose any inertial frame he prefers as the reference and that each frame will have its own definition of simultaneity. This gives differences in the observed space and time intervals between events for the different frames, but has nothing to do with clock rates. He also seems to take words out of semantic/technical context and assigns that meaning to "the theory" - and then complains that the theory does not make sense.

One of the problems with GR is that one has to view the whole thing in context and then make simplifications for the case you are studying. This is why many people like SJW views SR and GR as separate theories - it is a commonly done in Solar system work to make the calculations less tricky.

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#57
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Re: GPS and Relativity Misconceptions 1

10/28/2011 3:45 AM

Tell me, since according to modern cosmology it is gravity that holds galaxies together, that attracts galaxy to galaxy, in what special case does it apply when gravity is absent? When and where exactly is gravity absent?

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#58
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Re: GPS and Relativity Misconceptions 1

10/28/2011 6:50 AM

Every version of cosmology is based on GR full stop. Gravity is the dominant, or 2nd most influential force, depending whether the version includes vacuum energy or not.

One can ignore gravity only where it plays no significant role, e.g. free falling far from massive bodies, say over a limited region of interstellar or intergalactic space.

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#59
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Re: GPS and Relativity Misconceptions 1

10/28/2011 11:51 AM

So basically SR would only apply to places we will never ever be in my or your lifetime or the lifetimes of the next 20 or so generations and probably even further. yet you use its length contraction, time dilation, and relativity of simultaneity in places you just admit it would not apply. Next I am sure you will come full circle and explain to me how it does apply even where gravity exists and actually believe you are not contradicting yourself., just as you believe SR and GR do not contradict themselves. Just as you believe that A can be slow and B can be slow but that somehow doesn't make a contradiction because somehow you can decide which is moving so you have chosen a preferred frame yet it isn't one. And you still never answered the question. If A is moving and B is stationary, what does B's clock read in regard to A?

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#60
In reply to #59

Re: GPS and Relativity Misconceptions 1

10/28/2011 12:00 PM

I can't believe someone is arguing - aggressively - with Jorrie and AH on this... If this makes me a sheep for following blindly, then fine, I'm ready to shear.

I'm outta here.

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#61
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Re: GPS and Relativity Misconceptions 1

10/28/2011 12:18 PM

SJW, unless you are prepared to read properly what I've written on relativity and cosmology and ask some thoughtful questions, I must ask you to please stop trolling this Blog.

I've never done it before, but I may delete replies if necessary.

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#62
In reply to #61

Re: GPS and Relativity Misconceptions 1

10/28/2011 1:06 PM

So because I point out errors you can't answer I am trolling? I asked a pertinent question, what does B's clock read in regards to A? Simple, straightforward question, no ambiguities. yes, much easier to delete than hear opposing viewpoints. I've read what you and many others have wrote and they all have the same runaround, the same twisting of words to try to bamboozle their readers with mysticism not science. Is it you can't or don't want to answer the question because you already know the answer? That the answer will contradict what you said earlier about knowing which frame is moving? I have discounted all possibilities of B moving, only A moves, what does B's clock read in regard to A?

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#63
In reply to #62

Re: GPS and Relativity Misconceptions 1

10/28/2011 1:27 PM

Tell me what you do not understand in this part of my reply 38, then maybe I can help you.

SJW: "According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates, i.e. one works more slowly than the other."

"No, this is not what the SR theory says, if you take everything in context. You must move clocks away from each other and then bring them back together again. Only then can you predict and measure which clock 'works more slowly'. This is the essence of the 'twins paradox' and it does not work 'one-way' only. I know that there are people trying to 'prove' that it also works 'one-way', but it is simply not valid."

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#64
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Re: GPS and Relativity Misconceptions 1

10/28/2011 1:35 PM

No, it is because you are acting obstinate.

You don't get it because I believe you don't want to get it. You are set in your beliefs, which are not open to change.

That is fine if that makes you happy. There is nothing wrong in believing what you want to believe for whatever reason your heart desires.

However, if you are going to debate this subject you need to understand both sides of the argument. Otherwise you are being disingenuous to others and particularly to yourself.

Why would anyone want to debate with you if you refuse to listen and understand their side of the argument?

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#65
In reply to #64

Re: GPS and Relativity Misconceptions 1

10/28/2011 3:16 PM

Tell me, if the earth was rotating 1000 mph faster would time remain the same? If not how would you know? If so how would you know? So isn't it true you judge the correctness of all clocks based upon a preferred frame, that of the ECI? If all frames are relative then any frame can be chosen to judge the correctness of any other clock. So the idea of no preferred frame is not correct is it? GPS clocks work fine in the Sun centered frame, why not use that since the earth orbits the Sun?

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#66
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Re: GPS and Relativity Misconceptions 1

10/29/2011 11:02 AM

You wrote, "Tell me, if the earth was rotating 1000 mph faster would time remain the same?"

Of course it would. How could you perceive otherwise? It is just like the Twin Paradox. Both twins can watch the clock tic by and to each one it seems to be ticking at the exact same rate it always has. The away twin inside the spaceship senses time going by just like he did before launch.

Your question exactly punctuates what I have been charging all along; that you don't understand GR or SR, even at the basic levels, otherwise you would not be asking the questions you do.

You can not critique a theory that you don't understand and you have been wasting your time (and not to mention how many others here) with the way you are trying to resolve this argument.

You need to leave your prejudices at the door and sit down and actually learn the theory.

You appear to be intelligent, but you are so stubborn that if you were to just apply that same degree of stubbornness to actually educating yourself you would be a freak'n genius.

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#67
In reply to #66

Re: GPS and Relativity Misconceptions 1

10/29/2011 1:19 PM

No, YOU would perceive no difference, but an outside observer would say time slowed on the earth. So who is correct, someone on the earth or the outside observer? When the twin returns home who is correct, the stay at home one or the one that moved? Velocity has no affect on clocks, only acceleration. At 1G of thrust my clock will remain synched with one on earth, yet at 1G with enough fuel I could eventually obtain a velocity of a fraction of c, and if the time of light observational delay between points was removed, both clocks would read identical.

We can easily test this, begin 1G acceleration in a spacecraft and sync its clock to earth, proceed on a looping path and as you fly back by the other clock compare times. I will bet they remain perfectly synched (within reasonable errors for gravity fields and E/M affects), even though the velocity of the spacecraft has changed.

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#68
In reply to #67

Re: GPS and Relativity Misconceptions 1

10/29/2011 3:57 PM

QED

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#69
In reply to #68

Re: GPS and Relativity Misconceptions 1

10/29/2011 4:06 PM

This is the entire problem with your misunderstanding of acceleration and velocity. When an object falls in earth's gravity it is not just traveling at 9.8 m/s, it is "accelerating" at 9.8m/s per second. When a satlillite appraoches apogee it is accelerating due to gravity and when it approaches perigree it is decelerating, i.e. it's velocity changes. It has nothing to do with velocity, it is the acceleration or deceleration which changes the clocks timing, velocity is a byproduct of acceleration. A clock on the equator has a greater acceleration outwards due to centrifugal force than one at the poles. You have misconstrued this acceleration as a velocity aspect as have all others before you. Clocks on planes do not alter time due to velocity, they alter time as they are undergoing acceleration with respect to clocks on the earth, a constant acceleration above and beyond that provided by the centripudal force of clocks on the surface. The time differences of traveling east or west has nothing to do with velocity but acceleration with respect to the direction of the E/M field. Your entire premise is based upon the faulty assumption that velocity changes clocks, velocity has nothing to do with it, it is acceleration that causes this affect. It is not two clocks with different velocities but two clocks with different accelerations with respect to one another. When you can understand this error in your basic thinking, then perhaps your misconception will begin to clear up. Until then there is no sense in going further.

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#70
In reply to #69

Re: GPS and Relativity Misconceptions 1

10/29/2011 5:02 PM

When an object falls in earth's gravity it is not just traveling at 9.8 m/s, it is "accelerating" at 9.8m/s per second.

We all know that. Time is related to velocity. That's what special relativity us all about. Do you think you are smarter than Einstein? Give us all a break and get lost.

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#71
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Re: GPS and Relativity Misconceptions 1

10/29/2011 6:10 PM

Give me a break and wake up to reality, velocity has never changed anything, just acceleration as acceleration mimics the gravitational force. Please, show me one clock that has ever changed that was not under acceleration? That you equate velocity and acceleration as being one and the same thing does not make it so. That you equate the clock changes to velocity and not the acceleration only shows your misconceptions about the differences between the two. At 1G constant acceleration once I adjust my clock for that I no longer need to continually adjust it, even though my relative velocity is continuing to increase. But as I said it is useless as you cannot even understand the difference between velocity and acceleration.

You all have fun lost in your own little reality.

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#72
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Re: GPS and Relativity Misconceptions 1

10/29/2011 11:16 PM

SJW: "Clocks on planes do not alter time due to velocity, they alter time as they are undergoing acceleration with respect to clocks on the earth, a constant acceleration above and beyond that provided by the centripudal force of clocks on the surface."

I suppose you have convincing evidence of this?

Even you mentor (Ronald Hatch, I suppose) will not agree with you...

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#73
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Re: GPS and Relativity Misconceptions 1

10/30/2011 5:56 AM

Don't put words into my mouth, he's not my mentor, just a smarter man than you and I. And I suppose you have evidence it is the velocity and 'NOT" the acceleration? Not fancy math, an actual experiment? No you do not because every test done was done under acceleration. Since planes "must" accelerate to even fly, there is more direct evidence it is the acceleration and not just velocity. Since GPS satellites accelerate at apogee and decelerate at perigee, once again there is more direct evidence it is the acceleration and not just velocity. If they taveled in a perfect circle you would never need adjust them once adjusted for altitude and acceleration to get to velocity. Your velocity calculations just mistakenly apply it to the velocity aspect and not the acceleration aspect. Acceleration in space causes gravity like effects. Velocity alone in space causes nothing. Stop the acceleration and you are instantly weightless even though your velocity has increased from previously. The evidence points to acceleration, not velocity.

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#74
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Re: GPS and Relativity Misconceptions 1

10/30/2011 6:52 AM

Since you maintain that aircraft suffer time dilation (slower clocks) due to acceleration, I suppose you can give us some figures as evidence? Like figures of time lost against acceleration on some flight for which data were published by someone.

This is an extraordinary claim and it will be sensational if you can come up with proof, not just the usual word mincing.

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#75
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Re: GPS and Relativity Misconceptions 1

10/30/2011 12:55 PM

Let me ask you a couple questions and you can answer your own question above. Do clocks slow the more they are affected by gravity? Does velocity alone without acceleration in space produce gravity like effects? Are you suggesting that physics is different in different parts of the universe? Even the calculations you use for time dilation supposedly based upon Lorentz calculations, is not the same formula you use for length contraction, also supposedly based upon Lorentz calculations. Tell me, why do you divide the one and multiply the other if it is the same cause for both actions? Perhaps a little bit of math fudging to make it work? Had you attributed both to the proper cause, acceleration, you would not have to fudge the math. Are you suggesting that a free floating object is space is length contracted? Regardless of its velocity without acceleration an object in space is free falling, at least this is what theory says. How is it that free falling objects are length contracted?

F=M*A without which you do not get V.

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#76
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Re: GPS and Relativity Misconceptions 1

10/30/2011 1:27 PM

I must then conclude that you do not have any evidence for your claims. If you have, you are missing a unique opportunity to make it onto the foreground.

Everything that I presented on this forum is backed up by decades of solid experimental evidence, which I have regularly referred to throughout this Blog. All you have come up with so far is some fairly poor, bordering on cranky references. So, now (again) is the time to put or...

You are wasting your own and our time here.

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#77
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Re: GPS and Relativity Misconceptions 1

10/30/2011 8:08 PM

So tell me, without sidestepping the question. Discounting all gravitational affects, will a clock, let's say A, stationary with respect to the Sun stay in sync with a clock, let's say B, moving at 600,000 mph opposite the Sun's direction around the galaxy?

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#78
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Re: GPS and Relativity Misconceptions 1

10/31/2011 1:18 AM

Ah, positive question with no strings attached.

The short answer is, no they will not stay in sync. But the difference will depend quite a bit on relative to what you specify the 600,000 mph. (Sorry, there are strings attached to the answer )

To make sense of your experiment, you will have to assume that gravity works as normal, but that (hypothetically) it has no effect on clocks. That's because to complete the thought experiment scientifically, you will have to 'orbit' that clock around the galaxy and back to the Sun again. I presume you want to avoid acceleration as well, so you will have to hypothesize a clock that just happen to be flying past the Sun in an opposing direction around the galaxy.

The reason for laboring all this: depending on your relative speed specifications, there actually may or may not be any difference in elapsed time. If the two clocks orbit the galaxy in precisely opposing orbits, their relative speed will be ~1,000,000 mph and there will be no difference. With your 600,000 mph, there is no way they can have even closely opposing orbits and there will be a difference.

The crux is however, you have to get the clocks together again, otherwise you have no unequivocal means of detecting which one actually lost time, if any.

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#79
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Re: GPS and Relativity Misconceptions 1

10/31/2011 2:26 AM

Let's round that to 630 Km/s, does your answer still stand that the clocks will diverge in time?

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#80
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Re: GPS and Relativity Misconceptions 1

10/31/2011 3:03 AM

Read again what I wrote above: "If the two clocks orbit the galaxy in precisely opposing orbits, their relative speed will be ~1,000,000 mph and there will be no difference. With your 600,000 mph, there is no way they can have even closely opposing orbits and there will be a difference."

The same for 630,000 mph, assuming you meant relative to the Sun.

They will diverge, because the Sun is going at about +500,000 mph relative to the Galactic centered inertial frame and the other clock at about 500,000 - 630,000 = -130,000 mph. The latter clock will still orbit the Galaxy, but in a highly elliptical orbit that may perhaps never return to the Sun's vicinity. If it does, you can check the difference easily. Otherwise, you have many problems...

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#81
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Re: GPS and Relativity Misconceptions 1

10/31/2011 1:08 PM

Actually the Sun has been estimated to be traveling anywhere from 552 to 630 km/s around the galactic core. So why the difference? If two satellites in opposite orbits at the same velocity stay in sync, why would two clocks in opposite orbit around the galaxy at the same velocity not stay in sync?Barring any effects from gravitation from stars passed, etc.

The problem is theory says any frame can be taken as stationary and non-rotating, yet there is nothing in the vast universe that is stationary or non-rotating. The very fact that someone thinks they can assume a spot on earth can be stationary and non-rotating shows how faulty the thinking is. This has led to all sorts of errors, like Black Holes, Neutron Stars, Dark Matter, Dark Energy, and the list goes on.

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#82
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Re: GPS and Relativity Misconceptions 1

10/31/2011 2:46 PM

My information says the sun orbits the galaxy at between 217 and 250 km/s, which I took to be about 500,000 mph, but the exact value is irrelevant to the issue, I guess.

"If two satellites in opposite orbits at the same velocity stay in sync, why would two clocks in opposite orbit around the galaxy at the same velocity not stay in sync?"

I don't follow the question. I thought I said clearly that if two clocks orbit the galactic center at the same speed, but opposite directions, they will stay in sync. It is when they have different orbital speeds relative to the center that they will get out of sync.

"The problem is theory says any frame can be taken as stationary and non-rotating, "

No, relativity theory does not say exactly that. It says we can imagine a (non-rotating) inertial frame to move with a point in the rotating frame for a relatively short time. Then we can apply all the relativity principles of an inertial frame to that point, like over a short distance light moves in straight lines and is isotropic at the same speed in all directions. The latter is true because we synchronize the clocks in the inertial frame the Einstein way.

We can do the same even in the presence of gravity. In practice, if the area of interest is small compared to the curvature radius, we can use free falling inertial frames to very good accuracy. Over larger distances, light does not move in straight lines in a rotating frame; hence also not at the same speed in all directions. This also means we cannot synchronize clocks the usual Einstein-way. This is where the Sagnac effect comes into play, but that's the topic of the third 'chapter'.

Since this thread is not about all that other fancy stuff (black holes etc.) you mentioned, I will refrain from comment. I have many other threads on those in this Blog - check the index above.

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#52
In reply to #46

Re: GPS and Relativity Misconceptions 1

10/27/2011 11:44 PM

If you want to discuss Einstein's theories, then post what he said about them - not some quack. All you have proved is that you can't believe all you read on the internet.

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