International Terrestrial Reference Frame

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MrKappa

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  • Math abstracts reality... it does not create it...
International Terrestrial Reference Frame
« on: September 30, 2008, 07:31:35 PM »
The International Terrestrial Reference frame is a system which calibrates the earth to a fixed point in space.

Recently they have calibrated the system to Geo-Center as opposed to calibrating it to stellar objects. This apparently has led to the conclusion that the earth is 5mm smaller than previously thought.

Here is some of the raw data.

http://itrf.ensg.ign.fr/doc_ITRF/egu2007/Altamimi-egu_070417.pdf

Some people suggest the oscillations are evidence of seasonal thermal expansion. I would be interested in anyones thoughts on this subject.

Is this evidence for a round earth?

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trig

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Re: International Terrestrial Reference Frame
« Reply #1 on: September 30, 2008, 08:02:59 PM »
This is easily attributable to the Conspiracy. They will close their eyes and see only the fact that they cannot reproduce the experiment themselves, even though they have several experiments they can do and they do not dedicate a few hours and maybe a few dollars to do them.

This is the intellectual dishonesty you will find in most of the "Flat Earthers", who will not try to learn from anyone else, just find excuses.

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MrKappa

  • 448
  • Math abstracts reality... it does not create it...
Re: International Terrestrial Reference Frame
« Reply #2 on: September 30, 2008, 09:34:55 PM »
This is easily attributable to the Conspiracy. They will close their eyes and see only the fact that they cannot reproduce the experiment themselves, even though they have several experiments they can do and they do not dedicate a few hours and maybe a few dollars to do them.

This is the intellectual dishonesty you will find in most of the "Flat Earthers", who will not try to learn from anyone else, just find excuses.

I am more interested in the mechanics of how it works rather than if it is a conspiracy or not.

My main concern is how the system is calibrated. It would appear that they use fixed point on the surface of the earth to find a zero reference frame and from that they measure fixed points on the earth.

It is circular logic at first look and to tell you the truth I was under the impression it was calibrated to stellar objects. Which would actually make more sense to me.

Am I wrong to scrutinize this?

They are continually rolling out new specifications for the system. How can anyone make any sort of accurate conclusion if the actual measurement itself is continually changing.

This looks like scalar logic... Scale the system to meet the requirements of what you believe to be the correct answer. For anything accurate to arise from a measurement. The scale itself should remain the same from one year to the next. Correct?

For example...

1992 1 meter = 1 meters...

1993 1 meter = .97 meters...

1994 1 meter = 1.23 meters...

Is this not destined to continually lose accuracy the more it is changed. Why do they need to roll out constant revisions? It does not make sense to me since it should be calibrated to external objects rather than a dynamic object which itself is the object being measured.

If I am wrong... I will accept your reason as to why.




ADDITION... My Mistake... I have been at war with zealots who are using things they do not understand to prove something they believe to be correct... The ITRF is nothing without the The International Celestial Reference System: ICRS


Does anybody know anything about this system?

http://hpiers.obspm.fr/webiers/

http://hpiers.obspm.fr/eop-pc/
« Last Edit: September 30, 2008, 10:28:24 PM by MrKappa »

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trig

  • 2240
Re: International Terrestrial Reference Frame
« Reply #3 on: October 01, 2008, 08:27:36 AM »
In almost every aspect of science you will find the same phenomenon: as measurements become better, the reference standards have to be redefined. In 400 years we have passed from the "simple" realization that we are not in the center of the universe to the point where we can measure the position of the moon to within a few centimeters.

In my lifetime we have passed from the point where any milestone was good enough as a reference to the point where you can see every milestone moving due to plate tectonics. We passed from the time when the rotation of Earth was a good enough standard for time to the current situation where we know to a few milliseconds the true length of a rotation of Earth.

As soon as the cyclical characteristic of these measurements becomes predictable, a new reference frame will be introduced. This is just how science works.

Re: International Terrestrial Reference Frame
« Reply #4 on: October 02, 2008, 02:01:16 AM »
This looks like scalar logic... Scale the system to meet the requirements of what you believe to be the correct answer. For anything accurate to arise from a measurement. The scale itself should remain the same from one year to the next. Correct?

For example...

1992 1 meter = 1 meters...

1993 1 meter = .97 meters...

1994 1 meter = 1.23 meters...

Is this not destined to continually lose accuracy the more it is changed. Why do they need to roll out constant revisions? It does not make sense to me since it should be calibrated to external objects rather than a dynamic object which itself is the object being measured.

I am not sure what you are referring to.  The definition of a meter has been consistent since 1983...

Quote
The definition states that the meter is the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second. The speed of light is

c = 299,792,458 m/s

The second is determined to an uncertainty, U = 1 part in 1014 by the Cesium clock. The General Conference made the iodine stabilized Helium-Neon laser a recommended radiation for realizing the meter at this time. The wavelength of this laser is

λHeNe = 632.99139822 nm

with an estimated relative standard uncertainty (U) of 2.5 x 10−11.

In all of these changes in definition, the goal was not only to improve the precision of the definition, but also to change its actual length as little as possible.

Based on that, I don't see the length of a meter changing by the degree that you are suggesting.  I went to the websites that you linked and I couldn't find any evidence of that either.  Do you have a reference for that?

If I am wrong... I will accept your reason as to why.


Quote
Does anybody know anything about this system?

I have only heard of the system in passing.  For normal work requiring 0.1 meter accuracy, it doesn't come into play.  This level of accuracy seems to only come into play if you are taking things that move millimeters per year, or even less.  I could be mistaken though.  It is something that is only at the periphery of my job where we deal with correcting for datums and such.