Re: [time-nuts] The GPS velocity of light versus neutrinos
Has anyone measured the speed of light with GPS clocks in the same way that
neutrinos are measured - say between mountain tops?
I'm pretty sure that won't work very well. The problem is that air isn't
vacuum. The index of refraction changes slightly with temperature.
The subtle changes in the index of refraction are what causes mirages.
The San Andreas fault (and friends) runs right down the middle of Silicon
Valley. The USGS has a big research group here. There are two convenient
mountains.
They used to do laser ranging between the mountain tops to track the fault
motions. In order to get good data, they had to run a helicopter along the
beam to measure the air temperature. (Maybe they also measured other things
like humidity. ??) I don't remember where I heard that story. It was a
long time ago.
These days, the USGS uses GPS. They don't need mountain tops. It's not
uncommon to see them slightly off a highway.
Maybe I'll remember to ask more at their next open house.
For anybody in the area... The next open house in Menlo Park is May 19+20,
2012.
http://openhouse.wr.usgs.gov/2012/index.html
They have them every 3 years. Kids welcome. I always have fun.
--
These are my opinions, not necessarily my employer's. I hate spam.
It an awful long time since I did nuclear physics....back then the neutrino
was massless and the standard model didn't exist. There were some "way-out"
models being proposed.....smokey globe!!
A couple of things occur to me....they dont actually measure the time
outgoing of the neutrinos...they infer it.
You can't measure anything with out perturturbing it in some way, even
slightly....then there is the Uncertainly Principle ....if they measure the
speed how do they know where they were.
Ah well (sigh) I suppose far younger brains that mine have taken all this
into account.
I will go back to saving string(s) you never know when it will be useful
:-))
Alan
G3NYK
----- Original Message -----
From: "Hal Murray" hmurray@megapathdsl.net
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Monday, November 21, 2011 9:06 PM
Subject: Re: [time-nuts] The GPS velocity of light versus neutrinos
Has anyone measured the speed of light with GPS clocks in the same way
that
neutrinos are measured - say between mountain tops?
I'm pretty sure that won't work very well. The problem is that air isn't
vacuum. The index of refraction changes slightly with temperature.
The subtle changes in the index of refraction are what causes mirages.
The San Andreas fault (and friends) runs right down the middle of Silicon
Valley. The USGS has a big research group here. There are two convenient
mountains.
They used to do laser ranging between the mountain tops to track the fault
motions. In order to get good data, they had to run a helicopter along
the
beam to measure the air temperature. (Maybe they also measured other
things
like humidity. ??) I don't remember where I heard that story. It was a
long time ago.
These days, the USGS uses GPS. They don't need mountain tops. It's not
uncommon to see them slightly off a highway.
Maybe I'll remember to ask more at their next open house.
For anybody in the area... The next open house in Menlo Park is May
19+20,
http://openhouse.wr.usgs.gov/2012/index.html
They have them every 3 years. Kids welcome. I always have fun.
--
These are my opinions, not necessarily my employer's. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
On Mon, Nov 21, 2011 at 4:08 PM, Alan Melia alan.melia@btinternet.com wrote:
You can't measure anything with out perturturbing it in some way, even
slightly....then there is the Uncertainly Principle ....if they measure the
speed how do they know where they were.
OK, So assume an unlikely huge position uncertainly of one meter. On top of
that let's assume the surveyor got it wrong too and missed by a full
meter. Both of these added together can only account for about 10%
of what they saw. Light moves across one meter in about 3nS You
need to explain 60nS If the result is because of uncertainty in the
location then the we are talking about 20 meters of position error.
Chris Albertson
Redondo Beach, California
Hi
You can have a surveyor come out and locate your gizmo to sub one inch accuracy for a lot less than a clock trip costs. A one meter ( or 3 ns) error would be pretty large these days. Both have been demonstrated / proven so often that they aren't really open to challenge.
The total error is a sum of lots of things. Location and time of day are the easy stuff...
Bob
On Nov 21, 2011, at 7:27 PM, Chris Albertson albertson.chris@gmail.com wrote:
On Mon, Nov 21, 2011 at 4:08 PM, Alan Melia alan.melia@btinternet.com wrote:
You can't measure anything with out perturturbing it in some way, even
slightly....then there is the Uncertainly Principle ....if they measure the
speed how do they know where they were.
OK, So assume an unlikely huge position uncertainly of one meter. On top of
that let's assume the surveyor got it wrong too and missed by a full
meter. Both of these added together can only account for about 10%
of what they saw. Light moves across one meter in about 3nS You
need to explain 60nS If the result is because of uncertainty in the
location then the we are talking about 20 meters of position error.
Chris Albertson
Redondo Beach, California
time-nuts mailing list -- time-nuts@febo.com
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On 11/21/11 5:15 PM, Bob Camp wrote:
Hi
You can have a surveyor come out and locate your gizmo to sub one inch accuracy for a lot less than a clock trip costs. A one meter ( or 3 ns) error would be pretty large these days. Both have been demonstrated / proven so often that they aren't really open to challenge.
The total error is a sum of lots of things. Location and time of day are the easy stuff...
OK, So assume an unlikely huge position uncertainly of one meter. On top of
that let's assume the surveyor got it wrong too and missed by a full
meter. Both of these added together can only account for about 10%
of what they saw. Light moves across one meter in about 3nS You
need to explain 60nS If the result is because of uncertainty in the
location then the we are talking about 20 meters of position error.
in the first paper, the distance uncertainty was given as 20cm
You guys missed my point. I did not mean that survey and timing errors are
so large What I meant was that even if you assume unreasonably large
errors (like a surveyor being off by a full meter) you still don't get
60nS.
If I were to bet money, still I'd bet on some experimental error. That is
the safe bet. But I'd sure be happy to loose
On Mon, Nov 21, 2011 at 7:57 PM, Jim Lux jimlux@earthlink.net wrote:
On 11/21/11 5:15 PM, Bob Camp wrote:
Hi
You can have a surveyor come out and locate your gizmo to sub one inch
accuracy for a lot less than a clock trip costs. A one meter ( or 3 ns)
error would be pretty large these days. Both have been demonstrated /
proven so often that they aren't really open to challenge.
The total error is a sum of lots of things. Location and time of day are
the easy stuff...
OK, So assume an unlikely huge position uncertainly of one meter. On
top of
that let's assume the surveyor got it wrong too and missed by a full
meter. Both of these added together can only account for about 10%
of what they saw. Light moves across one meter in about 3nS You
need to explain 60nS If the result is because of uncertainty in the
location then the we are talking about 20 meters of position error.
in the first paper, the distance uncertainty was given as 20cm
_____________**
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Chris Albertson
Redondo Beach, California
On 11/21/11 9:05 PM, Chris Albertson wrote:
You guys missed my point. I did not mean that survey and timing errors are
so large What I meant was that even if you assume unreasonably large
errors (like a surveyor being off by a full meter) you still don't get
60nS.
If I were to bet money, still I'd bet on some experimental error. That is
the safe bet. But I'd sure be happy to loose
Ah yes.. even an obvious egregious screwup in the time or distance
measurement still wouldn't account for the relatively huge difference
that's been observed.
I don't know about experimental error (in the sense of measurement
uncertainty)..
I'd go for some unexpected systematic error or factor unaccounted for.
(naturally, that "unaccounted for factor" might be that neutrinos don't
happen to follow gen'l relativity)
On Nov 21, 2011, at 10:57 PM, Jim Lux wrote:
On 11/21/11 5:15 PM, Bob Camp wrote:
Hi
You can have a surveyor come out and locate your gizmo to sub one inch accuracy for a lot less than a clock trip costs. A one meter ( or 3 ns) error would be pretty large these days. Both have been demonstrated / proven so often that they aren't really open to challenge.
The total error is a sum of lots of things. Location and time of day are the easy stuff...
OK, So assume an unlikely huge position uncertainly of one meter. On top of
that let's assume the surveyor got it wrong too and missed by a full
meter. Both of these added together can only account for about 10%
of what they saw. Light moves across one meter in about 3nS You
need to explain 60nS If the result is because of uncertainty in the
location then the we are talking about 20 meters of position error.
in the first paper, the distance uncertainty was given as 20cm
Of which the survey likely contributed next to nothing and stuff like earth tides contributed the majority of the error ….
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On Tue, Nov 22, 2011 at 3:17 PM, Bob Camp lists@rtty.us wrote:
in the first paper, the distance uncertainty was given as 20cm
Of which the survey likely contributed next to nothing and stuff like earth tides contributed the majority of the error ….
See http://operaweb.lngs.infn.it/Opera/publicnotes/note132.pdf
I think most of the uncertainty came from the non-GPS survey. They had
to stop traffic in the highway (OPERA is in a cavern at an exit of the
highway inside of a tunnel) but they could only close one lane. So
bureaucracy is a more plausible answer :)
Javier
Hi
Earth tides and even more un-stoppable events like politics …
Bob
On Nov 22, 2011, at 1:28 PM, Javier Serrano wrote:
On Tue, Nov 22, 2011 at 3:17 PM, Bob Camp lists@rtty.us wrote:
in the first paper, the distance uncertainty was given as 20cm
Of which the survey likely contributed next to nothing and stuff like earth tides contributed the majority of the error ….
See http://operaweb.lngs.infn.it/Opera/publicnotes/note132.pdf
I think most of the uncertainty came from the non-GPS survey. They had
to stop traffic in the highway (OPERA is in a cavern at an exit of the
highway inside of a tunnel) but they could only close one lane. So
bureaucracy is a more plausible answer :)
Javier
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