Hi Tom,
Based on mass and radius, a clock here on Earth ticks about 6.969e-10
slower than it would at infinity. The correction drops roughly as 1/R below
sea level and 1/R² above sea level. For practical and historical reasons we
define the SI second at sea level.
Yes, the change in clock
You people are evil. Now you have me wondering where I can get a microgram
level accurate scale. Simply tracking the weight of a 'constant' (anyone
got a silicon sphere with exactly 1 mole of Si atoms in it? :)) over time
would be an interesting experiment.
As a geologist, I also have to say,
pmo...@gmail.com said:
Let me rephrase what I'm after. The geoidal uncertainty sets a hard limit
on clock comparison performance on the Earth's surface (for widely-spaced
clocks). At some point, as Chris Albertson noted, the clocks will measure
the potential and not the other way around.
I wish I could take the credit for being evil here, but no.
What the natural consequence is that every atomic clock of this type
should have a gravitational sensor that compensates for gravitational
shift, as it now has become a frequency shift component. The first
degree compensation should
On Mon, 3 Nov 2014 11:54:41 -0800
Peter Monta pmo...@gmail.com wrote:
Sorry if this is a bit off-topic. I'd like a simple, clear explanation for
the layman that drills down on exactly how the current definitional scheme
can be realized to arbitrary precision. For example, assume that we must
But won't the doppler effect change as the Cs atoms fall down the gravity
well? :)
On Tue, Nov 4, 2014 at 3:14 PM, Attila Kinali att...@kinali.ch wrote:
On Mon, 3 Nov 2014 11:54:41 -0800
Peter Monta pmo...@gmail.com wrote:
Sorry if this is a bit off-topic. I'd like a simple, clear
On Tue, 4 Nov 2014 11:04:58 -0800
Peter Monta pmo...@gmail.com wrote:
Let me rephrase what I'm after. The geoidal uncertainty sets a hard limit
on clock comparison performance on the Earth's surface (for widely-spaced
clocks). At some point, as Chris Albertson noted, the clocks will measure
Story I heard this morning
The highest accessible peak in the Adirondacks I think would be
Whiteface at 4,867 ft, though that would be by ski lift and not all the
way to the top. The highest point accessible by car in the Northeast
would be Mt. Washington here in New Hampshire at 6288 ft. Hmm
Lester Veenstra lester at veenstras.com Tue Nov 4 16:56:29 EST 2014 wrote:
And you can get a I climbed Mt. Washington sticker for your clock.
+++
It may be a little OT but I actually worked on the summit for the
Mount Washington Weather Observatory for 4 winters as well as climbing
This morning, as I was driving to work,
I heard this really cool story on NPR radio here in NYC.
This is the link to the story:
http://www.npr.org/2014/11/03/361069820/what-time-is-it-it-depends-where-you-are-in-the-universe
What a nice way to start the week.
Past stories with similar
Yes, A story about time and frequency standards. They actually used
numbers like 10E16 in the story. Apparently at that level your clock can
measure a change in elevation of a few centimeters because of the
relativistic effects of the reduced gravity field in just a few cm.
On Mon, Nov 3, 2014
Small correction: The numbers were 10E-16.
One important concept that was discussed was this:
If the next generation clock was even more accurate
(maybe by an order or two), then no two clocks
can ever agree on the time.
Minute changes in gravity and other factors will
always make each clock
Have you read Tom's story about his family trip up Mount Ranier with a Cesium
clock?
Project GREAT: General Relativity Einstein/Essen Anniversary Test
Bob
From: xaos x...@darksmile.net
To: time-nuts@febo.com
Sent: Monday, November 3, 2014 10:17 AM
Subject: Re: [time-nuts] NPR Story I
Anniversary Test
Bob
From: xaos x...@darksmile.net
To: time-nuts@febo.com
Sent: Monday, November 3, 2014 10:17 AM
Subject: Re: [time-nuts] NPR Story I heard this morning
Small correction: The numbers were 10E-16.
One important concept that was discussed was this:
If the next
On Mon, Nov 3, 2014 at 8:17 AM, xaos x...@darksmile.net wrote:
Small correction: The numbers were 10E-16.
No I think it was one part in 10E16 ;) But the interesting thing was
they used numbers rather then saying something like really super ultra
tiny.
But you are right, no two clocks will
x...@darksmile.net said:
I was planning a similar trip from Astoria Queens, NYC which is sea level,
to Adirondack Mountains, upstate New York.
You will need clocks that are better than Tom's. :)
He parked at 5,000 feet. Do any roads go that high in the Adirondacks? How
high can you park?
In a normal car, bring a generator. Using a big 6 cyl. engine to drive a
tiny 20 amp alternator is not so good. And that alternator is not designed
to run 24x7 at full load.The Prius is on the other hand a very good
generator and with some add on equipment can power your house. The Prius
albertson.ch...@gmail.com said:
But you are right, no two clocks will ever agree at that level because they
will experience different gravitational fields.
What if I adjust the elevation (aka gravity) of one of them until it matches?
Or at least gets within the resolution and ADEV of the
Why Strontium over Caesium?
Is it because it just sounds more hi-tech ? LOL
Maybe stupid question to most here, but I do
not know the answer.
-GKH
On 11/03/2014 12:59 PM, Chris Albertson wrote:
On Mon, Nov 3, 2014 at 8:17 AM, xaos x...@darksmile.net wrote:
Small correction: The numbers were
It's surprisingly large. I have a scale that can measure 20g down to a
microgram (and worked on one that can do a gram at nanogram resolution).
Taking the microgram scale up one floor in a building was easily detectable...
I don't remember the exact number but it think it was in the 1
Found it on page 17 of Mettler's excellent article:
Adverse Influences and Their Prevention in Weighing
http://us.mt.com/dam/mt_ext_files/Editorial/Generic/2/Weigh_Uncertain_Number1_0x0003d6750003db6700091746_files/adverse_influences.pdf
It works out to be -0.3 ppm/meter.
Chris Albertson writes:
But you are right, no two clocks will ever agree at that level because they
will experience different gravitational fields. At this level the reason
to have a clock is no longer to tell time. It is to measure the
gravitational field.
I have a question about
On Mon, Nov 3, 2014 at 10:15 AM, Hal Murray hmur...@megapathdsl.net wrote:
albertson.ch...@gmail.com said:
But you are right, no two clocks will ever agree at that level because
they
will experience different gravitational fields.
What if I adjust the elevation (aka gravity) of one of
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Yes, A story about time and frequency standards. They actually used
numbers like 10E16 in the story. Apparently at that level your clock can
measure a change in elevation of a few centimeters because of the
relativistic effects of the reduced gravity field in just a few cm.
Hi Chris,
.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak
Sent: Monday, November 03, 2014 3:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] NPR Story I
The highest accessible peak in the Adirondacks I think would be
Whiteface at 4,867 ft, though that would be by ski lift and not all the
way to the top. The highest point accessible by car in the Northeast
would be Mt. Washington here in New Hampshire at 6288 ft. Hmm...
David
On 11/3/14
On Mon, Nov 3, 2014 at 1:18 PM, Mike Feher mfe...@eozinc.com wrote:
Anyway, regarding time and gravity, I certainly believe the mathematics of
Einstein and others, however, I have a hard time believing that man-made
instruments to measure the effects of gravity on time is valid. For example
I have a question about that. If I understand correctly, recent IAU
resolutions have decoupled the definition of the SI second from the
terrestrial geoid, which is too fuzzy to be used for a definition. Instead
the geoid potential is held fixed by (or defined by) a constant. Potential
with
, 2014 1:07 PM
Subject: Re: [time-nuts] NPR Story I heard this morning
The highest accessible peak in the Adirondacks I think would be
Whiteface at 4,867 ft, though that would be by ski lift and not all the
way to the top. The highest point accessible by car in the Northeast
would be Mt
On 11/3/2014 3:54 PM, Tom Van Baak wrote:
When it comes to frequency standards the official SI second is
defined only for sea level. We know time and frequency are bent by
speed or gravity;
According to the BIPM: At its 1997 meeting the CIPM affirmed that:
This definition refers to a caesium
, November 03, 2014 1:07 PM
Subject: Re: [time-nuts] NPR Story I heard this morning
The highest accessible peak in the Adirondacks I think would be
Whiteface at 4,867 ft, though that would be by ski lift and not all the
way to the top. The highest point accessible by car in the Northeast
would
I don't see anything in the BIPM definition of the second regarding sea level.
Hi Mike,
The usual wording for the definition of the SI second also includes the word
unperturbed. That little word covers a host of physics and engineering
effects and can keep graduate students busy for years.
Not to put too fine a point on it, but my practical understanding is that
any two or more clocks generally do *not* agree (that is - yield identical
phase/frequency information) ever, anyway. So atomic horology - and beyond
- means that we continue to ?adjust? ?compensate? clocks of whatever
, November 03, 2014 2:52 PM
Subject: Re: [time-nuts] NPR Story I heard this morning
Not to put too fine a point on it, but my practical understanding is that any
two or more clocks generally do *not* agree (that is - yield identical
phase/frequency information) ever, anyway. So atomic
Because for optical clocks Strontium is better suited than Caesium.
Caesium was at one time judged as the best suited for atomic beam
designs, but is not considered the best for fountain clocks, since
caesium has larger cross-section than rubidium, so the effect of
collisions becomes larger.
(I noticed earlier in the thread, folks writing 10E-16 when I think they
meant 1E-16, at least based on the Fortran notation I learned a long time
ago. I am living proof, that a good Fortran programmer can write spaghetti
code in any language!)
On time quantization:
Planck Time is 3.59E-44
On 11/3/14, 1:50 PM, Tom Van Baak wrote:
I have a question about that. If I understand correctly, recent IAU
resolutions have decoupled the definition of the SI second from the
terrestrial geoid, which is too fuzzy to be used for a definition. Instead
the geoid potential is held fixed by (or
On Tue, Nov 4, 2014 at 4:28 AM, Tim Shoppa tsho...@gmail.com wrote:
(I noticed earlier in the thread, folks writing 10E-16 when I think they
meant 1E-16, at least based on the Fortran notation I learned a long time
ago. I am living proof, that a good Fortran programmer can write spaghetti
39 matches
Mail list logo
