On Thu, 2011-02-10 at 21:31 -0800, Tom Van Baak wrote:
Magnus Mark Rob,
I know we're getting a bit far from the OP or from leap seconds,
You don't say
-paul
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Since the velocity of the atomic clock causes relativistic dilation,
surely it is not the altitude-above-sea-level, but the radial distance
from the earths axis that we are talking about???
1)
This seems to be a common misunderstanding. Realize that
the relativistic dilation we're talking about
On 10/02/11 16:18, Tom Van Baak wrote:
Since the velocity of the atomic clock causes relativistic dilation,
surely it is not the altitude-above-sea-level, but the radial distance
from the earths axis that we are talking about???
1)
This seems to be a common misunderstanding. Realize that
the
On Thu 2011/02/10 07:18:53 -0800, Tom Van Baak wrote
in a message to: Leap Second Discussion List leapsecs@leapsecond.com
Yes, the radius of the earth is slightly dependent on latitude,
perhaps that's what you're thinking about. But a clock at sea
level at lat 0 will run the same as and a clock
On Fri 2011-02-11T10:01:37 +1100, Mark Calabretta hath writ:
A clock at the equator has a tangential velocity of 500m/s
whereas for one at the pole it is 0m/s. The difference,
The vice-president of IAU Comm 31 posed a question about this at the
General Assembly meeting on 1970-08-19, so this
Oooh! Google Sagnac and you also get lots of trendy pseudoscience from sites
like anti-relativity.com. What fun!
--
On Feb 10, 2011, at 4:01 PM, Mark Calabretta wrote:
On Thu 2011/02/10 07:18:53 -0800, Tom Van Baak wrote
in a message to: Leap Second Discussion List leapsecs@leapsecond.com
On Thu 2011/02/10 16:34:19 PDT, Rob Seaman wrote
in a message to: Leap Second Discussion List leapsecs@leapsecond.com
Unfortunately, Sagnac's experiment has never been performed
accurately enough to discern whether the period of absolute rotation is
the solar day of 24 hours or the
Something else is wrong here too. National UTC timing labs
are all over the world, at a variety of latitudes and altitudes.
No one corrects for latitude as far as I know; only altitude.
Then there's Relativistic Time Shifts for 'Flying Clocks':
On Thu 2011/02/10 21:31:32 -0800, Tom Van Baak wrote
in a message to: Leap Second Discussion List leapsecs@leapsecond.com
A clock at the equator has a tangential velocity of 500m/s
whereas for one at the pole it is 0m/s. The difference,
amounts to about 100ns/day as per your later
On 07/02/11 20:10, Tom Van Baak wrote:
It is also why TAI's rate was adjusted in the 1990's to compensate for
the red-shifted data that had been collected at NIST in Boulder, since
it sits at about 5400' (1700m) above sea level (as well as other
facilities not at sea level).
Warner
Are you
Since the velocity of the atomic clock causes relativistic dilation,
surely it is not the altitude-above-sea-level, but the radial distance
from the earths axis that we are talking about???
I.e. surely both latitude and altitude affect the ceasium? I mean the
velocity of the atomic clock as it
In message 1297295931.7518.8.camel@localhost, Paul Sheer writes:
Since the velocity of the atomic clock causes relativistic dilation,
surely it is not the altitude-above-sea-level, but the radial distance
from the earths axis that we are talking about???
No, the velocity factor (special
On Mon, 7 Feb 2011, Hal Murray wrote:
Doesn't it depend upon gravity (aka sea level)? Is that standardized?
Yes. The SI second is defined independent of any reference frame. The
TAI second is the SI second as realised on the geoid. There are other
timescales that are based on SI seconds in
Doesn't it depend upon gravity (aka sea level)? Is that standardized?
Hal,
Yes and no.
The SI second is defined in the local reference frame. So your
cesium clock at sea level ticks SI seconds for you there. Your
cesium clock on a mountain ticks SI seconds for you there. The
fact that the
On 02/07/2011 10:58, Tom Van Baak wrote:
Now to make a time-scale out of these identical but differing SI
seconds does require some statement of common elevation. So
this is why reported clock data is all adjusted to sea level in the
computation of TAI (and hence UTC).
It is also why TAI's
On 02/07/2011 12:10, Tom Van Baak wrote:
It is also why TAI's rate was adjusted in the 1990's to compensate
for the red-shifted data that had been collected at NIST in Boulder,
since it sits at about 5400' (1700m) above sea level (as well as
other facilities not at sea level).
Warner
Are
On Mon 2011-02-07T14:39:10 -0700, Warner Losh hath writ:
Are you sure you aren't confusing red shift (which has been
a known factor since the 60's) with blackbody shift (which
only arose in the 90's as clocks hit the 1e-15 level)?
I may well be confused between the two...
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