Why we need to keep adding leap seconds

Why we need to keep adding leap seconds
http://phys.org/news/2015-07-adding-seconds.html

The length of the solar day – or the time it actually takes the Earth
to complete a rotation – is no longer precisely as long as a standard
day, and it has not been for a century. This is because the Earth's
rotation continues to slow.

The main reason it's lagging is tidal friction from the Moon, which
by itself would increase the length of the day by 2.3 milliseconds
each century.

However, other geological process on Earth that shift mass around
will also have an effect on the rotation rate, since the system mus
conserve its total angular momentum. This can end up increasing the
Earth's rotation rate as well as decreasing it.

For example, the 2005 earthquake in Indonesia that caused the tsunami
also decreased the length of the day by 2.68 microseconds.

So we have to keep adding leap seconds to keep the time of noon at
Greenwich (Greenwich Mean Time) in line with noon as measured by the
atomic clock (International Atomic Time). This guarantees that the
solar time (the rise and fall of the sun) doesn't fall too far out of
sync with our clocks.

Taking time

The task of adding these seconds was initially taken on by the Bureau
International de l'Heure, the executive body of the International
Commission of Time, which itself was part of the International
Astronomical Union (IAU).

In 1987 the IAU created a new organisation, the International Earth
Rotation and Reference Systems Service (IERS). And from 1st January
1988, it became responsible for the leap second.

The leap second itself is an irregular occurrence. Between 1990 and
1999 there were seven leap seconds added. Yet between 2000 and 2009,
only two extra seconds were added. In fact, it is so irregular that
leap seconds are only announced by the IERS six months in advance.


Read more at: http://phys.org/news/2015-07-adding-seconds.html#jCp

On Friday, July 3, 2015 at 3:45:25 AM UTC+1, Sam Wormley wrote:
Why we need to keep adding leap seconds
http://phys.org/news/2015-07-adding-seconds.html

The length of the solar day - or the time it actually takes the Earth
to complete a rotation - is no longer precisely as long as a standard
day, and it has not been for a century. This is because the Earth's
rotation continues to slow.


A few days ago you insisted that the Earth is into the next full rotation after 23 hours 56 minutes 04 seconds

On Thursday, July 2, 2015 at 8:45:25 PM UTC-6, Sam Wormley wrote:

Read more at: http://phys.org/news/2015-07-adding-seconds.html#jCp

The article does not note, though, that when the time was switched to atomic
time, the _current_ length of the day was not used as the basis. Instead, an
existing uniform time scale, Ephemeris Time, was used as the model (which,
incidentally, also gave the length of the SI second) and thus the length of the
second back in the 19th Century was used for the atomic second.

John Savard

On Fri, 3 Jul 2015 05:33:37 -0700 (PDT), Quadibloc
wrote:
On Thursday, July 2, 2015 at 8:45:25 PM UTC-6, Sam Wormley wrote:
Read more at:
http://phys.org/news/2015-07-adding-seconds.html#jCp
The article does not note, though, that when the time was switched
to atomic
time, the _current_ length of the day was not used as the basis.
Instead, an
existing uniform time scale, Ephemeris Time, was used as the model
(which,
incidentally, also gave the length of the SI second) and thus the
length of the
second back in the 19th Century was used for the atomic second.
John Savard

That's the normal way of changing standards: The difference between
the old and the new standards skall be too small to measure with the
precision of the old standard.

On Friday, July 3, 2015 at 3:45:25 AM UTC+1, Sam Wormley wrote:
Why we need to keep adding leap seconds
http://phys.org/news/2015-07-adding-seconds.html

The length of the solar day - or the time it actually takes the Earth
to complete a rotation - is no longer precisely as long as a standard
day, and it has not been for a century. This is because the Earth's
rotation continues to slow.


The invention of the fictional 'solar time/solar day' was to make a comparison with 'sidereal time' and that owes its existence to the exceptionally disruptive conclusion drawn by John Flamsteed using stellar circumpolar motion,a watch and the 24 hour day. The lousy attempt is now to divorce 'sidereal time' altogether from its origins in all those hideous graphics -

http://www.astronomy.ohio-state.edu/...s/sidereal.gif


The 24 hour system and the Lat/Long system are bound not only to each other but also to the Earth's geometry organized around the planet's rotational characteristics so it is impossible to change the incremental value which tie 1 degree of geographical separation from 4 minutes of timekeeping.

The story of timekeeping from the second to the minute to the hour to the 24 hour day involved the parent observation that defines the Earth's orbital position in space using the number of rotations to return the Earth to that position. It is either vandalism,thuggery or both that conjures up the poor narrative of relating a second of timekeeping with a 'slowing Earth' and far worse than the Middle Eastern thugs who try to destroy an ancient heritage for self-serving ends.

It should be a honor to be in the presence of the great astronomers who first created the first leap correction where timekeeping merges with the daily and orbital cycles but unfortunately men choose to make fools of themselves by ignoring the principles and external references on which all timekeeping is founded.

On 03/07/2015 14:44, Paul Schlyter wrote:
On Fri, 3 Jul 2015 05:33:37 -0700 (PDT), Quadibloc
wrote:
On Thursday, July 2, 2015 at 8:45:25 PM UTC-6, Sam Wormley wrote:
Read more at:
http://phys.org/news/2015-07-adding-seconds.html#jCp
The article does not note, though, that when the time was switched
to atomic
time, the _current_ length of the day was not used as the basis.
Instead, an
existing uniform time scale, Ephemeris Time, was used as the model
(which,
incidentally, also gave the length of the SI second) and thus the
length of the
second back in the 19th Century was used for the atomic second.
John Savard

That's the normal way of changing standards: The difference between the
old and the new standards skall be too small to measure with the
precision of the old standard.

The alternative approach in geochronology is to accept that the old
standard value is wrong but keep everything referenced to that standard
value (good to 4 sig fig) whereas modern kit can measure to 6 sig fig
with suitable samples. The ration for 146/144 is a constant on Earth.

Nd146/Nd144 = 0.7219 is by convention to keep all results comparable.

The other isotopes form a radioactive clock used for dating.

http://quake.mit.edu/hilstgroup/MIT-...Patchett04.pdf

It is a bit embarrassing plotting speed of light with error bars as a
function of time. Several different methods got very precise but
systematically inaccurate answers that were not spotted as flawed until
later when the next even better experimental technique came along.

ISTR one involved a simple mistake applying a correction for phase
velocity to correct for imperfect vacuum applied with the wrong sign.
The experimentalist was so highly regarded that people following his
technique and refining it made the same basic mistake.

I recall the annotated graph was in an elementary or undergraduate
relativity text but the title escapes me and I don't own a copy.
(if someone recognises it from this description I'd like a scan)

--
Regards,
Martin Brown

On Friday, July 3, 2015 at 5:12:41 PM UTC+1, Martin Brown wrote:

Voodoo and bluffing that can be found anywhere and no doubt will continue.

For those really wishing to find themselves in the presence of astronomers and astronomy, they can consider the original event from which all human timekeeping radiates -

".. on account of the procession of the rising of Sirius by one day in the course of 4 years,.. therefore it shall be, that the year of 360 days and the 5 days added to their end, so one day shall be from this day after every 4 years added to the 5 epagomenae before the new year" Canopus Decree 238 BC

The trick is to ignore the rising and setting of the stars above and below the local horizon and switch perspective to the line-of-sight observation where the stars move in sequence behind the central Sun and its glare -

https://www.youtube.com/watch?v=eeQwYrfmvoQ

Defining the Earth's orbital position in space using the first appearance of Sirius far enough to be seen at dawn one day uses rotations as a guide and all the nonsense of atomic clocks is not going to obscure this great astronomical fact where timekeeping and cyclical dynamics merge to a close approximation.

Sad to say it is a matter of competence.

On Fri, 3 Jul 2015 09:22:59 -0700 (PDT), oriel36
wrote this crap:

On Friday, July 3, 2015 at 5:12:41 PM UTC+1, Martin Brown wrote:

Voodoo and bluffing that can be found anywhere and no
doubt will continue.

For those really wishing to find themselves in the presence
of astronomers and astronomy, they can consider the
original event from which all human timekeeping radiates -

".. on account of the procession of the rising of Sirius by one
day in the course of 4 years,.. therefore it shall be, that the
year of 360 days and the 5 days added to their end, so one
day shall be from this day after every 4 years added to
the 5 epagomenae before the new year" Canopus Decree 238 BC

The trick is to ignore the rising and setting of the stars above
and below the local horizon and switch perspective to the line-of-sight
observation where the stars move in sequence behind the
central Sun and its glare -


Defining the Earth's orbital position in space using the first
appearance of Sirius far enough to be seen at dawn one day
uses rotations as a guide and all the nonsense of atomic clocks
is not going to obscure this great astronomical fact where
timekeeping and cyclical dynamics merge to a close approximation.

I think you should bring this matter to Star Fleet and suggest the
probable corrections. Commander Data should be of great help. I'm
sure nothing is of more importance to them. Make it so!




This signature is now the ultimate
power in the universe

Once the Earth's orbital position was locked in to a close approximation using the number of natural noon cycles as a gauge with the additional rotation sealing the proportion between rotations and orbital circuits, the next process was equalizing the observed variations in each of those daily cycles to a 24 hour average.

The key to it all is the use and substitution of the terms 'average' for 'constant' for both share a common meaning. The average 24 hour day substitutes for constant rotation via the Lat/Long system hence an inviolate correspondence between planetary geometry,timekeeping and rotation.


The most important adjustment is switching the older idea of the Sun's motion through the background field of stars to the essential line-of-sight observation that the stars progress behind the Sun due to the orbital motion of the Earth.

https://www.youtube.com/watch?v=MdFrE7hWj0A


It is here that the flaws show up with the original proposals which merge timekeeping with the daily and orbital cycles and especially as Huygens relates it -

"Here take notice, that the Sun or the Earth passeth the 12. Signes,
or makes an entire revolution in the Ecliptick in 365 days, 5 hours 49
min. or there about, and that those days, reckon'd from noon to noon,
are of different lenghts; as is known to all that are vers'd in
Astronomy. Now between the longest and the shortest of those days, a
day may be taken of such a length, as 365 such days, 5. hours &c. (the
same numbers as before) make up, or are equall to that revolution: And
this is call'd the Equal or Mean day, according to which the Watches
are to be set;." Huygens

The Equation of Time and therefore the average 24 hour day relies on gauging the Earth's cycles,including the planet's orbital circumference, using full rotations . It is all safe in my hands regardless as to whether readers believe that the Earth turns once each 24 hour day or not.

On Friday, July 3, 2015 at 8:50:24 PM UTC+1, Lord Vath wrote:
On Fri, 3 Jul 2015 09:22:59 -0700 (PDT), oriel36
wrote this crap:

On Friday, July 3, 2015 at 5:12:41 PM UTC+1, Martin Brown wrote:

Voodoo and bluffing that can be found anywhere and no
doubt will continue.

For those really wishing to find themselves in the presence
of astronomers and astronomy, they can consider the
original event from which all human timekeeping radiates -

".. on account of the procession of the rising of Sirius by one
day in the course of 4 years,.. therefore it shall be, that the
year of 360 days and the 5 days added to their end, so one
day shall be from this day after every 4 years added to
the 5 epagomenae before the new year" Canopus Decree 238 BC

The trick is to ignore the rising and setting of the stars above
and below the local horizon and switch perspective to the line-of-sight
observation where the stars move in sequence behind the
central Sun and its glare -


Defining the Earth's orbital position in space using the first
appearance of Sirius far enough to be seen at dawn one day
uses rotations as a guide and all the nonsense of atomic clocks
is not going to obscure this great astronomical fact where
timekeeping and cyclical dynamics merge to a close approximation.

I think you should bring this matter to Star Fleet and suggest the
probable corrections. Commander Data should be of great help. I'm
sure nothing is of more importance to them. Make it so!




This signature is now the ultimate
power in the universe

There are a bunch of middle Eastern military thugs taking sledgehammers to the ancient structures in the city of Palmyra presently as they see nothing only the propagation of their own agenda to the exclusion of everything else. Like you,they are unable to see the importance of a heritage as it fits in with the development of human civilization and all the more dismaying as the Western version of attempting to destroy the links between timekeeping and the great motions of the Earth goes on her day in and day out without the slightest sense of wrongdoing much less apologies.

People made the decision to walk from this forum rather than face the issues which can be resolved in a reasonable way. As for you, well.....