Sam Wormley wrote:
On 3/10/10 2:17 PM, Mike Coon wrote:
Wolfgang S. Rupprecht wrote:
Or the effect of NASA launching most of the rockets towards the
east...

Swirling the atmosphere to the west (effect of exhaust gas) and thus
slowing the Earth down?

Mike.

Yup, Momentum, Angular Momentum and Energy are all conserved in
closed systems.

Erm, where's the closed system? There aren't many real ones about. though
it's a good abstract idea. And what's it got to do with burning rocket fuel
to get mechanical energy and momentum?

Mike.
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J. J. Lodder wrote:
Invoking angular momentum conservation
saves a lot of argument.

But is still tricky. When a spacecraft fires its jets to rotate it rather
loses the "angular momentum" of the gas that shoots off into space...

Mike.
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On 3/10/10 12:46 PM, oriel36 wrote:

The idea of a single addition/subtraction of a 'leap second' is
repugnant in the extreme given that it shows no clear understanding of
the calendar system,what it does and how it got to be that way,up to
and including the 86,400 leap second correction every 4th year in
order to correct the 365/366 day calendar cycle back to the raw
astronomical cycle.

Now Gerald, you should realize that sometimes leap seconds
are added (or subtracted) to keep so the civil time and sidereal
day will stay synced, just like we add (or don't add) leap days
to keep the seasons synced with the sidereal year.


The calendar represents the convenience of a linear progression of
years using the equable/average 24 hour day from a raw orbital cycle
and if an individual learned that much they would have achieved a good
day's work.

On 3/10/10 5:18 PM, Mike Coon wrote:
J. J. Lodder wrote:
Invoking angular momentum conservation
saves a lot of argument.

But is still tricky. When a spacecraft fires its jets to rotate it rather
loses the "angular momentum" of the gas that shoots off into space...

Mike.

When you take into account the spacecraft AND the expelled gas, the
conservation laws hold for the spacecraft-gas system. It cannot be
any other way.

On Mar 11, 2:37*am, Sam Wormley wrote:
On 3/10/10 12:46 PM, oriel36 wrote:

The idea of a single addition/subtraction of a 'leap second' is
repugnant in the extreme given that it shows no clear understanding of
the calendar system,what it does and how it got to be that way,up to
and including the 86,400 leap second correction every 4th year in
order to correct the 365/366 day calendar cycle back to the raw
astronomical cycle.

* *Now Gerald, you should realize that sometimes leap seconds
* *are added (or subtracted) to keep so the civil time and sidereal
* *day will stay synced, just like we add (or don't add) leap days
* *to keep the seasons synced with the sidereal year.


The leap day is a consequence of determining the annual motion of the
Earth through the constellations in 365 days 5 hours 49 minutes using
the average 24 hour day which is based on the average return of the
Sun to noon,given that the natural noon cycles are unequal -

"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

http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html

A leap day and consequently the 86,400 leap seconds is the only valid
addition as it corrects the annual 5 hour 49 difference every 4th year
back to the constellation all framework,the system is so old and so
accurate that the 11 minute difference to 6 hours had amounted to 10
days before the Gregorian correction and it has nothing to do with the
seasons.

A calendar generates the convenience of a linear progression of years
using average 24 hour days or rather,converts the raw astronomical
cycles into the human devised timekeeping averages,because of its
nature,the timekeeping system we use today would have had to come from
the mind of a single unknown individual - I honor him while you do
not.

The idea of a direct external reference for daily rotation using the
circumpolar motion of the constellations,hence your individual 'leap
second',is so intellectually vacuous that it is indeed repugnant for
it all goes back to the silly statement of one person in the late 17th
century -

"... our clocks kept so good a correspondence with the Heavens that I
doubt it not but they would prove the revolutions of the Earth to be
isochronical... " John Flamsteed

What he was looking at and you still are, is a timekeeping average
within the confines of the 365/366 day calendar system and it is a
travesty that in the 21st century that you choose to be bound to the
error of a single person who links the dynamic of the Earth directly
with a celestial sphere framework or what amounts to the same thing -
the circumpolar motion of the constellations -

http://www.youtube.com/watch?v=BYy0EQBnqHI

The price of your single 'leap second' and the reasoning you attach to
it is horrifying and should be for all intelligent people,that it
continues reflects badly on us as a race yet the people who will truly
be seen as brilliant will be those who work towards correcting the
matter rather than those who continue to defend that silly mistake of
Flamsteed even though I know Newton built on that calendar based
framework by trying to force the orbital motion of the Earth into the
365/366 day framework.







The calendar represents the convenience of a linear progression of
years using the equable/average 24 hour day from a raw orbital cycle
and if an individual learned that much they would have achieved a good
day's work.

Sam Wormley wrote:
When you take into account the spacecraft AND the expelled gas, the
conservation laws hold for the spacecraft-gas system. It cannot be
any other way.

Correct. The trickiness is not in the physics but in remembering to have the
right definition of "system".

Mike.
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On Mar 3, 10:07*pm, Sam Wormley wrote:
Earth knocked for a loop
Chile’s February 27 temblor, tectonically linked to another giant quake
50 years ago, sped up the Earth’s rotation and tipped the planet’s axis.http://www.sciencenews.org/view/gene...Earth_knocked_...

Here is another link that gives some interesting insight...

http://science.nasa.gov/headlines/y2...tm?list1340211

\Paul A

On Mar 10, 6:37*pm, Sam Wormley wrote:

* *Now Gerald, you should realize that sometimes leap seconds
* *are added (or subtracted) to keep so the civil time and sidereal
* *day will stay synced, just like we add (or don't add) leap days
* *to keep the seasons synced with the sidereal year.

Oops. If civil time were kept in synchrony with the sidereal day, we
should be eating lunch in the middle of the night once a year.

Instead, it is kept in synchrony with the average of the synodic day,
that the day might remain forever sunny and bright, and the dark and
cold time might forever be banished to the night.

John Savard

On Mar 10, 10:19*pm, oriel36 wrote:

The price of your single 'leap second' and the reasoning you attach to
it is horrifying and should be for all intelligent people,

If I use a mechanical clock whose pendulum is not the right length by
a slight amount, I would have to adjust it every so often to keep
correct time.

Our society has chosen to use, as its standard second, one based on
the length of the second of Ephemeris Time as established in the 19th
Century. The Earth's rotation slows down over time because of the
tides - through "empirical" Newtonian causes such as gravity
transferring angular momentum to the Moon - and so 86,400 copies of
this standard second don't, quite, add up to the average of a natural
solar day.

It used to be that we used a slightly different second to reckon the
time of day than we did to calibrate our radio stations and the like,
and this problem did not arise. Now, we use a second that is ever so
slightly too long, so our clocks are slow by the heavens, and must be
set back by a second once a year. This may be mistaken, in the sense
of being a bad choice of standard, it may even be pretentious, but it
requires no fallacy of reasoning.

John Savard

On Mar 10, 6:37*pm, Sam Wormley wrote:

* *Now Gerald, you should realize that sometimes leap seconds
* *are added (or subtracted) to keep so the civil time and sidereal
* *day will stay synced, just like we add (or don't add) leap days
* *to keep the seasons synced with the sidereal year.

Evidently the battle with Gerard has fatigued you more than you know.

Not only is civil time kept in synchrony with the synodic day - as the
sidereal day would lead night and day to switch places once a year...
but the calendar is kept in sync with the tropical year.

The tropical year is about 365.2422 days, which is why we omit three
leap years in 400 years to get 365.2425 days instead of 365.25 days.

The sidereal year, on the other hand, is slightly _longer_ than 365.25
days, so we would have to add *extra* leap years to keep in sync with
that. But we would rather have the year tell us when to plant our
crops than tell us when to expect the heliacal rising of Sirius.

John Savard