earth's tilt

On Sep 22, 1:29*am, GogoJF wrote:
On Sep 21, 3:58*pm, oriel36 wrote:









On Sep 21, 9:13*pm, Sam Wormley wrote:

* * * *Eventually I engaged, Gerald, trying to understand why he rants
* * * *and what might be the basis of his misunderstanding. His trouble
* * * *is rooted in the Anglican interpretation of the rotation of the
* * * *earth. Gerald regularly expresses his utter contempt and disgust
* * * *that we professors and teachers of astronomy note that the earth
* * * *rotates once, four minutes shy of 24 hours.

The equatorial circumference is found to be 24901 miles which makes
1037.5 miles for each 15 degrees of geographical separation.If you do
not accept that the Earth turns at a rate of 15 degrees/1037.5 miles
per *hour then perhaps you can give the alternative values which
eventually are bounded within the 24901 mile circumference.I don't
express contempt for professors,they literally express contempt for
their students,astronomy and terrestrial sciences and common sense.

So,here we are in the 21st century trying unsuccessfully to explain
that the Earth turns once in 24 hours with each of these 24 hour days
keeping in step with each rotation without fail and if dismay is not
something that accompanies you day in and day out at such a huge loss
as this core fact,then we become less men much less astronomers or
teachers.

The effect can be
* * * *observed by anyone, that the stars rise in the east 4 minutes
* * * *earlier each night. School kids, using two sticks can sight any
* * * *prominent star in the nighttime sky two nights in a row and time
* * * *that the star lines up with the two sticks every 23h 56m and 4s.

It is not possible to explain the daily and orbital motion of the
Earth using circumpolar motion and a system based on the 24 hour day
formatted as 365 days/366 days for that is exactly what you are
looking at.

* * * *We notice that the sun appears to travel south in the winter and
* * * *back north in the summer. From a fixed perspective one can see
* * * *that the sun rises and sets at a different place along the horizon
* * * *everyday, changing most rapidly near equinoxes and coming to what
* * * *seems like a standstill at the solstices. And yet it moves!

* * * *Science is all about observation and experiment. We enhance our
* * * *understand of nature all around us, by taking the time to observe
* * * *and think, often needing little more than sticks, eyes, feet, and
* * * *brains plus a zest for learning and understanding.

Here's goes nothin'. *We could shorten the second by a fraction of
itself by .0077315 of; thereby, creating more "ticks" in a single day
to equal exactly 24 hours- not 23hrs., 56 mins, and 4 sec.. *But...
what will this accomplish? *365.25 days in a year divided by 12 months
equals 30.4375 days to the month. *How do we reconcile the perfect 24
hour day with each month and year?

Far from criticizing you,I welcome your attention in trying to make
the system work but as you will soon discover,it can only operate one
way and should you follow the development of the timekeeping systems
from the creation of the calendar system using two specific references
and then follow on with the development of the 24 hour AM/PM system
and the Lat/Long system using a secondary set of references you may
understand perfectly why most of the topics in this era don't really
stand up to scrutiny as error and distortions become obvious.

I passed a guy in a coffee shop yesterday reading the book on the
Longitude problem and how John Harrison provided the solution using
time and an accurate watch and I had to smile at the romance of it all
and I mean what I say,not unthinking robots with no feeling for the
principles which connect timekeeping to the great cycles of our planet
and described by Harrison himself using the 24 hour AM/PM system in
tandem with the Lat/Long system

"The application of a Timekeeper to this discovery is founded upon the
following principles: the earth's surface is divided into 360 equal
parts (by imaginary lines drawn from North to South) which are called
Degrees of Longitude; and its daily revolution Eastward round its own
axis is performed in 24 hours; consequently in that period, each of
those imaginary lines or degrees, becomes successively opposite to the
Sun (which makes the noon or precise middle of the day at each of
those degrees and it must follow, that from the time any one of
those lines passes the Sun, till the next passes, must be just four
minutes, for 24 hours being divided by 360 will give that quantity; so
that for every degree of Longitude we sail Westward, it will be noon
with us four minutes the later, and for every degree Eastward four
minutes the sooner, and so on in proportion for any greater or less
quantity. Now, the exact time of the day at the place where we are,
can be ascertained by well known and easy observations of the Sun if
visible for a few minutes at any time from his being ten degrees high
until within an hour of noon, or from an hour after noon until he is
only 10 degrees high in the afternoon; if therefore, at any time when
such observation is made, a Timekeeper tells us at the same moment
what o'clock it is at the place we sailed from, our Longitude is
clearly discovered." John Harrison

What Wormley and other professors who follow Flamsteed's inaccurate Ra/
Dec conclusion try to do is extend the AM/PM system to include stellar
circumpolar motion even though the return of a star in 23 hours 56
minutes 04 seconds is a trivial observation which requires no cause in
terms of planetary dynamics.Had people enough patience to revisit the
few principles which restrict the references to the return of Sirius
as an annual event for the creation of the calendar system and the
daily return of the Sun ,with its uneven periods,as the sole reference
for the daily cycle and the AM/PM and Lat/Long designations then a lot
of trouble could have been avoided and we would be discussing amazing
things.

On Sep 21, 7:05*pm, GogoJF wrote:

Why are we so damned determined to maintain that the duration of the
second stay the same throughout the year and time in general?

Because the microhenry and the millifarad and the watt and the ampere
and the megohm are joined together, in part, by the second. If that
changed during the course of a year, how would we turn our radios to
the correct station?

John Savard

On Friday, September 21, 2012 7:50:41 PM UTC-7, oriel36 wrote:
On Sep 22, 12:20*am, palsing wrote:

On Friday, September 21, 2012 2:14:49 PM UTC-7, oriel36 wrote:

Viewed from Mars,the Earth's polar coordinates will be seen to precess



360 degrees to the central Sun like so -



http://upload.wikimedia.org/wikipedi...precession.svg



The problem, however, is that the graphic to which you refer above shows the 26,000-year motion of the Earth's axis WRT the fixed stars, and NOT the yearly motion of the Earth in its orbit. THIS is the definition of precession. During a single year the Earth's axial inclination changes every day WRT the sun, but currently remains aimed almost directly at Polaris.





If you need convincing after looking at the sequence of images of

Uranus which clearly show a planet's polar coordinates,acting like a

beacon for a planet's orbital behavior,turn wrt to the central Sun

then you will have no difficulties accepting that this is what the

Earth's motion will look like from Mars or any other vantage point.Now

that you have discovered this single rotation of the polar coordinates

to the central Sun over the course of an annual orbit,when daily

rotation is added you have the variations in the natural noon cycle

along with a smoother explanation for the seasons.



So,the graphic demonstrates,under your own admission,that the polar

coordinates turn about an ecliptic axis and this is supported by

actual imaging -it takes only a simple imitation analogy and a broom

to complete the explanation that the precession of the equinoxes is an

orbital feature,not an axial one.















It is no more than an observational certainty which matches other



planets in the solar system -



http://www.daviddarling.info/images/...gs_changes.jpg



I hope you understand that this series of photos only shows the changing aspect of Uranus as seen from Earth, because each planet is simultaneously moving WRT each other as they circle the sun at different rates. Uranus has its own "polar star" towards which its axis continually points.





What can I do but chuckle at this given the distances of Earth to

Uranus and it can't be other than the polar coordinates actually do

change to the central Sun just as our own polar coordinates are now

turning through the circle of illumination at the equinox,same orbital

dynamics but different inclination .You are fine,if you feel it

necessary to reach a conclusion like that then continue being a

magnification enthusiast with pride as the type of interpretation

needed to make sense of those sequence of images is out of reach for

you and many others presently.

















If a person can't handle the annual orbital cycle,there is little



point moving on to greater orbital variations that are the precession



of the equinoxes.



Well, I would agree wholeheartedly with this statement.

I'm so sorry, but talking to you is very much like talking to a brick wall. No matter how simple the explanations, you ignore points of fact that don't suit you, and just barge forward with your own one-track thoughts.

You don't understand that a complete cycle of precession is a 26,000 year deal, and THAT is what your graphic is depicting. Your broom handle analogy tells you absolutely nothing about precession, nothing at all, it only serves to illustrate that right now the Earth's axis points continuously at Polaris, 365/24/7.

http://sphotos-b.xx.fbcdn.net/hphoto...67384675_n.jpg

\Paul A

On Sep 22, 5:49*pm, palsing wrote:
On Friday, September 21, 2012 7:50:41 PM UTC-7, oriel36 wrote:
On Sep 22, 12:20*am, palsing wrote:

On Friday, September 21, 2012 2:14:49 PM UTC-7, oriel36 wrote:

Viewed from Mars,the Earth's polar coordinates will be seen to precess

360 degrees to the central Sun like so -

http://upload.wikimedia.org/wikipedi...precession.svg

The problem, however, is that the graphic to which you refer above shows the 26,000-year motion of the Earth's axis WRT the fixed stars, and NOT the yearly motion of the Earth in its orbit. THIS is the definition of precession. During a single year the Earth's axial inclination changes every day WRT the sun, but currently remains aimed almost directly at Polaris.

If you need convincing after looking at the sequence of images of

Uranus which clearly show a planet's polar coordinates,acting like a

beacon for a planet's orbital behavior,turn wrt to the central Sun

then you will have no difficulties accepting that this is what the

Earth's motion will look like from Mars or any other vantage point.Now

that you have discovered this single rotation of the polar coordinates

to the central Sun over the course of an annual orbit,when daily

rotation is added you have the variations in the natural noon cycle

along with a smoother explanation for the seasons.

So,the graphic demonstrates,under your own admission,that the polar

coordinates turn about an ecliptic axis and this is supported by

actual imaging -it takes only a simple imitation analogy and a broom

to complete the explanation that the precession of the equinoxes is an

orbital feature,not an axial one.

It is no more than an observational certainty which matches other

planets in the solar system -

http://www.daviddarling.info/images/...gs_changes.jpg

I hope you understand that this series of photos only shows the changing aspect of Uranus as seen from Earth, because each planet is simultaneously moving WRT each other as they circle the sun at different rates. Uranus has its own "polar star" towards which its axis continually points.

What can I do but chuckle at this given the distances of Earth to

Uranus and it can't be other than the polar coordinates actually do

change to the central Sun just as our own polar coordinates are now

turning through the circle of illumination at the equinox,same orbital

dynamics but different inclination .You are fine,if you feel it

necessary to reach a conclusion like that then continue being a

magnification enthusiast with pride as the type of interpretation

needed to make sense of those sequence of images is out of reach for

you and many others presently.

If a person can't handle the annual orbital cycle,there is little

point moving on to greater orbital variations that are the precession

of the equinoxes.

Well, I would agree wholeheartedly with this statement.



You don't understand that a complete cycle of precession is a 26,000 year deal, and THAT is what your graphic is depicting.

The graphic depicts the same thing we see as Uranus moves along its
orbital circumference as the polar coordinates are carried around in a
circle to the central Sun -

http://www.daviddarling.info/images/...gs_changes.jpg

The polar coordinates simply act like a beacon for this quasi-rotation
insofar as in order to maintain constant axial alignment to
Polaris,the polar coordinates do turn to the central Sun and that is
what the graphic actually demonstrates -

http://en.wikipedia.org/wiki/File:Earth_precession.svg

Half the Earth is always in daylight and half in orbital darkness with
the circle of illumination bounding this feature,aside from the daily
turning through the circle of illumination in splitting day from
night,there is a separate turning to the central Sun going on as well
so that all locations on Earth experience the same thing as they do at
the North and South Poles in terms of a single orbital day/night cycle
and coincident with an orbital period.

So,the polar coordinates are carried around in a circle by the orbital
behavior of the Earth and they do not 'tilt' towards and away from the
Sun as the older and more awkward explanations have it.Eventually some
enterprising individual who can work with the advanced graphics of
today will put that graphic above in motion and in context of the
orbital circuit around the Sun.

The Earth has a wonderful equatorial climate with a lesser polar
influence which causes gentle seasonal fluctuations in daylight/
darkness over large areas of the planet compared to the extreme polar
climate of Uranus with its wild fluctuations - this is what
astronomers must teach whether they are paid or not.






Your broom handle analogy tells you absolutely nothing about
precession, nothing at all, it only serves to illustrate that right
now the Earth's axis points continuously at Polaris, 365/24/7.

http://sphotos-b.xx.fbcdn.net/hphoto...1080610519_967...

\Paul A

On Sat, 22 Sep 2012 09:49:54 -0700 (PDT), palsing
wrote:
the Earth's axis points continuously at Polaris, 365/24/7.

....and what does 365/24/7 really mean? It ought to be either 365/24
(which leaves out the leap day) or 52/7/24 (which leaves out one day
each year, and also the leap day). Writing 365/24/7 is redundant.

On Saturday, September 22, 2012 11:08:25 AM UTC-7, Paul Schlyter wrote:
On Sat, 22 Sep 2012 09:49:54 -0700 (PDT), palsing wrote

the Earth's axis points continuously at Polaris, 365/24/7.



...and what does 365/24/7 really mean? It ought to be either 365/24

(which leaves out the leap day) or 52/7/24 (which leaves out one day

each year, and also the leap day). Writing 365/24/7 is redundant.

OK, I could have said "all day, every day"... and I also could have specified "nearly at Polaris"...

On Sep 22, 7:08*pm, Paul Schlyter wrote:
On Sat, 22 Sep 2012 09:49:54 -0700 (PDT), palsing

wrote:
the Earth's axis points continuously at Polaris, 365/24/7.

...and what does 365/24/7 really mean? It ought to be either 365/24
(which leaves out the leap day) or 52/7/24 (which leaves out one day
each year, and also the leap day). Writing 365/24/7 is redundant.

What it tells you is that the primary unit of timekeeping was always
1461 rotations in proportion to 4 orbital circuits with the unused
trivial reduction of 365 1/4 rotations to one orbital circuit.All
primary and secondary references are outriggers of this proportion and
especially the secondary reference of the natural noon cycle as it
applies to the AM/PM system and the Lat/Long system.You can hardly
know why the original references produce an orbital discontinuity in
that the assertion of constant rotation against the orbital period
corresponds to an 11 minute over compensation for each orbit ties in
with precession of the Equinoxes in a very complicated way.I haven't
even dealt with this feature to my own satisfaction.

https://groups.google.com/group/sci....04f6dc31?hl=en

You are not much better Schlyter,using the 'tilt' of the Earth for the
global variations in the natural noon cycle was simply a dumb thing to
do and ten years later it looks like a mess now that the wandering
analemma Sun is discredited and the actual cause of the variations in
the natural noon cycle has been explained in a very simply way using
time lapse footage of Uranus and two separate rotations to the central
Sun.

How much astronomy has changed within the last ten years as all these
causes and effects become clearer with imaging and observational data
that I can now put my hands on through the internet.Even you have
changed along with many others in being forced into smaller and
smaller intellectual circles and mostly narrow minded and mean
spirited in nature.

In sci.astro.amateur message , Thu, 20
Sep 2012 22:11:43, Davoud posted:


I don't have time to do the searching at the moment, but I have to
think that ancient natural philosophers, whether in Greece or Persia or
China or parts unknown, knew the extent of the Earth's axial tilt.

http://en.wikipedia.org/wiki/Earth%27s_Axis#History.

--
(c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05 MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.

In article
,
GogoJF wrote:

snip

Maybe the "second"naturally slows down and speeds up and we are not
aware of it.

Not sure what you're getting at, but the rate of the Earth's rotation
does vary, over both longer terms (a slowing trend) and shorter (chaotic
oscillations including "nutation"); the current method of dealing with
the resulting discrepancies is the addition of "leap seconds" when
converting between UTC (formerly Greenwich time) and uniform time.

--
Odysseus

On Sep 22, 4:56*am, Quadibloc wrote:
On Sep 21, 7:05*pm, GogoJF wrote:

Why are we so damned determined to maintain that the duration of the
second stay the same throughout the year and time in general?

Because the microhenry and the millifarad and the watt and the ampere
and the megohm are joined together, in part, by the second. If that
changed during the course of a year, how would we turn our radios to
the correct station?

In fact, this explains why we have "leap seconds", and why we
emphasize the "sidereal day" as the period of the Earth's rotation
instead of the solar day (which is affected by the Equation of Time).

We have chosen, as more useful and convenient, to define our units of
time, and practice the craft of timekeeping, so as to regulate our
machines first and foremost, and only secondarily, almost as an
afterthought, to keep track of the Sun and the daytime - since it
doesn't really matter if solar noon comes a few minutes late or early.

And this is what has Oriel so exercised. But then, he has told us that
he is a Christian, and so why should I be surprised that he objects to
what has been called a Faustian bargain - the one that led to the
"dark, Satanic mills" of the Industrial Revolution.

I don't think that our use of human ingenuity to make our lives easier
is wrong, but we have made mistakes in the course of it. But it was
our own ingenuity, not a bargain with a demon. And we are already
recognizing the need to respect the environment and make amends to
indigenous people.

Thus, I don't think that we have to worry about Diana and Mother
Nature getting together and destroying our present civilization... so
that we can spend 3,000 years balancing the cha (or possibly the
Dao?), as we turn into really cool people with big muscles, until a
great climactic confrontation comes by, and one Michael Levy comes to
help us with magical powers from an alternate reality...

John Savard