Shadow of sundial a straight line on equinox day?
Peter Lewis
Does the shadow of a simple sundial form a straight line plus/minus a
few hours around equinox (at all latitudes)? And a curve at all other
times?
Thanks.
Sam Wormley
I'm not sure what you are asking, Peter.
http://en.wikipedia.org/wiki/Equation_of_time
http://en.wikipedia.org/wiki/Sundial
http://en.wikipedia.org/wiki/File:Equatorial_sundial_topview.gif
Chris L Peterson
Only if your sundial is at the equator. While the Sun rises in the east
and sets in the west everywhere on Earth (on the equinox), it only
crosses the zenith at the equator. Consider an extreme example of a
sundial at one of the poles. The Sun makes a complete circle around the
horizon. That's going to produce a sundial shadow that's nearly a
perfect circle.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
Sam Wormley
> Hi, I couldn't derive or visualize this using simple geometry.
>
> few hours around equinox (at all latitudes)? And a curve at all other
> times?
>
> Thanks.
OK -- I get your question now.
http://solarclockgarden.truman.edu/images/sundial_04.jpg
http://images.google.com/images?q=locus%20of%20point%20tip%20shadow%20sundial
Sam Wormley
Here is the original reference: http://solarclockgarden.truman.edu/sundial.htm
Peter Lewis
Sam, thanks for clarifying the question and also the references. May
I know at what latitude is the solarclockgarden picture meant for?
The equinox line is pretty straight, but the solstice curves do not
appear symmetrical.
Peter Lewis
> Sam Wormley wrote:
>
> Here is the original reference:http://solarclockgarden.truman.edu/sundial.htm
Thanks for anticipating my next question, and beating me to it.
Peter Lewis
The example at http://solarclockgarden.truman.edu/sundial.htm is
clearly not at the equator. Seems to be in conflict with Chris'
explanation.
After thinking about it for a bit more, Chris, your polar example
would produce no shadow as the sun rays at the gnomon would be
parallel to the ground at the pole. Am I correct?
Sam Wormley
Flat horizontal surface - Equinox Shadow tip follows a straight line.
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Sundials.html
Other dates hyperbolic paths (between Arctic and Antarctic circles).
Chris L Peterson
<kingk...@gmail.com> wrote:
>The example at http://solarclockgarden.truman.edu/sundial.htm is
>clearly not at the equator. Seems to be in conflict with Chris'
>explanation.
Well, that's not a very typical sundial. It has a vertical gnomon, not
one pointing towards the pole. I don't see how the equinox shadow could
be as indicated (since on that day the Sun rises and sets very near
cardinal east and west), unless it has something to do with the shape of
the surface below the gnomon. The report says it is on some sort of
slope.
>After thinking about it for a bit more, Chris, your polar example
>would produce no shadow as the sun rays at the gnomon would be
>parallel to the ground at the pole. Am I correct?
Well, it depends. Refraction actually brings the Sun higher, so it
circles a little above the horizon. And even if there were no
atmosphere, the Sun is an extended object, so there is a penumbral
shadow that is closer that the horizon.
The pole is a sort of singularity, and it might be confusing. But you
can imagine that you are just a little below the pole, where the Sun
will rise in the east, travel across the sky crossing the meridian just
a little above the southern horizon (for the north pole), and set in the
west. It seems pretty clear that the gnomon's shadow isn't going to
trace a straight line under those circumstances.
Sam Wormley
oriel36
Want to know the answer ?, then turn to the Christian Cathedrals which
contain meridian lines denoting the occurence of natural noon -
http://en.wikipedia.org/wiki/Santa_Maria_degli_Angeli_e_dei_Martiri
http://www.math.nus.edu.sg/aslaksen/teaching/heilbron.html
A meridian line towards the geographical poles becomes progressively
longer while at the Equator,where equinox conditions permanently
exist,a meridian line is not required considering daylight/darkness is
always equal in splitting hemispherical seasonal variations.
What occurs at the Equator and everywhere North and South of that
position is that the natural noon cycles vary by the same amount
regardless of seasons and this is why determining natural noon by
meridian line,by sundial gnomon or the procedure demonstrated by
Huygens relies strictly on the moment of natural noon timewise rather
than any apparent inclination -
"Draw a Meridian line upon a floor and then hang two plummets, each
by a small thred or wire, directly over the said Meridian, at the
distance of some 2. feet or more one from the other, as the smalness
of the thred will admit. When the middle of the Sun (the Eye being
placed so, as to bring both the threds into one line) appears to be in
the same line exactly ...you are then immediately to set the Watch,
not precisely to the hour of 12. but by so much less, as is the
Aequation of the day by the Table"
http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html
The astrolgers here cannot get past the idea that daylight/darkness
variations and 'axial tilt' have nothing whatsoever to do with the
global Equation of Time correction even though they promote it.They
will just as quickly tell you that there is an external celestial
reference for the daily cycle through 360 degrees even though millenia
of observations demonstrate otherwise.
There is no mystery to the difference between the natural noon cycle
and the 24 hour cycle which allows the 24 hours of Saturday to turn
into the 24 hours of Sunday and provides the geometrical basis of a
constant daily cycle which manifests itself today in the 'Earth hour'
as the Earth rotates through 15 degrees in that hour.The astrologers
believe differently but their view is basically a late 17th century
hoax which was allowed to emerge unhindered.
Brian Tung
> Only if your sundial is at the equator. While the Sun rises in the east
> and sets in the west everywhere on Earth (on the equinox), it only
> crosses the zenith at the equator. Consider an extreme example of a
> sundial at one of the poles. The Sun makes a complete circle around the
> horizon. That's going to produce a sundial shadow that's nearly a
> perfect circle.
Are we talking about the same question? At any latitude less than 90
degrees, an "ideal" Sun (point source, no refraction) travels in a great
circle across the sky. The gnomon's tip generates a plane with that
great circle because they're coplanar. That plane should intersect with
the plane of the sundial in a straight line, no matter the inclination
of the two.
At all other times, the gnomon's tip and the (less than great) circle
travelled by the Sun should generate a cone. The intersection of that
cone with the plane will be a hyperbola.
--
Brian Tung <br...@lunabase.org>
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Brian Tung
> The pole is a sort of singularity, and it might be confusing. But you
> can imagine that you are just a little below the pole, where the Sun
> will rise in the east, travel across the sky crossing the meridian just
> a little above the southern horizon (for the north pole), and set in the
> west. It seems pretty clear that the gnomon's shadow isn't going to
> trace a straight line under those circumstances.
Whaah? It sets in the west, yes, but the shadow is at infinity then,
so no contradiction. The shadow could easily track (let's say) 100 m
north of the east-west line at the gnomon, and still be exactly due
east when the Sun sets. A hundred meters divided by infinity is still
zero.
William Hamblen
> Chris L Peterson wrote:
>> Only if your sundial is at the equator. While the Sun rises in the east
>> and sets in the west everywhere on Earth (on the equinox), it only
>> crosses the zenith at the equator. Consider an extreme example of a
>> sundial at one of the poles. The Sun makes a complete circle around the
>> horizon. That's going to produce a sundial shadow that's nearly a
>> perfect circle.
>
> Are we talking about the same question? At any latitude less than 90
> degrees, an "ideal" Sun (point source, no refraction) travels in a great
> circle across the sky. The gnomon's tip generates a plane with that
> great circle because they're coplanar. That plane should intersect with
> the plane of the sundial in a straight line, no matter the inclination
> of the two.
>
> At all other times, the gnomon's tip and the (less than great) circle
> travelled by the Sun should generate a cone. The intersection of that
> cone with the plane will be a hyperbola.
It seems to me that the apparent daily path of the Sun is a small circle
unless the declination of the Sun is zero.
Bud
OG
"Peter Lewis" <kingk...@gmail.com> wrote in message
news:0fc51aa0-b263-4300...@b7g2000pre.googlegroups.com...
Web page refers to Kirskville MO
40°11′37″N
92°34′46″W
Brian Tung
> It seems to me that the apparent daily path of the Sun is a small circle
> unless the declination of the Sun is zero.
Yes, OP is talking about equinox, where declination of the Sun is zero.
cano...@yahoo.com
Yes, on the Earth at the equinoxes, a simple vertical gnomon sundial,
regardless of latitude, traces a straight line within the limits of
visual detection. There are a number of minor technical exceptions.
This is because of the extreme distance of the Sun, all rays from the
Sun appear to fall in parallel lines at all points in on the Earth's
globe. At the equinoxes, the rays of the Sun aer parallel to the
lines of latitude and the equator. Hence, the Sun's shadow traces a
straight line. At other times of the year, the Sun's rays are at an
angle to the lines of latitude, hence, the Sun's shadow from a gnomon
does not trace a straight line - it traces a parabola.
Here's an animation of images taken on the equinox at a public sundial
in Salt Lake City:
http://members.csolutions.net/fisherka/astronote/observed/ALSSundial/img/pix43animated.gif
A diagram showing northern hemisphere shadow traces for a vertical
gnomon throughout the year can be found at:
http://www.mysundial.ca/tsp/sundial_types.html
According to Evans, the Greeks divided the latitudes of the earth into
five major divisions based on the behavior of a simple gnomon
sundial.
The word "tropic" means "to turn" - refering to the point at the
solistices at which the trace of the Sun's daily shadow turns back
toward the gnonom. The Tropic of Capricorn defines the most southerly
latitude in the northern hemisphere in which the Sun can pass directly
overhead - that is the most southerly line on the sun dial traces
depicted in http://www.mysundial.ca/tsp/sundial_types.html will cross
directly over the gnonom. For sundials places at latitudes higher
than the Tropic of Cancer, the most southernly shadow cast by the
sundial will never reach the gnonom. For the equatorial region, the
Sun will cast its most northernly and southerly traces on either side
(north-south) of the gnomon. For the Tropic of Capricorn, the
opposite shadow case of the Tropic of Cancer occurs.
The two remaining regions are the arctic and anarctic, where the Sun
can disappear below the horizon across multiple days and cast no
shadow.
For a citeable source, try:
Evans, James. 1998. The History and Practice of Ancient Astronomy.
Oxford Univ. Press. ISBN: 0195095391
Waugh, Albert, Edmund. 1973. Sundials: Their Theory and Construction.
Dover. ISBN: 0486229475
Rohr, Rene R.J. 1996. Sundials: History, Theory, and Practice. Dover.
ISBN: 0486291391
You might find the following resources of interest:
François Blateyron's Shadows sundial software Plots the dial for a
variety of sundials particularlized for your observing point.
http://pagesperso-orange.fr/blateyron/sundials/shadowspro/gb/
The Shadows freeware version includes the ability to run simulations
tracing the Sun's shadow on a dial throughout a year. Blayteron's
software is really something. Check it out.
Shadows sundial gallery
http://pagesperso-orange.fr/blateyron/sundials/shadowspro/gb/usersundials.htm
North American Sundial Society. 2006. Registry of North American
Sundials. Website. << http://sundials.org/registry/ >> accessed
6/2006
British Sundial Society. 2006. Dials of Distinction. In The British
Sundial Society Homepage. Website. (Photographs of English sundials).
<< http://www.sundialsoc.org.uk/ >> accessed 6/2006
British Sundial Society. 2006. Sundials on the Internet. Website.
(Links to pictures of sundials around the world) << http://www.sundials.co.uk/
accessed 6/2006
Get Hooked on Gnomonics http://www.mysundial.ca/tsp/tsp_index.html
Basic bibliography on sundials
http://members.csolutions.net/fisherka/astronote/observed/ALSSundial/html/Biblio.html
Brian Tung
> This is because of the extreme distance of the Sun, all rays from the
> Sun appear to fall in parallel lines at all points in on the Earth's
> globe. At the equinoxes, the rays of the Sun aer parallel to the
> lines of latitude and the equator. Hence, the Sun's shadow traces a
> straight line. At other times of the year, the Sun's rays are at an
> angle to the lines of latitude, hence, the Sun's shadow from a gnomon
> does not trace a straight line - it traces a parabola.
It's only a parabola if the surface of the sundial is coplanar with the
north celestial pole, since this is the axis of the cone generated by
the gnomon's tip and the path of the Sun (to first order, ignoring the
variation in declination of the Sun over the course of a day). Some
sundials are in fact mounted this way. In all other cases, the path is
a hyperbola. The asymptotes of the hyperbola are the lines drawn from
the gnomon to the rising and setting Sun. At the equinoxes, these
asymptotes are both identical to the east-west line, and the hyperbola
degenerates into a straight line.
Brian Tung
> Does the shadow of a simple sundial form a straight line plus/minus a
> few hours around equinox (at all latitudes)? And a curve at all other
> times?
Heh, you've started a lively little discussion.
Assuming
* I've understood you correctly. :)
* The Sun is a point source.
* Atmospheric refraction is negligible.
* Variation in the Sun's declination during the day is negligible.
* The sundial is planar. (Some have cylindrical or other curved
surfaces, for reasons we can ignore here.)
Then the answer to your question is yes, the Sun's shadow does traverse
a straight line at the equinoxes.
Reasoning: The Sun's path during the course of a day is an arc of a
circle on the celestial sphere. At the equinoxes, this circle is a
great circle, like the equator on the Earth; at all other times, it's
less than great, like the 10 degree north latitude circle.
The Sun causes the gnomon's tip to cast a shadow. We see this shadow as
a point on the surface of the sundial, but it's really a line extended
from the gnomon's tip out to infinity, extending away from the Sun (just
as the Earth casts a shadow out into outer space, which occasionally
strikes the Moon, during a lunar eclipse).
On most days, because the Sun's path is less than great, this shadow
line traces out a cone (just as a line drawn from the center of the
Earth to points on the 10 degree suoth latitude circle would describe a
cone). What we see over the course of the day is the intersection of
this cone with the plane of the sundial. From conics, the intersection
of a cone with a plane is a conic section: a circle, an ellipse, a
parabola, or a hyperbola. If the sundial is level, the path is a
hyperbola.
However, at the equinoxes, the cone degenerates to a plane (just as a
line drawn from the center of the Earth to points on the equator would
also describe a plane). The intersection of this plane with the plane
of the sundial is necessarily a straight line, unless the two planes
are parallel, as they would be for a level sundial at the poles. As
you correctly said, there is *no* shadow for such a sundial at all on
that day.
I'm afraid there I can't think of a much simpler way to explain this
in text. With graphics it would be much easier, so see the Web sites
cited by others.
oriel36
> Unofficial C5+ Home Page athttp://www.astronomycorner.net/c5plus/
> The PleiadAtlas Home Page athttp://www.astronomycorner.net/pleiadatlas/
> My Own Personal FAQ (SAA) athttp://www.astronomycorner.net/reference/faq.html
I am afraid that all your descriptions are entirely astrological as
the sundial reflects the motions of the Earth with respect to the
central Sun and nobody ,at least so far,has provided an accurate
description of either the Sun returning to the meridian line via the
dual 360 degree components of daily rotation and orbital orientation
change which generates the natural noon variations or the seasonal
variations apart from the Equator where Equinox conditions are
permanent.
All these scientists going to the 'Copenhagen conference' and not one
of them will understand the basic dynamics behind the seasons
demonstrating what they know about global climate background,how it is
due to the motions of the Earth and distance from the Sun and what
they know is pretty dangerous.
You are fine to discuss the motion of the Sun and shadows,I need
people who can translate those observations into astronomical
principles based on the Earth's motions and that is proving more
difficult than I thought.
oriel36
> Chris L Peterson wrote:
> > Only if your sundial is at the equator. While the Sun rises in the east
> > and sets in the west everywhere on Earth (on the equinox), it only
> > crosses the zenith at the equator. Consider an extreme example of a
> > sundial at one of the poles. The Sun makes a complete circle around the
> > horizon. That's going to produce a sundial shadow that's nearly a
> > perfect circle.
>
> Are we talking about the same question? At any latitude less than 90
> degrees, an "ideal" Sun (point source, no refraction) travels in a great
> circle across the sky. The gnomon's tip generates a plane with that
> great circle because they're coplanar. That plane should intersect with
> the plane of the sundial in a straight line, no matter the inclination
> of the two.
>
> At all other times, the gnomon's tip and the (less than great) circle
> travelled by the Sun should generate a cone. The intersection of that
> cone with the plane will be a hyperbola.
>
> --
> Brian Tung <br...@lunabase.org>
> Unofficial C5+ Home Page athttp://www.astronomycorner.net/c5plus/
> The PleiadAtlas Home Page athttp://www.astronomycorner.net/pleiadatlas/
> My Own Personal FAQ (SAA) athttp://www.astronomycorner.net/reference/faq.html
Allow me to bring everyone up to speed until somebody else comes along
with a better description which follows the same lines,at least in
terms of the motions of the Earth.This is the first time it has been
explained in any sort of detail.
As the Earth orbits the Sun,it turns through 360 degrees with respect
to the central Sun,not at a pivotal point but in a circle at 23 1/2
degrees to the rotational poles .Had we a photo-wizard here who can
alter the images to show the Earth terminator in an upright
position,it is possible to obtain a limited view of what is happening
-
http://www.youtube.com/watch?v=nwTrYVBcx9s
Above the tropics and towards the rotational poles (within reason) ,a
location will experience a period where the Sun is entirely absent or
entirely present during the annual cycle until the rotational North or
South poles where the location experiences a year long cycle of day
and night in the absent of daily rotation.A sundial will register the
specific way the Earth orbits the central Sun in the absence of daily
rotation from Spring Equinox to Fall Equinox as the Earth turns
through a circle at 23 1/2 degrees from that location where it is
taken up at the opposite pole as the geographic pole is brought into
or out of the orbital shadow by the orbital specific.
What all of you are trying to do is explain the behavior of a sundial
from a strictly daily rotational/tilt point of view whereas the best
perspective is to look at Equatorial and polar extremes and then sort
of what is what but especially the polar view where rotation is
absent.At the poles,not only will the orbital specific be isolated,it
will show an uneven motion during the 6 month period from Spring to
Fall Equinoxes due to variations in orbital speed showing up as uneven
changes in orientation through the central Sun,it is this uneven
change when allied with daily rotation that register as uneven natural
noon cycles.
Remember now,the orbital component turns through a 23 1/2 degree
circle rather than a pivotal point in causing seasonal variations
everywhere but at the Equator where Equinox conditions prevail.It is a
100% geometric certainty even if it is a little intricate to gauge but
set aside sundial books and take a look at the Earth from space for a
change before delving into the matter especially as it has not been
explained properly before.
Dave Typinski
>
>On Fri, 27 Mar 2009 21:33:08 -0700 (PDT), Peter Lewis
><kingk...@gmail.com> wrote:
>
>>The example at http://solarclockgarden.truman.edu/sundial.htm is
>>clearly not at the equator. Seems to be in conflict with Chris'
>>explanation.
>
>Well, that's not a very typical sundial. It has a vertical gnomon, not
>one pointing towards the pole. I don't see how the equinox shadow could
>be as indicated (since on that day the Sun rises and sets very near
>cardinal east and west), unless it has something to do with the shape of
>the surface below the gnomon. The report says it is on some sort of
>slope.
If the ground were sloping down slighly from the gnomon on a bearing
of about 350°, then it should produce that plot.
Anyone near enough to Kirksville, Missouri to go check it out?
--
Dave
Peter Lewis
as I have difficulty trying to visualize all the descriptive sentences
that have been written.
Yes, my question question assumes:
> * The Sun is a point source.
> * Atmospheric refraction is negligible.
> * Variation in the Sun's declination during the day is negligible.
> * The sundial is planar.
In fact, my sun dial is just a vertical stick. Until I read the
references (http://www.mysundial.ca/tsp/sundial_types.html) given by
some of you, I didn't realize there was a vertical gnomon and a polar
pointing gnomon. I learned something valuable.
What I was seeking was an intuitive proof, a visual illustration that
makes it really obvious, that the line formed by the shadow of the tip
around equinox would be a straight line.
canopus55's:
> At the equinoxes, the rays of the Sun aer parallel to the
> lines of latitude and the equator. Hence, the Sun's shadow traces a
> straight line.
got me thinking that I have got the answer. I sketched out the earth
and sun on Mar 21, as seen from a point "vertically above" the
eclliptic plane of the earth's orbit around the sun. But from this
point of view, the latitudes would still not be straight lines to the
sun. They would be curves as the north pole is 23.5 degrees to the
"right" of center, not 90 degrees. But if I tilt my head 66.5 degrees
to the "left" and the earth's rotational axis is parallel to my view,
the latitudes would be straight lines.
Is this the best I can use to explain to a 6th grader?
Thanks.
oriel36
Set up a wastepaper basket or some other object in the middle of the
room representing the central Sun.Get a broom or a stick representing
the rotational orientation/tilt of the Earth and point it to some
distant object straight ahead to some fixed point representing Polaris
(assuming it is a gymnasium).Ask the student to walk around the basket/
Sun while keeping the broom pointing always on fixed point and they
will discover that to do this they may start forwards,representing the
Fall Equinox but must starting moving sideways and a full 180 Degrees
(Spring Equinox) after they started,they will be eventually walking
backwards until they move sideways at the point of summer solstice and
walking forward again until they reach the starting position of the
Fall Equinox.Explain to them that the seasons are due to the specific
way a planet orbits the central Sun rather than the old 'tilting'
explanation that does not take orbital motion into account.
A more detailed explanation for an adult is much more difficult and
made moreso by the lack of imaging to carry the orbital point,the
following excellent graphics were found on an astrology website and
relate specifically to your point using the Tropic of Cancer -
http://www.astrologyclub.org/articles/ecliptic/spring_equinox.gif
http://www.astrologyclub.org/articles/ecliptic/summer_solstice.gif
http://www.astrologyclub.org/articles/ecliptic/fall_equinox.gif
http://www.astrologyclub.org/articles/ecliptic/winter_solstice.gif
The common feature you will notice is that the geographical poles
maintain a 23 1/2 degree latitudinal distance to where the circle of
illumination intersects the Tropic of Cancer/Capricorn,for practical
purposes using the polar view of the Northern hemisphere.
The geographical poles do not precess through 360 degrees over an
annual orbit but rather the Earth,taken from any arbitrary orbital
point,will move forward until 180 degrees later it is orbitally moving
backwards,as the analogy of broom/wastebasket.The descriptions using
'axial tilt' alone do not taken orbital motion into consideration but
simply tilt the Earth towards and away from the Sun and omit the
orbital description.An adult is expected to gauge that the roughly 2
billion mile distance between Uranus and the Sun adequately explains
this fundamental orbital feature but nobody,at least so far, has
clued in to the fact that the Earth has the same orbital specific
motion -
http://astro.berkeley.edu/%7Eimke/Infrared/UranusAo/ur_time_2001_2005...
There are,of course,higher levels and more refined points to develop
or discuss but for teenagers they will delight in discovering that
they have to walk around a central object in a specific way to keep
the broom handle pointing in the same direction.Tell them that a
sundial at the North pole,where no rotation exists,would still
register a day and night cycle but that it takes a full year to
complete it therefore a shadow on a sundial,at least from spring to
fall equinox when the Sun is visible at the pole,would be seen to move
across its face demonstrating the way a planet orbits the Sun.
Dave Typinski
>
>canopus55's:
>
>> At the equinoxes, the rays of the Sun aer parallel to the
>> lines of latitude and the equator. Hence, the Sun's shadow traces a
>> straight line.
>
>got me thinking that I have got the answer. I sketched out the earth
>and sun on Mar 21, as seen from a point "vertically above" the
>eclliptic plane of the earth's orbit around the sun. But from this
>point of view, the latitudes would still not be straight lines to the
>sun. They would be curves as the north pole is 23.5 degrees to the
>"right" of center, not 90 degrees. But if I tilt my head 66.5 degrees
>to the "left" and the earth's rotational axis is parallel to my view,
>the latitudes would be straight lines.
>
>Is this the best I can use to explain to a 6th grader?
I've had some success using a globe with toothpicks inserted normal to
the surface, a dark room, and a flashlight for the sun. Just set the
spin axis of the globe relative to the flashlight for the portion of
the year you want to explore, then mark the tip of the
toothpick-gnomon's shadow as the globe rotates.
It's also a great way to show why clockwise is, ah, clockwise: because
all this stuff was developed in the Northern hemisphere where the tip
of the gnomon's shadow moves, ah, clockwise!
--
Dave
Quadibloc
> Set up a wastepaper basket or some other object in the middle of the
> room representing the central Sun.Get a broom or a stick representing
> the rotational orientation/tilt of the Earth and point it to some
> distant object straight ahead to some fixed point representing Polaris
> (assuming it is a gymnasium).Ask the student to walk around the basket/
> Sun while keeping the broom pointing always on fixed point
Yes! This is how the Earth moves around the Sun, and how the Earth's
rotational axis is oriented!
> and they
> will discover that to do this they may start forwards,representing the
> Fall Equinox but must starting moving sideways and a full 180 Degrees
> (Spring Equinox) after they started,they will be eventually walking
> backwards until they move sideways at the point of summer solstice and
> walking forward again until they reach the starting position of the
> Fall Equinox.
If "walking backwards" means walking away from the direction "straight
ahead" where the distant object is located, that is true enough.
Normally, when a person is walking around in a circle, he is still
"walking forwards" all the time, so that he doesn't trip over his own
feet. (But if I start talking *that* way, I would start to agree with
you that axial rotation is 24 hours and not 23 hours, 56 minutes, and
4 seconds.)
> Explain to them that the seasons are due to the specific
> way a planet orbits the central Sun rather than the old 'tilting'
> explanation that does not take orbital motion into account.
When the term "tilt" is used, it is accompanied by illustrations of
the orbital motion you have referred to. Nobody tries to claim that a
"variable axial tilt" is valid astronomy.
> The geographical poles do not precess through 360 degrees over an
> annual orbit but rather the Earth,taken from any arbitrary orbital
> point,will move forward until 180 degrees later it is orbitally moving
> backwards,as the analogy of broom/wastebasket.
Yes, yes, this is exactly right. But this is also exactly what
everyone else is saying.
> The descriptions using
> 'axial tilt' alone do not taken orbital motion into consideration but
> simply tilt the Earth towards and away from the Sun and omit the
> orbital description.An adult is expected to gauge that the roughly 2
> billion mile distance between Uranus and the Sun adequately explains
> this fundamental orbital feature but nobody,at least so far, has
> clued in to the fact that the Earth has the same orbital specific
> motion -
No, that the pole of Saturn or the pole of Uranus points in a fixed
direction, and its orbit around the Sun changes the relationship of
that fixed direction to the ever changing direction between the Sun
and those planets is, and always has been, what astronomers say today.
John Savard
Peter Lewis
> On Mar 30, 11:04 am, oriel36 <kelleher.ger...@gmail.com> wrote:
>
Really appreciate all the effort to explain further. But I feel the
discussion is deviating slightly from what I am seeking.
I am not trying to explain the seasons. I think I have got that, at
least I think so.
What I am trying to do is to easily explain that the tip of a gnomon
will trace a straight line around equinox. (As the equinox is
strictly just a moment in time, I assume plus or minus a few hours
around that moment would still be valid.)
Purpose of this exercise? By collecting sun dial data, using the
lines on different days to demonstrate that the earth is tilted and
revolving round the sun.
The equinox opportunity was two Saturdays ago, and it was cloudy, but
I got some good data on Mar 19.
Brian Tung
> Really appreciate all the effort to explain further. But I feel the
> discussion is deviating slightly from what I am seeking.
Gerald and John like to go rounds at each other. Not sure why.
--
Brian Tung <br...@lunabase.org>
The Astronomy Corner moved to http://www.astronomycorner.net/
Unofficial C5+ Home Page at http://www.astronomycorner.net/c5plus/
The PleiadAtlas Home Page at http://www.astronomycorner.net/pleiadatlas/
oriel36
> On Mar 31, 5:00 am, Quadibloc <jsav...@ecn.ab.ca> wrote:
>
> > On Mar 30, 11:04 am, oriel36 <kelleher.ger...@gmail.com> wrote:
> > ...
>
> Really appreciate all the effort to explain further. But I feel the
> discussion is deviating slightly from what I am seeking.
>
> I am not trying to explain the seasons. I think I have got that, at
> least I think so.
>
I am mindful that you and everyone else here has received the outlines
of a different and more productive explanation for the seasons but
this requires a slight backtracking to have a look at what was wrong
with the old explanation.The specific problem was trying to do too
much with too little by referencing rotational orientation/tilt to the
central Sun,something like this -
http://www.astronomy.org/programs/seasons/pictures/09reasons-for-seasons-general.gif
It is when they try to explain what happens between Solstice and
Equinox that these explanations run into unsurmountable trouble
insofar as they lack the wider perspective of orbital motion and the
specific way a planet orbits the Sun.
The new explanation keeps rotational orientation fixed to an external
reference such as Polaris thereby allowing the orbital motion to do
the job or rather,the specific way a planet orbits the Sun.Again,using
the analogy, to keep the broom pointed at the same spot as a person
walks around a central object shows that at one time the left arm will
face the object/Sun then the back,then the right shoulder at the
opposite side to the point of departure and then the front before
returning to the left arm.This will occur at the North Pole where
there is no rotation hence the orbital specific which goes on
regardless of daily rotation and rotational orientation/tilt.
I would like to show you graphics and time lapse motion but none exist
at present even though the explanation is correct.
> What I am trying to do is to easily explain that the tip of a gnomon
> will trace a straight line around equinox. (As the equinox is
> strictly just a moment in time, I assume plus or minus a few hours
> around that moment would still be valid.)
>
> Purpose of this exercise? By collecting sun dial data, using the
> lines on different days to demonstrate that the earth is tilted and
> revolving round the sun.
>
Maybe one of your students may go on to work on climate or some other
productive work where the motions of the Earth are involved,just about
everything in other words,but they are not going to stand a chance if
you yourself do not understand what it happening with the motions of
the Earth first before translating into what happens on a sundial,not
the other way around.
Modern imaging and graphics are just too good yet while Sam, in
another thread,has these excellent graphics from NOAA and NASA on
space weather,there is a huge void of graphics explaining planetary
seasons and none which identifies the specific way the Earth orbits
the central Sun as the dynamic for the seasons along with daily
rotation.
It is your duty as a teacher to teach your kids properly and rather
than teach them the old explanation that the Northern hemispheres
tilts to the Sun in summer and tilts away in winter,use the broom
(tilt), the object at the center of the room (Sun) and their footwork
(orbital motion) to carry the point that it is the orbital motion of
the Earth and its slow orbital turning to the central Sun that causes
the seasons.Try to limit your students to pointing the broom at the
central object/Sun ,as the old explanations try to do,and they will
entirely miss the point.
> The equinox opportunity was two Saturdays ago, and it was cloudy, but
> I got some good data on Mar 19.
If you travel to the Equator,it is always the Equinox there so you
never miss the opportunity -
I apologise for the poor explanation but these are the outlines of a
very complicated process that links planetary motions with terrestrial
effects,I do not have a monopoly on the explanation and do not require
anyone to restrict themselves to it.The broad outlines of the seasonal
explanation requires the respect it deserves rather than having to
cobble together bits and pieces from various websites to carry the
point,if they can do this for space weather they can certainly do it
for our home planet.
oriel36
> A more detailed explanation for an adult is much more difficult and
> made moreso by the lack of imaging to carry the orbital point,the
> following excellent graphics were found on an astrology website and
> relate specifically to your point using the Tropic of Cancer -
>
http://www.astrologyclub.org/articles/ecliptic/spring_equinox.gif
http://www.astrologyclub.org/articles/ecliptic/summer_solstice.gif
http://www.astrologyclub.org/articles/ecliptic/fall_equinox.gif
http://www.astrologyclub.org/articles/ecliptic/winter_solstice.gif
>
> The common feature you will notice is that the geographical poles
> maintain a 23 1/2 degree latitudinal distance to where the circle of
> illumination intersects the Tropic of Cancer/Capricorn,for practical
> purposes using the polar view of the Northern hemisphere.
The points of intersection where the geographical poles are referenced
to the Artic circle and the circle of illumination at 23 1/2
latitudinal distance rather than the tropics of Cancer as seen in the
four sequence of graphics.
The geographical poles, where rotation is absent, scribe a 360 degree
circle through solar radiation and the orbital shadow by virtue of
the orbital turning with respect to the central Sun,again,taken at any
arbitrary orbit point the forward motion of the planet will have
translated into a backward motion at a point 180 degrees from the
orbital starting point.
I would like to say I was baiting somebody into making a comment but
it was a genuine error on my part to mix the latitudinal markers.
Dave Typinski
>
>Really appreciate all the effort to explain further. But I feel the
>discussion is deviating slightly from what I am seeking.
>
>I am not trying to explain the seasons. I think I have got that, at
>least I think so.
>
>What I am trying to do is to easily explain that the tip of a gnomon
>will trace a straight line around equinox.
Well... try this. Maybe. From a spatial reasoning perspective, if
you're handy with three dimensional visualization.
Form a plane from the Sun that touches the tip of the gnomon. Orient
the plane parallel to the equatorial plane.
The *only* time such a plane can be oriented parallel to the
equatorial plane is at the equinoxes.
Since it's parallel to the equatorial plane, then it's also parallel
to any line of latitude *and* normal to Earth's spin axis.
Since it's parallel to the gnomon's line of latitude, the intersection
of this plane with Earth's surface is a circle of latitude.
Since it's normal to Earth's spin axis, the gnomon's tip moves within
this plane and the shadow traces out that circle of latitude, which
looks like a straight line to us flatlanders. Thus the straight line.
What about the curve?
At any other time of the year, that plane cannot be parallel to the
equatorial plane and cannot be normal to the Earth's spin
axis--although it's intersection with Earth's surface is still a great
circle.
Since the plane is not normal to Earth's spin axis, the gnomon lifts
the plane up (toward the North side of the plane of the ecliptic) and
back down (south of...) again as Earth's rotation carries the gnomon
around. Or, you can think of the gnomon defining a new plane--and
thus a new great circle--for every moment in time as it slews around
the Earth.
That means the plane's intersection with Earh's surface is a
*different* great circle at any given moment--even though all those
great circles contain points close to the gnomon.
Thus, the tip of the shadow traces out a curve, not a straight line.
In fact, the tracing on an equinox is really an "S" shape--it's just
that the curvature is so slight that for all practical purposes it's a
straght line.
Visualization of the degenerate solutions for gnomons above 67°
latitude is left for another day.
This would make for a great Blender animation. I'll add it to the
list.
--
Dave
oriel36
I strongly suggest that you use the broom as wastepaper basket
analogy in order to grasp the basic orbital motion of the Earth as it
turns 360 degrees to the central Sun,this way you avoid referencing
'tilt' to the central sun.
If Mr Lewis is a teacher then he should be capable of spotting
condescension when he sees it or the old usenet trick of spouting junk
in order to sound like a point is being made when it reveals
ineptitude.
The benchmark for seasonal explanations is altogether different than
the old 'tilt' towards and away from the Sun but simply allowing the
specifics of orbital motion to accomplish seasonal variations with
'axial tilt' serving a much more productive role via planetary
comparisons.
Dave Typinski
>
>On Mar 30, 8:46 pm, Dave Typinski <möb...@trapezium.net> wrote:
>>
>> I've had some success using a globe with toothpicks inserted normal to
>> the surface, a dark room, and a flashlight for the sun. Just set the
>> spin axis of the globe relative to the flashlight for the portion of
>> the year you want to explore, then mark the tip of the
>> toothpick-gnomon's shadow as the globe rotates.
>
>analogy in order to grasp the basic orbital motion of the Earth as it
>turns 360 degrees to the central Sun,this way you avoid referencing
>'tilt' to the central sun.
That seems unlikely... is the broomstick tilted with respect to the
wastebasket (Sun) and the floor (ecliptic)?
--
Dave
Quadibloc
> I am not trying to explain the seasons. I think I have got that, at
> least I think so.
>
> What I am trying to do is to easily explain that the tip of a gnomon
> will trace a straight line around equinox.
Other people in this thread were, I hope, trying to answer your
question; I was replying to someone who has his own idiosyncratic
explanation for the seasons.
By a straight line, I suppose you're talking about the fact that the
figure-8 shape of an analemma looks like an X in the middle part. So
basically the issue is that the curvature of a sine wave is at a
minimum when it crosses the zero vallue... circular motion
approximates tangential motion in a straight line...
So during the day, the tip of a gnomon still moves in a circle or an
ellipse, but from one day to the next at the same time, the shadow of
the tip of the gnomon is at successive points in nearly a straight
line around the equinox. The Earth is moving sideways...
It is hard to think of a really simple explanation for this one,
because too many different pieces are involved.
John Savard
acridin...@googlemail.com
>
> - Show quoted text -
If you want to do this properly buy a globe of the Earth with the
correct axial tilt. Put a light or a candle in the centre of a table.
Point the north pole of the globe at your point representing Polaris
and, maintaiing this orientation move the globe round the candle. You
will note that you don't have to have any complicated extra orbital
motion to explain the seasons since it will be obvious that the Earth
rotates about it's tilted (with respect to the orbital plane) axis
which maintains its orientation with Polaris - or to put it another
way the "Celestial Sphere".
If you can't understand this there is something wrong with your brain
oriel36
The broom points to a distant object representing daily rotation to
Polaris so that at the North geographical pole where rotation is
absent, from late Sept to late Mar ,the observer will see this view
only -
http://www.youtube.com/watch?v=XTTDWhky9HY
As no rotation is present at the North pole and as the Earth orbits
from Sept to March,it must orbitally turn to the central Sun to
maintain that perspective.A teacher and any student can do this simply
by noticing how they first move forward ,the sideways and then walk
backwards to keep the broom pointing in the same direction without
having to consider daily rotation.
It is a 100% observational certainty that the cause for the seasons
is the specific way a planet orbits the Sun by an intrinsic turning
through 360 degrees therefore it takes dual 360 degree motions - daily
rotation and the orbital turning to explain the seasons -
http://astro.berkeley.edu/~imke/Infrared/UranusAo/ur_time_2001_2005.jpg
The analogy is easy to follow and absolutely correct and it
represents a major modification which can only be understood when
considering global climate.If people cannot even grasp what causes the
seasons there is absolutely no way they can understand climate .It is
that important or will be for Mr Lewis's students.There biggest
obstacle is not the material itself but the people who cannot alter
their view away from hemispheres 'tilting' towards and away from the
Sun but taking a wider view which involves looking at the orbital
motion of the Earth.
oriel36
'Axial tilt' is simply the consequence of the daily rotation of a
sphere,in this case,the Earth -
http://www.youtube.com/watch?v=XTTDWhky9HY
The students walking around the central object,denoting orbital motion
around the Sun,do not need to twirl and walk around the central
object at the same time,they simply acknowledge that the broomstick
pointing to the same fixed point represents daily rotation hence they
only have to consider how the Earth orbits the Sun,or in their
case,the specific way they must walk around the central object to keep
the broom pointing in one direction all the time.
The 'tilt' goes from being a cause to being just a useful reference
for the orbital motion of the Earth,at least as far as the seasons go,
as the actual dynamic for seasonal change is the fascinating way a
planet orbits the Sun.Because of Uranus and its distance from us and
from the central Sun,there is simply no argument when you can actually
see daily rotation as one thing and the seperate forward motion keeps
the planet pointing in one direction by changing its orbital
orientation to the central Sun just like the analogy I give of broom/
wastebasket -
http://hubblesite.org/newscenter/archive/releases/1999/11/video/b
This is not a competition as to what or what is not valid,but there is
a competition to see who can provide the best explanation using images
and graphics.It is also quite serious given the undercurrent of global
climate that runs through it yet first things first,and that means a
modification that is so visible,even to students,that it is much more
difficult to ignore than affirm.
starman
Wow, it looks like you have finally been able to explain it in a way
that most everyone else here has understood all along. Now the big
question for you is, do you know why the rotational axis of the earth
(broomstick) remains fixed to the same distant point in space while the
earth orbits the sun? I have a feeling this is going to open a whole new
can of worms.
cano...@yahoo.com
> It's only a parabola if the surface of the sundial is coplanar with the
> north celestial pole, since this is the axis of the cone generated by
> the gnomon's tip and the path of the Sun (to first order, ignoring the
> variation in declination of the Sun over the course of a day). Some
> sundials are in fact mounted this way. In all other cases, the path is
> a hyperbola. The asymptotes of the hyperbola are the lines drawn from
> the gnomon to the rising and setting Sun. At the equinoxes, these
> asymptotes are both identical to the east-west line, and the hyperbola
> degenerates into a straight line.
Thanks for the correction, Brian. I meant to say hyperbola and not
parabola. - Kurt
cano...@yahoo.com
> Snip> I sketched out the earth
> and sun on Mar 21, as seen from a point "vertically above" the
> eclliptic plane of the earth's orbit around the sun. But from this
> point of view, the latitudes would still not be straight lines to the
> sun. They would be curves as the north pole is 23.5 degrees to the
> "right" of center, not 90 degrees. But if I tilt my head 66.5 degrees
> to the "left" and the earth's rotational axis is parallel to my view,
> the latitudes would be straight lines.
>
> Is this the best I can use to explain to a 6th grader?
>
> Thanks.
A basketball with markers taped to the poles and a flashlight at more
than 10 meters works.
There the NASA JPL Space Simulator may be of help:
For 2009, the equinoxes and solstices are at:
2009
Equinoxes Mar 20 11 44 Sept 22 21 18
Solstices June 21 05 45 Dec 21 17 47
Use March 20, 2009 at 11:44 UT in the simulator. Look at the Earth
from above and from "The Sun". Compare the position of the Earth as
seen from the Sun. The Sun will appear to be directly over the
equator. http://en.wikipedia.org/wiki/Equator
Because the Sun has no visual parallax when viewed from the Earth, the
rays of the Sun appear to be parallel, no matter whether you are look
at the Sun from a high latitude or from the equator. That's why the
Sun traces a visual straight line for all gnonoms.
Try running the simulator at other times of the year. You'll see that
the Sun does not appear to be directly over the equator. That's when
the Sun's shadow traces a hyperbola. Think in terms of conics - a
plane intersecting a sphere.
- Kurt
Quadibloc
> Now the big
> question for you is, do you know why the rotational axis of the earth
> (broomstick) remains fixed to the same distant point in space while the
> earth orbits the sun? I have a feeling this is going to open a whole new
> can of worms.
I suppose his answer is that it does so because the other planets,
like Uranus, are observed to do so as well. After all, that's why he
thinks that Earth's magma should have bands with different rotation
periods, like Jupiter's atmosphere.
Not for him the Newtonian empiricism of explaining this by
conservation of angular momentum.
John Savard
oriel36
>
> - Show quoted text -
The flawed view imposes the usual solstice markers with the Northern
hemisphere 'tilted' away from the Sun in winter and 'tilted' towards
the Sun in summer suggesting an inclusive reference of 'tilt' to the
central Sun over the course of a year and this inclusive view is
utterly counterproductive as there is no means to describe what
happens between solstice and Equinox using the orbital motion of the
Earth.The tendency to use 'axial tilt' referenced to the Sun from
Copernicus onwards was based on the following observed view in the
absence of making planetary comparisons -
http://www.liverpoolmuseums.org.uk/nof/sun/images/high_low_sun.gif
http://www.astronomy.org/programs/seasons/pictures/09reasons-for-seasons-general.gif
The one and only proper view is to using rotational orientation/tilt
as a reference for a distant point in space (Polaris) representing
daily rotation ,,and allow the orbital specific motion to provide the
dynamic for seasonal change rather than referencing 'tilt' to the
central Sun,this way,it is fairly easy to gauge what happens between
Solstice and Equinox whereas the 'axial tilt' to the Sun without
taking into the orbital specific cannot work.
I reiterate,not a single scientist on the planet understands climate
in the absence of appreciating what actually causes the seasons due to
the motions of the Earth around the Sun and specifically the
modification which explains both the seasons and the separate issue of
the variations in the natural noon cycle.If tyhe images of Uranus
showing dual 360 degree motions with respect to the central Sun makes
this a 100 % observational and geometry certainty then it is
absolutely certain that scientists who cannot appreciate this no
nothing of global climate and whether warming is due to human
influences ,astronomical causes or some other terrestrial factor.
dke...@hotmail.com
Hi
I thought I might add a little here. At the equinox, the suns shadow
would
follow the line of latitude where the person is located. For most any
location
that wasn't near the poles, this would seem to be a straight line,
although,
as drawn on the suface of the earth, it would curve, as all latitude
lines
do. If one had a truly flat board, not one that followed the Earth
curvature,
it would cast a straight line.
Dwight
Quadibloc
> The geographical poles do not precess through 360 degrees over an
> annual orbit but rather the Earth,taken from any arbitrary orbital
> point,will move forward until 180 degrees later it is orbitally moving
> backwards,as the analogy of broom/wastebasket.The descriptions using
> 'axial tilt' alone do not taken orbital motion into consideration but
> simply tilt the Earth towards and away from the Sun and omit the
> orbital description.
What you are saying is correct - the geographical poles always stay in
the same direction. The analogy of the broom and the wastebasket
correctly describes how the Earth's orbital motion changes their
relationship to the Sun.
But this same change in the relationship between the Earth and the Sun
means that the natural noon cycle has to lose a day each year compared
to the Earth's axial rotation, if one takes the view in which the
Earth moves around the Sun with a fixed axis as the true reference for
motion. And you keep complaining about the "sidereal day", and by
doing so you contradict the accurate things you are saying here about
the seasons.
John Savard
palsing
> All these scientists going to the 'Copenhagen conference' and not one
> of them will understand the basic dynamics behind the seasons
> demonstrating what they know about global climate background,how it is
> due to the motions of the Earth and distance from the Sun and what
> they know is pretty dangerous.
>
> You are fine to discuss the motion of the Sun and shadows,I need
> people who can translate those observations into astronomical
> principles based on the Earth's motions and that is proving more
> difficult than I thought.
What a monstrous ego you have, to state that not one of the great
scientific minds of these times understands the basic dynamics of the
seasons, whereas you yourself know them perfectly. You are simply
delusional.
You are certainly correct when you lament the fact that it will be
more difficult than you thought to find even one person who thinks the
way you do...
oriel36
> On Mar 28, 11:50 pm, oriel36 <kelleher.ger...@gmail.com> wrote
>
> > All these scientists going to the 'Copenhagen conference' and not one
> > of them will understand the basic dynamics behind the seasons
> > demonstrating what they know about global climate background,how it is
> > due to the motions of the Earth and distance from the Sun and what
> > they know is pretty dangerous.
>
> > You are fine to discuss the motion of the Sun and shadows,I need
> > people who can translate those observations into astronomical
> > principles based on the Earth's motions and that is proving more
> > difficult than I thought.
>
> What a monstrous ego you have, to state that not one of the great
> scientific minds of these times understands the basic dynamics of the
> seasons, whereas you yourself know them perfectly. You are simply
> delusional.
>
If I ask any one of you what causes the seasons,the answer will be
that the Earth's 'tilt' is the cause but the actual dynamics behind
seasonal change are daily rotation and the specific way the Earth
orbits the Sun.I have already pointed out why the old hemispherical
'tilt' towards and away from the Sun gives no indication of the
orbital specific which is required to explain the seasonal daylight/
darkness variations therefore this has nothing to do with
superiority , priority of discovery or any self-serving purpose but
rather a statement of observational facts based on the motions of the
Earth.I will repeat it,those people attending the conference have no
idea about global climate as they have no framework,based on the
background conditions set by the motions of the Earth,into which to
gauge their premises and conclusions such as whether global warming is
due to human ,natural terrestrial or astronomical influences.
> You are certainly correct when you lament the fact that it will be
> more difficult than you thought to find even one person who thinks the
> way you do...
There is far more to celebrate than lament and especially using the
power of moderm imaging which is absolutely crucial to modifying the
explanation for why seasonal variations in daylight/darkness occur,in
fact,people will genuinely like the new explanation when they 'axial
tilt' as representing daily rotation as an independent motion, which
allows them to extract the genuine orbital details and treat that
motion separately.
From an astronomical viewpoint,I see the danger of dumping so much
emphasis into carbon dioxide levels as the cause for climate
variations without a clear understanding of the background for
climate and that invariably involves astronomy and the motions of the
Earth however,I still believe that the seasonal explanation is
enjoyable just in itself before applying a better foundational
background for seasonal weather patterns against the climate
background.
The trick is to get NOAA and NASA to see it for although I see these
wonderful Spaceweather sites,there is an enormous void where the
Earth's own seasonal patterns are explained and I this has to
change.The limitation of 'axial tilt' is before them as is the better
explanation and resolution using the specific way a planet orbits the
central star.
Dave Typinski
>
>The broom points to a distant object representing daily rotation to
>Polaris so that at the North geographical pole where rotation is
>absent, from late Sept to late Mar ,the observer will see this view
>only -
>
>http://www.youtube.com/watch?v=XTTDWhky9HY
>
>As no rotation is present at the North pole
The rotation is still there, it's just hidden under a zero radius.
>and as the Earth orbits
>from Sept to March,it must orbitally turn to the central Sun to
>maintain that perspective.
Better to say that the spin axis always points to the same place in
deep space and that the *apparent* turning of it with respect to the
Sun is a consequence of combining rotation about one axis (the spin)
with rotation about another axis not parallel with the spin axis (the
orbital motion).
>A teacher and any student can do this simply
>by noticing how they first move forward ,the sideways and then walk
>backwards to keep the broom pointing in the same direction without
>having to consider daily rotation.
Yep, exactly.
>It is a 100% observational certainty that the cause for the seasons
>is the specific way a planet orbits the Sun by an intrinsic turning
>through 360 degrees therefore it takes dual 360 degree motions - daily
>rotation and the orbital turning to explain the seasons -
It's better to forego the "intrinsic turning" stuff. The Earth spins
as it orbits, and its spin axis isn't normal to its orbital plane.
That's really all there is to it; no need to make it more complicated.
--
Dave
starman
> On Apr 1, 5:00 am, starman <star...@bluesky.net> wrote:
>>
>>Wow, it looks like you have finally been able to explain it in a way
>>that most everyone else here has understood all along. Now the big
>>question for you is, do you know why the rotational axis of the earth
>>(broomstick) remains fixed to the same distant point in space while the
>>earth orbits the sun? I have a feeling this is going to open a whole new
>>can of worms.
>
It is you who does not understand the *fundamental* cause of the seasons
if you can not explain why the earth's rotational axis remains fixed in
space towards the star Polaris while it (the earth) orbits the sun. If
you don't know the answer, it shouldn't take you more than a minute or
two to Google it. But of course the 'real' astronomers all ready know
the answer without having to look it up.
oriel36
> oriel36 wrote:
> > On Apr 1, 5:00 am, starman <star...@bluesky.net> wrote:
>
> >>Wow, it looks like you have finally been able to explain it in a way
> >>that most everyone else here has understood all along. Now the big
> >>question for you is, do you know why the rotational axis of the earth
> >>(broomstick) remains fixed to the same distant point in space while the
> >>earth orbits the sun? I have a feeling this is going to open a whole new
> >>can of worms.
>
> > The flawed view imposes the usual solstice markers with the Northern
> > hemisphere 'tilted' away from the Sun in winter and 'tilted' towards
> > the Sun in summer suggesting an inclusive reference of 'tilt' to the
> > central Sun over the course of a year and this inclusive view is
> > utterly counterproductive as there is no means to describe what
> > happens between solstice and Equinox using the orbital motion of the
> > Earth.The tendency to use 'axial tilt' referenced to the Sun from
> > Copernicus onwards was based on the following observed view in the
> > absence of making planetary comparisons -
>
> >http://www.liverpoolmuseums.org.uk/nof/sun/images/high_low_sun.gif
>
>
> > The one and only proper view is to using rotational orientation/tilt
> > as a reference for a distant point in space (Polaris) representing
> > daily rotation ,,and allow the orbital specific motion to provide the
> > dynamic for seasonal change rather than referencing 'tilt' to the
> > central Sun,this way,it is fairly easy to gauge what happens between
> > Solstice and Equinox whereas the 'axial tilt' to the Sun without
> > taking into the orbital specific cannot work.
>
> > I reiterate,not a single scientist on the planet understands climate
> > in the absence of appreciating what actually causes the seasons due to
> > the motions of the Earth around the Sun and specifically the
> > modification which explains both the seasons and the separate issue of
> > the variations in the natural noon cycle.If tyhe images of Uranus
> > showing dual 360 degree motions with respect to the central Sun makes
> > this a 100 % observational and geometry certainty then it is
> > absolutely certain that scientists who cannot appreciate this no
> > nothing of global climate and whether warming is due to human
> > influences ,astronomical causes or some other terrestrial factor.
>
> It is you who does not understand the *fundamental* cause of the seasons
> if you can not explain why the earth's rotational axis remains fixed in
> space towards the star Polaris while it (the earth) orbits the sun. If
> you don't know the answer, it shouldn't take you more than a minute or
> two to Google it. But of course the 'real' astronomers all ready know
> the answer without having to look it up.
I am the first to give credit to contemporary imaging and time lapse
footage as the main resource for modifying the explanation for the
seasons by isolating the orbital motion of Uranus and interpreting the
change in orientation of the rings to the Sun while keeping the daily
rotational orientation/tilt pointing in the same direction in space.It
takes just a basic acknowledgment of distances between Earth and
Uranus and Uranus and the Sun to carry this 100 % observational and
geometric certainty -
http://astro.berkeley.edu/~imke/Infrared/UranusAo/ur_time_2001_2005.jpg
It just takes a broom pointing to a fixed external point , a
wastepaper basket and the specific way to move around the basket to
mesh with the observed planetary orbital specific.
I have explained that the old habit of referencing 'axial tilt' to the
central Sun to explain the seasons is borne from hemispherical rather
than global observations that modern imaging allows and no more need
be said only a backward glance at the two common graphics for this
type of flawed explanation that omits the orbital specific -
http://www.liverpoolmuseums.org.uk/nof/sun/images/high_low_sun.gif
http://www.astronomy.org/programs/seasons/pictures/09reasons-for-seasons-general.gif
Even I accept that the people who can best interpret contemporary
imaging may not be here in this forum therefore you remain with the
limited hemispherical view of the Earth's 'tilt' towards the Sun in
summer and its 'tilt' away in winter but that is useless for today's
investigations into climate.The 6 month seasonal variations in
temperatures,say,between January and July, is many,many magnitudes
greater than purported temperatures rises due to global warming yet
scientists do not know what causes the seasonal temperature variation
even though it requires only two motions.This is why nobody at that
conference will have understand global climate yet will try to tell
people how to live and what to buy without knowing where the
temperature variations are coming from.
Golden California Girls
> It is you who does not understand the *fundamental* cause of the seasons
> if you can not explain why the earth's rotational axis remains fixed in
> space towards the star Polaris while it (the earth) orbits the sun. If
> you don't know the answer, it shouldn't take you more than a minute or
> two to Google it. But of course the 'real' astronomers all ready know
> the answer without having to look it up.
Real astronomers don't feed the troll.
Real astronomers also know the earth's axis of rotation is not fixed. Look up
nutation and precession.
starman
I don't have to look it up. I've known about both of those phenomena
since I was a teenager. I didn't want to add more confusion to his
existent confusion. One step at a time.
Whoops, I'm feeding another troll.
starman
Let's forget about the global warming issue until you first give a
satisfactory answer to the pending question in this thread. You are
basing your understanding of the relationship between the inclination
(tilt) of the earth's rotational axis in relation to it's orbital plane
(around the sun), on imaging and other observations, which is fine.
However I'm asking you to explain the underlying principle of physics
which causes the observed behavior of the planets such as Uranus, which
you like to use as an example. Specifically, why does the earth's
rotational axis remain fixed to the same point in space, like your
broomstick analogy, while the earth orbits the sun? Or to put the
question in the negative, why *doesn't* the axis of the earth's rotation
always point *towards* the sun during it's annual orbit? If this were
true, it would be like the broomstick always pointing towards the basket
in the center of the room while the student walks around it. I think you
will agree that this is not the case but why? It might be helpful if you
do some research on a child's toy which is often used as an
instructional aid in a high school physics class. Hint: The name begins
with the letter 'G'.
oriel36
>
> > Even I accept that the people who can best interpret contemporary
> > imaging may not be here in this forum therefore you remain with the
> > limited hemispherical view of the Earth's 'tilt' towards the Sun in
> > summer and its 'tilt' away in winter but that is useless for today's
> > investigations into climate.The 6 month seasonal variations in
> > temperatures,say,between January and July, is many,many magnitudes
> > greater than purported temperatures rises due to global warming yet
> > scientists do not know what causes the seasonal temperature variation
> > even though it requires only two motions.This is why nobody at that
> > conference will have understand global climate yet will try to tell
> > people how to live and what to buy without knowing where the
> > temperature variations are coming from.
>
> Let's forget about the global warming issue until you first give a
> satisfactory answer to the pending question in this thread.
It is not just about global warming as a signature of climate
variations but the minimum requirement to understand the topic through
the daily rotational an annual orbital motions of the Earth as these
combine to cause the seasons,for then and only then is it possible to
provide the framework for global climate.The satisfactory answer is
that the old hemispherical 'tilt' of winter/summer emerged over 500
years ago via Copernicus as he tried to explain hemispherical weather
patterns (seasons) through gauging the rotational orientation to the
central Sun thereby limiting all things to that reference -
http://www.liverpoolmuseums.org.uk/nof/sun/images/high_low_sun.gif
http://www.astronomy.org/programs/seasons/pictures/09reasons-for-seasons-general.gif
Taken this from the Northern hemisphere, perspective the description
fails should anyone try to explain what happens from Solstice to the
Equinox,for any given latitude other than the Equator and above the
Arctic circle.It is easier to take a wider view by noting that 'tilt'
substitutes for daily rotation thereby isolating the orbital motion of
the Earth.A simple Youtube video demonstrates that 'tilt' is just an
effect of daily rotation -
http://www.youtube.com/watch?v=XTTDWhky9HY
oriel36
I mistakenly hit the send button and do not feel like removing the
post.
The teacher here can safely teach his students what causes the seasons
without adding complications such as variable orbital speed or how the
natural noon cycles vary due to the specifics of orbital motion allied
with daily rotation.He is under no obligation to explain why the old
explanation based on hemispherical 'tilt' towards and away from the
Sun was an inclusive,limited and ultimately flawed way to explain the
seasons whereas it takes the orbital motion of the Earth and the
specific way its orbits the Sun to account for the entire seasonal
cycle.I often used the analogy of a crank pin as it 'orbits' the
central shaft to carry the point for the orbital behavior of the
planet but this is in lieu of people who will provide exciting
descriptions via graphics or images -
http://www.youtube.com/watch?v=YV9WkQkUHZ4
If you are absolutely intent on dumping everything into daily rotation
and its orientation/tilt then go right on ahead,I would always appeal
to others to try and provide the new and better description which uses
the orbital specific to do the job.It is indeed very important but not
as a weapon to promote or deny global warming but strictly something
that can be enjoyed with the consequences for climate following from
the modification.
starman
My only intention was to get you to do a little research to discover the
name and principles of the device or educational tool starting with the
letter 'G' which explains why the rotational axis of the earth remains
fixed to the same location in space, like your broomstick does in the
room. Haven't you ever wondered why this is so? I guess you made no
attempt to do that research. All I'm asking for is the name of that
device. If you can not provide it, you do not truly understand the
underlying physical principles which govern the behavior of any rotating
body, whether it be a planet or just a child's toy top. I imagine there
are more than a few readers here who are waiting to see if you can do
it. No spoilers please.
Last chance, what's the word?
Dave Typinski
>
>oriel36 wrote:
<snip>
>
>My only intention was to get you to do a little research to discover the
>name and principles of the device or educational tool starting with the
>letter 'G' which explains why the rotational axis of the earth remains
>fixed to the same location in space, like your broomstick does in the
>room. Haven't you ever wondered why this is so?
>
Does /anyone/ know? We sure can describe [phenomenon in question],
and have made excellent use of past observations to generate a very
accurate predictive algorithm... but I think the jury's still out on a
good explanation of /why/ [phenomenon in question] works the way it
does.
Yes, yes... I know that's not what you meant. Just felt like
splitting hairs tonight and making the point.
--
Dave
oriel36
I am perfectly delighted to leave you with the old hemispherical
'tilt' towards and away from the Sun whereas the actual dynamic for
seasonal is the specific way the Earth orbits the Sun,once the new
explanation is grasped the orbital specific is almost impossible to
ignore,if not conceptually then observationally via Uranus .The role
of rotational orientation/tilt then serves a more productive purpose
in determining whether a planet has equatorial or polar -like seasons.
If you wish to commit yourself to explaining the seasons by dumping
everything into daily rotation/spin/tilt then good for you,I am sure
the rest would like to hear it but effectively there is not a
scientist on the planet who understands global climate at this moment
in time given the inability to adapt to the new explanation for the
seasons which rearranges observations in a more effective way as is
the custom of genuine astronomers.I have explained where the problem
existed with the original explanation of Copernicus and how to resolve
it using analogies,graphics and actual observations of a planet with
two 360 degree observed motions with respect to the central Sun -
http://hubblesite.org/newscenter/archive/releases/1999/11/video/b/
Whether it is a genuine teacher trying to teach students or genuine
astronomer or climatologist,the basic analogy of broom substituting
for daily rotation and orientation/tilt thereby leaving the orbital
motion and the specifics of that motion to account for the seasons,it
all depends on taking responsibility for a change and that this is
important yet enjoyable.
I repeat,it is impossible to comment on global climate without first
comprehending what causes the largest temperature fluctuations as the
Earth orbits the Sun over the course of a year,turn what way you or
anyone else will,so when I ask you what causes the seasons you know
what your answer should be.
palsing
> I repeat...
************
Boy, that's the truth... over and over and over ad nauseum...
oriel36
It is worth repeating that there are no scientists on the planet with
a basic understanding of the motions of the Earth which cause seasonal
fluctuations in temperature ,that is not taunting,baiting or
grandstanding but rather an explicit statement as to what is known
about global climate.All those thousands and thousands of scientists
with their deep concern for planetary climate but ask them how the
motions of the Earth generate the seasons and they will not know as it
requires acknowledgment of the orbital specific.
The wider population is saturated with climate news now that it is big
business,these two articles being just two of many 100's today -
http://www.reuters.com/article/environmentNews/idUSTRE5314S520090402
The fact is that you cannot explain what causes the seasons and
neither can those people running around proclaiming that the sky is
falling through human influences.Until people understand the basic
principles of global climate and especially the motions of the Earth
and distance from the Sun that sets the background for weather then
scientists are being anti-scientific.The orbital motion and the
specific way a planet orbits the Sun causes the seasons and you can
remain with your old hemispherical 'tilt' explanation but it never
worked.
Quadibloc
> What I am trying to do is to easily explain that the tip of a gnomon
> will trace a straight line around equinox. (As the equinox is
> strictly just a moment in time, I assume plus or minus a few hours
> around that moment would still be valid.)
Ah, you aren't referring to it's shadow on consecutive days. I was
going to note that the Equation of Time doesn't have inflection points
on the equinoxes, because there is also a component due to the Earth's
elliptical orbit.
Instead, what happens around the equinox that leads to a straight line
is that the Sun is in the plane of the Earth's equator - so if you had
a sundial consisting of a pencil sticking up perpendicularly from a
flat disc parallel with what would be the horizontal on the equator...
the shadow would move _through_ the base of the pencil.
Since that means the Sun is moving through a great circle in the sky,
its apparent motion is confined to a flat plane.
John Savard
starman
> starman <sta...@bluesky.net> wrote:
>>My only intention was to get you (oriel36) to do a little research to discover the
>>name and principles of the device or educational tool starting with the
>>letter 'G' which explains why the rotational axis of the earth remains
>>fixed to the same location in space, like your broomstick does in the
>>room. Haven't you ever wondered why this is so?
>
> Does /anyone/ know? We sure can describe [phenomenon in question],
> and have made excellent use of past observations to generate a very
> accurate predictive algorithm... but I think the jury's still out on a
> good explanation of /why/ [phenomenon in question] works the way it
> does.
>
> Yes, yes... I know that's not what you meant. Just felt like
> splitting hairs tonight and making the point.
> --
> Dave
I agree if you address the phenomenon in question here or any involving
matter in general, you could argue that we don't understand why matter
behaves as it does on the most basic level. In fact we don't really know
the source for matter or mass. That is the domain of quantum mechanics.
But as you say, we do have a sufficient understanding of the device in
question to apply that knowledge on the scale of human interaction with
matter. It's similar to the difference between Newtonian physics and
that of Einstein. The latter works fine for explaining the behavior of
matter in everyday life but if breaks down at very high velocities or
extreme gravity. That was the genius of Einstein.
starman
>
> It is worth repeating that there are no scientists on the planet with
> a basic understanding of the motions of the Earth which cause seasonal
> fluctuations in temperature ,that is not taunting,baiting or
> specific in their descriptions thereby invalidating just about
> everything concerning global climate.There may be thousands and
> thousands of scientists just like you,repeating over and over again
> through many articles each day that carbon dioxide is creating
> temperature variations but now you know they have no framework into
> which to put that premise and conclusion.
>
> I rely on people who take some joy from seeing how the orbital motion
> of the Earth keeps the rotational orientation ,due to daily
> rotation,fixed to a point in space (such as Polaris) and thereby that
> orbital specific is responsible for seasonal changes.
>
> It makes you look like astrologers but that is not the point,the point
> is finding genuine individuals,teachers or institutions who can adapt
> and accept this major modification for what it is.
Absolutely amazing. You didn't even address my challenge to discover the
name of the device which demonstrates the behavior of the earth's
rotational axis. You seem to be aware that the rotational axis remains
fixed in space but you don't have a clue why this is so.
One final question for you; how did you first learn about the behavior
of the earth's rotational axis? Weren't you the least bit curious to
know more about the principle which explains that phenomenon? Any high
school physics student could explain it. Why can't you?
oriel36
> Dave Typinski wrote:
> > starman <star...@bluesky.net> wrote:
> >>My only intention was to get you (oriel36) to do a little research to discover the
> >>name and principles of the device or educational tool starting with the
> >>letter 'G' which explains why the rotational axis of the earth remains
> >>fixed to the same location in space, like your broomstick does in the
> >>room. Haven't you ever wondered why this is so?
>
> > Does /anyone/ know? We sure can describe [phenomenon in question],
> > and have made excellent use of past observations to generate a very
> > accurate predictive algorithm... but I think the jury's still out on a
> > good explanation of /why/ [phenomenon in question] works the way it
> > does.
>
> > Yes, yes... I know that's not what you meant. Just felt like
> > splitting hairs tonight and making the point.
> > --
> > Dave
>
> I agree if you address the phenomenon in question here or any involving
> matter in general, you could argue that we don't understand why matter
> behaves as it does on the most basic level.
There are many terms thrown around today like 'profound
irresponsibility' in respect to financial markets but these things
have nothing in comparison to the scientific equivalent and the
absolute total lack of common sense on the most basic of
questions,premises and conclusions of which the seasonal topic is the
most important but just one among many.
In fact we don't really know
> the source for matter or mass. That is the domain of quantum mechanics.
> But as you say, we do have a sufficient understanding of the device in
> question to apply that knowledge on the scale of human interaction with
> matter. It's similar to the difference between Newtonian physics and
> that of Einstein. The latter works fine for explaining the behavior of
> matter in everyday life but if breaks down at very high velocities or
> extreme gravity. That was the genius of Einstein.
The old cobblers of qm/relativity have now past their shelf life as
the internet has created a new approach to investigations of
terrestrial and terrestrial phenomena,in other words,the old trickle
down format no longer works and hasn't done for many years.If you
want me to explain to you how it does not just originate with Newton's
distortions of heliocentric reasoning in terms of his absolute/
relative time and space distinctions but precedes it with Flamsteed's
poor premise and conclusion regarding daily rotation through 360
degrees and the return of a star to a meridian as an external
celestial reference.It all ties in with this topic and the inability
of the world's scientists to appreciate what causes the seasons.
I am sure some of these fine gentlemen can explain to you where Newton
gets his absolute/relative space from by distorting the resolution for
retrogrades or the absolute/relative time definition via the natural
noon Equation of Time correction (related to sundials) but all that
stuff is now behind me as I look for people who clearly wish to
discuss and discover cause and effect such as the new seasonal
explanation via the specifics of orbital motion.
oriel36
I have looked at the website from NOAA,an organisation I respect and
their explanation for the seasons tries to do reference daily rotation
and the 'tilt' generated from that motion to the central Sun thereby
it is impossible to appreciate the actual dynamic via orbital motion -
"Lastly, on the winter solstice near December 21st, the Sun is
positioned directly over the Tropic of Capricorn at 23.5 degrees south
latitude. The southern hemisphere is therefore receiving the direct
sunlight, with little scattering of the sun's rays and a high sun
angle producing long days. The northern hemisphere is tipped away
from the Sun, producing short days and a low sun angle."
http://www.crh.noaa.gov/fsd/astro/season.php
The rotational axis,taking a Northern hemispherical view,is fixed to
Polaris because of the specific way the Earth orbits the central Sun
and that is both your answer and the one which provides the reason for
the seasons.If you have problems with this,use a broom handle to
substitute for daily rotation and its fixed orientation,walk around a
central object representing orbital motion around the Sun and the
specifics of your 'orbital' motion will show how hemispheres are
brought to the Equinox and Solstice positions by keeping the broom
handle focused on one specific spot.
No offence to the semi-geocentric/heliocentric description of the
seasons by the main organisation responsible for weather and
climate,their description is simply that of the old hemispherical from
the Sun 'tilt' towards and away from the Sun with no precise
explanation between Solstice and Equinox ,an explanation easily
explained via the orbital specifics.
The challenge is not climate change,the challenge for future
investigators is brushing aside people who have no interest or no
intelligence in matters of astronomy or climate and dealing with the
matter in a responsible way.It still stands that whatever the volume
of discussion about climate,there is not a single person who
understands global climate and it does come down to the simple
question as to what causes the temperature fluctuations and daylight/
darkness variations associated with the seasons.
I do not beg questions off you but I will say that if you are content
with your 'tilt' to the orbital plane as the explanation for the
seasons then good for you but it does not explain anythin.
Dave Typinski
>> is finding genuine individuals,teachers or institutions who can adapt
>> and accept this major modification for what it is.
>
Oriel doesn't address direct challenges. Instead, he does what every
good politician does: he answers the questions he wishes he'd been
asked, not the questions actually asked.
I think it was Donald Rumsfeld who stated that this was his way of
approaching press conferences.
--
Dave
starman
He certainly is an interesting though slippery character. Reminds me of
a savant. He repeats the same phrases over and over but in his case he
almost convinces one that he knows what he's talking about. To his
credit he does have a better than average command of the English
language. There must be some kind of disconnect between his ability to
reason and his language skills. Maybe something went wrong along the
way. What I find strange is he was apparently able to accurately deduce
how the earth's rotational axis behaves, based mostly on images, but he
shows no interest in understanding why. It's amusing that he thinks he's
the only one on the planet to discover the true behavior of the earth's
axis. Talk about delusions of grandeur.
Oh well, it was fun for a while. My apologies to those who indulged my
attempts to learn more about this guy. I imagine most here have him kill
filed. I'll continue to read his posts, if for no other reason than
trying to crack this mystery.
oriel36
>
> >>oriel36 wrote:
>
> >>>It makes you look like astrologers but that is not the point,the point
> >>>is finding genuine individuals,teachers or institutions who can adapt
> >>>and accept this major modification for what it is.
>
> >>Absolutely amazing. You didn't even address my challenge...
>
> > Oriel doesn't address direct challenges. Instead, he does what every
> > good politician does: he answers the questions he wishes he'd been
> > asked, not the questions actually asked.
>
> > I think it was Donald Rumsfeld who stated that this was his way of
> > approaching press conferences.
> > --
> > Dave
>
> He certainly is an interesting though slippery character. Reminds me of
> a savant. He repeats the same phrases over and over but in his case he
> almost convinces one that he knows what he's talking about. To his
> credit he does have a better than average command of the English
> language. There must be some kind of disconnect between his ability to
> reason and his language skills. Maybe something went wrong along the
> way. What I find strange is he was apparently able to accurately deduce
> how the earth's rotational axis behaves, based mostly on images, but he
> shows no interest in understanding why. It's amusing that he thinks he's
> the only one on the planet to discover the true behavior of the earth's
> axis. Talk about delusions of grandeur.
You are bound to read something like that in the descriptions of the
orbital specific due to the ideology you follow whereas the actual
statement is fairly simple - not one scientist at present understands
global climate due to their inability to explain correctly,at least
at present, the annual temperature fluctuations and daylight/darkness
variations otherwise know as the seasons.The chances of the correct
explanation based on a modification of the original variable
inclination reasoning of Copernicus depends on how quickly the truly
awful error which originated through Flamsteed in justifying the
motions of the Earth via timekeeping averages of the Equatorial
coordinate system is dealt with.The fact that Newton built on this
flawed system only obscures things further with the additional
complication of empiricism and its institutional dominance.This latter
complication of Newton/empiricism has little or nothing to do with
astronomical interpretation ( it merely obscures astronomical methods
and insights) as it represents something akin to Piltdown man by
distorting existing data to fit a preconceived agenda,in Newton's
case,trying to fit planetary motions into terrestrial
ballistics.Einstein merely extended the luxury Newton give himself in
creating his false 'frame of reference' for retrograde resolution to
unlimited choices,great if you are a mathematician but useless for
astronomers who rely on strict controls for observing,interpreting and
drawing premises and conclusions.
Aside from the enormous exercise in scientific forensics,the technical
matter still remains as to how to move forward with the recognition
that it takes the full orbital circumference and motion of the planet
around the Sun to explain why huge temperature variations occur
between January and July for different parts of the planet. The
tendency to reference everything off daily rotational orientation to
the central Sun,via the Ra/Dec complication, is the major bottleneck
which can be resolved by fixing that rotation/orientation to an
external point and using it as a reference for the specifics of
orbital motion,by analogy,broom handle substitutes for daily rotation
leaving the specific way to walk around a central object as denoting
orbital motion.
> Oh well, it was fun for a while. My apologies to those who indulged my
> attempts to learn more about this guy. I imagine most here have him kill
> filed. I'll continue to read his posts, if for no other reason than
> trying to crack this mystery.
The technical details for the modification of seasonal fluctuations
and variations are based on observational certainties,something which
only contemporary imaging provides and especially the images of Uranus
-
http://hubblesite.org/newscenter/archive/releases/1999/11/video/b/
The empirical tendency is to draw a conclusion and find data to fit
that conclusion but the Piltdown man episode shows how destructive
that can be by sending men down conceptual dead ends.The astronomical
version of 'Piltdown man' is provided by Flamsteed in his search to
resolve terrestrial longitudes by using timekeeping averages to reach
a conclusion for the motions of the Earth.It took over 40 years after
the initial discovery for men to finally come to their senses and
identify the monumental hoax but a backward glance to what happened
while the Piltdown was still conceived as being something real does
not make pleasant reading -
"Can virtually all scientists be wrong about such an important matter
as human origins?" The answer, most emphatically is, "Yes, and it
wouldn't be the first time." Over 500 doctoral dissertations were done
on Piltdown, yet all this intense scrutiny failed to expose the fake.
" (Parker, 1981)
The error by Flamsteed looks harmless at first glance,but like the
fragments of the Piltdown man skull in the hands of somebody involved
in astronomy ,it is possible to decipher the implications arising from
the terrible mistake -
"... 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..." Flamsteed
Like Piltdown man,after its exposure,there are huge positives to look
forward to.There has been an enormous build-up of imaging and data
that no longer needs to be limited to the astrological restrictions
imposed in the late 17th century and preconceptions or conclusions
derived from that framework therefore new avenues open up while
dealing with the forensics of the mistakes separately.
It is because such emphasis has been placed on carbon dioxide levels
without the presence of an accurate global climate framework that
requires immediate attention unlike the slow and anonymous departure
of the troublesome Piltdown man hoax,in short,somebody has to take
responsibility for its astronomical equivalent.While it is fine to
drop pollution levels and respect the planet,it is not fine to draw
conclusions without first understanding basic astronomical principles
in respect to climate and weather and that requires a solid foundation
based on the daily and annual motions of the Earth.
Quadibloc
> The chances of the correct
> explanation based on a modification of the original variable
> inclination reasoning of Copernicus depends on how quickly the truly
> awful error which originated through Flamsteed in justifying the
> motions of the Earth via timekeeping averages of the Equatorial
> coordinate system is dealt with.
He did _not_ use "timekeeping averages" of any kind.
> The
> tendency to reference everything off daily rotational orientation to
> the central Sun,via the Ra/Dec complication, is the major bottleneck
> which can be resolved by fixing that rotation/orientation to an
> external point and using it as a reference for the specifics of
> orbital motion,by analogy,broom handle substitutes for daily rotation
> leaving the specific way to walk around a central object as denoting
> orbital motion.
Rather, he began from considering the Earth's axis to be fixed in
direction in space, and the relationship between that axis and the
direction to the Sun changing due to the Earth's orbital motion around
the Sun, just as you give in your analogy of the broomstick.
Since the relationship of the Earth's daily motions to the Sun is
complicated by the axis of the rotation being not perpendicular to the
ecliptic plane, and by the Earth's orbit being a Keplerian ellipse and
not a circle, his next step was not to use solar noon, or an average
of solar noon, or a calendrical system. His next step was to use a
*mechanical clock*, whose pendulum periods would be uniform,
regardless of whether or not they were geared to the average of mean
solar noon, and to compare the Earth's motions to the starry heavens -
because the Earth's axis, and the Earth's orbit, are judged from the
fixed (or, at least, very slowly moving) directions to the stars.
Doing so, he correctly observed the _fact_ that the Earth's axial
rotation is uniform when judged against the distant stars. Beginning,
therefore, with an Earth upon which no forces act to speed up or slow
down its rotation - of course, that is an oversimplification, as the
tides do slow down the Earth's rotation over a very long time - the
annual variation in the sundial, from the Equation of Time, can be
derived from the Earth's orbit being elliptical, and inclined to the
Earth's poles.
If you begin from the things that are simple and uniform, and combine
them together, you can build up to reach the complexity of the natural
noon cycle, and understand it. You insist we must start only from the
natural noon cycle, and not make any attempt to understand. And you
wonder why we, who already do understand what Newton and Flamsteed
have taught us, refuse utterly to follow you, seeing no merit in your
exhortations.
John Savard