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You wrote:
“….unless you are absolutely intent in remaining with 'axial tilt' in which case you are welcome to remain with that flawed premise and conclusion.” To me this is the strongest evidence yet that you don’t accept the concept of axial tilt – am I correct in this? So what is the angle between the plane of the earth’s orbit and the axis around the earth rotates? Are you saying that it is 90 degrees or some other figure? If axial tilt exists then I cannot see how variable day night length doesn’t automatically follow. On December 21st the north polar regions are in 24 hours of darkness but ON THE SAME DAY the south polar regions have 24 hours of daylight. How do you account for via any other mechanism other than axial tilt? Where you live have you not noticed that the maximum angle above the horizon that the sun reaches varies throughout the year? How do you account for via any other mechanism other than axial tilt? You wrote: "Again, if daily rotation ceased, every location would experience one daylight/darkness cycle over the course of an annual orbit as a location slowly turns through 360 degrees and any intelligent person can then assume that this motion exists simultaneously with daily rotation." Yes indeed we all agree that the motion of the Earth around the sun exists simultaneously with the daily rotation. These two motions in combination with axial tilt and the non-circular orbit accounts for day and night, the variable length of day and night and the seasons. -- Martin Nicholson - Daventry, UK http://www.martin-nicholson.info/index.htm Dealing with John Greaves FAQ http://www.geocities.com/badastrobuster/index.htm |
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Again,thanks for setting aside the less than technical responses
directed at me. On Oct 24, 10:43*am, ukastronomy wrote: You wrote: “….unless you are absolutely intent in remaining with 'axial tilt' *in which case you are welcome to remain with that flawed premise and conclusion.” To me this is the strongest evidence yet that you don’t accept the concept of axial tilt – am I correct in this? It is a matter of precision - axial tilt or rotational orientation is not,I repeat, not responsible for seasonal variations in daylight/ darkness,it stands to reason given that no seasonal variations occur at the Equator in terms of daylight/darkness however the global variation in the natural noon cycle occurs there just as it does for all points North and South of the Equator. So what is the angle between the plane of the earth’s orbit and the axis around the earth rotates? Are you saying that it is 90 degrees or some other figure? If axial tilt exists then I cannot see how variable day night length doesn’t automatically follow. I do not know what you expect me to do,I have shown that daily rotation cause of the day/night cycle so the variations in the annual daylight/darkness variations have to be found elsewhere hence looking at the specifics of orbital motion.While I am under no obligation to remain focused on rotational orientation (tilt) I do so as a courtesy for your excellent and dignified way you have comported yourself. Rotational orientation (tilt) only dictates how extreme the seasonal variations are for any given latitude,for instance,there are no seasonal variations at the rotational Equator of Uranus,in other words,the daylight/darkness cycles remain the same just as it does on Earth.The unique rotational orientation of that planet shows just how extreme the seasonal variations are over the course of an annual orbit for both sides of the Equator however the cause of the seasonal variations in daylight/darkness remain the same as for the Earth in the specifics of orbital motion and not 'tilting' or 'pointing' towards the Sun. http://hubblesite.org/newscenter/arc...999/11/video/b The reason Uranus is so spectacularly useful in explaining the seasons is that its unique rotational orientation (tilt) almost shows what happens in the absence of daily rotation insofar as a location will orbitally turn through 360 degrees to the Sun separate to daily rotation. On December 21st the north polar regions are in 24 hours of darkness but ON THE SAME DAY the south polar regions have 24 hours of daylight. How do you account for via any other mechanism other than axial tilt? The extreme variations in daylight/darkness are due to both daily rotation and orbital motion and at both poles where rotation is at its least,within reason,those location experience a single cycle of daylight/darkness.The global perspective ignores hemispherical concerns by dropping axial inclination as the dynamic for seasonal variation and puts the dynamical cause in the Earth's orbital motion - http://www.youtube.com/watch?v=nwTrYVBcx9s The motions of Earth are behaving exactly like Uranus apart from the degree of fixed rotational orientation. Where you live have you not noticed that the maximum angle above the horizon that the sun reaches varies throughout the year? How do you account for via any other mechanism other than axial tilt? The daylight/darkness cycle remains constant at the Equator while further North and South the geocentric view of variable solar inclination becomes progressively larger the closer to the geographical poles where the variation is extreme.The answer remains the same by way of two motions rather than a single orientation of 'axial tilt'.What you see in the U.K. is a set relationship between daily rotation and the the change in the way the planet has orbitally turned to the central Sun.You will know this by setting you stopwatch to a sundial when natural noon is observed and marking the difference between the two following natural noon cycles,the time difference amounts to the amount the Earth has orbitally turned to the central Sun allowing for constant daily rotation.Kepler thought variable daily rotation causes the noon cycles to vary but the variation is strictly an orbital component. You wrote: "Again, if daily rotation ceased, every location would experience one daylight/darkness cycle over the course of an annual orbit *as a location slowly turns through 360 degrees and any intelligent person can then assume that this motion exists simultaneously with daily rotation." Yes indeed we all agree that the motion of the Earth around the sun exists simultaneously with the daily rotation. That is imprecise, when treating orbital motion in isolation from daily rotation,the planet will turn slowly through 360 degrees over an annual orbit and allied with daily rotation will generate the seasonal and natural noon effects,experiences and observations. This 360 degree component is intrinsic to the planet itself meaning that the turning occurs as a consequence of orbital motion around the central Sun and in turning,does not follow daily rotational orientation.The limited view of the Earth from space showing the sequence of events and this orbital turning shows up as the circle of illumination appearing to pivot off the Equator however I simply turn to Uranus,learn the lesson of two separate motions and account for the same motions as the Earth orbits the Sun - http://www.youtube.com/watch?v=nwTrYVBcx9s You can actually see why variations in the seasonal daylight/darkness cycle do not exist at the Equator and all with the magnificence of modern imaging. These two motions in combination with axial tilt and the non-circular orbit accounts for day and night, the variable length of day and night and the seasons. The seasons amount variations in daylight/darkness over and above seasonal weather patterns however the specifics are in the orbital motion of the Earth and its relationship with daily rotation.Again,'tilt' or rotational orientation only determines how pronounced the seasonal variations are for any given latitude but the cause of the seasonal variations belongs strictly to orbital motion. I really have to acknowledge your input as the first person to take this matter seriously in the way it should.The original explanation by Copernicus is quite clear on axial/equatorial 'tilt' and has never been tested in any meaningful way since its appearance in De Revolutionibus - "To this circle, which goes through the middle of the signs, and to its plane, the equator and the earth's axis must be understood to have a variable inclination. For if they stayed at a constant angle, and were affected exclusively by the motion of the centre, no inequality of days and nights would be observed. On the contrary,it day or the day of equal daylight and darkness, or summer or winter, or whatever the character of the season, it would remain identical and unchanged." Copernicus Copernicus wrote that many years before Kepler's refinement which modified orbital geometry to elliptical with variable orbital speed and the hint of a better explanation for the season arises from that variable speed as the Earth orbits the central Sun or rather,the specific way the Earth orbits the Sun.Given that you have kept this topic open,I request that you take another look at the premise and conclusion and try to open up the matter for discussion with others as you have done with me.I insist that it is the power of modern imaging that makes the new explanation possible and the possibilities it opens up are truly spectacular even at this stage in outlines,truly !. You can expect nothing but trouble should you choose to depart from the 'axial tilt' dynamic as the cause for the seasons but simultaneously the rewards far exceed all the complaints directed at you even if you end up concluding that 'axial tilt' causes the seasons and the natural noon cycle variations. -- Martin Nicholson - Daventry, UKhttp://www.martin-nicholson.info/index.htm Dealing with John Greaves FAQhttp://www.geocities.com/badastrobuster/index.htm |
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On Oct 24, 10:24*am, oriel36 wrote:
The original explanation by Copernicus is quite clear on axial/equatorial 'tilt' and has never been tested in any meaningful way since its appearance in De Revolutionibus - *"To this circle, which goes through the middle of the signs, and to its plane, the equator and the earth's axis must be understood to have a variable inclination. For if they stayed at a constant angle, and were affected exclusively by the motion of the centre, no inequality of days and nights would be observed. On the contrary,it day or the day of equal daylight and darkness, or summer or winter, or whatever the character of the *season, it would remain identical and unchanged." Copernicus As we know, the inclination of the Earth's axis to the ecliptic (which is "this circle" in the quote above) has a fixed and unalterable inclination. Otherwise, the celestial pole would not remain fixed in its position close to the star Polaris. Does this then mean Copernicus was wrong? I do not think so. Because his conclusion only follows from his premise within a system such as that of Tycho Brahe. That is, if the inclination of the Earth's axis, when compared to the line from the Earth to the Sun, does not change, then the length of the day could not alter in the course of a year. But if the orientation of the Earth's axis remains constant, while the direction from the Earth to the Sun changes, then an axis not perpendicular to the plane of the orbit will cause areas close to the poles to be always in sunlight for part of the year, and always in darkness for another part. Thus, I believe that the apparent difference between what Copernicus has stated and what modern astronomy accepts is not real, and the mystery would be resolved through the context of what you have quoted. John Savard |
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Quadibloc wrote:
On Oct 24, 10:24 am, oriel36 wrote: The original explanation by A kook arguing with a computer program(oriel) ![]() That bloody program will always spout variations of one theme, and let people believe it reponds to them. But it doesnt. You might as well listen to random hiss from a radio. |
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oriel36 wrote:
Again,thanks for setting aside the less than technical responses directed at me. On Oct 24, 10:43 am, ukastronomy wrote: You wrote: “….unless you are absolutely intent in remaining with 'axial tilt' in which case you are welcome to remain with that flawed premise and conclusion.” To me this is the strongest evidence yet that you don’t accept the concept of axial tilt – am I correct in this? It is a matter of precision - axial tilt or rotational orientation is not,I repeat, not responsible for seasonal variations in daylight/ darkness,it stands to reason given that no seasonal variations occur at the Equator in terms of daylight/darkness If you look at the length of day data on the net for a place such as Kampala ( 20 arc seconds from the equator) you'll see that this is not a true statement. |
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![]() Sjouke Burry wrote: A kook arguing with a computer program(oriel) ![]() That bloody program will always spout variations of one theme, and let people believe it reponds to them. But it doesnt. You might as well listen to random hiss from a radio. The above is easy to verify. Try to get oriel36 to understand and answer the question "what is the sum of two plus two?". IT can't answer because IT wasn't programmed to handle that situation. |
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On Oct 25, 2:11*am, OG wrote:
oriel36 wrote: Again,thanks for setting aside the less than technical responses directed at me. On Oct 24, 10:43 am, ukastronomy wrote: You wrote: “….unless you are absolutely intent in remaining with 'axial tilt' *in which case you are welcome to remain with that flawed premise and conclusion.” To me this is the strongest evidence yet that you don’t accept the concept of axial tilt – am I correct in this? It is a matter of precision - axial tilt or rotational orientation is not,I repeat, not responsible for seasonal variations in daylight/ darkness,it stands to reason given that no seasonal variations occur at the Equator in terms of daylight/darkness If you look at the length of day data on the net for a place such as Kampala ( 20 arc seconds from the equator) you'll see that this is not a true statement. 'Axial tilt' is not responsible for the seasonal variations in daylight/darkness and if you cannot figure it out by comparing the rotational orientations of Earth and Uranus along with the observed orbital orientation change (with heliocentric orbital motion inferred) then there is very little I can do to help you interpret the images - http://hubblesite.org/newscenter/arc...999/11/video/b An astronomer is expected to be precise therefore the "length of the day" as you call it,is actually the length of the natural noon cycle,something quite apart from seasonal and hemispherical daylight/ darkness cycles.While both have a global resolution using two 360 degree motions,the tricky part may actually picking up on the 360 degree orbital component as intrinsic to the planet itself with orbital motion around the central Sun inferred. The rotational orientation (tilt) of the Earth only dictates how pronounced the seasonal daylight/darkness variations are while the actual cause of the seasonal variations in daylight/darkness arise from the orbital motion and specifically the 360 degree change in location with respect to the central Sun allied with daily rotation. http://www.youtube.com/watch?v=nwTrYVBcx9s Before you disappear ,learn that the combination of the slow and uneven orbital change,allied with constant daily rotation and using natural noon as a benchmark creates an observed variation in observed noon therefore the natural day varies at the Equator and all points on the planet however the symmetry between daylight and darkness at the Equator remains the same. No use blurting out 'axial tilt' at me every time I try to present to new explanation for the seasons by isolating the orbital component derived from orbital motion,a genuinely curious person just asks what happens to a location if daily rotation is absent and they get their answer from locations at the geographical poles where daily rotation is almost absent - a location will turn through 360 degrees with respect to the central Sun and take an entire orbit to do so. Don't you think that the wider population should receive a proper explanation for the second most immediate experience after the day and night cycle (due to daily rotation) insofar as seasonal variations in daylight/darkness are due to the way the Earth orbits the Sun.Without that proper explanation the link between astronomy and,areas such as climatology ,geology and other terrestrial studies will almost be impossible ?. Take it up with Martin if you do not feel comfortable continuing the conversation with me. |
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On Oct 25, 8:31*am, oriel36 wrote:
An astronomer is expected to be precise therefore the "length of the day" as you call it,is actually the length of the natural noon cycle,something quite apart from seasonal and hemispherical daylight/ darkness cycles. I would suspect that when he spoke of the "length of the day", he was referring to the length of the daylight portion of the cycle, and not the daily change in the Equation of Time. Do you, then, not have an objection to holding axial orientation responsible for the length of the daylight portion of the cycle (along with the interaction between the daily and yearly motions, which interaction in this area is regulated by the axial orientation)? The reason why there is also an effect of axial orientation on the Equation of Time, it being responsible for the portion that goes through two cycles in a year, is complicated, but I do illustrate it on my web site. http://www.quadibloc.com/science/eot.htm but I do not believe he is raising that issue at all. John Savard |
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