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Please note: Many of the everyday things around us are poorly understood.
One such thing is the Moon Illusion. I intended to post this question on Maximaria's Venus Rising thread but time slipped away so I ask it here instead. The rising moon appears three times as large
as when it is directly overhead. Why?
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Dear milum:I remember an article about this in Scientific American a long time ago. No way
of finding that. All I remember is that it is an illusion, which I have noticed many times.
I'll try searching Internet, but am not confident of finding anything good.
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Dear milum: I'll be double dipped in doo-doo, on my siearch for psychology moon size illusion I found this URL http://facstaff.uww.edu/mccreadd/
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Same with the sun...and with setting. Though I think the size at setting is smaller than the size at rising. Interesting, milo...something so obvious, and yet I never gave it any real thought until this.
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Yes Doc Bill, the folks behind that URL might have hit upon the mechanics of the lllusion. Now we should look for an evolutionary advantage for this deceptive portrayal of the external world. I will quote from books and summarize and bring WO'N up to speed.
The rising full moon appears huge on the horizon, although an hour later, when well up, it seems normal in size. This is the moon illusion. Aristotle, Ptolemy, and Confucius all commented on it. At present there exists more than a dozen solutions to the size-distance paradox with each theory having a musing of advocates but so far no consensus.
Most of the distance objects that we see in this world are closer when seen overhead than when seen in the far distance. Clouds are closer than mountains, so it seems natural to assign greater size to the visible objects on the horizon than to those overhead. But the sun and the moon are not in this group, they are exta-terrestrial and are virtually identical in size when on the horizon and when at their zenith. So why does the eye's mind see them as such?
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Dear milum: my vision just won't take reading that entire URL carefully. One thing I didn't see
mentioned was comparison of photograph at moonrise, and same lens photo at moon zenith.
I'm also surprised that a small percentage of people have a different illusion.
I cannot think of any evolutionary tie-in to the illusion.
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an article about this in Scientific American a long time ago. No way of finding that
I remember that article too, can't locate it immediately. The most recent mention of it is in
"...In Brief; March 2000; by Collins, Musser, Martindale,Yam; 3 Page(s)
Heart of Darkness; Superbug Cleans Up; Moon Illusion Explained; Lou Gehrig's Virus?; Surrogate Cat; One Last Stretch; Shrinking to Survive; Organic Space"
located through SciAm.com Archives. Only goes back to 1993, though.
A few years ago Scientific American offered a complete index of lhe last fifty years of so on a floppy disc; I don't know whether they still do. By now they could have a CD with the complete library on it, as like National Geographic does. I should look into it again; I have all the issues (just about) back to 1949 or so when the New Management took over (Gerald Piel, Dennis Flanagan, etc.) and it would be handy!
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Fascinating stuff, milum!...Thanks! 
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Pretty impressive collection of SciAm magazines wofahulicodoc, I couldn't pull up the 2000 issue that you referred to, but if you remember the point of it, it would be nice to know.
The following observations were lifted from the book The Story of Light by Ben Bova (remember him?) They are in no marching order but sorta dance up to the question, Why did Mother Evolution make the sun and moon appear so fat when they are on the horizon?
***Flatworms, like every other animal, tend to keep their eyes (two, four, or six, depending on the species) close to their brains. Even though their eyes are little more than little cups of light-sensitive material, being close to the brain shortens reaction time. And if you make your living preying on the microscopic jungle fauna of protozans, tiny snails, and worms; milliseconds count.
***The molluscs developed true vision. Snails, scallops, the squid, and the octopus all have developed eyes with real lenses and sophisticated retina. Still, it is rather startling to see a row of bright blue eyes peeking out from the edges of a scallop shell.
*** Spiders have eyes remarkably like those of the most advanced snails, a good example of convergent evolution. But like a cheap camera that doesn't have automatic focus, the spider must move back or creep closer to the object of his desire in order to get a clear look.
*** Insects, of course, developed compound eyes. Thousands of individual lenses, packed close together, are individually connected to protorecptor cells by tubes rather like a miniature version of the tube of a telescope. With thousands of individual images being carried to the brain, insects are very sensitive to motion in their field of view. Ever tried to stomp a roach, swat a fly, or slap a mosquito?
*** The human eye is among the best of the image-forming sort that biologists have taken to calling "camera-type" eyes in a sort of reverse wordplay that delights etymologists.
( to be continued in PM )
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Jumping from eyes-close-to-brains-in-lower-animals to brains themselves, I recall a little gem of a puzzle published by John de Cuevas in October 1994, whose solution read: The juvenile sea squirt wanders through the sea
searching for a suitable rock or hunk of coral
to cling to and make its home for life
When it finds its spot and takes root
it doesn’t need its brain any more
so it eats it
It’s rather like getting tenure -- Daniel Dennett, Consciousness
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Boys,
Well, I think you can all tell I'm not much of a techie when it comes to all of this, but I knew I just read the explanation of this moon/sun illusion whilst rummaging through some of the url's posted in here around high altitude sprites and anthropic principles etc. So here it is. I can't believe I found it!
http://www.suite101.com/article.cfm/science_sky/92077
One of the things I am most grateful for living at just this time on earth is that the full moon rises just at dusk and is up in the sky the entire night long. I think that is amazing, astoundingly beautiful, and inspiringly mystical. But surely, there have been whole epochs on earth when this was not the case, when the full moon rose during the day, and was on the other side of the earth during the night.
This must have been the case for some epochs of time, don't you think. Where are our astronomers in here? And where are all the women on this thread? Are they not as enthralled as am I as they look up into that velvet deep....Sometimes I know just what those coyotes must be howling about!
Oh, and Milum, it's maGimaria, not maxi(ugh! That sounds like a feminine product)
And call me an 'anthropomoron' (I'd do that little trademark thingy claiming that word as my own, that Faldage taught us newbies to do, but I was sure I would never presume to use it, so it's lost way back in the threads....), but I take it as a sign that *The Great Mystery* does indeed love me for giving me this gift, and moreso, that I have the heart and mind (as well as the fearlessness *and* humility!) to love my *Creator* back. Which I do, with all my heart and soul. And I just thought that *I* needed to state this in here somewhere for all of you who experience the 'breath of the buffalo' so differently from me. My reality relies completely on weaving synchronicities, which so many of you poo-poo. But it matters not to me, as its my world I'm living in....and I'm actually having a rather good time...and happy to share it with all of you...
And thanks milum for bringing this up. I'm always looking for thoughts about galaxies and evolution, paleontology and other mysteries we ignore as we go about our silly tasks from day to day.
Now, does anyone want to talk about the Void?
mm
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One of the things I am most grateful for living at just this time on earth is that the full moon rises just at dusk and is up in the sky the entire night long. I think that is amazing, astoundingly beautiful, and inspiringly mystical. But surely, there have been whole epochs on earth when this was not the case, when the full moon rose during the day, and was on the other side of the earth during the night.
the moon is full when it is on the opposite side of it's orbit around the earth from the sun. we don't get a lunar eclipse every month only because the moon's orbit is tilted a bit.
it's no more mystical than anything else you can say about orbiting bodies.
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I couldn't pull up the 2000 issue that you referred to, but if you remember the point of it, it would be nice to know.
Easier to type it in than to summarize it:
In Brief: Moon Illlusion Explained
Lloyd Kaufman and his son James H. Kaufman, working at the IBM Almaden Research Center, have gathered concrete data to explain the ancient optical illusion that causes a full moon near the horizon to appear bigger than a moon seen overhead. By measuring viewers' perception of the distance to artificial moons projected onto the sky, the researchers showed that the "apparent distance" to the moon -- rather than the real distance -- determines its perceived size. When the moon is on the horizon, the brain picks up distance cues from the surrounding terrain and interprets the moon as being farher away. This, in turn, causes the brain to see a larger moon. (The new work opposes alternative explanations based on "apparent size.") The study appeeared in the January 4 [2000] Proceedings of the National Acdemy of Sciences. --D.M."
--Scientific American, Vol 282, No. 3 (March 2000), p.22.
(The article is signed with the initials D.M. but it's not I; after turning back a few pages in the issue I conclude that they belong to one Diane Martindale.)
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Oh, tsuwm, that's such a perfect response! Mystery is in the soul of the beholder. And surely you would expect by now that *I find the Whole Thing to be mystical! And I am quite sure you do not, and therein lies your charm (for me)!
"the moon is full when it is on the opposite side of it's orbit around the earth from the sun. we don't get a lunar eclipse every month only because the moon's orbit is tilted a bit". tsuwm
Precisely! Now I find that just absolutely remarkable! And inspiring! And quite a mystery indeed that there even *is a living, breathing, expanding, evolving universe....
Then again, doesn't really matter, either way, imho...as we're all along for the ride together, in the end....
In any event, I have spent the whole morning on this only to come to find that the url I posted is not the one I meant. Oh it's somewhat related, but I actually did come across the exact question, about the moon illusion, and it had to do with the relation of the image at rising and setting to actual objects on the horizon, such as mountains or buildings. And it had something to do with that tricking the mind into creating a false image of a spatial relation that doesn't actually exist. I'm really sorry I couldn't retrieve it. And in fact, I'm not sure if the answer was really correct, although it was stated as such. It was answered on a children's science question page. I have searched through my 'history' site of all the hits my family has been making online the past two weeks. And while I certanly have a few things to talk to them about (!?!) I could not find the question page.
So, sorry, Milum. I thought I had it for you.
I'm going to turn this thing off and go lie on my back on the sand in the glorious sunshine and plug my chakras into Gaia for a recharge.
xo mm
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from my very old mwcd (sorry, I know it's a crummy book, but it's the one I have):
"mystical: having a spiritual meaning or reality that is neither apparent to the senses nor obvious to the intelligence....involving or having the nature of an individual's direct, subjective communion with god or ultimate reality (the experience of inner light)"
and better yet:
"The Creator is the beginning of life and its ending, the Great Mystery within all things and around all things, the Universal Energy....In many Native languages the word for Creator... was a verb, indicating the movement, the activity, the motion, the pulsation of this sacred, never-ending force." - Sun Bear, Dancing with the Wheel
Yeah.
That pretty well describes what I know, how I experience it. And I find it equally fascinating that we don't all feel the same. Remarkable!
But, isn't it ultimately all One? One gigantic/infinite system/illusion/being...
m
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Man has invented his doom
First step was touching the moon. ~ Bob Dylan
*** Ptolemy believed that the moon on the horizon was magnified by the thick moist layers of air through which it had to pass "just like the apparent enlargement of objects in water which increases with the depth of immersion". But if Ptolemy had a neat new camera he would had seen that the high moon and the horizon moon, would have photographed and measured as the same size. The distortion was therefore within the human's brain's idea of perception.
*** The Ponzo Illusion: In a drawing, two blocks of equal size are superimposed on a railroad track that converges towards the horizon, as if the lower block was at the near end of the track and the upper block farther away. The human brain always percieves the upper block to be much bigger, even after being told that the two blocks are identical in size. But as Abu Ali al-Hasan noted in the eleventh century and modern investigators have confirmed--this illusion ain't the whole story. The moon appears swollen even without perspective data-- for example when seen over a featureless seascape from a ship. Why?
*** Lloyd Kaufman, a professor of psychology, and his son James, a physicist, working in computer science, animated a stereo image of the full moon on a laptop computer. By looking at the display and crossing your eyes you could see the moon in 3-D, floating in space. A computer animation program then moved one of the images so that the moon seemed to be receding into the distance. You might expect, and the researchers had assumed, that people watching this animation would assign a smaller size to the receding moon. Instead the brain does just the opposite: As the stereographic Moon on the computer screen moves away, it appears to grow larger.
*** Most people when asked to point halfway (45 degrees) between the zenith and the horizon, point to a spot much nearer the horizon. Evidently we perceive the sky not as a dome but as a lens-shaped ceiling, the top of which is much closer than the horizon. The brain assumes that the moon, when near the zenith need not be terribly big since it's not too far away. But when the moon is near the horizon, the brain concludes that, if it's more distant than all those things, wow, it must be really big.
(This is, in effect, the idea that SciAm magazine found as a conclusive explanation.)
So, irregular constructions of the major ingredients of life are allowed and forgiven by Mother Evolution (that is, the absurd enlargement of the sun and moon) and life goes on, happily and unmindfully blissfully with them.
I think not. I think that the perceptive illusion of an exaggerated size of the sun and moon has an evolutionary function. Anybody else?
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an evolutionary function. Anybody else?
An "adaptation" need not confer an advantage; it need only confer no disadvantage. Perhaps adaptation is not the best word for this type of change.
Or, if there be an advantage, it has nothing to do with celestial objects, but is merely an adjunct to the very real advantage of knowing how close that bird of prey was to our long ago ancestors. I believe this was discussed in one of the links. Things directly overhead are generally closer than things on the horizon.
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It's very interesting to consider Ptolemy's contributions to astronomy and how Copernicus completely knocked them down centuries upon centuries later.
Something that is amazing about Ptolemy is how he charted the movement of the visible planets, accounted for their brief periods of retrograde movement by theorizing that each planet moved in small circles while taking the big orbit around Earth--not just turning on each axis, but an actual small repeated circular movement like a Cheerio loop repeated around the orbit. Ptolemy's belief was supported by his remarkable--incredible, really--ability to map out accurately the positions of the visible planets as they (to him) rotated around the Earth and his ability to account for retrograde movement of the planets. It was his mathematical accuracy in showing and predicting those positions that caused his theories to be respected.
Of course, he was finally incorrect. Today it's too easy to give him little consideration since we are privy to developments in astronomy.
But he's worth taking a look at just to realize how far his mind did see, if only into a universe that was not quite what it actually is--at least as far as we know today what it is.
On another note, it was interesting to read that the Pope declared that Copernicus--after his death and upon the publication of his observations and findings -- a heretic because his writings were not in accordance with the Bible, and it wasn't until 1992--after the launching of the Hubble telescope!-- that that pope stated that Copernicus was not a heretic. Copernicus gets a lot of credit for putting the sun in the center of the solar system, but Aristarchus, 2000 years (I believe) before Copernicus had done the same. His theories were not respected. There is some ancient Chinese scholar who had theorized the same, but his name escapes me.
I enjoy trying to grasp the minds of these past thinkers better no matter how inaccurate or accurate they may have been. It's the process of thinking that fascinates.
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What eventually caused the Ptolemaic view of the solar system to be discarded was that its math became too difficult. The math for the Copernican view was much simpler. I remember from an astronomy class in college being told that everything, even the equatorial bulge, could be explained in terms of an unmoving Earth with the entire universe rotating around it, but the math is very difficult. On the other hand, it all depends on your context. If you're charting a path from the Earth to Mars you'd do a lot better considering the Sun unmoving and the planets in orbit around it, but if you're charting a path from New York City to Kalamazoo, Michigan you're better off with a stationary Earth.
When you come down to it, Copernicus was just as wrong as Ptolemy, but one step further out. The Sun is not stationary, but is in orbit around the center of the galaxy and the galaxy is flying around through space at the mercy of any other large agglomeration of gravitational bodies. You choose your math to fit the problem.
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Hey wordwind, glad you joined in. I also love thinking about the minds of those who lived at other times, how their reality was/is so different from ours, and how they have influenced our 'present'. All of us linked together through webs of time and space...
But isn't It (the big *It/Creation/the Universe, including all our planets and moons) always evolving/devolving? And aren't we as humans (sentient beings) always *limited to what we (collectively/individually) know at any specific point in time? Especially now, when we think we know so much (HA!)I don't believe we will ever get there (to the Knowing) empirically (though it won't surprise any of you to know I'm sure one could get there lyrically! :)....
So, you guys can entertain yourselves doing the math (oh, and I'll enjoy watching you all and learning beside you).
To me its just Shakti (female, creative, nurturing force) dancing for her beloved Shiva (male, unknowable, unmoveable power)....
And yes Faldage, evolution is so misunderstood. And it is certainly not geared to the 'fittest', rather, it advantages the 'fit'...over time....
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Arrrrgh!
Unmoveable!?!
Immovable. There, that's better....
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an old Irish folk song:
Risin’ of the Moon (1:53)
“Oh then tell me Sean O’Farrell tell me why you hurry so”
“hush me bhuachaill hush and listen” and his cheeks were all a glow
I bear orders from our Captain get ye ready quick and soon
for the pikes must be together by the Risin’ of the Moon
CHORUS
By the Risin’ of the Moon, By the Risin’ of the Moon
for the pikes must be together by the Risin’ of the Moon
“Oh then tell me Sean O’Farrell where the gatherin’ is to be”
“In the old spot by the river right well known to you and me
one word more for Signal Token whistle up the marchin tune
with your pike upon your shoulder by the Risin of the Moon
By the Risin’ of the Moon, By the Risin’ of the Moon
with your pike upon your shoulder by the Risin of the Moon
Out of many a mud walled cabin eyes were watchin through the night
many a manly heart was throbbin’ o’re the blessed morning light
murmers passed along the valleys like the banshee’s lonely croon
and a thousand pikes were flashin by the Risin of the Moon
By the Risin’ of the Moon, By the Risin’ of the Moon
and a thousand pikes were flashin by the Risin of the Moon
Down there by that singin river where the gatherin’ was to be
high above their shinin’ weapons hung their own beloved green
death to every foe and traitor forward strike the marchin’ tune
and hurrah my boy for freedom ‘tis the Risin’ of the Moon
‘Tis the Risin’ of the Moon “Tis the Risin of the Moon
and hurrah my boy for freedom ‘tis the Risin’ of the Moon
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Dear milum, forgive me for a diversion. As well as the size illusion of
Sun going down, there is the mysterious green flash just after sun disappears.
There are quite a few URLs about it, but none of the pictures in them look like
what I remember seeing so often on the troopship heading for the Philippines.
I'd be interested to hear other members recollections of this phenomenon.
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...the mysterious green flash just after sun disappearsNot the name of an obscure superhero but indeed a recognized phenomenon. I hate to sound like a broken record (how many young'uns out there have ever heard a broken record?!) but Scientific American did an article on that too, I would guess ten to twenty years ago. It even had a full-color picture of it on the cover! Edit: And here's the latest Scientific American squib on the subject: http://makeashorterlink.com/?T25E56923Note the distortions of perceived time: "(We also call interested readers' attention to "The Green Flash," by D. J. K. O'Connell, in Scientific American, January 1960, pp. 112-122.)" "Ten or twenty years ago," he says...right!
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Before reading this thread and the links I hadn’t thought about it but had assumed the moon illusion was due to refraction. So this was all new and fascinating stuff, for which many thanks. Having read and reread the links I think I grasp how and why the mind reacts as it does but the detailed explanations were clumsy and hard work to get through.
The points that wwh raised are answered there however; a camera does not make the same error as the eye/mind combination and different people see the illusion differently because their minds are fooled to differing degrees.
Worrying to hear that the same phenomenon has probably contributed to air and road accidents though.
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I too learned (in the dimly remembered past) that the different size (and color) was due to refraction by the additional layers of atmosphere. I never had any reason to think otherwise until now.
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If it were refraction, it would shrink in the vertical axis and do nothing in the horizontal.
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Green Flash
For the most part the following is in agreement with the URL found by wofahulicodoc. But it extends the reasoning and elaborates on some additional points that might be of general interest.
(From the book Color and Light in Nature by David K, Lynch and William Livingston.) Extracted and paraphrased below...
***Contrary to popular opinion, green flashes are quite common, especially over water. Indeed they happen to some degree every time the sun sets (or rises). The difficulty is in observing them. They last only for a second or two and they happen when the sun's light is rapidly fading. If we look at the sun's disk directly, our eyes are likely to be dazzled and there is a risk of missing the smaller green flash just above, before the solar disk goes dark.
*** Observing green flashes at sunrise is more difficult. It is hard to determine the exact location on the horizon where the sun will rise. The green flashes first, then the sun rises red beneath. So if you see the edge of the rising sun first you've missed the flash. Turn the boat around and head for home.
*** (Contradicting wofahulicodoc's URL) "...binoculars or a small telescope may be helpful. A setting sun presents no danger to the eyes."
*** The duration of the green flash depends in part on the rate at which the sun sets. During summer at high latitudes, the sun approaches the horizon at a grazing angle and passes below the horizon so slowly that the green flash may last for several seconds. During Admiral Bird's expedition to Little America in 1929, the green flash was observed off and on between irregular ice floes for a period of 35 minutes.
*** The green flash occurs because of dispersion in the atmosphere. Since the index of refraction depends on wavelength, all images passing through the atmosphere are dispersed vertically. Near the horizon, the apparent sun is composed of a continuum of such images, each at its own wavelength and location. Refraction is greatest for the shortest wave lengths, so that the blue image of the sun is highest in the sky. As the total amount of dispersion is much less than the diameter of the sun the images overlap except for the extreme upper and lower edges. The lower part of the sun is red for the same reason that the upper part is green: dispersion.
*** Recent work on green flashes shows then to be more complicated than first thought...
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In reply to:
One of the things I am most grateful for living at just this time on earth is that the full moon rises just at dusk and is up in the sky the entire night long. I think that is amazing, astoundingly beautiful, and inspiringly mystical. But surely, there have been whole epochs on earth when this was not the case, when the full moon rose during the day, and was on the other side of the earth during the night.
I do not believe that that is possible. As stated earlier, the moon is full when its orbit about the earth places it directly away from the earth. (More clearly, the earth is right between the moon and sun.) Thus lunar eclipses can only occur on a full moon and solar eclipses can only occur on a new moon, on those occasions when the moon's orbit is in the same plane as the earth's and the sun's. The full moon will always rise at about sunset and set around sunrise because of the orientation that makes it full in the first place. The exact time will vary depending on the observer's distance from the equator. The corollary to this is that crescent moons will be visible at different points during the daytime.
What I find scientifically mind-boggling about the moon is that its rotation is such that we always see the same face of it. This seems to me to be an extraordinary coincidence, and I would love to hear more on the subject from anyone more learned in astronomy.
The spell checker suggests replacing moon's with mooned.
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journeyman
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journeyman
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Well, I don't profess to have a logical mind. So I guess I'll have to ponder just what it means to me now if indeed the full moon always rises at dusk (depending more or less upon one's relation to the equator), and sets sometime around dawn, throughout all history. That's almost *more beautiful in its symmetry. Quite remarkable really. Is it true?
And how useful to have been able to count on the bright glow of the full moon to carry out all those ancient rites in the middle of the night!
And this spell checker is the most ridiculous thing I have ever come upon. Utterly useless, which is too bad as my spelling needs work!
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Pooh-Bah
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Well picture the half moon. At half moon, the moon is at right angles from the line connecting the sun and the earth. The light from the sun is hitting the moon, and from our vantage on earth, it looks like a tennis ball lit up from one side with a flashlight. Thus we see what appears to be a half disc. At full moon, it like we have our backs to someone who is holding a flashlight, and we're facing a tennis ball (which is a little higher than our heads so it isn't eclipsed by our shadow) and it is illuminated by the flashlight. We see the whole face of the tennis ball that is illuminated.
So if at full moon, the earth is between the sun and moon, then during the day you're on the part of the earth that is facing away from the moon. As the earth continues to rotate, the moon appears at one horizon, while at the time the sun is disappearing over the other horizon.
Gibbous moons occur as the moon is beyond the earth (from the sun) but not quite 180 degrees. Crescent moons occur when the moon is nearer to the sun than the earth.
This phenomenon is related to the way that we can only see Venus in the morning or evening. Venus's orbit is inside the earth's orbit, so at night when our part of the planet is poitning away from the sun, we're also pointing away from wherever Venus might be. But sometimes in the mornings or evenings, Venus can be seen low in the sky brightly reflecting the light of the sun.
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Carpal Tunnel
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Carpal Tunnel
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MM, Ænigma, our spellchecker, is ridiculous and frustrating only if you want it to function normally. That would soooo not fit in with the rest of this board. Have fun with it and use your RL dictionary to check spellings.....or better yet, spell however pleases you. That werks for us, right musick? 
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Pooh-Bah
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old hand
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OP
old hand
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What I find scientifically mind-boggling about the moon is that its rotation is such that we always see the same face of it. This seems to me to be an extraordinary coincidence...
Thats an easy one Alex, *the tidal pull of the earth through time has slowed the moons rotation around its axis to match the moon's orbital period, so that it has zero rotational momentum relative to the earth.
But the moon pulls back, and acts as a brake on the eastward spinning earth. Geologic findings (one the Pottsville Formation in Northern Alabama) indicate that 900 million years ago, a day on the then fast spinning earth, was only about 18 hours long.
But the same braking force was acting on the moon as well. And since the moon has only 1% of the mass of the earth, the moon "locked up" a long time ago and keeps the same side always facing the earth.
Then be it ours with steady mind to clasp
The purport of the skies-- the law behind
The wandering courses of the Sun and Moon.
________________________________________- Lucretius
* Adapted from Seeing in the Dark ~ Timothy Harris.
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Carpal Tunnel
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Remember our discussion a while back about the asteroid Cruithne? How we learned that its orbit is horseshoe-shaped?
I'd love to see the math on that.
I'd love to hear Copernicus's reaction to that math.
I've got here in my notes:
"Cruithne's path is much more complicated than simple satellite motion; pondering the diagrams carefully should help clarify matters....Hoseshoe orbits are named because of their shape in a reference frame which corotates with their accompanying planet, and have been known theoretically for many years. "
--Paul Wiegert, previously of the Dept. of Physics and Astonomy, York University, Toronto, Ontario
Point is: There aren't just elliptical orbits--or circular as Copernicus thought. The horseshoe one is the oddest one I know of. Any other unusual orbits we should know about?
AnnaS: I promise you two very good words tomorrow. I left my physics book at home.
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journeyman
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journeyman
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ok, ok. You guys are great! I'm so glad I found all of you. People who think! Imagine that...Poeple who love to think and want to learn.... green flashes, high altitude sprites, speleogenisis (well, I'm STILL waiting on that one).
It's all good.
Thanks, mm
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Carpal Tunnel
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The horseshoe one is the oddest one I know of. Any other unusual orbits we should know about?
I believe there are sun systems that have figure-8 orbits...
formerly known as etaoin...
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journeyman
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journeyman
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My mother used to sing this song to us at the piano when we were children. She's from an irish family; grandpa was a union man who worked for the railroads, and they had the sign of the hobo on their house when she was a child, even though it was the depression and they didn't have enough food for the four little girls.
This song was beautiful, and I can hear the melody and sing the words in the memory of my mind. Thanks Juan, for taking me back to a gentler place and time in my life....
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old hand
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OP
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MOON lllUSION EXPLAINED * Great, I said. Anu's subject entry font renders the capital I's and the small case l's the same. This is an excellent example of how the mind/eye translates reality into a trans-reality that has evolutionary function.
* Shoot, I said. When posted the I's and l's are differentiated. I guess I'll have to make all of them l's to make my point.
* Milum, wofahulicdoc said without really saying, you have misspelled the word "lllusion". You have spelled it "lllusian".
* Oh well, I said. Maybe that will trick people into overlooking the three l's. Human Vision*** The human eye/mind system can detect a change of only 2% within a brightness range of 1 to 100,000 candles per square meter. This acute distinction allows us to navigate a path by either sunlight or moonlight, a difference of a million in illuminance. *** Each eye has a field of vision of over 100 degrees, and together our eyes are able to sense the presence of objects over an entire hemisphere, especially if they move. Although our field of view covers a wide angular area, there is a central region ,the fovea, which is more richly endowed with photoreceptors than any other part. When looking directly at an object, the feature of interest is directed to the fovea. Look at any word in this sentence. Focus on it. If you've focused you can't read its neighbor; now look at the semi-colon just made and try to scrutinize both parts simultaneously. It can't be done. The angle between them is only 0.3 degrees, and the remaining field of view falls of the retinal surroundings- the macula. We read by swift little stops and starts- one word at a time. *** Each eye has a little blind spot at the connection to the optic nerve. We do not perceive this spot in our field of view. Instead the surrounding field fills it it, a process that is not fully understood. Thanks, probably to early learning, several other potential distractions are suppressed; that nose that protrudes into the scene; an image which is sharp only at the fovea and becomes indistinct at the periphery: and the eye's need for constant movement. *** Find yourself a rainbow. Fixate on a part of the rainbow. Persist. Remember the eye naturally wanders. Suddenly you will become aware that the rainbow has vanished. Any motion of your eye will make it instantly reappear. The eye is a motion detector that requires constant movement to function. In truth if we could stop eye motion at will we could make any object fade away, the rainbow is just an easy subject because of its smoothness and lack of detail. (be back in an eye blink)
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Carpal Tunnel
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Mr Minderbinder, sir! Mr Minderbinder! How long you gotta look at a word with your eyes still before you stop perceiving the words around it? I can see around the words, sir! Does that mean I'm abnormal?
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Carpal Tunnel
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>Maybe that will trick people into overlooking the three l's.
on the contrary, the three l's seem to have tricked (at least) one person into overlooking the mispelll.
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Carpal Tunnel
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overlooking the mispelll.
And here I was trying to figure out how to get in a comment on the Illusian Fields.
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Carpal Tunnel
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...overlooking the mispelll.
...I'll bet the OED is telling
there isn't any three-l spelling.
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Carpal Tunnel
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three-l spelling
One of the esses got transmorgrified and sent to the tail of the word.
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Carpal Tunnel
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no three-l spelling?
on the contrary, OED has 'frillless'. other possibilities: gallless, smellless..
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Carpal Tunnel
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. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Looking-glass.
It is unlucky to break a looking-glass. The nature of the illluck varies; thus, if a maiden, she will
never marry; if a married woman, it betokens a death, etc. This superstition arose from the use
made of mirrors in former times by magicians. If in their operations the mirror used was broken,
the magician was obliged to give over his operation, and the unlucky inquirer could receive no
answer.
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Carpal Tunnel
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lllama
big fire.
llllama
bigger fire.
formerly known as etaoin...
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Carpal Tunnel
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*** Find yourself a rainbow. Fixate on a part of the rainbow. Persist. Remember the eye naturally wanders. Suddenly you will become aware that the rainbow has vanished. Any motion of your eye will make it instantly reappear. The eye is a motion detector that requires constant movement to function. In truth if we could stop eye motion at will we could make any object fade away, the rainbow is just an easy subject because of its smoothness and lack of detail.
In the same respect, it is well-known that you can see the Pleiades, "The Seven Sisters," much more vividly if you don't look directly at them with the naked eye. When you look directly at the constellation, they tend to fade or disappear all-together.
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Carpal Tunnel
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>all-together.
Perhaps you meant all together or altogether [OneLook®]
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Carpal Tunnel
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Oh, geez, tsuwm...are you hyphenventilating again? [shaking-head-and-rolling-eyes e] (had to get some hyphens in there for ya, somewhere)
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Carpal Tunnel
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Carpal Tunnel
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My word will be my "Om" and my "Everything"
Whoa! I can see the whole paragraph!
Oon jellimon.
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Carpal Tunnel
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I have always wondered why the ancients spoke of seven sisters, but today the senth one seems to be missing. Apparently the answer to that is not known. I did find a star chart with names of the stars: http://www.seds.org/billa/twn/m45x.html
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Carpal Tunnel
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It has to do with rods and cones....
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Carpal Tunnel
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the ancients spoke of seven sisters
Graves said that there were seven visible, but one blew or something in historical (or just slightly prehistorical) times and that that fact is accounted for in the myth. ICLIU.
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old hand
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OP
old hand
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Hmmm...No worthwhilewind I don't think this crew quite ready to seek nirvana, instead I think they need a koanic jolt to their modern day romote-clicking television sensibilities so that they might begin to understand the strange world that exists around them so that once again they can walk as equals among free thinking men.
Ah what the hell, let's try it anyway. (WO'N this extends your point about indirect viewing.)
*** Astronomers have learned that they can see very dim stars if they don't look directly at them. Sailors also know that this is the best way to see a dim light and use this technique of "averted vision". It works because the fovea contains only cones, which require a higher level of light than the rods, even though they distinguish color and images. The rods, exquisitely sensitive to even the lowest levels of light, are distributed around the fovea. To use them best, the eye must not aim directly at the object to be viewed. Thus to make out a dim pinpoint against the background of the night sky, the rods work best, and they are not in the fovea at all but spread around the central region of the retina.
*** During November in 1992 I studied the habits of blackbirds. In particular a flock (700 +) that nested at night in a huge magnolia tree in downtown Birmingham. At first light, after a warming spell on the nearby electric wires, the flock would fly (two to eight miles) towards the rising sun to neighborhood feeding grounds, separating into bird units of one, twos, threes, fours, or fives .
Then late in the afternoon they would begin to gather into long high flying bands, now flying westward towards the setting sun. Then upon arrival at the magnolia tree they would alight on the electric wires and warm their feathers and wait until someone or something, decided it was time to go to bed. Who or what decided, was my quest. I never did find out, but each time, at a point before the sun fully set, in an instantaneous flapping rush of 1,400 wings, the electric wires were emptied and the magnolia tree became full and the magnolia tree became dark and still for the night.
The rush to the tree took less than three seconds, and it was always complete to the last bird; no stragglers arrived after the single rush. I knew then of the green flash but never saw it, but now I suspect the trigger was a blue (or violet) flash that is unavailable for seeing by the unaided human eye .
*** The next time you go to the supermarket to check out the apples or peaches, turning them over to look for bruises or spoilage, remember that you are using your color vision in the same way your distant forebears did.
You will also be using your stereoscopic vision, the ability to focus both your eyes on the same spot in order to determine depth or distance. Stereoscopic vision must have been an important asset for creatures that lived in high trees, where missing a branch as you swung home could mean a screaming, fatal fall.
Those days of tree dwelling must have left an indelible imprint on our minds. The three most common fears among humans are fear of darkness, fear of falling, and fear of snakes. To a tree dwelling animal, darkness meant danger unless it was safely bundled into a warm, cozy nest. You can not see where you are going in the dark, and even our early ancestors depended heavily on vision; they were diurnal (daylight active) creatures, not nocturnal animals. Fear or falling is obvious to a tree-dwelling species. Infants display an innate fear of heights at the age of only a few months. And snakes must have been one of the few predators that could reach our monkey ancestors up in their leafy nests. Even in the dark. ~ Ben Bova ~ Story of Light
Conclusion
The rising and setting sun triggered directional and vital temporal responses in early man. Genetic amplification of the external signal of the sun (and to a lessor extent, the moon) to a image greatly magnified, was so advantageous to our predecessors that today, try as we might, our mind/eye system won't allow us to see the sun or the moon on the horizon, any other way.
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Carpal Tunnel
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journeyman
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journeyman
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Well, I have never had a (n overwrought)fear of snakes, quite the contrary, had a wild garter as a pet in my youth compliments of my nature loving father. And I do not fear falling; quite the contrary, I am terrified of *jumping which I seem irresistibly compelled to do when I get near the edge of something up high. And darkness, well it isn't inherently scary; I sort of like it, back to the safety of the womb I suppose. So I'm not sure just how universal those are. I don't think I'm goin' too far along with all that tree jumping stuff. Most of our worldview got imprinted when we came down from those trees, stood upright and started running around on those savannahs!
Still I liked the story of the blackbirds, the collective mind of them, I suppose, and it reminds me of the true story of the wild parrots of Long Beach and San Fransico which I just may have to write....(finally home from work on the left coast and none of you are awake....)
mm
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Carpal Tunnel
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nail down Faldage's so he can foveate!
So, lemme get this straight. Y'all want me to narrow my vision?
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Carpal Tunnel
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See if you can nail down Faldage's so he can foveate!
I would, my dearest WW, but... is it legal?
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