orb@whuts.UUCP (SEVENER) (03/09/88)
Knowing full well that the Reaganistas will not accept my explanation of the principle of refraction, I will herein post quotes from "An Introduction to the Meaning and Structure of Physics" by Leon N. Cooper. It is an introductory college physics textbook. Also knowing full well that Mr. Carr will undoubtedly attempt to weasel out of his totally inaccurate explanation of refraction and how it applies to a view of the Sun, whereas it does not apply scarcely *at all* to the ability to see Cuba from Key West, I will post further proof of Mr. Carr's lack of understanding of refraction. To wit: Article 11721 of talk.politics.misc: From: jfc@athena.mit.edu.UUCP TS : 1)the Sun is up in the sky being refracted through an TS : atmosphere many miles thick. JFC :This is my point. JFC : JFC :The figure I quoted, .5 degrees, is for the sun on the horizon. JFC :This means its light passes through the equivalent of about 200 JFC :miles of sea-level air. Light from Cuba passes through half this JFC :much air, so will be refracted by half as much (in both cases the JFC :light travels almost horizontally through the air, so the reasoning JFC :is valid). Actually, I was not thinking clearly myself in this passage. The reason the Sun is refracted whereas day to day objects (including those seen over the sea) in air are not, is due to the change in density of the atmosphere at higher altitudes and the abrupt change to the vacumn of space. Cooper's text says this (p. 181): "Light traveling through a vacumn, or through a uniform medium in a straight line and with finite speed, has what seems to be an inertial property." "We now consider the behavior of light as it passes from one *homogeneous medium* to another, for example as it passes from -------------------- air to water." Further, (p. 182), Cooper says: "This constant, known as the index of refraction, is a property of the two materials and differs for different materials. For example there is one index of refraction for an air-water surface, another for an air-glass surface, and a third for a glass-water surface." There is *no such thing* as an "index of refraction" for SeaLevel air. There undoubtedly *is* some index of refraction for air at sealevel density versus air in the upper atmosphere, and of course there is *certainly* an index of refraction for an air-vacumn surface. Which leads back to my original point: Michael Friedman could not *possibly* have seen Cuba from Key West. Mr. Carr, Mr. Swan, and others jumping in to attack me and defend Mr. Friedman's statement on the grounds that refraction makes it possible are all wrong. And I hope this teaches them all a lesson about "seeing what they want to see" and believing what they want to believe. Meanwhile, I have been bombarded with attacks from every rightwinger on the Net on every statement I have ever made in this newsgroup, or rather a very small subset of the statements I have made in this newsgroup. I cannot possibly respond to all of them. All I can say is: this particular exchange was one which may demonstrate to others on the net just who has credibility and who does not. Remember it in the future... tim sevener whuts!orb see
oconnor@sungoddess.steinmetz (Dennis M. O'Connor) (03/09/88)
An article by orb@whuts.UUCP (45263-SEVENER,T.J.) says:
] Actually, I was not thinking clearly myself in this passage.
] The reason the Sun is refracted whereas day to day objects
] (including those seen over the sea) in air are not, is due to
] the change in density of the atmosphere at higher altitudes
] and the abrupt change to the vacumn of space.
There is NO "abrupt change to the vacuum of space", the
atmosphere just gets thinner, and thinner, and thinner ...
] Cooper's text says this (p. 181):
] There is *no such thing* as an "index of refraction" for SeaLevel
] air. There undoubtedly *is* some index of refraction for air at
] sealevel density versus air in the upper atmosphere, and of course
] there is *certainly* an index of refraction for an air-vacumn
] surface.
This shows a clear lack of undersanding as to what "index of
refraction" is. "Index of refraction" is a property derived from the
speed of light of the material referenced to the speed of light in a
vacuum. Even a vacuum has an index of refraction : 1.
Also, the idea that "SeaLevel" air doesn't have an index of
refraction is easy to disprove. Just look across a hot road someday.
The "heat ripples" you see are caused by the difference in the
refractive index of HOT vs. COOL "SeaLevel" air. Hold on
to this fact, it is important : the index-of-refraction
of air changes with pressure and temperature and humidity level.
In fact, increased pressure raises the index, increased
temperature lowers the index, and increased humidity
increases the index.
The property of "total internal reflection" may come into
play here. This property applies to light traveling
in a high-index material as it meats a low-index material.
If the angle is approach is close to tangential,
the light reflects off the interface as if it was a mirror,
and remains in the high-index material. Fiber optics
are based on this principle.
] Michael Friedman could not *possibly* have seen Cuba from Key
] West. Mr. Carr, Mr. Swan, and others jumping in to attack
] me and defend Mr. Friedman's statement on the grounds that
] refraction makes it possible are all wrong.
Sorry, but if we postulate a layer of air at the correct
altitude that is less dense (certainly true), less moist
(not uncommon) and/or hotter (very possible over the ocean),
it is entirely possible that total internal reflection
will occur at the interface (even if gradual) to this
boundary, in effect creating a "mirror in the sky" by
which a person might indeed be able to see over the horizon.
] And I hope this teaches them all a lesson about "seeing
] what they want to see" and believing what they want to
] believe.
I hope this teaches you to be more thorough in your
scientific reasoning. This is NOT a personal attack.
But your "science" is TERRIBLE.
] All I can say is: this particular exchange was one which may
] demonstrate to others on the net just who has credibility and
] who does not.
] Remember it in the future...
]
] tim sevener whuts!orb
Tim, seeing as you come off as pretty ignorant about optics,
atmospherics and science in general, these words of yours appear
particularly, well, ill-considered and ironic, perhaps.
--
Dennis O'Connor oconnor%sungod@steinmetz.UUCP
ARPA: OCONNORDM@ge-crd.arpa
(-: The Few, The Proud, The Architects of the RPM40 40MIPS CMOS Micro :-)jfc@athena.mit.edu (John F Carr) (03/10/88)
Again, I remind those who have no doubt as to Tim Sevener's error to
stop here. This has gone on too long.
In article <3895@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes:
: Knowing full well that the Reaganistas will not accept
Tim, I ask you again to define "Reaganistas" in terms of
groups with which we are familiar.
: my explanation of the principle of refraction,
: I will herein post quotes from "An Introduction to the
: Meaning and Structure of Physics" by Leon N. Cooper.
: It is an introductory college physics textbook.
And my calculations are based on (besides common sense and scientific
reasoning) the CRC Handbook of Chemistry and Physics, an astronomy
textbook, and class notes for an astronomy course.
: Also knowing full well that Mr. Carr will undoubtedly
: attempt to weasel out of his totally inaccurate explanation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
See below.
: of refraction and how it applies to a view of the Sun,
: whereas it does not apply scarcely *at all* to the ability
^^^ ^^^^^^^^ ^^^^^^^
Actually, the way I parse this string of negatives Tim has just said
my calculations are valid.
: to see Cuba from Key West, I will post further proof of
: Mr. Carr's lack of understanding of refraction.
: TS : 1)the Sun is up in the sky being refracted through an
: TS : atmosphere many miles thick.
: JFC :This is my point.
: JFC :The figure I quoted, .5 degrees, is for the sun on the horizon.
: JFC :This means its light passes through the equivalent of about 200
: JFC :miles of sea-level air. Light from Cuba passes through half this
: JFC :much air, so will be refracted by half as much (in both cases the
: JFC :light travels almost horizontally through the air, so the reasoning
: JFC :is valid).
: Actually, I was not thinking clearly myself in this passage.
: The reason the Sun is refracted whereas day to day objects
: (including those seen over the sea) in air are not, is due to
: the change in density of the atmosphere at higher altitudes
^^^^^^^^^^^^^^^^^^^
No. See below. The change in density of air is highest at lower altitudes.
See the Handbook of Chemistry and Physics.
: and the abrupt change to the vacumn of space.
^^^^^^^^^^^^^^^^^^^^^^^^^^^
The earth's atmosphere at low to medium altitudes is well approximated by
a decaying exponential. There is NO ABRUPT TRANSITION TO SPACE. Remember
Skylab? It was in space. There was air up there. Don't trust me, ask
anyone who is involved in any way with space travel.
: Cooper's text says this (p. 181):
: "Light traveling through a vacumn, or through a uniform medium
^^^^^^^^^^^^^
Here is the key. Air is not uniform.
: in a straight line and with finite speed, has what seems to
: be an inertial property."
: "We now consider the behavior of light as it passes from one
: *homogeneous medium* to another, for example as it passes from
: --------------------
: air to water."
And here is my other point, that light does not pass between media,
so this law of refraction does not apply.
: Further, (p. 182), Cooper says:
: "This constant, known as the index of refraction, is a property
: of the two materials and differs for different materials. For
: example there is one index of refraction for an air-water surface,
: another for an air-glass surface, and a third for a glass-water
: surface."
This is irrelevant, since there are no discontinuities involved.
Also, this is not the correct definition of "index refraction".
The index of refraction is measured relative to vacuum, and is
defined by (speed of light in material) * (index of refraction) = c.
: There is *no such thing* as an "index of refraction" for SeaLevel
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is absolutely, totally wrong. No politics involved. I gave the
index of refraction for air in my posting (1 + 280x10^-6, approx).
: air. There undoubtedly *is* some index of refraction for air at
: sealevel density versus air in the upper atmosphere, and of course
: there is *certainly* an index of refraction for an air-vacumn
: surface.
: Which leads back to my original point:
No, it doesn't. It does, however, lead to mine: that Tim Sevener has
even less understanding of physics than I thought. My reasoning was
from first principles (i.e. I drew a diagram comparing path lengths
and light travel time for two slightly displaced paths and used the
definition of index of refraction [and I am capable of deriving rough
values for n by calculating resonances of electrons when excited by
light]). Tim quotes an introductory physics text which only gives the
result for a special case. More on this at the end.
: Michael Friedman could not *possibly* have seen Cuba from Key
: West. Mr. Carr, Mr. Swan, and others jumping in to attack
: me and defend Mr. Friedman's statement on the grounds that
: refraction makes it possible are all wrong.
I see. Tim is right and we are all wrong. I can think of a few
in my department who will be interested to hear this. Just think
of all the astronomers and planetary scientists who will have to
redo all their life's work because they corrected for refraction
which doesn't exist. On the other hand, there will be no need for
the several lectures of 12.117 which teach refraction, saving many
man-hours of time.
: And I hope this teaches them all a lesson about "seeing
: what they want to see" and believing what they want to
: believe.
: Meanwhile, I have been bombarded with attacks from every
: rightwinger on the Net on every statement I have ever made
: in this newsgroup, or rather a very small subset of the
: statements I have made in this newsgroup.
:
: I cannot possibly respond to all of them.
:
: All I can say is: this particular exchange was one which may
: demonstrate to others on the net just who has credibility and
: who does not.
: Remember it in the future...
I believe so. I suspect that Tim has discredited yourself with anyone
who has any scientific training. Is there anyone in this group who
supports Tim's reasoning on the subject (especially the above nonsense)?
This question is different from the question, "do you believe Mike
Friedman saw Cuba?"
: tim sevener whuts!orb
: see
Tim: have you ever heard of. . . .Calculus? What about limits?
One gets the continuous analog of Snell's law by taking the
infinite limit of a number of thin layers with a finite difference
in index of refraction. The result is that refraction is proportional
to the derivative of n wrt distance.
A challenge to Tim: derive, from first principles, the laws of refraction
in such a way that you can show they do not apply to continuously changing
media. If you do that, I will post the derivation by which I got my
answer. Start at any level you want (if you don't know quantum physics, etc.,
to figure out the index of refraction for materials, you can assume an
index of refraction for air of 1 + rho * 280 / rho(0) x 10^-6).
For a good illustration of this effect, a cover of Scientific American
a few years ago had a picture of a laser beam passing through a tank of
fluid with a strong density gradient. Can anyone provide a reference?
The final proof of refraction by air: look at the air above a road on a
hot day. See the ripples? They are caused by differential refraction.
John Carr "No one wants to make a terrible choice
jfc@Athena.MIT.EDU On the price of being free"
--Neil Peartdlleigh@mit-amt.MEDIA.MIT.EDU (Darren L. Leigh) (03/10/88)
In article <9857@steinmetz.steinmetz.UUCP> sungoddess!oconnor@steinmetz.UUCP writes: >An article by orb@whuts.UUCP (45263-SEVENER,T.J.) says: [ many flames and counter-flames about atmospheric reflection ] >Sorry, but if we postulate a layer of air at the correct >altitude that is less dense (certainly true), less moist >(not uncommon) and/or hotter (very possible over the ocean), >it is entirely possible that total internal reflection >will occur at the interface (even if gradual) to this >boundary, in effect creating a "mirror in the sky" by >which a person might indeed be able to see over the horizon. There really doesn't have to be a layer of anything. Light tends to bend toward regions of higher index of refraction and so can travel in curves. This is the principle behind a "graded index" fiber optic cable, where there is no abrupt change between areas of higher and lower indices of refraction. Instead, the index varies gradually, being highest in the middle and falling off with larger radius. The light travels in neat curves -- it bends back before it can escape the fiber. AT&T does lots of fiber optics stuff. Tim ought to ask around and have someone explain things to him. Did Mike Friedman see Cuba? Who cares. ============================================================================= Darren Leigh dlleigh@media-lab.mit.edu 362 Memorial Dr. mit-amt!dlleigh Cambridge, MA 02139 Condorito Lives!
dlm@codas.att.com (Don_Million) (03/11/88)
Who was ever foolish enough to think they were going to get in "The Last Word" on this subject?
orb@whuts.UUCP (SEVENER) (03/11/88)
In article <3588@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes: > : my explanation of the principle of refraction, > : I will herein post quotes from "An Introduction to the > : Meaning and Structure of Physics" by Leon N. Cooper. > : It is an introductory college physics textbook. > >And my calculations are based on (besides common sense and scientific >reasoning) the CRC Handbook of Chemistry and Physics, an astronomy >textbook, and class notes for an astronomy course. Which has nothing to do with the issue involved here. We are not talking about an astronomical object - we are not talking about a transition from SeaLevel air density to a practical vacumn. We are talking about a tangent line of sight which at the *maximum* is 2059 feet high out of an atmosphere 180 miles thick. This is *not* the same as the case of the Sun which is 93 million miles away. Now let's talk about the actual atmospheric densities at Sea-Level versus 2059 feet versus the upper atmosphere. According to the Encyclopedia of Atmospheric Science and Astrogeology (p. 781) here are some standard pressures for values of concern here: height pressure refractive index Sea Level 29.92 inches 1.00029 3000 feet 26.81 inches ?? 18000 feet 14.94 inches ?? (mine) Space ~0 inches ~1.00000 What is the refractive index for air pressure of 29.92 inches compared to the refractive index for air pressure of 26.81 inches? I could not find the refractive index for air pressure of 26.81 inches. I *could* find the refractive index for air pressure at Sea Level, i.e. 29.92 inches. That turns out to be the very small value of 1.00029. This is compared to a refractive index of 1.33 for water, and of course, 1.0000 (the standard of measurement) for a perfect vacumn. (New Columbia Encyclopedia, p.2294) Even if we assume some exponential relation between air pressure and the refractive index, we are talking about a very *small* difference here. A crude extrapolation would be we are talking about a refraction index of 1.00015. But we don't even have to get into that to prove John Carr's figures are totally off. And we don't need calculus or differential equations or anything else to prove him wrong. All that is needed is simple geometry,trigononmetry and logic. To make Carr's case the strongest possible, suppose we take his figure for the refraction of the Sun, to wit: >In article <3267@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (me) writes: JFC : The amount of refraction depends strongly on atmospheric conditions. JFC : The only figure I know is the apparent displacement of (for example) JFC : the Sun on the horizon. This is .5 degrees This is the absolute *maximum* refraction that is possible. All this means is that whereas in my original calculations I took the cos of 1 degree and divided the radius of the Earth to obtain the height of the horizon line. Under the best scenario then instead we take the cos of .5 degree which is .99996, then divide the radius of the Earth by that value to obtain the total height we get: 3963.2/.99996 = 3963.36 The height of this line, accounting for a refraction displacement of .5 degrees will then be: 3963.36 (height of line of sight with .5 degree refraction) -3963.20 (radius of the Earth) -------- .16 miles * 5280 feet/mile = 844.8 feet And again, we find that this is unequivocally *higher* than the highest point in Cuba within 90 miles of Key West which is 344 feet high. Of course this is accepting John Carr's figure of 0.5 degrees displacement for the Sun on the horizon which is an *overestimate* for something less than 3000 feet high. You are wrong, wrong, wrong, Mr. Carr. Mr. Swan and the whole bunch of you. Ask any of your Physics professors about it John. tim sevener whuts!orb
daver@sci.UUCP (Dave Rickel) (03/12/88)
Nifty piece on atmospheric refraction in _The Inventions of Daedalus_, a collection of articles from The New Scientist. According to Daedalus, if the earth were 13 km less in radius, the bending due to atmospheric refraction would be equal to the curvature of the earth. Neat. On a clear day, you could see the back of your head (given a good telescope and a lack of mountain ranges). I remember an article on Venus where it stated that due to atmospheric refraction, the ground would appear to curve upwards when viewed from its surface. I think the Soviets have gotten pictures back from the surface-- was this affect noticeable? david rickel decwrl!sci!daver
g-rh@cca.CCA.COM (Richard Harter) (03/13/88)
In article <3904@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes:
Sundry calculations and noises deleted.
For reasons that escape me, some person claimed to have seen Cuba from
a Florida key, and Mr. Sevener find this claim to be politically repre-
hensible and in fact false, since, according to Mr. Sevener, this is
physically impossible.
I do not know whether the person in question actually saw Cuba or whether
the local atmospheric conditions are right for this. However, in fact,
sightings at distances greater than 90 miles across level ground are
common and well known. Some, in Northern Africa, are stable situtations
that have been seen since classical times. There is no a priori reason
that X could not have seen Cuba.
Followups have been directed to talk.politics.misc only, since I have
seen precious little science in this discussion.
--
In the fields of Hell where the grass grows high
Are the graves of dreams allowed to die.
Richard Harter, SMDS Inc.jfc@athena.mit.edu (John F Carr) (03/13/88)
I have heard enough of the nonsensical idiocy which Tim has been posting on
this subject for the last weeks. I will simply say that this latest article
shows his utter lack of comprehension of the basic physical principles
behind refraction (if he understood the physics he would know how to
find the refractive index of air at any reasonable temp/pressure), and
(hopefully) leave it at that.
I will refute this latest article if *anyone other than Tim* expresses any
doubt about his errors. Else, I'll assume we all see his mistakes.
My challenge to Tim still stands.
Tim: I learned much of this from my professors, there is no need to ask
them and involve them in this discussion. I will post a more detailed
derivation when the above condition is met: someone else is not convinced
that you are wrong. What was your major? I am majoring in Aerospace
Engineering and Planetary Science (which includes astronomy) (I am a double
major: those are two seperate fields). I think I am in a position to make
statements on subjects such as refraction.
John Carr "No one wants to make a terrible choice
jfc@Athena.MIT.EDU On the price of being free"
--Neil Peartleem@jplpro.JPL.NASA.GOV (Lee Mellinger) (03/14/88)
In article <3904@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: :In article <3588@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes: :> : my explanation of the principle of refraction, :> : I will herein post quotes from "An Introduction to the :> : Meaning and Structure of Physics" by Leon N. Cooper. :> : It is an introductory college physics textbook. :> :>And my calculations are based on (besides common sense and scientific :>reasoning) the CRC Handbook of Chemistry and Physics, an astronomy :>textbook, and class notes for an astronomy course. : :Which has nothing to do with the issue involved here. :We are not talking about an astronomical object - we are :not talking about a transition from SeaLevel air density to a :practical vacumn. We are talking about a tangent line of :sight which at the *maximum* is 2059 feet high out of an atmosphere :180 miles thick. : : :tim sevener whuts!orb Can you say "inversion", I knew you could. A well known atmosphereic effect, see numerous past articles in Scientific American. Lee -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- |Lee F. Mellinger Jet Propulsion Laboratory - NASA| |4800 Oak Grove Drive, Pasadena, CA 91109 818/393-0516 FTS 977-0516 | |-------------------------------------------------------------------------| |UUCP: {ames!cit-vax,psivax}!elroy!jpl-devvax!jplpro!leem | |ARPA: jplpro!leem!@cit-vax.ARPA -or- leem@jplpro.JPL.NASA.GOV | -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
orb@whuts.UUCP (SEVENER) (03/15/88)
In article <3699@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes: > >Tim: I learned much of this from my professors, there is no need to ask >them and involve them in this discussion. I will post a more detailed >derivation when the above condition is met: someone else is not convinced >that you are wrong. What was your major? I am majoring in Aerospace >Engineering and Planetary Science (which includes astronomy) (I am a double >major: those are two seperate fields). I think I am in a position to make >statements on subjects such as refraction. I don't care what your major is - your scientific reasoning is totally wrong. Once again to repeat some major points of this argument so far: 1)Michael Friedman claimed to "see" Cuba while standing on the shore on Key West. 2)I pointed out that: a)I, my roommate and others have been to Key West, the shores of Lake Michigan and other such bodies of water and never been able to see the opposing shore. I asked if anybody could testify to being at Key West and been able to see Cuba. Nobody, outside of Michael Friedman, has personally testified to being able to see Cuba from Key West. b)I also pointed out that it was *physically impossible* to see Cuba from Key West, given the curvature of the Earth. The highest point anywhere close to the 90 mile point from Key West on Cuba is 344 feet. The height of the tangent line of sight from Key West to a point 90 miles away is 2059 feet. I.e. there is a difference of *1700* feet between the tangent line of sight and the highest point in Cuba close to 90 miles from Key West. I asked if there were errors in my calculations. Nobody has found any yet. Even John Carr admits they are correct. c)John Carr, however, claimed that based on his knowledge of refraction from his Astronomy classes, that the light from the Sun was refracted 0.5 degrees. Mr. Carr claimed that since the light from Cuba to Key West was being refracted through sea-level density atmosphere that it should *also* refract that light by values similar to that for the Sun and other astronomical objects. d)I pointed out that this was a totally erroneous view of refraction. Refraction *only* occurs in a *non*uniform medium or when going from one uniform medium to another. I provided quotes from Leon N. Cooper's "An Introduction to the Meaning and Structure of Physics" to back up this point about refraction. To the extent that a medium such as a gas varies continuously in one direction, i.e. decreased density as one leaves Earth, then to that extent it will be continously refracted. On the other hand, to the extent a medium is *uniform*, then light will not be refracted *one iota*. I further pointed out that the actual difference in atmospheric pressure between sealevel air and air at 3000 ft is 29.92 inches vs 26.81 inches according to the Encyclopedia of Atmospheric Sciences and Astrogeology(p.781-783). I would argue this is far closer to being a *uniform* medium than a nonuniform medium. Mr. Carr continues to insult my scientific understanding of refraction. I would say his argument is not with me but with Leon Cooper, the authors of the Physics Encyclopedia and other sources which all give exactly the same view of refraction as something which only occurs either in shifts of medium or *non*uniform media. e)Just to give Mr. Carr's hypothesis the greatest benefit of the doubt I calculated the distance from the Earth of a tangent line of 0.5 degrees instead of 1 degree as in my original calculation. I.e. assuming the *total* refraction Mr. Carr himself states for the Sun. (actually according to the Physics Encyclopedia the value is 35 minutes. Only 5 minutes different than 0.5 degrees. For once, John Carr has something right even if he fails to understand why) That distance comes out to be 844.8 feet. A difference of *500* feet from the highest point close to 90 miles from Key West of 344 feet! I.e. even *IF* light from Cuba were refracted to the same extent as light from the Sun (which it is *NOT*!), it is *still* impossible to see Cuba from Key West. f)Finally, it turns out that the Physics Encyclopedia says that changes in the index of refraction of a gas are *proportional* to the density of the gas. This would mean the index of refraction at 3000 feet can be derived as follows: index of refraction at 3000 feet = 1 + (26.81/29.92 * .000293) = 1.000263 Thus the index of refraction at sea-level is 1.000293 and at 3000 ft is 1.000263. I.e. .00003 different! I would call that basically a uniform medium as far as refraction is concerned! Here is the way I would evaluate the situation: 1)Michael Friedman was wrong to claim he could see Cuba from Key West. It is physically impossible, even with refraction. Of course neither Friedman, Carr, Swan, et al are willing to concede this point, although I have provided references and respected sources for every step of my argument 2)John Carr was wrong to claim refraction from Key West to Cuba is the same as that from Key West to the Sun because of the distance the light travels in sea-level density air. I was also wrong to make any argument based on similar reasoning such as my argument that the Sun was further away. Both arguments have nothing to do with *refraction* which *only occurs* from a *change* in medium, whether it's a change in gaseous density or change in substance from air to water, air to glass, air to vacumn, etc. Mr. Carr is still unwilling to concede he was wrong on this point. Instead he insults my scientific understanding even when I have posted direct quotes from basic physic textbooks to support my point. 3)Even if John Carr were right to argue that the index of refraction between an atmospheric density of 26.81 inches and 29.92 inches is the same as that between 29.92 inches and 0 inches, he is *still* wrong in contending that a refraction of 0.5 degrees would make Cuba visible from Key West. In fact, even with a refraction of 0.5 degrees the highest point in Cuba of 344 feet is still 500 feet below the tangent line of sight *with refraction*'s height of 844.8 feet. 4)This whole incredibly boring and senseless argument is simply typical of the argument style of Mr. Carr, Mr. Friedman, et al. When caught flat-out wrong, Mr. Friedman resorted to all manner of obfuscating dodges - "I was on a 15 foot jetty" "a difference between .99980 and .99989 could be siignificant", "Refraction makes it possible", "ad nauseum, ad infinitum". Mr. Friedman never even bothered to calculate if a 15 ft jetty, difference in the 100,000th decimal place or refraction makes a bit of difference. *I* had to calculate and show such things were totally insignificant. Mr. Carr posted elaborate calculations based on a total misapprehension of what refraction is, and insulted my scientific understanding for quoting from an elementary college physics textbook to show he should know better. I have provided references to every one of my points. Let Mr. Carr debate the authors of those references. To wit: References Rand-McNally World Atlas for highest points in Cuba, radius of the Earth "An Introduction to the Meaning and Structure of Physics" by Leon N. Cooper for the definition of refraction. Also for meaning of refraction, "New Columbia Encyclopedia", and "Physics Encyclopedia" "Encyclopedia of Atmospheric Sciences and Astrogeology" for atmospheric density at 3000 ft versus sea-level "Physics Encyclopedia" for the fact that refractivity of a gas is proportional to density, for the index of refraction of 1.000293 at sea-level and for the value of 35 minutes for total refractive displacement of the sun's light on the horizon tim sevener whuts!orb
dplatt@coherent.com (Dave Platt) (03/17/88)
Ummm... perhaps I shouldn't stick my head up and get it shot off,
but... is it possible that what Michael Friedman saw from Key West was
actually a bank of clouds located directly above the island of Cuba?
As I recall, islands in [sub]tropical waters often have semi-permanent
cloud banks hovering above them. The island landmass rises up some
distance above the ocean surface; it interrupts the smooth flow of air
along the ocean surface, forcing moisture-laden air to rise upwards (or
sideways) around the island peak. If the air is forced to rise several
thousand feet, it'll encounter cooler ambient air at the higher
altitudes, cool down, and some of its moisture will condense and form a
cloud.
Seems to me that an island-effect cloud could easily rise a mile or
more above Cuba's highest peak under typical conditions; this would
raise the cloud tops well into view from Key West, according to the
figures recently posted.
I believe I've read that sailors exploring the Pacific ocean depended
rather heavily on this phenomenon to locate islands... the clouds could
be seen from a much greater distance than the islands themselves.
--
Dave Platt
UUCP: ...!{ames,sun,uunet}!coherent!dplatt DOMAIN: dplatt@coherent.com
INTERNET: coherent!dplatt@ames.arpa, ...@sun.com, ...@uunet.uu.netjfc@athena.mit.edu (John F Carr) (03/17/88)
Tim: in your inevitable response please make one of the following two
statements:
1. You are wrong.
2. EVERYONE else in this newsgroup is a member of a right-wing conspiracy,
and therefore you are the only one who has any idea what he is talking
about. Else, why hasn't anyone supported you and why have so many
said you are wrong?
In article <3925@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes:
>In article <3699@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes:
:I don't care what your major is - your scientific reasoning is totally
:wrong.
I will join with the majority in making this accusation of you.
:Once again to repeat some major points of this argument so far:
:
:1)Michael Friedman claimed to "see" Cuba while standing on the
: shore on Key West.
He claimed to see it, not "see" it.
:2)I pointed out that:
First, you pointed out that Mike Friedman was lying and it was totally
impossible. Since you accuse him of lying rather than being mistaken
you must prove that he KNEW he was not seeing Cuba. You have never done
this.
: a)I, my roommate and others have been to Key West, the shores of Lake
: Michigan and other such bodies of water and never been able to see
: the opposing shore.
So what? This is not proof that it is impossible under all conditions.
: I asked if anybody could testify to being at Key West and been able
: to see Cuba.
: Nobody, outside of Michael Friedman, has personally testified to
: being able to see Cuba from Key West.
At least two articles mentioned friends who had.
: b)I also pointed out that it was *physically impossible* to see
: Cuba from Key West, given the curvature of the Earth.
: The highest point anywhere close to the 90 mile point from Key
: West on Cuba is 344 feet. The height of the tangent line of
: sight from Key West to a point 90 miles away is 2059 feet.
: I.e. there is a difference of *1700* feet between the tangent
: line of sight and the highest point in Cuba close to 90 miles
: from Key West.
: I asked if there were errors in my calculations.
: Nobody has found any yet.
: Even John Carr admits they are correct.
I say they are correct but not complete. Therefore, they are not the proof
you must provide.
: c)John Carr, however, claimed that based on his knowledge of refraction
: from his Astronomy classes, that the light from the Sun was refracted
: 0.5 degrees. Mr. Carr claimed that since the light from Cuba to Key West
: was being refracted through sea-level density atmosphere that it
: should *also* refract that light by values similar to that for the
: Sun and other astronomical objects.
I claimed that since the light from Cuba passed through a comparable
distance (I assumed, and later proved, that the distance is half as much as
sunlight passes through) it would be refracted similarly.
: d)I pointed out that this was a totally erroneous view of refraction.
: Refraction *only* occurs in a *non*uniform medium or when going from
: one uniform medium to another.
Exactly. You must have read the article I posted, since this is not your
earlier claim. And, it proves my point since air is not a uniform medium
(which you finally admitted in your last article).
: I provided quotes from Leon N. Cooper's "An Introduction to the
: Meaning and Structure of Physics" to back up this point about
: refraction.
Which quotes were irrelevant and, in one case, wrong (in stating that
index of refraction is only defined at an interface between two
different materials).
: To the extent that a medium such as a gas varies continuously in
: one direction, i.e. decreased density as one leaves Earth, then
: to that extent it will be continously refracted.
True.
: On the other hand, to the extent a medium is *uniform*, then light
: will not be refracted *one iota*.
No. A medium is or is not uniform. Close doesn't count. Air is not uniform,
so no further discussion of uniform media is relevant.
Also, light in a uniform medium is still bent by gravity (as Einstein and
others have proved). (I leave it to the reader to decide if this effect
is worth considering).
: I further pointed out that the actual difference in atmospheric
: pressure between sealevel air and air at 3000 ft is 29.92 inches
: vs 26.81 inches according to the Encyclopedia of Atmospheric
: Sciences and Astrogeology(p.781-783).
: I would argue this is far closer to being a *uniform* medium
: than a nonuniform medium.
No. NO. no.
Ho many ways can I say it? This is the flaw.
I proved that the small gradient of the index of refraction is enough,
when taken over long distances. Close to uniform doesn't count.
: Mr. Carr continues to insult my scientific understanding of
: refraction.
Or lack thereof.
: I would say his argument is not with me but with Leon
: Cooper, the authors of the Physics Encyclopedia and other sources
: which all give exactly the same view of refraction as something
: which only occurs either in shifts of medium or *non*uniform
: media.
Air is non-uniform. For most purposes the change in density is not
important, but it can not be wished away by saying air is uniform.
: e)Just to give Mr. Carr's hypothesis the greatest benefit of the
: doubt I calculated the distance from the Earth of a tangent line
: of 0.5 degrees instead of 1 degree as in my original calculation.
: I.e. assuming the *total* refraction Mr. Carr himself states for
: the Sun. (actually according to the Physics Encyclopedia the value
: is 35 minutes. Only 5 minutes different than 0.5 degrees. For once,
: John Carr has something right even if he fails to understand why)
: That distance comes out to be 844.8 feet.
: A difference of *500* feet from the highest point close to 90
: miles from Key West of 344 feet!
: I.e. even *IF* light from Cuba were refracted to the same extent
: as light from the Sun (which it is *NOT*!), it is *still*
: impossible to see Cuba from Key West.
You mean after all this discussion you still assumed the light traveled
in a straight line? It doesn't, so your geometric construction is
invalid. I included this in my article which you seem not to have read
very carefully.
: f)Finally, it turns out that the Physics Encyclopedia says that
: changes in the index of refraction of a gas are *proportional*
: to the density of the gas. This would mean the index of
: refraction at 3000 feet can be derived as follows:
:
: index of refraction at 3000 feet = 1 + (26.81/29.92 * .000293)
:
: = 1.000263
:
: Thus the index of refraction at sea-level is 1.000293 and at 3000 ft
: is 1.000263. I.e. .00003 different!
: I would call that basically a uniform medium as far as refraction
: is concerned!
I wouldn't. You just admitted that light is refracted, now you deny it?
Remember: I proved the amount by which light is recfracted, you cannot
simply say the atmosphere is close to uniform. Do the calculations and
you will see.
:Here is the way I would evaluate the situation:
:1)Michael Friedman was wrong to claim he could see Cuba from Key West.
The burden of proof is on you.
: It is physically impossible, even with refraction.
I have shown it is not impossible under all conditions, which is sufficient
defence.
: Of course neither Friedman, Carr, Swan, et al are willing to concede
: this point, although I have provided references and respected sources
: for every step of my argument
So have I. The difference is, my calculations and references are relevant.
:2)John Carr was wrong to claim refraction from Key West to Cuba is
: the same as that from Key West to the Sun because of the distance
: the light travels in sea-level density air.
I didn't: I claimed it was half this much. I then proved it was.
: I was also wrong to make any argument based on similar reasoning
: such as my argument that the Sun was further away.
: Both arguments have nothing to do with *refraction* which *only occurs*
: from a *change* in medium, whether it's a change in gaseous density
: or change in substance from air to water, air to glass, air to vacumn,
: etc.
: Mr. Carr is still unwilling to concede he was wrong on this point.
My original statement on this subject was correct.
: Instead he insults my scientific understanding even when I have
^^^^^^^^^^^^^^^^^^^^^^^
(I take a short pause to laugh at this.)
: posted direct quotes from basic physic textbooks to support my
: point.
:3)Even if John Carr were right to argue that the index of refraction
: between an atmospheric density of 26.81 inches and 29.92 inches
: is the same as that between 29.92 inches and 0 inches, he is
Which I did not...
: *still* wrong in contending that a refraction of 0.5 degrees would
: make Cuba visible from Key West.
I say again (is there an echo?): light does not travel in straight lines.
: In fact, even with a refraction of 0.5 degrees the highest point
: in Cuba of 344 feet is still 500 feet below the tangent line
: of sight *with refraction*'s height of 844.8 feet.
:4)This whole incredibly boring and senseless argument is simply typical
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I said this first, in the first article to have this subject line.
You chose to continue.
: of the argument style of Mr. Carr, Mr. Friedman, et al.
: When caught flat-out wrong, Mr. Friedman resorted to all manner
^^^^^^^^^^^^^^^^^^^^^^^^^^^
When caught flat-out wrong Tim kept "modifying his position" to avoid
admitting his mistakes. When I PROVED he was wrong, he still would not
admit it. When others proved him wrong and quoted sources, he continued
to hold ideology above the truth. When I cross posted articles from
sci.misc, he ignored them. When no one else on the net would associate
themselves with his arguments, he claimed a conspiracy against him.
: Mr. Carr posted elaborate calculations based on a total misapprehension
^^^^^^^^^^^^^^^
: of what refraction is, and insulted my scientific understanding for
^^^^^^^^^^^^^^^^^^
Please enlighten me then. You seem to have finally agreed to most of my
claims.
: quoting from an elementary college physics textbook to show he
^^^^^^^^^^^^^^^^^^^^^^^^^^^
Elementary physics courses don't cover continuous refraction.
: should know better.
: I have provided references to every one of my points.
: Let Mr. Carr debate the authors of those references.
: To wit:
:
:References
:Rand-McNally World Atlas for highest points in Cuba, radius of
:the Earth
I have assumed your geographic figures are correct. Judging by your
performance quoting other sources it would not surprise me if they
were not.
:"An Introduction to the Meaning and Structure of Physics" by Leon
:N. Cooper for the definition of refraction.
I have described how this was irrelevant or wrong (most likely the
author understands refraction; but he uses non-standard definitions
which fail when Tim tries to extend them beyond the limits of the
book.)
:Also for meaning of refraction, "New Columbia Encyclopedia", and
:"Physics Encyclopedia"
:
:"Encyclopedia of Atmospheric Sciences and Astrogeology" for
:atmospheric density at 3000 ft versus sea-level
:"Physics Encyclopedia" for the fact that refractivity of a gas
:is proportional to density, for the index of refraction of
:1.000293 at sea-level and for the value of 35 minutes for
:total refractive displacement of the sun's light on the
:horizon
These numbers are the same ones I used, within reasonable margins.
Have you read the sources which others have quoted? (such as Scientific
American)
Tim: Don't throw sources at me which do not discuss the specific effect
in question. Read the article in which I derived the refraction of
a light ray from Cuba. Then repost it showing exactly where I made
an error. (hint: there is one mistake in it which does not affect
in any way the validity of the calculation, if you had looked at the
article carefully you should have caught it. At least one other person
pointed it out to me in an email message.)
While you are trying to disprove my calculations, you will find it necessary
for proof of your claim to also show that there are never temperature
inversions in that area (since these would increases refraction).
John Carr "No one wants to make a terrible choice
jfc@Athena.MIT.EDU On the price of being free"g-rh@cca.CCA.COM (Richard Harter) (03/17/88)
In article <3925@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: ... Much material deleted ... > I further pointed out that the actual difference in atmospheric > pressure between sealevel air and air at 3000 ft is 29.92 inches > vs 26.81 inches according to the Encyclopedia of Atmospheric > Sciences and Astrogeology(p.781-783). > I would argue this is far closer to being a *uniform* medium > than a nonuniform medium. This is the fundamental error in Mr. Sevener's discussion. These are the *average* atmospheric pressures. Air density varies quite a bit from average. The highest and lowest recorded sea level densities are 31.75 inches are 26.18 inches respectively. Normal refraction at sea level is about 1/6 the curvature of the Earth. In temperature inversions (cold dense air close to the Earth, hot thin air above the cold layer), the refraction is much greater. Under unusual conditions at sea an object below the horizon can actually appear to be floating in the sky (looming). IT is quite possible to see things more than 90 miles away along sea level under the right atmospheric conditions. However, as someone else as noted, what one is much more likely to see is an island cloud bank rather than an island. Finally, much of the deleted material is not of scientific interest, except perhaps to psychiatrists. Could we leave the personal flaming to the politics subgroup. -- In the fields of Hell where the grass grows high Are the graves of dreams allowed to die. Richard Harter, SMDS Inc.
jwm@stdc.jhuapl.edu (James W. Meritt) (03/17/88)
In article <3925@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes:
. Refraction *only* occurs in a *non*uniform medium or when going from
. one uniform medium to another.
.
. To the extent that a medium such as a gas varies continuously in
. one direction, i.e. decreased density as one leaves Earth, then
. to that extent it will be continously refracted.
. On the other hand, to the extent a medium is *uniform*, then light
. will not be refracted *one iota*.
. Both arguments have nothing to do with *refraction* which *only occurs*
. from a *change* in medium, whether it's a change in gaseous density
. or change in substance from air to water, air to glass, air to vacumn,
. etc.
I notice that your references contain nothing on meterology. Perhaps this
is a cause of your misunderstanding?
While refraction occurs only in a non-uniform medium, a large number
of people would contend that the atmosphere is not such a media.
Thousands of meterologist, for instance. Anybody that observes things
through an atmosphere, and not straight up. As evidence to this
non-uniformity, go outside and look at a hot road. Do you "see" a
"puddle of water" (or in memory, have you?)? When you get there, it is
gone, yes? (ok, sometimes it really is a puddle, I mean besides those!)
What you see there is the sky! We have here light refracted dozens of degrees
in just a few feet of air! And the atmosphere changes radically due to
temperature (note: Cuba is _VERY_ warm, I have seen 106, water temp in 80's.
This is a good gradient) and humidity (100% on water surface, less on
up. Entire area is muggy, though).
Are you sufficiently closed minded that you cannot admit there are
things about which you do not know, or sufficiently prideful that
you cannot "back out"?
Disclaimer: Individuals have opinions, organizations have policy.
Therefore, these opinions are mine and not any organizations!
Q.E.D.
jwm@aplvax.jhuapl.edu 128.244.65.5oconnor@sungoddess.steinmetz (Dennis M. O'Connor) (03/17/88)
Tim Sevener needs to do some research on MIRAGES. Mirages
are not hallucinations : they can be photographed. If
someone did see Cuba from Florida, it was almost
certainly a MIRAGE.
The appropriate line for this discussion seems to be :
There are more things in Heavev and Earth, Tim Sevener,
than dreamed of in your, well, frosh physics book, anyway.
--
Dennis O'Connor oconnor%sungod@steinmetz.UUCP ARPA: OCONNORDM@ge-crd.arpa
( I wish I could be civil all the time, like Eugene Miya )
(-: The Few, The Proud, The Architects of the RPM40 40MIPS CMOS Micro :-)lazarus@athena.mit.edu (Michael Friedman) (03/19/88)
From Encyclopaedia Britannica Volume 12 of Macropaedia, p 119, 1984 (From the entry on microclimates) The superior image is convex upward and results from temperature inversions. These are most prevalent at sea with warm air overrunning colder water. Under special conditions the ray may be trapped in a relatively shallow layer. Where this occurs, or when the curvature of the ray is close enough to that of the earth, very distant objects are seen well beyond the horizon and may appear deceptively close. Unfortunately, the encyclopaedia does not say how far 'very distant' is. I think, however, that it is reasonable to assume that 90 miles is well within that range. PS. Warm air overrunning colder water is almost certainly the situation in the Florida Keys. These are the official opinions Mike Friedman of my organization. So, TOUGH!!
berryh@udel.EDU (John Berryhill) (03/19/88)
oconnor%sungod@steinmetz.UUCP writes: >Tim Sevener needs to do some research on MIRAGES. Mirages Someone else brought this up, but I thought it was obvious to most people here that this isn't going to happen over the water between Key West and Cuba. John Carr threw in a snide comment about temperature inversion. Everybody has seen the shimmering "pools of water" on a hot road in the summer. A "hot road," that is. In fact, the road surface has to be hotter than the air above it for this to happen. Would Mr. Carr please smugly explain how the water surface is going to be significantly hotter than the air above it on a nice day in Florida (not over the Gulf Stream either)? Temperature inversions are significantly influenced by the local geography. A nice flat sea isn't going to do much for you. -- John "I can't even see Cape May NJ from the ferry dock at Lewes across the Delaware Bay" Berryhill
jfc@athena.mit.edu (John F Carr) (03/19/88)
In article <1625@louie.udel.EDU> berryh@udel.EDU (John Berryhill) writes: >>Tim Sevener needs to do some research on MIRAGES. Mirages : Someone else brought this up, but I thought it was obvious : to most people here that this isn't going to happen over : the water between Key West and Cuba. John Carr threw in a : snide comment about temperature inversion. Everybody : has seen the shimmering "pools of water" on a hot road : in the summer. A "hot road," that is. In fact, the road : surface has to be hotter than the air above it for this : to happen. Would Mr. Carr please smugly explain how the : water surface is going to be significantly hotter than : the air above it on a nice day in Florida (not over the : Gulf Stream either)? : : Temperature inversions are significantly influenced by : the local geography. A nice flat sea isn't going to : do much for you. It should be obvious: a hot road, hotter than the air, creates a layer of hot air which reflects light coming from above. A body of relatively cold water creates a layer of cooler air, which refracts light down (that is, makes the source appear higher). Opposite temperature gradient, opposite effect. Refraction is increased if, as you say, the water is cooler. The air temperature in Florida does at times get hotter than water temperature. That will create a temperature inversion, but I don't know how big. Since no one has posted any specific numbers on this, I assume no one else does either. And that is the whole point of my argument: it has not been proved that it is impossible to see Cuba from Key West. John Carr "No one wants to make a terrible choice jfc@Athena.MIT.EDU On the price of being free"
bzs@bu-cs.BU.EDU (Barry Shein) (03/19/88)
I'm bored with this conversation, bored bored bored bored bored bored bored bored bored bored bored. Do I have to repeat myself? OK, bored board...oh, alright, I'm not going to stoop to that level. But it really is generating like a dozen or two dozen messages per day for weeks. Bored, bored, bored,...uh, there I go again... "If I have seen a little farther than my predecessors it is because I have stood on the shoulders of giants" (close, Sir Isaac Newton I believe) "History repeats itself, historians repeat themselves" -Lord Nose "Sit quietly and people may think you a fool, open your mouth and you will erase all doubt." -Sum Wag "It doesn't matter what they say kid, just so long as they spell your name right" -Someone to Ruby Keeler in "A Star is Born" "Wait, just one more time, what are you afraid of?" -William Shatner, Original Twilight Zone Episode -B
jwm@stdc.jhuapl.edu (James W. Meritt) (03/21/88)
In article <3874@bloom-beacon.MIT.EDU> lazarus@athena.mit.edu (Michael Friedman) writes: >PS. Warm air overrunning colder water is almost certainly the >situation in the Florida Keys. It was when I was there (between Cuba & US): Water temp low 80's, air temp low 90's. Not all that much diff, though. In winter it is probably a different story. When was this sighting suppose to take place? Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5
king@kestrel.ARPA (Dick King) (03/22/88)
In article <1625@louie.udel.EDU>, berryh@udel.EDU (John Berryhill) writes: > oconnor%sungod@steinmetz.UUCP writes: > >Tim Sevener needs to do some research on MIRAGES. Mirages > > Someone else brought this up, but I thought it was obvious > to most people here that this isn't going to happen over > the water between Key West and Cuba. John Carr threw in a > snide comment about temperature inversion. Everybody > has seen the shimmering "pools of water" on a hot road > in the summer. A "hot road," that is. In fact, the road > surface has to be hotter than the air above it for this > to happen. Would Mr. Carr please smugly explain how the > water surface is going to be significantly hotter than > the air above it on a nice day in Florida (not over the > Gulf Stream either)? Correct. To see pools of water the road must be hotter than the air. In the pools of water mirage, objects are seen lower than they "deserve" to be seen, so you see sky beneath the road surface [which you perceive as pools of water]. For Friedman to have seen Cuba, i think we all agree that light must be refracted so things are seen higher than they deserve to be, ie., above the horizon rather than below. For this to happen air aloft must be warmer than air near the surface. This is what an inversion is. [usually air gets colder as you ascend, at a rate i believe is called the "lapse rate"; a few deg F. per thousand feet]. This is also quite possible over the ocean, if the air above it has any light absorption power at all or if warm air blows in from Florida or Cuba or the gulf of Mexico [but this last might be humid enough to raise clouds]. Just a question. Why are we doing this? We all agree that Friedman could have seen clouds over Cuba - they only need to be at 2000 feet, which is rather low for clouds. It is of no significance when and whether it is possible to see Cuba from the Keys; the question we need to ask is whether Friedman was deluding himself, and i think we can all conclude otherwise. > > Temperature inversions are significantly influenced by > the local geography. A nice flat sea isn't going to > do much for you. > > -- > John "I can't even see Cape May NJ from the ferry dock at Lewes across > the Delaware Bay" Berryhill -dk
dredd@osiris.UUCP (Gaziggity B. Yazghizzer) (03/22/88)
Ok you hosers. I have just returned from Key West and I asked a fair number of the local people whether you can see Cuba, even on the clearest of days. The answer was/is a unanimous NO (maybe from the air, but no chance from land). There used to be a sign there that said "CUBA 90 Mi.", but I think it has been taken down. -Tom O'Toole J.H.U. Medical School asidonhopo@jhuigf.bitnet
bill@sigma.UUCP (William Swan) (03/22/88)
In article <3925@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: >3)Even if John Carr were right to argue that the index of refraction > between an atmospheric density of 26.81 inches and 29.92 inches > is the same as that between 29.92 inches and 0 inches, he is > *still* wrong in contending that a refraction of 0.5 degrees would > make Cuba visible from Key West. > In fact, even with a refraction of 0.5 degrees the highest point > in Cuba of 344 feet is still 500 feet below the tangent line > of sight *with refraction*'s height of 844.8 feet. Sevener never ceases to astound me. John Carr *never* argued this point, and would be foolish to. It is entirely and absolutely wrong, and is not really too far from the way Sevener tried to smear Friedman by implying that Friedman claimed to represent the official opinions of MIT (we never saw an apology for this, by the way, even though one has been called for). This kind of tactic is fundamentally dishonest, even though it leaves Sevener the "out" of saying that he never *said* that Carr argued this. It is a deliberate attempt to make the opponent out to be a fool, or stupid, and is the last resort of a dishonest debater who has found himself in the wrong. No doubt, if this had not been responded to, we would have seen references to it in later Sevener postings. Also, as I pointed out in my preceding posting, Sevener's assumptions in this calculation of the necessary degree of refraction are incorrect. -- William Swan {ihnp4,decvax,allegra,...}!uw-beaver!tikal!sigma!bill
orb@whuts.UUCP (SEVENER) (03/22/88)
In article <20748@bu-cs.BU.EDU> bzs@bu-cs.BU.EDU (Barry Shein) writes: > >I'm bored with this conversation, bored bored bored bored bored bored >bored bored bored bored bored. Do I have to repeat myself? OK, bored >board...oh, alright, I'm not going to stoop to that level. But it >really is generating like a dozen or two dozen messages per day for >weeks. Bored, bored, bored,...uh, there I go again... Of course. And that is the marvel of the Friedman/Carr/Reaganistas technique of disinformation. Take a point that is perfectly obvious to anyone with an ounce of common sense - like anyone who's lived by a largish body of water knows you can't see the other side - and just throw absurd speculations at it, pseudoscientific statements until one becomes bored of the tedium of a response. Throw in these rampant speculations with no basis with absolutely no calculations of their absolute import and then let your opponent *disprove* your disinformation. Wonderful for Friedman/Carr/et al. A lot of work for the person shooting down the disinformation. And of course, by now, who gives a damn? Enough mud is thrown in the waters that most people, even over something which should be as clear as this, simply throw up their hands and give up, or find following these tedious arguments over mundane and totally stupid points so boring they give up. So the disinformation wins.... And the Reaganistas continue to say they are infallible.... tim sevener whuts!orb
andrew@mit-caf.UUCP (Joe Bigelow) (03/22/88)
In article <1570@sigma.UUCP> bill@sigma.UUCP (William Swan) writes: > >This kind of tactic is fundamentally dishonest, even though it leaves Sevener >the "out" of saying that he never *said* that Carr argued this. It is a >deliberate attempt to make the opponent out to be a fool, or stupid, and is >the last resort of a dishonest debater who has found himself in the wrong. >William Swan {ihnp4,decvax,allegra,...}!uw-beaver!tikal!sigma!bill Who needs deliberate attempts? Is it not a well documented fact that they are stupid fools? I know you are but what am I? I know you are but what am I? I know you are but what am I? I know you are but what am I? I know you are but what am I? I know you are but what am I? Joey Bigelow, a Brooklyn boy at heart.
jwm@stdc.jhuapl.edu (James W. Meritt) (03/22/88)
In article <1570@osiris.UUCP> dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: > >Ok you hosers. I have just returned from Key West and I asked a fair number >of the local people whether you can see Cuba, even on the clearest of days. >The answer was/is a unanimous NO (maybe from the air, but no chance from land). Sounds good to me! Good sample size ("fair number"), varying conditions ("even on" implies "including less than") identical geology (dirts moves REAL slow) and no political bias (I guess. Maybe nobody wants to look at Cuba....) One experiment beats a thousand good theories! (personal opinion) Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5
orb@whuts.UUCP (SEVENER) (03/23/88)
In article <1570@sigma.UUCP> bill@sigma.UUCP (William Swan) writes: >In article <3925@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: >>3)Even if John Carr were right to argue that the index of refraction >> between an atmospheric density of 26.81 inches and 29.92 inches >> is the same as that between 29.92 inches and 0 inches, he is >> *still* wrong in contending that a refraction of 0.5 degrees would >> make Cuba visible from Key West. >> In fact, even with a refraction of 0.5 degrees the highest point >> in Cuba of 344 feet is still 500 feet below the tangent line >> of sight *with refraction*'s height of 844.8 feet. > >Sevener never ceases to astound me. > >John Carr *never* argued this point, and would be foolish to. It is entirely >and absolutely wrong, and is not really too far from the way Sevener tried >to smear Friedman by implying that Friedman claimed to represent the official >opinions of MIT (we never saw an apology for this, by the way, even though >one has been called for). Mr. Swan, you never cease to amaze me! Mr. Carr indubitably stated the following: 1)the total refractive displacement of the Sun on the horizon was 0.5 degrees. Actually in the Encyclopedias where I looked this up it was 35 minutes. So Mr. Carr was neither *wrong* nor *foolish* to argue this point as it is essentially correct. You are so #$%^&* that you apparently do not understand that. Look it up yourself, if you don't believe me. 2)Mr. Carr never calculated what height would be visible from a refractive displacement of 0.5 degrees over 90 miles. I did. I discovered that with a *TOTAL* displacement of 0.5 degrees one would be able to see a point 844.8 feet high from 90 miles away. This is still 500 feet higher than the 344 ft "peak" in Cuba which is actually 95-100 miles away. John Carr instead presented a convoluted series of equations based on false assumptions which purported to prove that Cuba could be visible from Key West. Somehow, despite the fact that astronomy texts list a *TOTAL* displacement of 0.5 degrees for the Sun, a figure which I proved would still make Cuba impossible to see from Key West, John Carr's convoluted equations showed that Cuba "miracule ala Reaganista"! was visible from Key West. Mr. Carr then proceeded to justify these astounding results by pointing out that light in a continuously changing medium will be refracted continuously rather than at a sharp angle as in going from air to water or air to vacumn. A point I never disputed. Regardless of whether the refractive displacement is continuous or not, authoritative texts list a *TOTAL* refractive displacement for the Sun of 0.5 degrees after going from a refractive index of 1.00293 to 1.000000 and after going through 180 miles of continuously changing atmospheric density. There is no way that the total refractive displacement going the 90 miles from Cuba to Key West with a difference of 0.000030 in refractive indices versus 0.000293 that there will be more refractive displacement than that viewing the Sun. I don't expect you to understand that, Mr. Swan. I am concluding it is hopeless to expect you to understand anything. tim sevener whuts!orb
eck@apollo.uucp (Mark Eckenwiler) (03/23/88)
In article <1570@osiris.UUCP> dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: > >Ok you hosers. I have just returned from Key West and I asked a fair number >of the local people whether you can see Cuba, even on the clearest of days. >The answer was/is a unanimous NO (maybe from the air, but no chance from land). >There used to be a sign there that said "CUBA 90 Mi.", but I think it has been >taken down. >-Tom O'Toole >J.H.U. Medical School >asidonhopo@jhuigf.bitnet How dare you raise the spectre of *empirical proof*? Aroint thee, varlet! I propose a simple remedy for the dispute. All talk.politics.misc readers will contribute $3 toward the cost of airfare from, say, Boston to Miami. (I, for one, would gladly pay that much to be rid of the foreground noise about Cuba, and I suspect many others will feel the same.) The observer should be a disinterested party. Of course, in fairness to the claims of certain parties, the expedition should take place during a part of the year when warm, sunny weather creates a favorable climate for temperature inversions and related phenomena. I volunteer. -eck P.S. For $5.25 we could probably get a package deal including 3 days at Disney World...but maybe our traveler, having tasted the forbidden fruit of reality, would linger, lotus-eater-like, never to return to the fantasy land of talk.politics.misc. Disclaimer: I lived in Anaheim in 1963.
lazarus@athena.mit.edu (Michael Friedman) (03/23/88)
In article <1570@osiris.UUCP> dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: >Ok you hosers. I have just returned from Key West and I asked a fair number >of the local people whether you can see Cuba, even on the clearest of days. >The answer was/is a unanimous NO (maybe from the air, but no chance from land). Oh well, I guess I didn't really see Cuba. Thanks for checking. >There used to be a sign there that said "CUBA 90 Mi.", but I think it has been >taken down. Any idea why? (Let's add that I was probably standing next to that sign when I looked out and saw whatever I thought was Cuba in that general direction. Although Tim is sure to take this as proof that I was busily perpetrating a rightwing conspiracy, I hope the rest of the net will realize I was merely in error.) These are the official opinions Mike Friedman of my organization. So, TOUGH!!
amlovell@phoenix.Princeton.EDU (Anthony M Lovell) (03/23/88)
In article <3952@bloom-beacon.MIT.EDU>, (Michael Friedman) writes: > > dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: >>Ok you hosers. I have just returned from Key West and >>there used to be a sign there that said "CUBA 90 Mi.", but I think it has been > >taken down. > > Any idea why? It's moved closer, perhaps? Any comment on the scientific possibility of such a move? Tim? Mike? Let's get a discussion going, here. -- amlovell@phoenix.princeton.edu ...since 1963. disclaimer: These are MY opinions. You only WISH they were yours.
bill@sigma.UUCP (William Swan) (03/24/88)
In <2136@phoenix.Princeton.EDU> amlovell@same (Anthony M Lovell) writes: >>> dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: >>> Ok you hosers. I have just returned from Key West and there used to be a >>> sign there that said "CUBA 90 Mi.", but I think it has been taken down. >>Any idea why? >It's moved closer, perhaps? Any comment on the scientific possibility >of such a move? Tim? Mike? Let's get a discussion going, here. Well, according to the theories of plate tectonics... :-) (I didn't mean it, honest, and don't you dare mess with the Followup line!) -- William Swan {ihnp4,decvax,allegra,...}!uw-beaver!tikal!sigma!bill
lazarus@athena.mit.edu (Michael Friedman) (03/24/88)
In article <2136@phoenix.Princeton.EDU> amlovell@phoenix.Princeton.EDU (Anthony M Lovell) writes: >In article <3952@bloom-beacon.MIT.EDU>, (Michael Friedman) writes: >> > dredd@osiris.UUCP (Gaziggity B. Yazghizzer) writes: >>>Ok you hosers. I have just returned from Key West and >>>there used to be a sign there that said "CUBA 90 Mi.", but I think it has been >> >taken down. >> Any idea why? >It's moved closer, perhaps? Any comment on the scientific possibility >of such a move? Tim? Mike? Let's get a discussion going, here. Mr. Lovell has brought up a very important factor which was ignored in the discussion about the visibility of Cuba from Florida - continental drift. In order to prove that I did not see Cuba it is not enough to prove that it cannot be seen now. It must be proven that it could not be seen in, say, 1975, or so. To do this you must prove either that Cuba is not moving away from the US due to continental drift, or that despite this movement Cuba was not visible even in 1975. I eagerly await further postings on this matter. These are the official opinions Mike Friedman of my organization. So, TOUGH!!
jfc@athena.mit.edu (John F Carr) (03/24/88)
In article <3980@bloom-beacon.MIT.EDU> lazarus@athena.mit.edu (Michael Friedman) writes:
: Mr. Lovell has brought up a very important factor which was ignored in
: the discussion about the visibility of Cuba from Florida - continental
: drift. In order to prove that I did not see Cuba it is not enough to
: prove that it cannot be seen now. It must be proven that it could not
: be seen in, say, 1975, or so. To do this you must prove either that
: Cuba is not moving away from the US due to continental drift, or that
: despite this movement Cuba was not visible even in 1975.
:
: I eagerly await further postings on this matter.
No need to wait any longer.
Next on the list of subjects not considered in this discussion:
the doppler shift of light reflected from Cuba due to the motion of
Cuba relative to Key West and the atmosphere. It is a well known fact
that the index of refraction is a strong nonlinear function of wavelength.
(This is the reason diffraction gratings are preferred over prisms.)
Depending on your assumptions of the velocity and reference wavelength,
doppler shift of light could be important. And also, we can't forget
earth tides. At certain phases of the tide, the velocity difference
between Cuba and Key West due to tidal deformation of the Earth by the
moon may even exceed the relative motion due to plate motion and deformation
At 'ebb' tide, Cuba and Key West will be pulled closer together by this effect
but have no relative velocity, while at other phases they will be further
apart but have a larger relative velocity. Adding to this the fact that
the Moon was closer to the Earth in 1975 than it is now, and so exerted
stronger tides, we have the potential for an important contribution to this
debate.
I request that these topics be addressed by Tim Sevener in his next followup.
I have good ideas about the magnitude of their effect, and I am sure most of
the scientifically aware people on the net do also, but I request that those
who have estimates of the magnitude of such effects keep them to themselves
for a short time as it would be best to have the first response come from Tim
so there can be no allegations of bias or lack of scientific knowledge.nrh@buzz.bellcore.com (Nat Howard) (03/25/88)
In article <3956@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: >And the Reaganistas continue to say they are infallible.... Quotes, please? And something that defines the quoted folks as "Reaganistas"?