User talk:Cleonis/archive1

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My name is Cleon Teunissen, I'm new to Wikipedia, and I'm particularly intrigued by the story of 'centrifugal force'. I'm fascinated by how adamant people can be about the subject.

Contents

[edit] Talk:Fictitious force

Hi Cleon, please don't delete discussion on article talk pages. You should refactor or archive (see Wikipedia:Talk page). Duk 10:14, 29 Jan 2005 (UTC)

Hi Duk, I guess I assumed that since the history is preserved there is no such thing as really deleting discussion from talk pages. I wanted to avoid clutter, so I removed section, mostly things I had written.
I followed the refactor link, but it didn't clarify all that much to me. I haven't seen the method to move to archive space yet. Cleon Teunissen 11:08, 29 Jan 2005 (UTC)
You are right, it is not obvious. Use the move button (to the right of edit this page).
To archive, move the talk page to talk:page_name/archive1 (this moves the edit history too). A re-direct is created (from talk page to archive). You need to replaced the re-direct with a link to the archive, so that when people go to the talk page they aren't re-directed. Its a good thing to do after a re-write (and I know that was your intention for cleaning up). I went ahead and did it. Duk 11:40, 29 Jan 2005 (UTC)
The purpose of my cleanup was to make the discussion accessable to others. I wanted to do some defragmentation. Much of my discussion with William M Connolley contained justification of my intentions on how to proceed, so after the rewrite the discussion was still relevant to the article. Cleon Teunissen 21:25, 29 Jan 2005 (UTC)
Indeed - please don't delete talk (you are right that it is there in history, but people shouldn't have to search through the history to find it). If you only want to archive part of the history, cutting and pasting would work too (cutting and pasting is usually deprecated: however, given that talk comments are mostly signed, author attribution is not such a great issue as it would be for cutting and pasting articles themselves). -- ALoan (Talk) 11:22, 30 Jan 2005 (UTC)

[edit] SSR

The entry is supposed to be about Kuhn's work. To say "we know" such things, in a page about a book which is often used to dispute the ontological basis of science, is not only inappropriate because it misrepresents the work, but is decidedly a form of POV, in a sense. Aside from that, Kuhn would note that whether we "know" (if you would even accept that) that matter is made of "atoms," the meaning of "atoms" has changed radically many times since it postulation (first as small bits of point matter, then as masses of positive charges surrounded by rings of electrons, then as positive and neutral charges bound by strong nuclear forces surrounded by wave/particle electrons according to a distribution pattern, then as quarks in various configurations, then perhaps as strings bound into greater complexities, etc. etc. etc.). To use a scanning tunneling microscope as a way to "refute" that makes as much sense as using a Leyden jar to argue for the liquidity of electricity. Personally I would want to, when I got the time, go over Kuhn's work again and use only the examples with which he uses (which if I recall focus primarily on the Maxwell/Einstein transition, which he saw as an exemplar of his theory) because it is an entry about the book. To weigh in one "who was right" (a way of approaching the issues Kuhn explicitly argues against) is not appropriate. --Fastfission 01:21, 16 Feb 2005 (UTC)

--Cleon Teunissen 12:12, 16 Feb 2005 (UTC) It is quite possible that the Leyden jar is mentioned in SSR. At first the scientists saw bottles to contain something with the properties of a fluid, later, they saw condensators, very thematic. The example does not apply: scanning tunneling imagery shows that at some magnification level matter is seen to be discontinuous. Recognizing that there is at that size range a "building blocks" level does not require a commitment to any concepts of the nature of these building blocks, which is why I chose scanning tunneling microscopy.
I feel that in writing a synopsis a balance needs to be struck. I have criticised the 'expert terms' section of the wikidedia paradigm shift article severely for popperianizing Thomas Kuhn. I guess the writer of those passages wanted to make Kuhn more palatable to people unfamiliar with the work of Thomas Kuhn.
In my synopsis I have done something similar. By stressing that with the benefit of hindsight we know the atomists were on the right track I want to give the reader some reassurance. I'm trying hard to sell Thomas Kuhn to a bigger audience. I want to catch and hold peoples attention.
I feel your phrasing is hypercorrect, I feel you are trying to be more Catholic than the pope.
In the synopsis I discuss two examples: chemistry in the time of Lavoisier and Dalton, and I discuss the Keplerian revolution. To my knowledge Thomas Kuhn has published three books (or three are better known than others). A book titled 'The Copernican revolution', SSR and a book on the history of evolving concepts in the early development of Quantum dynamics. I decided to discuss the Keplerian revolution in detail because it was pivotal in the evolution of Thomas Kuhn's thoughts, and it also allowed me to show how terribly bad popular accounts of the history of science often are. I feel as strongly as Thomas Kuhn that bad science history breeds bad science philosophy. --Cleon Teunissen 12:12, 16 Feb 2005 (UTC)

The problem is never a question of palatability, but accuracy. What was Kuhn actually saying? That's what the articles should reflect. I am not trying to be "hypercorrect," I'm simply trying not to prejudge the reader. It does not help the reader to understand Kuhn if we use terminology that Kuhn would never use. Kuhn would never say, "We know the atomists were correct" because his entire point was that we don't really know what correct will ever be. So clearly any explanation of what he said could never contain such a phrasing. Let us make clear which entries we are talking about, when talking about examples. The only problem I have with using the Copernican revolution as an example for paradigm shift is that he wrote it well before coming up with the idea of the paradigm shift; it is embryonic in many ways. If done carefully and illustratively, though, it could serve as a useful example to the reader, so I am fine with that. But the examples in the SSR entry should be taken from SSR, since it is an entry about that particular book. My goal here is to make sure the reader understands Kuhn on his own terms and in his own language. They can draw whatever conclusions they want from that (we could even include a Criticisms section which makes common objections clear). Pre-disposing them into a Whiggish mode of thought (this is "correct" this is "not correct") is the polar opposite of what Kuhn was saying should be done. It is important that we give the historical events in the terms and language Kuhn used them—while also presenting whether others criticized his historical facts, which some did—in order to explain Kuhn's philosophy of science (which is above all what the entries must be on, of course). --Fastfission 13:43, 16 Feb 2005 (UTC)

--Cleon Teunissen 16:19, 17 Feb 2005 (UTC) Personally, I think the art of persuasion is important; the social dimension of conducting science. In my opinion, a synopsis should be sufficiently accurate to avoid that the reader who later actually reads SSR is not surprised. I take palatability quite serious.
I'm not very demanding when it comes to calling something correct. The early greek philosophers concluded on the basis of the knowledge of their time that the earth had to be spherical in shape. I call that a correct assessment. What was discovered later does not refute that correctness, in my style of judgement. I suppose the way I use the word 'correct' is rather from an engineers point of view. My thinking leads to statements of the type: the concrete for the Pantheon in Rome was mixed correctly. I don't really see any other way of using the word 'correct' in a way that is meaningful.
I was not aware that in my memory the two books; Copernican revolution' and 'SSR' had become merged. In my memory, SSR discusses the Copernican revolution too. I've had a quick glance in SSR and to my shock I discovered that my memories are not reliable; I shall have to reread the book.
In the postscript added in the third edition of SSR, Thomas Kuhn stated explicitly that philosophical relativism was not his philosophy. I think that in SSR Thomas Kuhn took extreme care to preserve neutrality.:An example (introduction to the example: Kuhn explains that it is historically dubious to state that Ohm discovered Ohm's law, because Ohm's formulation of what later became known as Ohm's law was a step in a development towards a concept of electrostatic force that was not present before. What later became known as Ohm's law helped to create the paradigm in which Ohm's law is applicable.) When Kuhn describes an example like that he preserves a very fine balance. Kuhn does not prejudge the reader by stating: today we believe Ohm's law is valid; Kuhn avoids that sort of statement too!
I think your alterations prejudge the reader towards relativism in a way that Thomas Kuhn avoided.
In my synopsis I have chosen to simplify the exposition. I maintain a balance far less fine than what Thomas Kuhn maintained. Without that simplification, the synopsis would have been even longer. (It is already uncomfortably long.) --Cleon Teunissen 16:19, 17 Feb 2005 (UTC)
I don't think that saying "we believe" in any way prejudges philosophical relavitism—it not only does not make a statement about whether or not science can reach truth (simply because one does not assert that the current state of knowledge is truth does not mean that there is no truth), but it does nothing more than assert that indeed, we believe X to be true (in this case, matter is composed of atoms). I think your association with "belief" with something less than true is a positivist approach that Kuhn would disdain quite heavily, whatever you take his position to be on "the ontological question." But this is not about philosophical questions, this is about how to write history of science, and this is what concerned Kuhn more than anything else. Historical method and historicity demands that one does not judge the past by the standards of the present, at the very least. In science, that amounts to not saying, "well, they were wrong, because now we know X is the way things really are," if one is a conscientious historian. Surely you can see the advantage of that? Here's the rub: Does changing a statement from reading "we now know atomism to be true" to "we now believe atomism to be true" significantly imply relativism? Not to me it doesn't; it simply gets you out of the bind of trying to lecture the audience on what we "know", something which even a positivist would admit is always conditional on the current state of knowledge and interpretation. So surely this is not worth all of this discussion, ja? --Fastfission 02:59, 18 Feb 2005 (UTC)
About the verb 'to believe'. I didn't quite realize this verb has a range of meanings, from 'to believe' as in a 'belief system (an irrational belief system)' to a very neutral meaning. I agree that if I read your words with the most neutral sense of believe in mind, then there is no implicaiton of relativism.
The things you are saying to me: you are preaching to the converted. I have been preaching the same things to others. When I first read Thomas Kuhn I was deeply impressed, my thoughts were changed profoundly. But my thinking has kept developing, and I have realized now that I am not sufficiently able to separate my own thoughts from those of Thomas Kuhn. I think I will not edit wikipedia articles on Thomas Kuhn anymore.
I get the impression we are not talking about the same things, for I have avoided using words like 'true' and 'truth', it's quite unclear to me why you have started using them.
I am convinced that on the whole scientific theories have become wider in scope, that on the whole successive paradigms could account for wider and wider ranges of phenomena in a consistent explanatory framework.
I avoid the word 'truth'. I can work with the expressions 'working truth' and 'exhaustive truth'. Working truths have been achieved all through the history of science (and I tend to favor engineering achievements). An intention to uncover 'exhaustive truth' would be like trying to find the proverbial pot of gold at the end of the rainbow.
I quite like the example of concrete. The roman master builders had only trial-and-error to perfect their cement, and that was sufficient; they knew how to mix prime quality concrete. Concrete must be kept moist during the hardening, if the concrete dries prematurely it will be of inferior quality. Later progress in chemistry led to the insightfull knowledge that the hardening of concrete is a recrystallisation process. Water molecules become part of the crystal structure of the new material.
I reject the idea of aiming for 'exhaustive truth'; at the same time I am convinced that throughout the history of science and technology knowledge has deepened, increasing strenght.
In my opinion, a historian of science does not have to make modern knowledge invisible. In my opinion a historian of science should try to make the reader feel how a paradigm that was at some later point abandoned had at the time good scientific credibility, more so than other ideas of the time. I agree that Thomas Kuhn would have avoided the turn of phrase: "With the benefit of hindsight we know that[...]" But that turn of phrase is my very point. It can be seen only with the benefit of hindsight, it could not have been seen at the time, it would be a principle mistake to think it could have been seen at the time. --Cleon Teunissen 19:23, 18 Feb 2005 (UTC)
Just a quite note on believe vs know: we could use "think," and it would have the same possibility of valences. The reason that such an innocuous term seems to be so threatening in this context is that it adds a human character to the sciences, and adding a human character to anything is always a way to make something seem contigent, even when accurate (the same thing is done by iconoclasts when they want rob an icon or an image of its religious power: they show that it was made by a human hand). Just a note... --Fastfission 19:58, 18 Feb 2005 (UTC)


[edit] Image:Gravity not fictitious.png

The image namespace is for images; it is not really supposed to be for articles in their own right. I strongly suggest that you create a proper article in the Wikipedia main namespace and move your information there. Then you can link to the image using Wikipedia image syntax. If you need assistance I am more than happy to help. -- FirstPrinciples 11:20, Feb 20, 2005 (UTC)

I can understand your concerns... but I don't see why you had to move outside the main namespace. I would like to suggest that you raise this issue at Wikipedia:Village pump (assistance) and ask for advice there. If you want, I can ask for assistance on your behalf. -- FirstPrinciples 13:28, Feb 20, 2005 (UTC)

[edit] Principle of relativity

Since you wrote the article on the subject, I have a question I want to ask you. My understanding of the principle of relativity is that (among other things) it requires the laws of physics to be the same in all frames of reference. I want to be sure that this is absolutely true, or if it is only true for inertial frames. The reason I ask is because I linked the frames of reference page to the principle of relativity page. StuTheSheep 16:55, Mar 1, 2005 (UTC)

Thank you for clearing that up for me. StuTheSheep 05:40, Mar 3, 2005 (UTC)

[edit] Coriolis effect

Hi, I see you've done quite a lot of work on the Coriolis effect webpage. I think it should really be reformatted a bit, so that the long text in the beginning can be split into a few subheadings and stuff. Otherwise really good article. Houshuang 19:29, 4 Mar 2005 (UTC) (who has an envirosci exam in a few hours)

This looks very good! Don't have the time to go through it word for word now, but a lot more readable and easy to understand. Our physics prof actually encourages us to use Wikipedia, so having these kind of articles accessible and well written is a big boon.

THanks Houshuang 00:37, 9 Mar 2005 (UTC)

[edit] mass flow meter

Hey, Forbsey here. My apologies about wrongly stating that the article in question requires Wikification. I did not notice the Wikilinks in the bottom half of the page. The reason for this confusion was that from my experience of articles, many more Wikilinks are present than the amount on the article in question. Once again my apologies and i have taken away the -Wikify- from the page. Is there anyway of Categorizing the article? Forbsey 14:30, 6 Mar 2005 (UTC)

[edit] Geostrophic wind

I wish I could provide you my sources for the geostropic wind component of the wind article, but it's been some time since I wrote it, and I have no idea where I got the information (save that it was from a reliable source). Please do not hesitate to make corrections as you see fit. One of the great things about Wikipedia is that you can fine-tune the work of others, and if you find the explanation I provided muddled, I will not be offended if you can improve it. Denni☯ 21:54, 2005 Mar 14 (UTC)

[edit] Long straight isobars

...are what would occur on a non-rotating sphere, as my source has it (and which makes sense to me). Denni☯ 23:46, 2005 Mar 15 (UTC)

[edit] Rotating coordinate systems

Hi! While I agree with you that the rotation of our galaxy is neglible compared to everyday rotations, I would also argue that there is rarely if ever a need to use General Relativity in everyday situations: it is mainly important in astronomy and cosmology, and there the question of whether your coordinate system is fixed w.r.t. to the rotating Milky Way or w.r.t. to distant galaxies may very well make a difference. Cheers, AxelBoldt 21:11, 23 Mar 2005 (UTC)

[edit] Sagnac

I looked over your reference. I don't see where you got the "prefered frame" business from with it. Please take a careful look at my edit. I have done my best not to overly disrupt your write-up, which overall is actually quite good. However, that one point needed dealing with.

EMS

[edit] Sagnac again

> I assure you I have not confused the ring setup with an inertial frame of reference.

That is not your confusion. That is Sagnac's and many, many others.

> Sagnac interferometry measures rotation with respect to the local space-time geometry. According to general relativity, is it possible for space-time geometry to rotate with respect to its surrounding space-time geometry, but the amount of rotation is exceedingly small. See frame dragging and Gravity Probe B. The amount of space-time geometry rotation that general relativity predicts is too small for current ring interferometers to detect. Because of this a Sagnac interferometry measurement of the rotation rate of Earth, and astronomical observation of the rotation rate of Earth agree exactly. --Cleon Teunissen | Talk 22:53, 24 Mar 2005 (UTC)

I think that you are preaching to the choir here.

> You wrote:

> The Sagnac effect has been used to claim that a prefered frame of reference exists. This is due to a misunderstanding of the nature of the propagation of light and treating the rotating Sagnac ring as an inertial frame of reference.

> I did not treat the rotating Sagnac setup as an inertial frame of reference. I stated that a Sagnac interferometer shows a displacement of the interference fringes when it is rotating with respect to the local inertial frame. --Cleon Teunissen | Talk 22:59, 24 Mar 2005 (UTC)

Once again, the is how Sagnac interpreted the results. He was looking for evidence of the aether in an attempt to debunk relativity. He thought he had a rotating Michaelson-Morely experiment.

I kindly suggest reverting back to my edit, perhaps with the following sensence inserted after the ".. has been used to claim ..." sensence: "(This is how Sagnac himself interpreted the result of his experiment.)"

EMS

P.S. You seem to be sending me messages through a means other than what I am using. How do you send Wikipedia messages?

[edit] Modified Saganc page

Hi Cleon,

On the motives of Saganc, I have done some more research and think that you are right on that count.

On the equation: I think that it is better than the previous text. However, it still needs work. I need to "pad" it with explanatory text as to what is going on and why. Through that, the equation can be skipped by those who are not proficient with such stuff, while those who are can use it to verify the assertions being made.

I do admit that equations are a nuisance. On the one hand they establish the proper basis for justifying the blanket assertions that Sagnac is consistent with relativity. On the other hand they are not accessible to the average reader. However, to be honest with you, you are groping with the issues of SR and GR in your version, while the metric equation itself is the necessary description that handles those issues.

I'll let you know when I am ready with a new draft. Maybe later today, or more likely next week. Feel free to look in occasionally if you like.

--EMS 15:41, 25 Mar 2005 (UTC)

[edit] Sagnac talk

How about doing the discussion in User_talk:Ems57fcva/sandbox/Sagnac_Effect?

BTW - New edits are done.

--EMS 17:02, 25 Mar 2005 (UTC)

[edit] Re: Harress

Thanks for the info on Harress. I got what I had from another web page.

Can you provide me with a reference for what you wrote? I suggest that your explanation be incorporated into the page itself, but want to be able to back it up.

--EMS 18:52, 25 Mar 2005 (UTC)

[edit] Solar greenhouse (technical)

Thanks for your rational analysis on Talk:Solar greenhouse (technical). Trying to defuse an edit war can be rather frustrating. Please feel free to edit my compromise version, assuming it stays active :-). Vsmith 13:33, 26 Mar 2005 (UTC)

[edit] Saganc article ready

I think that the Sagnac Effect article is now ready for "prime time", unless you have some objection to it (which I would doubt since I noticed that you have tweaked it some). I have chosen to put in a section of uses of the effect, including a reference to the GPS. The more I thought about it, the more it seemed to me that this did belong in there.

[edit] Merged Sagnac effect page.

Dear Cleon,

Overall I liked your merger. I have updated your edit, removing a sentence from the 4th paragraph about the viewpoint being an intertial frame of reference. You aleady cover that issue in the previous sentence by saying that the rotation is with respect to an inertial frame, and I would leave it at that. You later on note that the Effect must be the same as viewed in any frame of reference. That really is the crux of Relativity anyway -- all phenomena should be the same a viewed in any reference frame(s).

(It really is a good question that the anti-relativists ask when they question why the Effect should appear even to a co-rotating observer. Unfortunately for them there is a good answer to it.)

I did some tweaking of what you wrote in the "Calculations" subsection. Mostly it was syntax and breaking up the first sentense to clarify your message, which as I noted above I like. I also tweaked my text a bit to better work with yours.

Beyond that, I do think that the Sagnac magnitude calculation belongs in that page, but that is a minor issue since it can be gleamed from the references.

Overall, I think that it is time to put the new page out there.

EMS

[edit] Frames of Reference

Cleon -
What you wrote is below. My text is indented. - EMS

According to my sources, general relativity is not generally invariant, and I think the sources I have consulted are knowledgable in this. Usually the covariance group of a physics theory and its invariance group coincide, like in the case of special relativity. This is not the case with general relativity.

I have no argument with this, although the Sagnac Effect does not use (or at least does not need) GR in it's explanation.

The philosophical conclusion that I draw is that physical phenomena relate to local inertial frames. It seems to me that physical phenomena take place in local inertial frames exclusively.

With this I must strongly disagree. The general principle of relativity states that "the laws of physics are the same in all frames of reference". Accordingly, all physical phenomena happen in all frames of reference. That motion prefers to occur along geodesic/inertial paths is true, but that does not make the view from inertial/geodesically moving observers preferred.

The mathematics of general relativity can handle any choice of coordinate system, including coordinate systems that rotate with respect to the local inertial frame. Calculations performed this way yield outcomes that are consistent with the outcomes of other appropriate calculations. However, it seems to me that coordinate systems that rotate with respect to the local inertial frame do not represent actual physics.

Excuse me. We, here on the surface of the Earth, exist continually in an accelerated frame of reference. Are you saying that your perceiving yourself sitting at rest with respect to your keyboard and typing into it is not "actual physics"? Are you saying the the fall of the water when you accidentally knock a glass over is not "actual physics"? Come off of that. Physical phenomena just plain occur. What differs between the various frames of reference (be they inertial or accelerated) is how the phenomena are described. It is easier to describe something like the Sagnac Effect in an inertial frame of reference. That does not mean that the view of a rotating or other accelerated observer is invalid.

I draw a distinction between 'performing calculations in the context of coordinate system that is rotating with respect to the local inertial frame' on one side, and on the other side, 'thinking about physics from the point of view of a rotating frame. I acknowledge that the calculations yield correct outcomes. I state that attempts to think about physics from the viewpoint of a rotating coordinate system do not have physical meaning.

If those things that are supposed to be invariant (such as elapsed proper time for the observer, local energy content, and locally experienced acceleration) all come out the same in another frame of reference, where is the lack of meaning? If someone jumps off of a cliff, would you really say that the person died after to the land below was accelerated into the him instead of that he fell to his death? I repeat: All physical phenomena occur in all frames of reference. It is actually quite counter to the principle of relativity to say that one reference frame (or set or reference frames) or another is preferred, and that the laws of physics only apply in such a frame.
Exercise - Compute the geodesics of motion for a rotating frame. You will find that they are usually helixes of some sort. Also for the null geodesics for lightpaths. Such descriptions of inertial motion are not simple, and are not easy to do, but I assure you that they are as correct the ones for an inertially moving observer. (If you really want to have some fun, compute how the Sagnac Effect looks from the viewpoint of an observer on the ring instead of at the center of rotation. I did that once. It is even more complex than the metric I provided, but once again the same effect is predicted.)
One more thing: In GR, it is easiest to do calculations for the Schwazschild Solution in the rest frame of the center of a massive object with respect to the distant stars. However, being at continuous spatial rest with respect to the Schwarzschild coordinates always means that one is in an acclerated frame of reference. To make matters worse, even a freefalling observer in a Schwarzschild field finds himself surrounded by a set of tidal potentials such that other observers at distant positions and at rest with respect to himself are also in accelerated frames of reference.

--EMS 22:27, 28 Mar 2005 (UTC)

P.S. Sorry to be long-winded, but I think I really needed to make my point. Otherwise there is no need for the General Principle of Relativity or the principle of general covariance.

[edit] Re: Principle of Relativity

Hi EMS, you need not have apologized for writing long texts. I am much worse.

I'd like to go back to the basics. Frst I will recapitulate very elementary stuff, to lay a foundation. then I will come to the point. Recapitulating When two objects collide with each other, and they remain stuck to each other, a lot of kinetic energy is converted to heat. For the calculation of the amount of kinetic energy gets converted to heat any inertial coordinate system can be chosen, the outcome of the calculation is always the same. (The most symmetrical choice of coordinate system being the coordinate system that is co-moving with the center of mass of the two objects that are going to collide.)

I do not believe that this is correct. The following quantities are transformed between reference frames:
  • The energy and momentum of the first object before the collision,
  • The energy and momentum of the second oject before the collision,
  • The energy and momentum of the combined object after the collision, and
  • The energy radiated by the combined object after the collision.
However, none of them are invariant between the reference frames. (The rest masses of the objects are invariants. This also applies to the heat, but its rest mass is zero.)

The reason that any inertial coordinate system can be chosen is that in all physical interactions there is no dependency on velocity, only relative velocity matters. You can set up the collision, measure the amount of heat that is released. Then the objects are co-accelerated for a while, and after this acceleration stage, the center of mass of the two object has a relative velocity to the initial situation. The two object are given the same relative velocity to each other again, and at collision exactly the same physics will occur.

The core concept of the principle of relativity is the conviction that everytime the relative velocity is the same, the same physics is occuring at the moment of collision. Any transient change-of-velocity stage is undetectable after the fact.

Ring Laser interferometer Now I'd like to look at the Ring Laser interferometer. The Canterbury (New Zealand) RLG uses a laser with a frequencyof 473 THz. Suppose that ring laser (like the original Sagnac setup) is build on a platform that can rotate. When that platform cancels the Earth rotation by counterrotating, then the counterpropagating beams are monochromatic coherent light, as is normal for lasers. But when this ring laser interferometer is co-rotating with Earth, then the laser light splits in two frequencies, and in the case of the Canterbury University RLG the frequency difference between the two counterpropagating beams is around 70.7 Hz. The thing to note is that a ring laser interferometer measures straight away, no calibration by outside comparison. Every real time measurement by a ring laser gyroscope is a measurement without memory of earlier measurements!

Initially the ring interferometer had a rotation rate of zero. Then a torque was applied to the platform to bring the rotation rate to one revolution per day, co-rotating with Earth. So there has been a transient torque, resulting in a new angular velocity that is a constant angular velocity. The changing of the angular velocity was transient. What is observed is that after the change of angular velocity there is different physics going on as compared to the initial situation. In the new situation there is frequency splitting. The transient change-of-angular-velocity stage is detectable after the fact.


The core concept of the principle of relativity is the conviction that everytime the relative velocity of two or more objects is the same, the same physics will occur. Any transient change-of-velocity stage (change of velocity of the common center of mass of the system under observation), is fundamentally undetectable after the fact.

On the other hand. If a change is detectable after the fact, by an instrument that operates without calibration by outside comparison, then it is shown that the physics has changed: a different physical interaction must be taking place as compared to before. --Cleon Teunissen | Talk 14:06, 29 Mar 2005 (UTC)

Retrieved from "http://en.wikipedia.org/wiki/User_talk:Ems57fcva"

You are talking past me. With the Canterbury U. RLG, we here on the Earth see it as non-rotating when according to the frequency shift it is rotating. On the other hand, to an observer in deep space, it does have a rotation because it is co-rotatating with the Earth. You want to treat one of those views as "correct". My point is that both views are correct!
The goal of relativity is to permit all observers to reconcile their views of the same events. It makes no difference if the observers are at rest with respect to one object or another, whether they are accelerating or nor, whether they are in deep space, station keeping just above the event horizon of a black hole, or on a satellite going around the moonlet of a giant moon of a planet of a star with the sattellite rotataing to provide artifical gravity. Each observer may have different views of how fast the objects were going, what their energies and momentum were, and even of the half-life of the heat that was radiated off. However, each can with the aid of the Lorentz Equations and the metrics tensors of GR determine that the views of the other observers was consistent with their own.
In the end, that is what Relativity is about: Determining that different views are consistent and/or transforming between the reference frames. Each view is correct for its observer. All frames of reference are valid. The Caterbury U RLG may allow us to determine the rotation rate of the Earth with respect to spacetime itself. However, that does not make the non-rotatating frame prefered except in that it is the easiest one in which to calculate the behavior of the light in the ring.

--EMS 16:03, 29 Mar 2005 (UTC)

[edit] centrifugal force

Why you think I am "dangerous" is beyond me. The edit to centrifugal force was correcting an incorrect statement which declared that centrifugal force was not a force because it did not produce acceleration. This is incorrect because the entire point of a centrifugal force is that what appears as centripetal force in a stationary reference frame appears as a centrifugal force in a rotating reference frame. This is a phenomena which emerges simply from classical mechanics, and does not require general relativity considerations. The final sentence in that paragraph simply mentions general relativity because the consideration of centrifugal force as the distinguishability of rotating reference frames is an important concept of general relativity. Centrifugal force does not require general relativity to explain in terms of rotating reference frames, but general relativity does use arguments containing centrifugal force. These were the reasons for the edits. — Cortonin | Talk 19:07, 29 Mar 2005 (UTC)

The mention of rotating reference frames is mandatory for a thorough description of centrifugal force. But the organization of where to place mention of general relativity in the centrifugal force article is a separate stylistic issue, and does not need to be within the section on inertia where I initially placed it. — Cortonin | Talk 19:07, 29 Mar 2005 (UTC)

You are correct in your description of the hammer thrower, because you are considering it from the non-rotating reference frame, in which there is only the centripetal force, and upon release of the hammer it simply continues in a straight line. However, let's try a rotating reference frame. We will take an observer, named Cleon, and place him in a closed elevator in outer space (with no gravity). Cleon cannot observe anything outside of his elevator, and can only observe the inside of the elevator. Now, there is a long rope tied to the top of the elevator, and a giant is using the rope to spin the elevator in a big circle over his head. From the giant's perspective, the non-rotating frame, the centripetal force applied by the rope makes the elevator accelerate radially inward and progress in a circle. But now let's consider Cleon's perspective, in which he can only see the inside of the elevator, which is a rotating reference frame. If Cleon holds a ball out, and lets go of it, the ball will accelerate toward the bottom of the elevator. Cleon is observing an acceleration. If Cleon is meticulous in his experimental observations, he will notice that this force is radially outward from a single point and proportional to the distance from that point. So from the rotating reference frame centrifugal forces do yield accelerations, and this is why the word "force" is used to describe them. — Cortonin | Talk 02:28, 30 Mar 2005 (UTC)
When you are saying "before I look outside" and "after I look outside", what you are saying is actually "when I consider it from the rotating reference frame" and "when I consider it from the non-rotating reference frame". And that's precisely what I have been saying. When you consider it from the non-rotating reference frame, then there is no acceleration, there is only inertia (the force observed is centripetal). When you consider it from the rotating reference frame then a centrifugal acceleration is observed (the force observed is centrifugal). — Cortonin | Talk 15:03, 30 Mar 2005 (UTC)
Careful consideration of rotating reference frames is required for a consideration of centrifugal force, since that's where the expression of it as a force comes from. See scienceworld for a short, but prominent, example (also note the presence of a centrifugal acceleration term in the equations). If you like, I can name some textbooks which discuss the coordinate transforms to a rotating frame which result in a centrifugal force term appearing. — Cortonin | Talk 15:03, 30 Mar 2005 (UTC)

If you want to consider conservation of energy, then go right ahead. Take a bucket in space with no gravity, fill the bucket with water, and put a fan or turbine on the bottom which powers an electrical generator. Then have the same giant spin it over his head. From the non-rotating frame the turbine is accelerated inward past the water held still by inertia, and electricity is generated. From the perspective of the rotating frame, the water is accelerated outward by centrifugal force through the turbine, and electricity is generated. Consideration of conservation of energy does not change the mechanics of the system, but it is STILL required to consider a rotating reference frame in order to have a centrifugal force. — Cortonin | Talk 16:37, 31 Mar 2005 (UTC)

What you have said in your note to me is that you do not need to consider rotating reference frames because you can translate anything into non-rotating reference frames and analyze it there. And yes, you're completely right. By extension of this, we can erase the concept of centrifugal forces (and coriolis forces) from physics with absolutely no loss in completeness of description. This is also true, and an equivalent statement. But this is a moot point, because the fact remains that we don't have that eliminated from physics. We in fact consider alternate coordinate systems quite regularly in physics, because it is often very convenient to do so. And as soon as we perform such a translation to a rotating coordinate system, then those additional fictitious force terms appear. — Cortonin | Talk 16:37, 31 Mar 2005 (UTC)

The part I disagree with you about, is that you are implying that you can still describe centrifugal force by transforming to a non-rotating reference frame. This is a non-useful semantical argument, because as soon as you translate to a non-rotating reference frame you are only describing centripetal forces and inertia. The only place in which centrifugal forces are observed is within a rotating reference frame. So yes, the physical effects are independent of the reference frame, but the appearance of the physics is different. — Cortonin | Talk 16:37, 31 Mar 2005 (UTC)

This is perhaps analogous in concept to where in special relativity, in one inertial frame two clocks moving in opposite directions will appear to be telling time at the same rate, but in an inertial frame where one of the clocks is stationary, then the clocks are longer telling time at the same rate. The physical effects are still independent of the choice of frame, but the appearance to the observer is different. — Cortonin | Talk 16:37, 31 Mar 2005 (UTC)

There are many cases where it is more convenient to consider the physics of a system from within a rotating reference frame. If you were an engineer who needed to consider the forces affecting a horse on a merry-go-round, you would do it from a rotating reference frame so that it would match up to your diagrams, and then you would be calculating the effects of centrifugal forces acting on the horse. Attempting to calculate this in terms of inertia from within a non-rotating reference frame would be a nightmarishly more difficult calculation. The description on the wiki page should reflect this usage. — Cortonin | Talk 16:37, 31 Mar 2005 (UTC)

Yeah, it did sort of describe that usage, just in unconventional terminology. I made a few small modifications to bring the language more in line with the type of conventional description you would find in a textbook. — Cortonin | Talk 02:58, 1 Apr 2005 (UTC)

[edit] Sagnac effect mechanisms

So I'm not happy with the idea of recognizing two incompatible mechanisms for causing the Sagnac effect. A unification seems in order, or at least a disambiguation. I follow my sources in thinking that the mathematical framework of general relativity can be interpreted in such a way that this unification is achieved. Key elements in this interpretation are the principle of equivalence and Einstein's views on Mach's principle. --Cleon Teunissen | Talk 19:49, 29 Mar 2005 (UTC)

Retrieved from "http://en.wikipedia.org/wiki/User_talk:Ems57fcva"

I think I may need some description as to what you think the "two mechanisms" are. The non-uniformity of the propagaion of light with respect to the mirrors is the reason in any case. What varies is the cause of that non-uniformity. In the case of an external intertial (or more inerital) observer, the cause is a visible rotation of the ring. For the co-rotating observer, the cause is a non-uniformity in the propagation of light which is an inherent part of that frame of reference.
I really don't see there are being two different mechanisms but instead two different views. Note that in both cases, the mirrors can be shown to be travelling in non-geodesic paths, and the same proper acceleration obtained for the mirrors even though they are "at rest" in the rotataing frame of reference. It is like what Einstein showed in EM with the generation of current: What changes is not the mechanism but instead how it is viewed.
If you want something really cute: Michaelson wanted to construct a ring interferometer which went around the Sun. That actually will show a Sagnac shift due to the orbital motion of the mirrors even though the mirrors are all in inertial/geodesic motion. After all, the Schwarzschild metric calls for it, and so will a metric transformed to the view of an orbiting observer.

--EMS 20:36, 29 Mar 2005 (UTC)

[edit] Now for the Equivalence Principle

Cleon -

The Equivalence principle, to which you indicate that you have contributed, is my next "target". I have a revision ready at

User:Ems57fcva/sandbox/Equivalence_Principle.

Just giving you heads-up. I will compose my objection next in its talk page, and see who else responds.

--EMS 05:00, 30 Mar 2005 (UTC)

[edit] Buys-Ballot's law

Hi Cleon,

A couple weeks ago you sent me a message about the Buys-Ballot's law, and you mentioned that it's treatment of the coriolis effect is incomplete. I really don't know much about meteorology, so I would encourage you to update the article as you see fit, if you are so inclined. My explanation was an attempt at describing it to laypeople, since I am most certainly one of those. Also, I was a little unsure about whether-or-not the Buys-Ballot's law and the coriolis effect cover the exact same topic. This, again, I leave in the hands of people who have expertise in this area... especially since lately I've become a WoW addict and haven't been contributing to Wikipedia as much as I used to. =o( -Eisnel 16:30, 30 Mar 2005 (UTC)

[edit] Re: Modeling the Earht's atmosphere

Cleon -

You have won on the coriolis effect business. As long as you are not using the term "geodesic" in your write-up with your hovercraft, I will have no quarel with it.

At this point, I either seriously review that page or leave you alone on it, and I will do the latter. I see no problems with what you presented on my talk page, and really lack the time to worry about this. Besides, you have shown me that you have a good grasp of many of the underlying concepts of physics in general, enough so that I expect to be satisfied with that page if you are.

--EMS 20:19, 5 Apr 2005 (UTC)

[edit] Please do not edit the EP page.

Cleon -

Please do not do major rewrites of the EP page. You do not understand the material. You do not understand the scope.

Slowly that page is coming into shape. It has the right form, but it needs to be fashioned some more. You elaborations did not help, and so I felt obliged to remove them.

As I said in the talk page: This is NOT GR itself. If nothing else there is too much misinformation on GR floating aroung in Wikipedia. That stuff needs to be placed as centrally and appropriately as possible.

--EMS 18:44, 25 Apr 2005 (UTC)

[edit] Re: Too many cooks

Cleon -

Yes. Please do step back.

However, if you can get more specific about how you think the EP page is going over people's heads, I am willing to listen. That is how you can play a role: with some constructive criticism. Just be advised that I want the EP page to get to the point, and fairly quickly. That is not to say that some elaboration would not be helpful, but the EP page must also stand on its own and communicate some fairly advanced concepts. (I agree that the EP page can do a better job of communicating, however.)

--EMS 20:02, 25 Apr 2005 (UTC)

[edit] The EP page

Cleon -

Back off on the EP. Just please do so. Your "Disputed" tag in the EP article is close to being vandalism, especially given the grounds for it that you list.

Please accept that you have a lot to learn about GR and the related concepts.

--EMS 18:09, 5 May 2005 (UTC)

[edit] Disputed tags

Cleon -

I have two rules about the use of a Disputed tag:

  1. The placer of the tag "owns" it -- As a general rule it is up to the placer to decide when to remove it.
  2. The placer has a responsibility to use this tag appropriately and for substantive and well-informed reason. Otherwise it is misleading and/or disruptive.

In the case of Joke137, he demonstrated reasonable cause for the placement of the tag, and so I left it up to him to remove it, as he did.

On the other extreme, a creationist tagging the evolution page as "disputed" would be vandalism.

You fall in between. You have questions and concerns, but for the most part you do not yet understand what the EP is and is not about. For example, you just complained about the WEP being stated with respect to Newtonian concepts. It is and should be stated that way for the reasons described in the EP talk page.

Your ignorance is not a reason to call that page "disputed". You do have some valid concerns, but you also keep wanting to bring into the explanation of the EP such things as cancelation (which is not a part of modern GR theory or even the WEP itself) and curvature which are not a part of the EP or of its underpinnings.

I will move that tag down to the bottom later today unless you give me good reason not to, and may even remove it soon. That page does still need work, but not in the ways you seem to think it should be changed.

--EMS 05:39, 6 May 2005 (UTC)

[edit] History of science articles on Wikipedia?

Hello,

I’m a historian working at the Center for History and New Media at George Mason University (http://chnm.gmu.edu/) and we are very interested in digital historical works, including people writing history on Wikipedia. We’d like to talk to people about their experiences working on articles in Wikipedia, in connection with a larger project on the history of the free and open source software movement. Would you be willing to talk with us about your involvement, either by phone, a/v chat, IM, or email? This could be as lengthy or brief a conversation as you wish.

Thanks for your consideration.

Joan Fragaszy

jfragasz at gmu dot edu


[edit] Respectfully disagree on Kevin Brown

Thanks for your message. Crank relativity work has always interested me, starting with a set of books by Thomas Jefferson Jackson See in the Caltech Math library in 1957. It seems to me that the Kevin Brown stuff, while it is not "crank" so far as I can stand to read it, is a miserable, dilatory attempt to derive in tens or hundreds of thousands of words what Einstein, Lorentz, Minkowski, Weyl, Schwarzschild, deSitter, Kruskal, Misner and collaborators, Oppenheimer and Snyder, and others did in perhaps one eighth the space. Brevity is the soul of wit, and if an author is only halfway brief, maybe he deserves half that title. There are so many unnecessary blind alleys introduced that the novice reader will be lost and the expert will be bored. Everyone tends to develop his own set of blind alleys, and hopefully reaches the truth, or close to it. To attempt to lead others down your own blind alleys and back out is a thankless task. In a more Socratic approach it can work - the professor asks the class (to pick an example that Mr. Brown takes pages and pages to explain) if the formula for the relativistic addition of velocities is relevant to the rate of collisions of particles in a plasma or the like. (It is not; the ordinary vector difference of the velocities in the laboratory, which can have magnitude as large as 2c, is the relevant quantity.) Can't this be said without so many primed reference frames, strawman equations, candidate setups for relative velocity in intricate notation? Well, if you like the work I will leave the reference in there, but remember: there is the danger of a bright young mind looking there and deciding relativity is such a morass that he switches to botany, or numismatics. Pdn 21:04, 17 Jun 2005 (UTC)

[edit] black hole electron

Cleon -

Could you give me a hand with something? - black hole electron. This is an article that got off on the wrong foot, since its creator mistook Don Stevens' original research as being Brian Greene's work on the subject. Now that article needs to either be fixed up or deleted.

Could you provide us, in the article's talk page, with a set of web and print references of this topic? It would be very good to have the proper material available for this, and you have a knack for finding relevant sources. Both me and Linas (the creator) agree that this is a valid subject for a Wikipedia article. It just is that the current text will not "cut the mustard". --EMS | Talk 03:54, 19 Jun 2005 (UTC)

About your turning this down: Fair enough, and thanks for getting back to me. Let's just say that the amount of effort that you put into your web searches when you are motivated shows and speaks well of you. It also speaks well of you that you will refuse to do a search rather than doing a half-hearted one. --EMS | Talk 02:39, 20 Jun 2005 (UTC)

[edit] isotropy of inertia

You wrote: "In a spaceship that is moving inertially, space is seen to be isotropic for acceleration of objects: if you have, say, two marbles of equal mass with a spring in between, and you release the spring so that the marbles are ejected in opposite direction, then the two marbles will be seen to move away with the same velocity as seen from that spaceship. This is isotropy of space for acceleration: no matter in what direction you apply a force to a particular object, the amount of inertia is always the same. (By contrast, in an accelerating spaceship, inertia of objects is not isotropic with respect to the accelerating spaceship.)"

But I do not agree and I am getting lost, to tell the truth. I think you may have in mind the "longitudinal relativitstic mass" and "transverse ralativistic mass" that used to be used in olden days when people were anxious to relate everything to a Newtonian framework. (see [1] or Goldstein's "Classical Mechanics.") Today, one just says that the 4-force is the derivative of the 4-momentum and usually does not fiddle with acceleration. But, assuming you have a reason to do that, I do not agree that the experiment with the spring ejecting the marbles yields an anisotropy in the accelerated frame, at least not if the spring acts fast in relation to the spaceship's change of velocity. I mean something like that is usually a model for a decay, perhaps fission of U238. That's usually not into two equal fragments, but it can be. You have to be in one blazes of an accelerated frame to say that the two fission fragments do not depart with equal momenta or velocities. If you do your experiment with a weak spring and very massive marbles, and the spaceship is accelerating very fast, you might be tempted to talk of an anisotropy of inertia or momentum, but in that case you need more sleep. You can easily detect by a variety of means that your spaceship is either accelerated or at rest in the launching dock under the influence of gravity, and you are drawing yourself into a morass by trying to introduce anisotropic inertia or mass. When Galileo dropped things off the tower of Pisa he did not decide that inertia is anisotropic. Pdn 22:10, 19 Jun 2005 (UTC)

Cleon, I put some more stuff on my own talk page more or less by mistake - please have a look. (Peter) Pdn 01:12, 20 Jun 2005 (UTC)

[edit] sorry for misquote

I agree is misquoted you in this case and I am sorry: " Returning to your idea that photons somehow differ from material particles in terms of some kind of isotropy, [...] Pdn 01:11, 20 Jun 2005 (UTC)"

My understanding is that motion of material particles and photons shares an isotropy, rather than differing.

You did say, however: "(By contrast, in an accelerating spaceship your measuring results will be consistent with an interpration that the speed of light is non-isotropic with respect to the accelerating spaceship.)" which I do not think is true. The isotropy of the velocity of light holds in inertial and non-inertial frames (e.g. the Michelson Morley experiment showed that). I see that you have written on the Sagnac effect and I anticipate you may raise that as an example of the non-isotropy of the speed of light, but it is actually an example wherein neighboring observers (in the rotating frame) did not follow Einstein's injunction to synchronize clocks by exchanging light signals; they chose instead to synchronize by a common signal from the axis of rotation, or by presetting their clocks before the reference frame went into rotation.Pdn 13:19, 20 Jun 2005 (UTC)