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Below you find a few comments on my site that we were sent to me by friendly readers. If you want to see yours removed, just let me know. Thanks in any case to all my readers, from all around the globe (and at least from the United States, Belgium, Netherlands, United Kingdom, Canada, Australia, Germany, India, France, Japan, Spain, Italy, Sweden, Israel, Croatia, Jordan, Puerto Rico, Algeria, Bahrain, Oman, Iceland, Portugal, Austria, Brazil, Slovenia, Ukraine, Slovak Republic, Ireland, Finland, Greece, Romania, Columbia, Czech Republic, New Zealand, Argentina, Luxembourg, Philippines, Puerto Rico, Poland, Iran, China, Switzerland, Oman, Korea, Hong Kong, Malaysia, Cyprus, Taiwan, Kuwait, Norway, New Zealand, Bulgaria, United Arab Emirates, Philippines, Saudi Arabia, Denmark, Chile, Turkey, Fiji, Gibraltar, Macedonia, Nederlandse Antillen, Bermuda, Vatican, Senegal, Syria, Armenia, Panama, Macau, Virgin Islands, North Korea, Cocos Islands, Libya, Tunesia, Pakistan, Quatar, Ethiopia, Trinidad, Bosnia-Herzegovina, Bangladesh, Vietnam, Estonia Serbia-Montenegro, and South Africa; if your country is not amongst the listed ones, please let me know).

Encouragement, Questions, Comments

I am having much difficulty grasping the "basics" behind String theory. I feel that one particular area I need insight into is dimensions. When I think about the expanding universe as 3 space dimensions and 1 time dimension, then it seems as if these space dimensions would be as infinite as the universe itself, and not something to be measured in length. But in your description of the "extra" six dimensions of the string theories, you refer to their size as basically microscopic and thus invisible. Maybe it is my pure lack of understanding that causes me to shake my head and wonder how one can attribute a "size" to a dimension, especially when compared to our normal three-dimensions. If upon reading this you feel that trying to explain dimensionality to me would take far too long, I understand completely. You need not bother responding in that case and I thank you for reading this anyways.

Anderson cmww,

Hi Anderson cmww, You assume first of all that the universe is infinite. That, we are not sure off yet. (A nice and technically correct, but harder reading on the subject you can find at NASA. The universe can be finite both in the time dimension, and in the space-dimensions. When the universe is finite in one of these dimensions, it makes sense to measure it. (Otherwise not.) Suppose for a second (to follow up on your notions), that the universe is infinite in the time-direction, and infinite in the three space directions that we are familiar with (up-down, left-right,far-near). Indeed, we would not talk about measuring those dimensions then.

Now, we could have extra dimensions. An extra dimension is a whole new direction that opens up. A standard analogy is the ant, running along a sheet of paper, perhaps for its whole life. The ant could describe its world with two coordinates. But, when it falls off, it would suddenly notice a third direction opening up -- the ant would have discovered an extra dimension. Now, we won't fall off our universe any time soon :), but nevertheless, like the ant, we may be unaware of extra dimensions. Again, the extra dimensions can be finite or infinite. When they are finite, and obey more or less standard laws of physics, we can measure them. For instance by sending a light signal (or graviton) into the extra directions, and waiting whether it will return after some finite time. Hope that answers part of your questions ..

Great website! I have a B.S. in Physics, and have read Brian Greene's "The Elegant Universe", and am thinking about getting Lisa Randall's "Warped Passages" Yet I'd appreciate any suggestions on books that contain a much larger number of illustrations and graphic analogies. This subject (strings to branes to hidden manifolds) simply screams for more diagrams to help describe the concepts. "Scientific American" has had a few good articles on M-theory, branes and string theory, with wonderful illustrations. But are there comprehensive books with many graphics that you would reccomend? (It would be a plus if said books had similar visuals for Supersymmetry and other ideas about how to go beyond the standard model.) Thanks for your suggestions,

Robert Kaiser Science Department Nashua High School South Nashua, NH

Thanks for your support, and your query.
I'm afraid you have dug deep enough to understand that there is not much out there in terms of visualizing string theory, supersymmetry, and other ideas beyond the standard model.
It seems to me it is hard to recommend anything, and that there is really a big hole in the bookmarket here, that you have fluently identified.
It remains to fill it.

You're probably used to comments and questions from crackpot laymen. Well, here's more. I'm an old trooper retired from a huge telecommunications company who admire the thoughts of theorists.

Do I understand this correctly::: The answer to all physical phenomena we behold can be explained with String Theories? And are these strings simply energy rather than matter? Although I try to absorb the words of the great physicists, I'm handicapped by a lack of talent in intricate mathematics. So here's what I probably incorrectly understand: Strings make up every particle in the universe. Strings are vibrating loops of energy an octillionth of fempto meter in length. (+or- a couple of atto meters) A string, or for that matter all that's a result of string activity' exists in 10 rather than three spacial dimensions. Even the most brilliant amongst us struggle visualizing that, although I guess it's necessary to theorize the extra dimensions to satisfy the arithmetic. I have little doubt that String Theory will prove to be the Grand Unified Answer. I hope you and your brilliant colleagues continue with your great work.

Johnny Putt

Hi John, Your summary is accurate, in fact. Most of your statements describe correctly what we believe to be a consistent picture of our universe. (Yes, every particle is a vibrational mode of a string, which is pure energy, and the extra dimensions do exist, and are difficult to visualize, etc.) However, professional string theorists are less certain than you are that this is a correct and final theory of nature. Some do, some don't, and only experiment can tell. That's why we're all curious to see whether it will be confirmed by experiment in the coming decades, or not. (These could be either experiments done in accelerators, as in Cern (in Geneva), or cosmological observations.)

And, thanks for your contribution to telecommunication !

Dr. Txxxxx,

I visited your website explaining string theory for the layman such as myself, and was definitely impressed. I should probably mention that I am a Christian. This may cause you to wonder why I would chose to read material concerning string theory. However, I believe that I should examine all explanations for the creation and operation of the universe, for I expect for my beliefs to hold up to rigorous testing. If what I believe is proven to be less likely than another explanation, then I should change my views.

I mentioned my religious and scientific views because in spite of our differences I found that your site was polite and considerate. In your responses section you replied to an e-mail from and individual who was having difficulty with someone who believed in creation. I was again impressed with your response to that person. While I am obviously on the other side of the debate, I completely agree that it is far better to define you own beliefs rather than try and argue someone else out of theirs. I also thoroughly agree with your comment about being nice and polite rather than using insults or mockery when debating or arguing. Nothing is gained for anyone when people on either side of the argument insult others.

Also, I admire your acknowledgement that while string theory is persuasive, yet is not full backed by data and proof. To be willing to say the truth, even when not all of it supports your case, is an attribute to be respected.

Finally, your choice not to give your name or credentials on the site is also deserving of respect. Again I agree that what should be considered is the facts, the content of your site, not who wrote it. In summary, while I doubt that our beliefs coincide, I am pleased and impressed with your polite, reasonable and respectful writing. While I did not get the opportunity to fully explore your explanation of string theory, I fully intend to return to your site and continued reading the material. -Aubrey R.

P.S. Having nearly an unlimited desire for knowledge, I went looking for who wrote the site after having read it. While I found your name and such, I still have no knowledge of your credentials (though they are clearly respectable) and still intend to judge the site only on the merits of the content.

I became interested in string/superstring theory about five years ago. However, what got me hooked on string theory was something I learned in high school many years ago, a something that has stayed with me to this day. The atom and its subatomic particles appear to mimic the galaxy and its planets. That held my imagination. It truly was the music of the spheres: everything was intertwined. Then came quantum mechanics v. Einstein's theory. It begged the question: why do cosmology and subatomic studies find essentially the same outward appearances and yet their laws are incompatible. String theory looks like the leap of our time. As a layperson interested in what things are all about, I am searching out explanations that will not require great mathematical or physics acumen. Your site is great, the best I have found; but I think you could simplify it still. Thank you so very much, however, for realizing that the world needs/wants to see what string theory is unveiling. Jane Casler

Hi Jane. It's good to hear you kept some of the initial enthousiasm that grabs us all when we start to appreciate in how wonderful a manner nature operates. It's great that you could partially satisfy your quest for further understanding by browsing through my site -- and yes, you are certainly right that large parts can be simplified further. Gradually but surely I try to fill the large gaps between the bones of the skeleton that has been put into place -- it takes more time than I have ..

Your story about relativity, found on the web, is nice. I like it very much, clear and intuitive. However, I miss an explanation of what are really space and time? Could You help me with this intricate question? In my view it is the bodies themselves that define space and time, their location and their motion. Saying that their motion is caused by curved spacetime, appear to me as a reason in circle. I would like to understand gravitation as corrections to Newton's gravitation law. Is that possible? Cheers, Kjell

Hi Kjell, Thanks for your encouragement. It's a difficult question to describe "space and time" as derived concepts, i.e. to explain there existence in terms of other quantities. There are ideas on this, where space-time emerges as a coherent state of elementary particles or strings (that form a vacuum that Is space-time -- this mechanism would be a special manifestation of a technical phenomenon called 'spontaneous symmetry breaking'.), but none of these ideas is quite convincing as yet. That leaves us with the possibility to just postulate the existence of space and time, and then to analyze objects in them, which are made off excitations of space-time (e.g. matter, gravitons, etc). That this may leave you unsatisfied is normal. Your feeling is shared by experts who have the tools to judge possible solutions -- none of the possible solutions that we have come up with convincingly answers your question. However, your other question has been answered in textbooks on general relativity. Indeed, it is possible to calculate that general relativity gives a correction to Newton's law, from first principles (in general relativity). The calculation is slightly non-trivial. You can find example calculations in Wald's book on GR, or in Weinberg's book (i guess). They require a considerable amount of math.

I found your site linked from a link-sharing site (linkdump.be), and I enjoyed it very much. I even sent the link to a friend of mine who is very interested in physics, and I'm sure he'll enoy it as much as I did.
I feel I should mention to you, however, that your site is riddled with numerous spelling errors. I understand that what I read is a work in progress, but the errors are very distracting. Of course, as an English teacher in an American high school, I may just be especially sensitive to such things, but besides the spelling problems, there were also several punctuation and grammatical errors, and there was also a very serious two-part factual error.
Before I was an English teacher, I was a Music teacher. In your Introduction section you use the example of music as a way to show how mathematics can be used to explain the world. You mentioned a string on a violin that sounds the note C. Well, there is no C string on a violin, at least not in standard tuning. The strings go (from low to high pitch) G, D, A, and E. There is a C string on a cello, so perhaps you could change your example to name that instrument intead of the violin, or perhaps you could simply change the C string in your example to a string that actually exists on the violin.
That would only fix the first part of the error, though. The second mistake is where you said that a C string with one quarter of its length removed would produce the note E. This is simply not correct. Shortening a string by 25% raises the pitch one major fourth, so your C string with one quarter of its length removed would produce an F, not an E.
That may seem like a relatively small error, and I suppose it is, since the example you used was only that, and your main point is not really affected by it. However, as soon as someone with a musical background comes along and reads that section, you immediately lose credibility with that reader. Compounded with the spelling, punctuation, and grammatical errors, your work begins to take on a decidedly amateurish aspect, and I know that's not what you want. You have a wonderful ability to explain complicated ideas in a simple way, and that is a rare gift among scientists. Correct language mechanics and a correction of the music example's errors would enhance that gift, and make your explanations much more clear to laymen such as myself.
Again, I enjoyed your site very much. Folks like you are what make the Internet valuable.
-Derek White
Sacramento, California USA

Thanks a lot for your constructive comments, Derek. I spellchecked all my files (but did not upload them yet) and corrected the musical mistakes you patiently pointed out. Your message is a shining example of useful feedback.

This really does help a layperson like myself to get to grips with this
fascinating theory. However, can you change the grey background behind the type
which makes it rather hard to read?
cheers
Heather

Ok, thanks, I tried to improve the colors. (Although I noticed the phenomenon on certain monitors, on particular platforms and with some browsers, I did not think it was gneric. But you are right in insisting on this point, since it is essential to me that I do not loose readers due to thoughtless design.) Thanks.

great website …
lets assume that we have a microscope capable of probing well into an atom … trillions of time more powerful than any microscope today … and we're able to observe a "string". What's the next logical question … "what makes up this string", right? when does this process sub-dividing stop?
tjf

Hi Tom. Up until now, we always had a reason to think that this subdivision would never stop. That
has changed. In string theory, there is no reason (yet) to believe that strings are made of smaller
components still. That does not imply that we will not find smaller components though. We might. (For the technical experts: what I'm referring to is, amongst other ingredients, the Landau pole of QED, the fact that GUTs do not incorporate gravity, and the indications that string bits exist as well as a description of an M-theory vacuum in terms of D-particles.)

Hi! I enjoy your
web site about String Theory. I'm an artist but I'm interested in
understanding the universe that serves me so well in my paintings.
My question is: Can you brand a particle or series of particles
before they develop a high uncertainty in momentum and then track
where they are at all times? >hank you, I'm enjoying reading your
site. Victor M, Peapack, New Jersey

Hi Victor,
No, you cannot, unfortunately. Any type of "branding" would be
subject to the same principle of uncertainty that does not allow us
to determine momentum and position of a particle simultaneously.
Note that implicitly, you are assuming some magic property of
the "branding" that will allow this procedure to escape from the
laws of physics (as we know them at this time). "Branding" of a
cell, or molecule in a cell, for instance (in biophysics) is
typically done with another atom. The branding is useful in that
context because it suffices to determine the position of the cell
(or molecule) within a particular uncertainty which is much larger
(!) that the fundamental bound described somewhere in my site.
Have fun painting, J

Hi !
Thank you for your response, that spurs me know more about the
subject. I think I understand your point but I'm also reluctant to
implicitly assume that the laws of physics as we know them now are
unchanging therefore precluding any thinking outside probability. I
guess I'm a hopeless optimist.
Victor M

Hello!

My name is Michael, and first I’d like to tell you how much I’ve enjoyed your web site I’ve found it to be most informative, well laid out, and very easy to read. Great job!

While reading your web site, a question occurred to me that I feel I should already know the answer to, but I don’t. So I’m hoping you can point me to further reading material on this subject. My question roughly is this: The second law of thermodynamics tells us that energy/matter will tend towards disorder over time. As far as I am aware, the second law transcends the boundaries of scale from the classical world into the quantum world. So if, for instance, an electron is to be considered a probability cloud, and is also considered a quanta of energy in it’s own right, would it be fair to say that the electron is merely energy that has reached the most disordered state allowed by it’s surroundings (i.e. the discrete energy levels of the electron cloud)?

To put the question in another form, do things tend towards disorder because that is the state in which the most states are available to them? Does the universe on every scale of physics “yearn” to allow for the broadest set of available states, and therefore the broadest set of possible futures?

Thank you for your very valuable time!

Michael

Thanks, Michael. It needs to be said though that you mix up a few things in your involved question. Let me just point out that thermodynamics teaches us properties of systems of a huge number of particles, and that its laws will not apply to single particles. (The discipline of statistical mechanics teaches us a lot about how to move from laws governing single particles to thermodynamical laws. It deserves a few sites of its own.) So, the scaling you apply to thermodynamical laws is not quite correct, and any conclusion you draw from them has to be taken with a few grains of salt.

Hello, my name is Dennis. If other dimensions do exist what are the possibilities of other worlds
or other universes?. Is it possible that there is a parallel world (for lack of a better term) that exists in
the same space as ours.
Thank You, Dennis H

Hello Dennis. Extra dimensions have nothing to do with extra universes. These issues may sound related, but are really quite distinct. Extra universes might exist but they are (when interpreted in a particular sense) of no consequence to us, so
perhaps we should not inquire into them. Extra dimensions are of great consequence to us: their consequences are measurable and may or may not be measured in the near future (e.g. in particle accelerators). As far as other civilizations are concerned: I' ld be happy to meet them.

Hi
I found your site after seeing a tv program (UK tv) on the subject. I've always been interested as a layperson in anything that helps me to imagine how the universe works & I find this latest theory extremely interesting, fascinating, real food for thought, despite my complete lack of any higher mathematical knowledge. I intend to read & re-read your writings until I can properly grasp the idea as images in my mind rather than just words (my own field of expertise) which are a poor substitute for the visual.
Thanks a lot for what you've done, I'm sure many more people around the globe feel the same.
Best regards
Colin T

Thanks a lot, Colin. Personally, I've always find it more instructive to consult more sources than to keep re-reading a single one, so that is what I recommend you to do. Have fun visualizing our crazy universe !

Very nice site. A few corrections: Standard Model: Photon spin is 1!
Nobel Prize! ( Not Price!)
There are numerous grammatical errors, but in general very readable!
You might mention how the beautiful conservation laws of 3+1 dimensions extends into the extra dimensions as explanations of such mysteries as charge conservation. I recommend the site to any one interested in a simple but basically correct translation of the frontier of physics. Marvin

Hi Marvin. Oops ! Did I really write something different than that the photon spin is 1 ? That was most definitely a typo. I cannot claim the same for the prizes, unfortunately -- I'm not a native speaker. Anyway, thanks for the suggested improvements, the corrections and the encouragement.

• Hello.

  Would you like support for your web site? I would love to take this opportunity to give you just that. I find your site very informative and well written. I am one of your intended readers too, a laymen. I have a technical background, however, lack the mathematical understanding to truly understand it all. For that I am saddened. In any event, I am grateful someone like yourself has taken the time to convey the material directly to me. (...)

  I will however ask this of you now. In no way am I questioning your credibility with respect to the subject material (I have read enough to know you are not making things up), but who are you exactly? I think you should put that in bold letters on the home page. This is who I am, these are my accomplishments and this is why you should feel confident reading these pages--something to that extent. I think you should do this for two reasons: one, it gives your site credibility and two, you deserve the acknowledgment for doing this work. (...)

  Adam D'Agosto Phoenix, Arizona

  Thanks a lot for the encouragement, Adam. I trust in the judgment of my readers as far as my credibility or acknowledgements go. My credentials are in fact of no importance -- you should judge the site by content, not by the credentials of the author. And the only acknowledgement I'm after is mails like yours, and a simple link on your web site if you have one. Enjoy the rest of the text.

• Another message from Adam:

  (...)

  In any event, I am currently reading The Elegant Universe by Brian Greene. I am sure you are familiar with it. Anyway, as you can imagine, a slew of questions come up in reading the text, but this is one that I am particularly interested in.

  That book is the best introductory text available now. A more technical introduction is on the way, but it still won't answer all questions. (End 2004 (?), by author B.Z.)

  In a very basic sense of String Theory, my question pertains to our perceptions of stings and point particles. My current view of electrons, protons and neutrons is that they are little "balls". Electrons are really little balls and the protons and neutrons are much larger balls.

  That's roughly right.

  Should I now replace that visual concept with a new picture that is something like this: an electron is a single string, and protons and neutrons are actually made up of several strings. Strings combine to make the quarks and the quarks combine to make the proton/neutron.

  Is that the gist? Or is a proton just one string like an electron?

  Yes, that is the gist. One "mode of vibration" of a string is an electron, and another mode of vibration of the string will be a quark. (In fact, these particles are not supposed to be that different from the viewpoint of GUT's, Grand Unified (field) Theories (theories that do not include gravitation). -- you can try to find out more about these GUT's on the web, although I'm afraid not many good explanations are freely available.)

  Thus, a proton will be a "bound state" of three quarks, i.e. of three strings (or, slightly more precisely, of three endpoints of open strings). Just like a hydrogen atom is a "bound state" of an electron and a proton.

  (...)

• I've read and referred your site to friends so many times I can no longer count. I am an avg. 28 y/o who has a passionate but purely layman appreciation for physics. I find your site fascinating and thought provoking, a true token to your ability to explain these complex concepts very well. It has also made me look at my particular focus at the moment with new eyes. Of late I have been researching something called Pulsed Abnormal Glow Discharge reactors, an over-unity electrical power generation system. I am continually awed by all the new things that are being theorized and discovered. Thanks for helping me get even a glimpse of how cool string theory is.

  Keep up the good work.

  Jamie Wilson Toronto, ON Canada

  Thanks a lot Jamie, that's a powerful compliment you give me. Keep referring to my site (:)) and always realize that for instance in the building of particle accelerators the tiniest of technological advances can sometimes save the day for the whole machine.

• "Thank you for the work you have done so far on this web site I can grasp much of what you are saying and look forward to further detail.

  Brian Pye."

  Thanks ! I hope to satisfy your curiosity in the future.

• " Hello,
  I am Stephen Currier. I have found your web site discussing the String Theory. I find this fascinating. I am enjoying your writings very much. I am an electrical engineer of average intelligence I suppose. I find the String Theory difficult to understand. (10 dimensional hyper space???) I haven't run across that type of description on your site yet. I find your straight forward style to be very informative. I will continue to read your page until I have seen all of it and established a good understanding of what you are sharing.

  Thank you very much for putting together a description of the String Theory that the more average person can appreciate. Keep up the great work!

  Kind Regards,
  Steve Currier"

  Thanks ! We all find String Theory fairly difficult to understand.

• "Looks good, interesting, I'll see if you are successful (I've recommended it to a couple of people w/o math backgrounds). One suggestion, if the main text area can be expanded - make the "Table of Contents" of variable width or minimizeable - on a laptop its distracting to have to scroll the lines back and forth. Good Luck From Steve Cohn"

  Thanks ! My design is not easily adapted to your needs, unfortunately. I'll keep your remark in mind when I redesign the site.

Advice ?

 




• In what kind of maths should one specialize in order to understand string theory ? CVK

  Good question -- difficult to answer.
  All elementary math is mandatory (including functional analysis, linear
  algebra and geometry -- for example, differentiating and integrating functions, diagonalizing matrices, and euclidean geometry). After that, differential geometry, Lie group theory, algebraic geometry and e.g. theory of modular functions comes in handy.
  In general, I would say that the more math you know, the better, but, at the same time it needs to be said that the best way to learn all this math may be to face the physics first, and then see what math to study.
  Good luck !

• I am currently on a debate site with a creationist. I have had no problem disputing his "evidence" that evolution is false, a global flood and the like. Recently, no matter what question someone asks him...he resorts to math as an answer.

  Ask him what color his car is, and you get a math equation. (Not really an example, but you get the idea).

  Recently, he posted this. I have no idea what he is talking about, but I was hoping you could shed some light on it:

  "There is a beginning to time that emerges especially from more complex derivatives of this and that beginning of time suggests something far different than a Big Bang, but not different from Strings.

  -Wp -Qh = T = Mc6 where Q is less than 0. - W = negative pressure x infinity -Q = -1/heat x infinity T = Time + Gravity + Energy in three coexisting levels (That's where we must use some imagination at first) Mc6 = the total content of mass per quanta, including the warping of gravity and time, and the maximum relative velocity prior to the threshold of infinity manifest in the void.

  From T emerges G then from G emerges E and all that we know to be manifest. A Big Banger will contest this and if unable to do so with math itself, will do so with derogative remarks. Nobody has asked in the related thread for me to expand on this. All I've received is "idiot" remarks, but nothing demonstrating an anti-equation."

  He has been called every single name in the book by others also debating him (not proper debate "etiquette" I suppose), but if you have read some of this guys posts, you can understand why.

  Thanks,

  Eric

  Hi Eric. My advice is not to waste your time on trying to convince this particular wo/man that s/he is talking nonsense. You will be much better off spending your time on studying more of the physics you like, and the math that is necessary to comprehend it. It will then be obvious to you which arguments to ignore, and which ones to respond to.

  Of course, if you struggle with determining your attitude in these kinds of debate, you may want to delve in to science philosophy or philosophy in general. You can try reading Kuhn and Feyerabend, for instance, or Descartes and Hume, or Derrida and Bricquemont-Sokal, and determine your own attitude in the (largely futile) debate on how to make strong arguments. Finally, you should read Wittgenstein, and throw his book away after finishing it.

  Furthermore, it certainly is not a good idea to call the person in question all the names in the book. It is more important to act as a nice person than to win a particular argument, it seems to me. So, don't follow that unpleasant strategy that your fellow-debaters embrace. Keep the debate civil, or choose to withdraw from the debate at an opportune moment. In this particular instance, this moment would occur fairly early.