Wilhemus, let's think expensively, shall we? And Sridattadev, did you have an arranged marriage? And where can I get some of that? Yes, I'm crossing the line, singularity, white hole, black hole, and orientifold of tact. And it is purposeful. I am a native american, and I love Indians (from India). Go figure...

    What is my caste considered in India, anyway? As an american with a bachelors degree in science (Physics/math minor), an overbearing attitude, and no job currently?

    And please check out my thread on Brian Greene's discussion board "Living in other Universes"? I think I'm on to something...

    https://www.facebook.com/#!/topic.php?uid=178097115549210&topic=270

    copy/paste that in your browser to get there...

      • [deleted]

      Dear Wilhelmus,

      I am currently working as software engineer in Raleigh, NC, USA and I have been here for past decade. I got married to my college sweetheart, its a love marriage, and we have 3 little boys. My wife is a scientist with a phd in biotechnology from MTU USA. I have a masters in Chemical Engineering from Uinversity of Louisian, Lafayette. Both my parents are Doctors and are working back home in India. I am not a mystic or casteist or religious fundamentalist. I am just a simple human, who happens to analyze the life as I live it and several fields of thought called science, philosophy, religion, spirituality. I found one thing common in all of these fields, that is my self. With out me there is no object, no subject, there is only absolutely nothing.

      I do admire the native indian culture which also admires the inner beauty of all creation. All the cultures and civilizations refer to this inner beauty in one way or antoher. Modern science is just catching up to this truth and I am trying to fill in the gap that scientists can never fill just by observing the external entities. Keep loving all as much as you can.

      Love,

      Sridattadev.

      • [deleted]

      Dear Tommy,

      You will be outcast in Inida :). Which is the best cast according to me. We were born free and we all die free, all this branding is just for resources and survival. Start being amazed by your existence, you could have been anything at any place and any time, but you are who you are as you choose to be. Slowly you will realize who you really are and then you will feel the absolute bliss of being alive. You will have nothing to prove to no one else but just let the world know that you are pure conscience and full of joy. You will want every one to know this simple truth and feel like you do.

      Love,

      Sridattadev.

      The following is from Brian Greene's facebook discussion group "Living in other Universes", but belongs here also in my humble. That is a very large group of threads, so since he was the introductory speaker at the world science fair recently, where among other things the winners of this Contest were announced, there is a better chance he will see these threads and address these issues from a more experienced position. Also, since this community is full of such excellent professionals, they also can clarify some of these issues.

      https://www.facebook.com/topic.php?topic=270&post=890&uid=178097115549210#topic_top

      lol, wow thanks. made me feel better for some reason! you would make a killing with a self-help book!

      Wait a minute here. Is an outcast the same as an untouchable? Would peeps not touch me and cross the street to avoid the I?

      Tommy Gilbertson

      Hello BG: I'm reading your book 'Hidden Dimensions' for the third time lol. It's very excellent. It's the first I've read by you. The good news is now I want to read 'Elegant' and that other one too! Can't wait.

      But I have one issue: you state that once the arrangement of all particles is described, then that is all there is. So in a Quilted Multiverse, for example, there would be an infinite number of other universes with exactly the same particle arrangement and hence identical worlds.

      I agree in one sense only, as it's my conclusion that there are two fundamentals to describing reality: the order of particle arrangements (in agreeance with you) and the duration of the various arrangements. Unless I really missed the mark, you missed this mark. For there could indeed be two versions of BG in parrallel universes, with identical particle arrangements. But in one universe BG becomes bald after 5 years, while in the other BG does not. Even though the two B's started out with identical particle arrangements, the duration of the 'hair' Parts descriptions are different. Hence, duration is critical when describing reality, and once you have described the order you would not be done. And it would not be all there is. Did I miss something in my readings?

      If you can, please peruse my essay entry in the last Contest on fqxi.org. I defined Consciousness using Boolean symbology and the results of the double-slit experiment. Of course, since then I've read you r book and for the first time heard another take on that experiment, where those experimenters cleaned their nickel sample and got different results when shooting electrons at it once again. And the classic double slit experiment is the result and explanation. I had planned on coming full circle, and again defining Consciousness using Boole logic again and representing some current experimental results from the Large Hadron Collider. Then I could eliminate C by equating the old (ds exp.--the equation in the Essay) and new (lhc). This would be a powerful result, describing youn'gs ds experiment in terms of lhc results, with not reference to Consciousness.

      Any thoughts? Am I going up an obviously large blind alley here? Thanks for your time. And the notes in your book for the 'mathematically inclined reader'.

      about 2 weeks ago · Delete Post

      Tommy Gilbertson

      also, you (if time allowed) really should have entered the fqxi.org essay contest. In your book THD, you directly address the question of whether the Universe is digital or analogue quite thouroughly in several section. Your take is it's both. That is also mine and the majority of substantive essays in the contest came to the same conclusion, including the winners.

      and so, even though my only priniciple when deriving an equation defining consciousness was G. Boole's law of thought X(X-1)=0: a thing cannot have a property X and not have it X-1 at the same time is sound in the realm of mental states, it would seem that in the quantum world (from my readings of your book and research), this priniciple is incomplete in some instances. And the modified principle could be X(X-1)=1. Which would mean if X meant a live cat, for example, that a cat can indeed be alive and dead at the same time. This is the opposite of GB's law of thought, and represents the probablilty mist or haze before a measurement of a quantum state.

      So the modified principle should be X(X-1)=P, where P is a number between 0 (never) and 1 (always), inclusive. This is terrible interesting, and would modify my derived equation for C as a result. Throw in a sprinkling of rules for commutativity of the symbols and we would be well on our way to an objective quantum definition of consciousness (objective because the equation would not refer to C--see comment above)...

      In this and the fqxi theads I always have the suspicion (due to lack of response) that I am wrong, mistaken, incomplete or just plain viewed as a cook.

      Do you, sir, join that bandwagon of silence? And like that excellent independent researcher Julian Barbour ignore my tiny voice while continually winning these essay contests? Throw me a bone (reply). You have no idea how much it would mean to me. Then again, I am known as the witch-Doctor over there in that community, probably because of my lack of circumspection in relation to these difficult and hard-to-verify-experimentally topics!

      Isn't string theory purely theoretical as well? In essense, defining C the way I have and string theoretic work are of exactly the same kind of research?

      about 2 weeks ago · Delete Post

      Tommy Gilbertson

      one last: I also dervied equation for I. Asimov's three laws in said Essay. they were derived a while ago after reading Mr. Boole's amazing book The Laws of Thought. I saved them and though they would never see the light of day, but the contest came along and I thougt I'ld give it a shot!

      This is probably getting boring, so I'll try to conclude quickly. My original impetus for deriving IA's laws symbolically was to re-combine them in terms of the laws: law one in terms of law 2 and 3, etc. At the time I had just started experimenting with the Italian Arduino controller board. My goal was to hard wire the laws into a little robot I made and see it's behaviour. blah blah if you like I can quote you on my website and put up links to your books. they are so good (well the one i read was HD) that I'll do this for free. You don't need my help, but I desperately need yours lol...

      about 2 weeks ago · Delete Post

      Ger'rey Marshall

      know two snow flakes are alike, just as know two personality's are alike, to me it makes know logical sense to having a double existing in some other universe. What purpose would it serve? Your conscious awareness is what makes you you, if their is know awareness of it being you, then it is not you. Even in your present physical life, if one suffers brain damage were by one loses their conscious awareness, or becomes senile with age, or falls into a coma, we all discribe that person as being gone or lost within their own body even when one dies, they are gone. Its only logical that you are unique to yourself which makes that inherent quality of being the special person you are; It makes know difference how much two idenical twins look alike physically, they still retain their own personality's, because of their conscious awareness of being alive at one single point within this universe as one's self.

      about a week ago · Report

      Tommy Gilbertson

      Very nice, GM. You definately are arguing fromt he Special Philosphy of Mind (I agree with you). But, as you may know, Brian Greene is on the opposite side of that philosophical pole...

      He believes nothing is special, and only the mathematical description of it matters, if complete. When it comes to us and our unique personalities, he claims that an identical pattern of particles in a parallel universe would be a complete copy. Another you. A real You, just like you. lol

      He's great, but mistaken on this one tiny detail, mayhap. hey i'll trade you the hidden universe for the Fabric of the Cosmos GM? Your thoughts?

      about a week ago · Delete Post

      Ger'rey Marshall

      I understand how most scientist feel, but what i think they do not understand is mathematics is also an indivisual thing that is limited to being the very thing it is, in other words mathematics is only able to calculate and measure things in this vast universe and is unable to calculate or measure the finer things that exist in the universe, such as love, hate, compassion, consciousness, subconsciousness, intellect, or just one's general feelings about all things in general, not to mention the extremely fluid life energy that i have found through logic that permeates through out the universe; These are all forces that elude calculations. Even the force of gravity can only be measured to a limited degree, because it is so thinly vailed that it almost escapes mathematical computations and can only be used in formulas to a limited degree. They have put all of their egg's in the mathematical basket, which has its limitations. There are other forces within the universe that have an extremely powerful impact, that cannot be calculated or measured in anyway shape or form and dark matter may prove to be just one more of these forces that exist.

      about a week ago · Report

      Ger'rey Marshall

      As far as other parallel universes out there, at best could only be some form of an energitic copy of the original universe that retains the conscious awareness of self. Just like when you go to make copies of an original document, there is only one original and the rest, well their just faxsimilies of the original.

      about a week ago · Report

      Tommy Gilbertson

      Unfortunately, that's the rules of Science proper: rule #1 There is no God, in the sense that He/She could arbitrarily change the laws of nature so we would discover nothing in our experiments. When you measure the strength of the em force of an electron, it is always the same. This is stated in the Scientific Method as, "The laws of the Universe are Knowable".

      Unfortunately again, our must current understanding of experiments and observations have made us conclude that there are some things in nature that can't be understood/knowable, like the space inwhich the wavefunction resides, or paralell universes, or exactly where a particle will be found. This means that either (or both!), there actually is a God, and Science has found this limitation to human knowledge thru discoveries of QM and GR, or that The laws or the universe are indeed unknowable. This is religion not science.

      There needs to be created a new framework, based on mathematical probability that incorporates this limit to our knowlege in Science, and the easy answers to questions like (why is the sky blue? why is the quarks mass what it is? etc) "God". This is a form of MetaPhysics that Aristotle greatly worte about, and needs to be fleshed out and extended. I begin this work in my essay mentioned far above in the fqxi.org Contest, and continue through independent research.

      But the conclusions are so new, they require a huge pardigm shift. I am no Copernicus, or Gallileo, or Hawking or Greene. So I'm withholding results until the idea is more accepted in the community. Can't afford to be labelled a 'quack' before I even have a reputation, now can I?

      about a week ago · Delete Post

      Ger'rey Marshall

      I was an atheist for many years, til i found the scientific evidents for a super consciousness that exist that could only come from God, which in no shape or form is anything like God is viewed in general. When i can find more time i will explain what the scientific evidents is i have discovered that turns out to be extremely profound in nature. I did begun to start to explain some, if you go to discussions and read before the Big Bang, you will get a partial brief summery of the conceptual idea that preps one for the evidents. I am into other things so I am not worried if people label me as a quack, but i do try to give examples and explain the evidents to the best of my abilities.

      about a week ago · Report

      Ger'rey Marshall

      The mathematical structure in the world of science is so rigid it prevents and limits them from seeing the little fine subtle details that exist within nature that reveals things about the universe that otherwise could never be seen through the process of mathematical computations. Math is a very powerful tool for unmasking many things about the universe and should be used were it can be best applied, i just feel it is relied upon to much to come up with what cannot be defined with mathematical equations, their by blinding one's ability to see beyond the universe of equations. If the mathematical equations was the answer to all things in the universe, then by now we are long past due for having a craft that can fly by some sort of anti gravitational field.

      about a week ago · Report

      James Kemp

      Think of all your other me's" as twins. Twins in this universe don't share a consciousness, so why should twins across Multiverses!

      on Thursday · Report

      Tommy Gilbertson

      I think a better analogy would be Clones. There have been no studies on human clones sharing consciousness, so it could go either way: clones may or may not share consciousnesses across different universes, or within this one.

      Just saw a fascinating film where biologists are re-discovering that programmed cell death is the way of evolution (and life in all animals--and perhaps plants). For example, our hands (and all other animals) are webbed when we are developing. And the skin between u ndergoes cell suicide to form the digits. Noone yet know s how this is accomplished, only that it is so. Also, 80-90% of our neurons in our nervous system all die off before we are born. Nature solved the problem of complex form and development by making way too much, and then using controlled cell death to create final forms. Death of the individual cell (the fundamental unit of life) is the way of life (societies of cells--you). Turns out the only reason all the cells in an animal's body don't die is because they are constantly being told not to by other cells in the community. Divide, grow, make, self, other, die, live: quite a conversation constantly going on in the trillions of cells in a multi-celled critter!

      To drag this metaphor a little to far maybe, maybe the multiverse is the same: make way too many. And use programmed universe death (the anthropic principle) to only keep universes where complex life can arise. Wow, that's really fascinating if I don't say so. And I just did!

      C'mon BG, chime in here! This discussion is getting pretty good! And whoever you other people are, Bravo! Good to see there are other thinking societies of cells out there! Don't feel quite so alone anymore, with my own measly trillions of cells chattering amongst themsel ves.

      Shut up, Self! Except those cells of you imploring your neighbors not to die. You keep on signalling. Except cancer cells. Please remind them that they can die right now if they want....

      23 hours ago · Delete Post

      Tommy Gilbertson

      and especially if they don't want...

      23 hours ago · Delete Post

      Tommy Gilbertson

      and we do have anti-gravity. it is not a secret but it is not commonly known. Five years ago Boeing made a press release that they are publicly pursuing this. And as you should know the military (Beoing's breadand butter) only releases that sort of knowlege after it is already 10-20 years old. Oh yeah, and in Sweden they have made frogs, worms, and other non-magnetic material float weightless. That's probably not what you mean GM, but math has indeed produced material results, like a few form s of anti-gravity. Jumping is also anti-gravity.

      23 hours ago · Delete Post

      Tommy Gilbertson

      Where's my Friends in this conversation? It's embarassing that my 400 'friends ' got nothing to say. I know for a fact many of them know quite a bit about philosophy, physics, and mathematics. Eh, they probably have jobs. Anybody know of any openings?

      P.S. QuANTUMWidgets.com for all your auto, motorcycle, and battery (any kind) needs. Cheapest prices globally.

      23 hours ago · Delete Post

      Ger'rey Marshall

      James Kemp, that is very logically right. If you personally are not consciously aware of some other self somewhere, it is not you yourself.

      17 hours ago · Report

      James Kemp

      We all know how intimately linked Mathematics & Physics are, mathematics are the tools physicists mostly use, the line becomes very blurred though.

      In other universes we have the ability to understand how universal constants may be different, speed of light, decay etc. etc. However ....... Can anybody offer any type of opinion or explanation (short please!) on why mathematical constants and general numeric constructs may or may not be different, will the value of pi still be 3.14159.... , fibonacci sequence, etc. Would calculus exist? Would prime numbers be the same? Will z^2 still equal x^2+y^2?

      2 hours ago · Report

      James Kemp

      PS - No such thing as anti gravity, otherwise it would be absolutely revolutionary. Physicists would be the 1st to know.

      Companies will have made things that look like anti-gravity effect but is not.

      29 minutes ago · Report

      Tommy Gilbertson

      Hello: a short answer is yes and no and seemingly! According to the Quantum Landscape Multiverse, for example, the physical constants depend on the shape of the hidden dimensions. Pi can be different than in this universe, and Z^2 may or may not equal x^2+y^2 . According to the Quilted Multiverse Theory, pi is always pi and z^2 same. According to the Holographic Multiverse, pi can seem the same or different whether the laws are studied in the bulk or on the boundary surface (pi can impersonate a different value).

      LIke the perspectives of a person falling through the event horizon of a black hole, and the perspective of a far-away observer, the two descriptions are very different. Yet both are correct. The language used (the perspective) changes the physical descriptions of the same events. Sounds like baloney, but that 's the way it is right now. I am paraphrasing all this from 'The Hidden Reality', which is sitting in front of me. A blurry line indeed can be sharp, depending on who's doing the observing!

      23 minutes ago · Delete Post

      Tommy Gilbertson

      Apparently, Brian Greene gave the introductory speech at the World Science fair last month, where winners of fqxi's essay contest were announced. So I think I'm going to cut and paste the last relevant threads here, to my own essay thread on fqxi's site, and continue these discussions there. Perhaps there is a better chance the man himself will see these comments, and chime in with a more expert opinion on those matters there. IF not, well, there are many Ph.D's, professionals, and astrophysicists in that community (who know a heck of a lot more and have published more than me). And maybe they will (continue to) chime in. Either way, this thread is monstrously long, even as it is getting hella interesting. Better chance to shape the conversation there?

      All are welcome to read the essays (including mine) for free and contribute to the threadologies. The essays are absolutely amazing, especially the winners, and answer (or at least make more definate) many of the issues addressed in this thread..

      http://fqxi.org/community/forum/topic/955

      13 minutes ago · Edit Post · Delete PostPrev12

      hi sridattadev:

      thanks for the personal info. that should have been addressed to me, not wilhelmus as I asked the question. and can't an arranged marriage become a love marriage given the right initial conditions?

      • [deleted]

      QuantumWidgets.com/QuantumCryptography.html

      • [deleted]

      Dear Tommy,

      You are absolutely right, everything is arranged (destiny) in the bigger picture and even relatively arranged can become a love affair after realization of love.

      Love,

      Sridattadev.

      • [deleted]

      Dear Tommy,

      Once you disclose who you really are (universal I), everybody would outcast you as you become too much to handle :). I like your idea about the book and my wife keeps telling me to write one, atleast for the kids :). Let me know if you would like to be a co author to lighten things up in the serious subject of realization :). I like your sense of humour, keep laughing away the life.

      Love,

      Sridattadev.

      Sorry i reported the 'nothing is the same link' as inappro[riate because it doesn't work and could you remove it?. The 'everything's eventual' link is fine...

      Thank you fqxi admin...

      • [deleted]

      Before continuing, let us simplify things a bit by letting HS=C, where C is consciousness (whatever that means in an experimentally testable sense). So this equation then means: the human soul is consciousness. Well maybe or maybe not. We will save that Theory until experiment can decide the validity or no... Maybe the soul is much more than consciousness. But surely a part of the soul is consciousness? Even if not, for the sake of brevity, let us assume that all human souls have consciousness. Then

      Developing equation 1: P=particle=DHSO=DCO

      P=P(0,0,0)(1-D)(1-C)(1-O)+P(1,0,0)D(1-C)(1-O)+P(1,1,0)DC(1-O)+P(0,1,0)(1-D)C(1-O)+P(0,1,1)(1-D)CO+P(1,1,1)DCO+P(1,0,1)DO(1-C)+P(0,0,1)(1-D)(1-C)O`

      trivial: P=DCO

      C=P/DO=0/0 (1-P)(1-D)(1-O)+1/0 P(1-D)(1-O)+1/0 PD(1-O)+0/0 (1-P)D(1-O)+PDO+1/0 PD(1-O)

      C=a(1-P)(1-D)(1-O)+b(1-P)D(1-O)+PDO {1}

      and

      0=P(1-D)(1-O) {2}

      and

      0=PD(1-O) {3}

      Interpretations:

      {1} consciousness is sometimes a wave that is not observed whether detected or not, and is always the result of an observation of a detection of a particle.

      {2}and {3} If a particle is not observed, whether detected or not as a particle, it does not exist. It is a non-real, virtual, wave until it becomes actual.

      Here's a much better editing...

      Before continuing, let us simplify things a bit by letting HS=C, where C is consciousness (whatever that means in an experimentally testable sense). So this equation then means: the human soul is consciousness. Well maybe or maybe not. We will save that Theory until experiment can decide the validity or no... Maybe the soul is much more than consciousness. But surely a part of the soul is consciousness? Even if not, for the sake of brevity, let us assume that all human souls have consciousness. Then

      C=a(1-P)(1-D)(1-O)+b(1-P)D(1-O)+PDO {1}

      and

      0=P(1-D)(1-O) {2}

      and

      0=PD(1-O) {3}

      Interpretations:

      {1} consciousness is sometimes a wave that is not observed whether detected or not, and is always the result of an observation of a detection of a particle.

      {2}and {3} If a particle is not observed, whether detected or not as a particle, it does not exist. It is a non-real, virtual, wave until it becomes actual.

      If All Human Souls posess Conciousness, then (as I have unassailably logically proved symolically) according to the many experimental results of the Classic Young's Double-Slit Experiment in technical jargon:

      I. 'Consciousness' is sometimes an unobserved Wave, when a particle is detected (which-way information) can sometimes maintian it's quantum state regardless.

      II. 'Consciousness' is whether measured (which-way info.) or no can be detected or not correspondingly.

      III. 'Consciousness' is Always the result of the detection of a Particle.

      IV. An undisturbed particle does not exist until measured.

      V. An undisturbed quantum wavefunction does not exist. A particle can exist & not exist at the same moment, which is preposterous to the Copenhagen Approach to the Measure Problem, and inversely coupled to the Many Worlds Approach to Quantum Mechanics.

      These results are the logical consequences of the data from literally 10s of thousands of experiments studying Young's DS Experiment. And the only Principle Assumption is that Something cannot have and not have a certain propertie' at the same moment in time...

      Next this shall be tied to the logical interpretation for 'Consciousness' on Modern Times, using the LHC proton exper. results in technical, precise , logical , jargon.

      The we shall be using the results of both ancient and modern numerous experiments to formulate the English Technical translation of 'Consciousness'.

      With experiments designed to Measure said and using data-mining to cull alread-existing published results.

      Unless somebody stops me.

      This makes me lean very heavily toward a Cyclic Multiverse unfortunately. Hail the Programmer!

      Oh, this is so impressive & fascinating that I must copy it from Mr. Reynold's Blog. Basically he worked on the S-Cam Satellite and the results are in from the Crab Nebula. Our most exact and independent and faithful cosmic time-keeper is a Pulsar in the Nebula, rotating at precisely 33 s a min. (apx.). And to get to the experimental results: the pulsar was for the first time in for all We thought the lifetime of the universe, so to speak. The Results show that Time Is Speeding Up!!! Time to climb the walls. But no, a mathematical device was able to parse the gathered photon data and futz with the time-stamps. lol. The Pular in the Crab Nebula exactly still rotates at the same rate, as it always has. All of a Sudden. This person is in my humble opinion the greatest hard sf writer alive. I say that weighlessly.

      Quote: Alastair Reynolds

      Wednesday, 10 August 2011Of battleship turrets and pulsars

      The Crab Nebula is the remnant of a supernova which exploded - or rather was seen to explode - in 1054AD. The pulsar at the heart of the nebula - the neutron star left over when the star's core collapsed at the moment of the supernova - was discovered in 1968, very shortly after Jocelyn Bell's discovery of the first pulsar using the Cambridge radio telescope.

      The pulsar, and its associated nebula, have been and continue to be of great interest to astronomers. But the pulsar itself has a direct practical application, in that it's a very precise and well-studied clock. Rotating once every 33 milliseconds, the pulsar acts as a cosmic lighthouse, sending out beams of electromagnetic energy which happen to sweep across the Earth. Visible in both the optical and radio bands, the pulsar offers a reliable means of determining the accuracy and precision of time-based astronomical observations.

      S-Cam, the instrument I helped work on, was a photon-counting detector. Each of its supercooled pixels was connected to a complex chain of electronics which enabled S-Cam to record not only the energy and position of incoming photons - individual particles of light - but also their arrival times. As each photon arrived, it triggered a cascade of electrons which rose and fell in a well understood fashion. The amplitude of that electron burst gave one an idea of the energy, or colour, of the photon, and the onset of the burst told one about the arrival time. S-Cam's electronics were connected to a GPS receiver, a piece of hardware which provided a definitive timestamp, accurate to millionths of a second, for each photon.

      The raw output data of S-Cam, in simple terms, therefore consisted of a long list of sequential photon events. There would be an arrival time - referenced to some offset zero point - then the X,Y coordinates of the pixel which had seen the event, and finally a parameter which was proportional to the energy of the photon.

      In other words, something like this:

      0.0045 3 5 15

      0.0067 1 4 28

      0.0143 2 5 09

      ... and so on. A typical observation could easily contain more than a million photon events, but we didn't need to concern ourselves with the individual lines of data; we had software to chew the numbers and spit out processed data in astronomically interesting formats: spectra, time versus intensity curves, and so on.

      Occasionally, though, we had to dig down really deeply into the data, because something didn't quite make sense.

      The Crab pulsar was a high-priority target for S-Cam for one simple reason: it offered us the only independent, microsecond-level test of our time-tagging. It was almost impossible to verify that the electronics chain was working well in the lab. We couldn't use the GPS hardware to generate a test signal because the GPS hardware was already part of the electronics chain - it would have been like trying to use a ruler to measure itself. We were confident that the instrument's absolute time-tagging was good to within a second, and we had no reason to doubt the precision of the individual photon events. But only an observation of the Crab would settle matters.

      To our relief, all seemed well. The "heartbeat" of the Crab, as revealed by our instruments, looked the way we expected it to. Importantly, the main peak - the higher of the two "blips" in the pulse profile - was arriving bang on the nail. We could be sure of this because the main dish at Jodrell Bank makes regular observations of the Crab, and the small variations in the Crab's rotation period are tracked and published from month to month.

      As an aside, the big dish at Jodrell - now the Lovell Telescope - was completed in 1957. The two hinge points, on which the dish swivels, incorporated components from the gun turret mechanisms of the British battleships HMS Revenge and HMS Sovereign.

      So, all well and good. We had our well-calibrated instrument with a reliable time-tagging system. We could then go ahead and do lots of actual astronomy, safe in the knowledge that the individual photon arrival times could be trusted.

      But it wasn't that simple. Much later in the program, some of our colleagues raised an interesting point. While our Crab pulse profile looked fine from a standpoint of absolute phasing, there was something a bit fishy about it. If the profile was a heartbeat with two spikes, then the spikes themselves were about 30% fatter than they should have been.

      We performed an exhaustive analysis of the system and its data processing software, trying to make the pulse profile conform. But nothing we did fixed the problem. And the deeper we looked into it, the more troubling the discrepancy began to look. That "fattening" of the pulse profile was a hint that, down at the level of the individual time tags, something was going wrong. Some percentage of the photons - some, but not all - were being assigned erroneous timetags.

      It only showed up in bright objects. If we go back to that list of photon events above:

      0.0045 3 5 15

      0.0067 1 4 28

      0.0143 2 5 09

      and imagine a small error - an addition or subtraction of some small number - being applied to the timetags. Now, those photons can't break the laws of physics - they must arrive in strict time order! And indeed, that's what appeared to be the case - most of the time.

      But occasionally we'd see a timetag where it appeared as if a photon had come in earlier than its predecessor:

      0.0045 3 5 15

      0.0067 1 4 28

      0.0059 2 5 09

      Now, this made no sense. And it only "showed up" in observations where we were getting a sufficiently high flux of incoming photons for one to hop the queue and seem to arrive earlier than the one before it.

      It took weeks to get to the bottom of the problem. And in the end it turned out to be due to a fault at the actual hardware level. A piece of electronic circuitry was not behaving properly, due - it eventually became clear - to a piece of stray conducting material bridging two parts of the electronics board. This component was a set of binary registers designed to convert the raw arrival time of the photon into a different data format, using something called a "Gray Code".

      Now what the hell is a Gray Code? I had no idea, but I quickly got an education. A Gray Code, or "reflected binary code" is a very clever mathematical procedure. Incorporating a Gray Code converter into our electronics made very good sense, because what a Gray Code ensures is that there are no sudden "spikes" in the data transmission system.

      Imagine sending pulses down an electronic line, encoding arrival times. If your photon events happened at nice intervals, you might get:

      0.991

      0.992

      0.993

      0.994

      0.995

      0.996

      0.997

      0.998

      0.999

      1.000

      1.001

      ... and so on.

      But that "roll over" from 0.999 to 1.000 is bad news, because instead of just one digit changing, four have changed. And (at least far as I understood it) that's not good in the context of electronic signal processing, where you want things to be as smooth as possible.

      The Gray Code solves that. It cleverly ensures that two successive values will only differ by exactly one bit, meaning that - as far as the electronics cares - there is nothing to hint that there has been a "roll over". Later, when you want the data to be intelligible, you apply a reverse Gray Code to put it back into its normal format. And that's exactly what was going on in S-Cam.

      Except that, during the Gray Code conversion, that stray bit of conducting material was screwing things up. Basically, if a digit appeared in one register, it would "contaminate" the one next to it, propagating an error throughout the data analysis.

      But this effect was so subtle that we had not seen it until someone noticed that our Crab pulse profile was too fat.

      Once we understood what was going on, it was relatively simple to construct some simulation software. This verified that we had a complete, self-consistent grasp of the problem. Of course, that didn't help us fix the data that was already affected by the fault.

      But actually, it did! By applying our understanding of the Gray Code issue, we were able to build a piece of software which took old datasets and unscrambled the erroneous time tags. It only worked for relatively bright, high-photon output objects - but those were exactly the ones where correcting the time tags really mattered. It was hugely satisfying, at the end of this months-long analysis, to be able to regenerate our original Crab pulse profile and see what we should have been all along.

      That's almost it - but for one curious twist. The Jodrell Bank observations were crucial to our understanding of the problem, and I've already mentioned that the Lowell Telescope rides on battleship turrets. Gray Codes have many real-life applications, but one of the most useful is in position encoders - especially for rotary shafts.

      Think of a shaft sticking up from the floor to the ceiling. Now imagine parts of the shaft painted in an insulating material, and other parts left in bare conductive metal. Now also imagine metal brushes contacting the shaft at different positions. As the shaft rotates, the brushes will either touch a conducting patch or an insulated patch. The question is, can you design a shaft such that these brushes always give an absolutely unambigous reading of the shaft's momentary rotation angle? Well, you can - but you have to use Gray Codes to do it. And one of the first uses for reliable position encoders was in ... you've guessed it ... battleship turrets.

      Posted by Al R at 08:15 7 comments

      Terrifying, then a happy ending to Science's Quest to Understand Reality.---TMG