Craig Hogan, a physicist at the University of Chicago and the Fermi National Accelerator Laboratory, is building an experiment to see if spacetime isn’t smooth like everyone thinks, but rather bit-like and chunky on the smallest scales. The experiment is the focus of the cover story "Is Space Digital?" in the February 2012 issue of Scientific American, as well as this short video.

18 Comments

1. 1. KeithCaserta 01:45 PM 1/17/12

   OK. So what happens, then, when space expands? Do the space "quanta" move further apart, or are new quanta created (from the vacuum energy?) to "fill in" the new gaps? Or does something else happen?

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2. 2. jtdwyer 02:53 PM 1/17/12

   If the "jitter" is produced as virtual particles oscillate in and out of existence, and they are the products of energy field interactions in space, space might appear to be "digital" or particulate when particles are detected, "analog" of smooth when energy is detected...

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3. 3. carlofab 03:55 PM 1/17/12

   Curious that in the machine age we thought the universe as a machine, operating with clock-like predictable precision.
   
   Now that we are in the digital age,we think of it as digital or composed of information.

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4. 4. Wayne Williamson 06:47 PM 1/17/12

   Interesting...I thought that they were using something like this to try and detect gravity waves....

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5. 5. And Then What? 08:34 AM 1/18/12

   I believe, in order to understand the underlying structure of Space-Time it will be necessary to make a complete disconnect between how we currently view Matter, Energy, and Space-Time itself and their relationship to one another. We assign properties of existence to Matter, Energy and Space-Time and visualize them through our senses and the tools we create. Thus the answers we get back will always be slaves to the underlying structure of the Architecture at the base of the construction of our questions. This approach has proven to be fruitful, in the past, and continues to provide answers today, but what I am saying is that the design of our approach itself may be what is blocking our view of the true relationship between Energy, Matter and Space-Time. It is like learning how to drive a car or swim. You do not really need to understand the underlying mechanics of either activity to actually accomplish your task. You can visualize many different scenarios, which would allow you to succeed, none of which may be true but if they satisfy your assumptions and allow for a statistically acceptable positive predictability, with regard to your successful completion of the task at hand, then they will suffice up to some level of understanding. It is only when we come face to face with a Reality that is inexplicable using the accepted Theories of the day that the cracks begin to appear. It happened in Newton’s Time and again in Einstein’s Time and it is about to happen soon in our Time due, in part, to the questions surrounding Dark Matter, Dark Energy, and the Power of the Punch from the LHC. I don’t know about anyone else but I’m loving it. As the old saying goes “May you live in interesting times”. Given the current state of the Global information highway and the thousands of brilliant Scientists tripping over themselves to put the new Theories in perspective, I cannot think of a more interesting time to live in.

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6. 6. Wilhelmus de Wilde 04:44 AM 1/21/12

   Bravo for the effort.
   But also read :
   http://www.physorg.com/news/2011-06-physics-einstein.html
   this article is about ESA's Integral gamma ray observatory that has provided results indicating that the quantum "graininess" of space/time is about 10^-48cm (Planck: 10^-33cm!).
   The opinion in the article is that these "grains" of space are information quanta, however if we have to treat these chunks as causal information quanta the we have to accept that there are two kind of chunks, the + and the - or the yes and the no, at any rate I do not think this is very much a progres, for what is then the cause of this differentiation ? Again we are entering the infinite road of causality.
   It far more logical by accepting that space has limits , it is scalar, our 3+1D causal space/time has an lower limit , beyond this limit it is no longer causal, we kind of enter here a new dimension where there is no before or after, the causal lines of information are no longer "present", we enter a dimension of possibillities.
   Human beings also have a beginning and an end, being born and die on our causal life-line, in this we follow our own space/time.
   It is our consciousness that can do the maths and deal with the infinities, in our causal world these infinities lead to paradoxes all over.
   (http://fqxi.org/community/forum/topic/913)
   So at he border of the ultimate lower limit , and this limit can be reached at every point in our space we touch the soap bubble of a Total Simultaneity, our consciousness being the contact line and creator of our causal time/life lines, like scisseling a statue out of a block of stone. (in principle the stone is beholding all possoble statues)
   
   keep on thinking free
   
   Wilhelmus

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7. 7. DAWorkman 04:11 PM 1/21/12

   I have a question about the experiment design that I hope someone will comment on. I will try to answer the question myself, but I would like confirmation or corrections to my thought process.
   
   How sensitive is the result to the length of the light path in either of the Interferometers? Do the light paths of the two interferometers have to be identical?
   
   My concern: the mirrors at the end of the interferometers may also be assumed to have jitter - correct? I suppose this can be reasoned away by assigning all the jitter to the beam-splitter and assuming the mirrors do not change relative to some 'theoretical' center of the beam-splitter. Comment on this geometry and whether or not it makes any difference in interpreting the experimental result.
   
   I am thinking that the second interferometer is more or less independent of the first as far as the result is concerned. What matters is the length of the light path of a single beam as measured from the beam-splitter to the reflecting mirror and back to the beam-splitter - correct? If jitter exists, the length of this path will fluctuate - correct? Knowing the precise length of the light path is not necessary - observing fluctuations in this length over time is what is important - correct?

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8. 8. jtdwyer in reply to DAWorkman 05:09 PM 1/21/12

   Regarding the experiment, how would inherent 'spacetime jitter' be discerned from Earthquakes, the vibrations of other massive Fermilab equipment and even gravity waves, for that matter?

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9. 9. jtdwyer 05:42 PM 1/21/12

   I agree with you regarding the supposed encoding of information in physics. Simply determining that spacetime were quantized does not infer that it is somehow encoded with any information.
   
   I'm merely a retired information systems analyst, but I do know that information must be physically represented by some persistent characteristic state. What physical characteristic of any bit of space could statically represent persistently stored data?
   
   That is the first issue with 'information' in physics. Beyond that basic ability to physically store data, for it to be useful in any way, binary data it must be encoded in some way that can be used by specific processes to store complex information - in this case the process must be able to interpret stored information and physically transform energy, matter or whatever to produce our "world".
   
   As the print article states, physicists "know not how the information is encoded, or how nature processes the 1's and 0's, or how the result the result of that process gives rise to the world." I can only consider this "information" theory to be completely imaginary.
   
   Again, even if spacetime can be shown to be quantized - that does not in any way infer that it is encoded with information use to produce the physical world. It also would not preclude the possibility that spacetime can also be demonstrated to be smooth and continuous: the uncertainty principle might apply to spacetime as well as fundamental particles.
   
   The whole idea of the 'holographic principle' seems to be misapplied here, as holographs typically encode three dimensional optical information as analog information! Why would it be presumed that the physical universe operates using digital information even if the results are all quantized at small scales? After all, the analog encoding of optical holographic information is typically stored in unitized physical segments...
   
   Again, I can only consider the concept of a information based implementation of the 'world' as a trendy but imaginary conception - without any physical basis!

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10. 10. brublr 07:05 PM 1/21/12

    I remember reading about this about a year ago in 'New Scientist' and the explanation given was that just as all information within a black hole is encoded (no idea how, I'm an architect)on the surface of a black hole, all the information within the observable universe is similarly encoded on its boundary. (and if the universe's negatively curved?)The planck length is at its calculated size of some -43 magnitude on the boundary but its 3d equivalent within the universe is correspondingly greater and enlarges as the universe expands. This much greater planck dimension was thought to be the source of the noise
    in the gravity wave detector in use at the time of Dr. Hogan's speculation and the greater sensitivity of this new detector may offer further data on the concepts.

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11. 11. Delialh_Rush 04:48 AM 1/22/12

    Academician Shnol has already found this “noise”, he registered fluctuations and created a base (many years of observations). These fluctuations define states of atoms, proteins, biosystems, everything. Hogan’s method is too complex, but his ideas (noise) have been already confirmed in Dubna. These fluctuations are that noise, which Hogan is going to find.

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12. 12. Wilhelmus de Wilde 11:34 AM 1/22/12

    @brublr: new scientist 9 july 2011

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13. 13. narsep 03:30 AM 2/1/12

    First and above all:
    1 Each photon’s worldline (path) is a straight line (not following any foamlike fluctuation that we realize only because our worldline differs that of photon or of any observable object).
    2 In order to avoid any discrepancies due to expansion, the temperature fluctuations have to be far less than 10^(-25) degrees (technically impossible).
    3 How the diffraction is going to be excluded as absolute vacuum does not exist?
    Good luck.
    http://www.fqxi.org/data/essay-contest-files/hadjidakis_Has_the_time_com.pdf
    
    

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14. 14. Zephir_AWT 09:33 PM 2/4/12

    Hogan's machine is just a huge waste of money. He tries to find holographic noise at the moment, we have the vacuum full of CMBR noise, which everyone can detect with his TV set. http://aetherwavetheory.blogspot.com/2009/09/awt-and-gravitational-waves.html

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15. 15. Zephir_AWT in reply to KeithCaserta 09:46 PM 2/4/12

    /*So what happens, then, when space expands?*/
    
    Because the light wave disperse with tiny density fluctuations and its wavelength/speed is changing during this http://aetherwavetheory.blogspot.com/2009/09/awt-and-big-bang-theory.html

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16. 16. Tallengold 06:17 PM 2/5/12

    of course space is digital made of particles of information all related to something else.Thats obvious to me and always has been and Italy sets off a alarm as well. In Quantum physics we know the theory works as evidenced by the technical revolution but we don t know exactly why it works the way it does,entanglement,action at a distance etc,etc yet we have continued to use and infiltrate virtually everything with this process we don t understand. If space is digital someone some force someone somewhere can direct these signals for our good or harm. I personally have dreamed of the future and this subject and I can you Scientific American article about the 10 most likely causes of threats to civilization completely missed the boat, the greatest threat is a digital threat to civilization.
    Here

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17. 17. Delialh_Rush 02:50 AM 2/9/12

    http://www.chronos.msu.ru/RREPORTS/shnol_liki.htm (use google translate).
    This is incredible! One is going to build interferometer (Hogan), another one (Shnol)found interference. He says he doesn’t know what it is. He has database (1951-2011). “What is it? Such narrow lines can not be probabilistic. "Poisson" is plus or minus the root of the "N". There can be no narrow lines. Only the interference of wave processes allows narrow picture. Let me ask the theorists, that's their business, which waves interfere”...
    

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18. 18. Joel454 06:10 AM 6/22/12

    a digitized space time would solve Zeno's paradox. Because it time and or space are not smooth then neither can be infinity divided.

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