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The universe's clock might have bigger ticks than we imagine

an abstract view of a wormhole with a clock overlaid
(Image credit: Shutterstock)

The smallest conceivable length of time might be no larger than a millionth of a billionth of a billionth of a billionth of a second. That's according to a new theory describing the implications of the universe having a fundamental clock-like property whose ticks would interact with our best atomic timepieces. 

Such an idea could help scientists get closer to doing experiments that would illuminate a theory of everything, an overarching framework that would reconcile the two pillars of 20th-century physics — quantum mechanics, which looks at the smallest objects in existence, and Albert Einstein's relativity, which describes the most massive ones.

Related: The 18 biggest unsolved mysteries in physics

Most of us have some sense of time's passage. But what exactly is time?

"We don't know," Martin Bojowald, a physicist at Pennsylvania State University in University Park, told Live Science. "We know that things change, and we describe that change in terms of time."

Physics presents two conflicting views of time, he added. One, which stems from quantum mechanics, speaks of time as a parameter that never stops flowing at a steady pace. The other, derived from relativity, tells scientists that time can contract and expand for two observers moving at different speeds, who will disagree about the span between events.

In most cases, this discrepancy isn't terribly important. The separate realms described by quantum mechanics and relativity hardly overlap. But certain objects — like black holes, which condense enormous mass into an inconceivably tiny space — can't be fully described without a theory of everything known as quantum gravity.

In some versions of quantum gravity, time itself would be quantized, meaning it would be made from discrete units, which would be the fundamental period of time. It would be as if the universe contained an underlying field that sets the minimum tick rate for everything inside of it, sort of like the famous Higgs field that gives rise to the Higgs boson particle which lends other particles mass. But for this universal clock, "instead of providing mass, it provides time," said Bojowald.

By modeling such a universal clock, he and his colleagues were able to show that it would have implications for human-built atomic clocks, which use the pendulum-like oscillation of certain atoms to provide our best measurements of time. According to this model, atomic clocks' ticks would sometimes be out of sync with the universal clock's ticks. 

This would limit the precision of an individual atomic clock's time measurements, meaning two different atomic clocks might eventually disagree about how long a span of time has passed. Given that our best atomic clocks agree with one another and can measure ticks as small as 10^(minus19) seconds, or a tenth of a billionth of a billionth of a second, the fundamental unit of time can be no larger than 10^(minus 33)seconds, according to the team's paper, which appeared June 19 in the journal Physical Review Letters.

"What I like the most about the paper is the neatness of the model," Esteban Castro-Ruiz, a quantum physicist at the Université Libre de Bruxelles in Belgium who was not involved in the work, told Live Science. "They get an actual bound that you can in principle measure, and I find this amazing." 

Research of this type tends to be extremely abstract, he added, so it was nice to see a concrete result with observational consequences for quantum gravity, meaning the theory could one day be tested. 

While verifying that such a fundamental unit of time exists is beyond our current technological capabilities, it is more accessible than previous proposals, such as the Planck time, the researchers said in their paper. Derived from fundamental constants, the Planck time would set the tiniest measureable ticks at 10^(minus 44) seconds, or a ten-thousandth of a billionth of a billionth of a billionth of a billionth of a billionth of a second, according to Universe Today.

Whether or not there is some length of time smaller than the Planck time is up for debate, since neither quantum mechanics nor relativity can explain what happens below that scale. "It makes no sense to talk about time beyond these units, at least in our current theories," said Castro-Ruiz. 

Because the universe itself began as a massive object in a tiny space that then rapidly expanded, Bojowald said that cosmological observations, such as careful measurements of the cosmic microwave background, a relic from the Big Bang, might help constrain the fundamental period of time to an even smaller level.

Originally published on Live Science.

Adam Mann is a freelance journalist with over a decade of experience, specializing in astronomy and physics stories. He has a bachelor's degree in astrophysics from UC Berkeley. His work has appeared in the New Yorker, New York Times, National Geographic, Wall Street Journal, Wired, Nature, Science, and many other places. He lives in Oakland, California, where he enjoys riding his bike. 

  • teotwawki.je
    Chronon time loops.

    When we try to observe a quantum event at a point in time, we encounter the uncertainty principal in that at a precise point in time, the exact state is uncertain (and vice-versa).
    This is famously illustrated by Schrodinger's cat and extrapolated into the multiple worlds / parallel universes model.
    I.e. if the quantum 'trigger' can be in any/every of a multitude of states at that precise point in time, then it can be thought as if it is in all of the states at once but in multiple parallel universes.
    I hate this idea.

    Perhaps 'a point in time' is not actually a single point but a loop of the smallest possible unit of time - a chronon. Hence a chronon time loop.
    So the passage of time is a series of over-lapping ovals, like a chain or a sequence of joined-up lower case 'e's.
    I.e. time doesn't just go straight forward, but it goes something like 2 steps forward and one step back.

    Our conscious perception has been shown to actually lag behind real-time events by a fraction of a second.
    Of course we don't notice this because it's a constant. Like watching a TV program via satellite - we never notice that we're seeing it a couple of seconds after it was transmitted because every instant of it is observed in the same sequence that it occurred, albeit not actually when it occurred.

    Perhaps we can only observe the beginning part of the time loop but the actual event itself 'occurs' throughout the time loop.
    While we are observing the event at only the initial part of the time loop, we will observe that the state is unknown because the event has not yet finished it's passage through the time loop. Thus we cannot know or see the outcome.
    At some point in the future, the consequence of that event will be known - perhaps the cat died. In which case we will know what the exact status of the quantum trigger must have been.
    Perhaps this retrospective is happening as feedback in the time loop.
    So that at the final part of the time loop, the event has happened and the outcome is feedback through the time loop to nail down what the exact quantum state should be at the initial part of the time loop.

    In this scenario, there is only one universe with only one time-line. And the state of the quantum trigger that threatens the cat is only uncertain to our incomplete observation, having been determined conclusively by the eventual outcome.
    Reply
  • TorbjornLarsson
    The problem with discrete time is that it doesn't work relativistically, we can't have "preferred" reference frames, and it is generally accepted that relativity says space and time is continuous on all scales. Rather, the scale problem comes when you use the reconciliation of general relativity and quantum field theory that we have - linearized gravity quantum field theory http://www.scholarpedia.org/article/Quantum_gravity_as_a_low_energy_effective_field_theory ]. You can't describe stuff on energy density scales higher than Planck energy density.
    Reply
  • TorbjornLarsson
    teotwawki.je said:
    Chronon time loops.

    When we try to observe a quantum event at a point in time, we encounter the uncertainty principal in that at a precise point in time, the exact state is uncertain (and vice-versa).
    This is famously illustrated by Schrodinger's cat ....

    I'm not sure how quantum uncertainty would affect time even if we have to observe it through clocks. See my other comment for a quantum field theory of gravity that physicists agree work for low energies.

    In general quantum superposition, which is what Schrodinger's cat illustrates, as well as quantum entanglement, depends on non-locality (and no hidden variables) of quantum correlations. I don't have a problem with that, since relativity enforces light cone locality in order to have causality but quantum physics opens up as much non-locality of correlations it can have. It is an exact balance and is made explicit in quantum field theory which obeys relativity - I would be much more worried if we didn't have a quantum field theory for gravity that applies for relativity of space and time .
    Reply
  • Xogroroth
    So, time became a "physical" particle now?

    As I see it: (Disclaimer: Please note the formulation of the sentence: I declare theory to follow here, NOT hardcore empirical fact. This means, when I "disagree" with something, this is within and from within the theory out, NOT from empirical point of view, as nothing has been actually or factually been proven either way. Thank you.)Time is not something material such as a particle.Same for Gravity (and most likely someone will invent Gravity Particles as well, since why not?).
    Now, Time IS Gravity and vice versa, that is, it once was a single fabric, together with the other known and yet unknown Forces, believed to be broken up in the early moments of the Universe's creation.
    I disagree.
    While these APPEAR to be split up, these are still one and the same fabric, interacting with one another in a constant, SEEMINGLY as separated, but this is "mere illusion".
    Each Force can act separate, or interact with others, as per the need of the moment.

    Time is Quantum Energy, like Gravity is Quantum Energy, the very same Energy, just acting in different ways.

    Manipulating Time will be possible, if we do not erase ourselves before this point, through manipulating Gravity.
    But to travel back and forth in Time?
    Come on!!!
    We might be able to slow Time to NIGH absolute 0, but like reaching Absolute 0 Time Passing will be like reaching 0° K or the mathematical 0 by dividing 1 until you get to 0: Never.
    There will always be a "rest".

    It is already debunked, that mass will become infinite past the speed of light.
    We WILL (if we live that long as species, that is) be able to move far beyond the speed of light:
    FTL is possible.
    Well, at least, for the infinite-mass at light speed error, specifically.
    We do not know what else will come up speeding to FTL.
    Never gotten there so far, thus this is unknown territory.

    Now, Einstein said, basically:
    When we move faster than light, the speed will bring us to a different location in the past, or, we would be moving back in time.
    Severe but understandable error: this is early 1900's, just in 1947 Yeager broke the Sound barrier, which to many scientist, was impossible, some even going as far as "entering the demon realm".
    Knowing this, well ...
    If we move faster than light, this would not affect time at all, though we would see time regressing in time: we would see time move backwards when observing the light outside. But that's mere illusion, an optical trickery.
    Thought experiment (since, well, we cannot yet do this in practical form):
    Let us for the sake of argument have a space ship, that is invulnerable, Gravity-Time-Dilation proof, has the ability to accelerate to X amount the speed of light instantly, and stop equally fast from this speed.
    This will be needed, unless we are suicidal.
    It is also equipped with the latest model of Quantum-Entangled Communication Device: the QECD V1.2, which allows us to instantly communicate with Terra (Earth) and back.
    Now, we are sitting on the surface of the sun, and we will go to Earth, at 4 times speed of light.
    As we jump from 0 to "4FTL", we will notice that communication with Earth is normal, uninterrupted (note, the ship has Gravity-Time-Dilation proof abilities thus I am ignoring that part) and though we speed at 4FTL, no abnormalities are noticed or detected.
    2 minutes later, we will arrive at Earth, in perfect normal condition.

    Which is actually logical:
    Speed does not affect time?
    And for crying out loud: Light is DARN slow.
    IF it was the ABSOLUTE limit, it would hop around at the cost of absolute 0 time.
    But no, it needs a FULL 8 MINUTES, from the sun to Earth.
    I am a cripple, but (hyperbole) I shuffle faster from the sun to Earth, so to speak?
    It is, in relative terms, INSANELY slow ... .
    So, if there's no new issue, reaching such velocities, we could go 1000 times light speed ...
    ... but we will not be able to cross Time, negative nor positive.

    Tachyon:
    Let's say for the sake of discussion, it was found.
    It travels at 1.6 FTL.
    But the fact that light is not capable to keep up/track the Tachyon, does therefore not mean, it ventured back in time?
    Time simply is too SLOW, the particle has not moved back not forwards in time, at all.
    Which is precisely what would happen to us on the ship, "seeing" time go back or forth, at insane speed.
    But that's mere optical illusion.

    While the speed of light no longer is the ultimate speed limit, a new one popped up, and it's not even an actual speed as in "distance/time", either.
    It is in fact "Time" itself, or, an almost infinitely small dot on the time line.
    This "point" in Proper-Space-Time can't be circumvented, that is the ultimate speed, just beyond our grasp, evermore.
    "We can in theory travel ... " nope.
    "The Cosmos foresaw this" (or The Cosmos/Universal Laws, it's not been "put there" purposely, of course, it was a manner of speaking), and created an inevitably impossible point of passing, preventing us to travel backwards in time.

    Naturally:
    Like all theories, this is pure speculation, based on current understandings.
    It could be dead ... no wait, rephrasing:
    It IS dead wrong, but it is DEAD RIGHT and all in-between as well, a pure Schrödinger- or Quantum state: Nought, one, and all in-between, at the same moment.
    And this until we can peer in the proverbial Schrödinger-box.

    Feel free to respond, keep it civil, and if you do want to "debunk this", do it in the correct way, provide background information, preferably backed up in "proof" for as far as proof can go in this field of science.
    I the end: You're wrong" just ain't a "debunk".
    Thank you.

    Xogroroth.
    Reply
  • Hayseed
    One can not understand the universe, without absolute time and absolute length. It's why the universe is the way it is. It demands AT and AL.

    The true dynamic of light does not require local time. The universe demands that a second of time is the same second everywhere. Time is the unifier of all motion.

    Science just doesn't know how to measure the relative velocity of light.

    Because light blinks.
    Reply
  • Xogroroth
    "One can not understand the universe, without absolute time and absolute length. It's why the universe is the way it is. It demands AT and AL. "
    Very nice, but no ball, AT ALL!!!!!
    Do you know your stuff, sir?
    Here's a fun wee bit:

    The Lie That Is Light…
    Or: How A Misinterpretation Became Doctrine.
    Antwerp, June 5th, 1999

    Introduction:While we are being taught that light is light, science made a serious mistake, based on what we see on Earth.
    While on Earth light is just that: light, it is therefore not in different places…

    The Facts:As we always have seen light as nothing more than that: light, we wrongly assumed that this is the case everywhere else…
    Sure, wherever on Earth one is, there is light appearing as light.
    Once we learned about space then, first through telescope, later through entering this cold, empty vastness, we saw a complete new form of Light (with a capital case as this is about the concept of Light, NOT light as in “a light”, same for the latter Dark) … “non-light Light” or simply… Dark!

    If Light isn’t Light, then what is going on, what and how do we “see” this Light?Light is a radio wave, like radiation, which in itself is “unseen” or Dark.
    Once light gets to interact with matter, it excites this matter, making it basically shiny, if you like.
    And this interaction of Dark with matter that created this shine, is what we visibly perceive as light.
    Still, once light, even if interacting still with matter, enters a shadowy area, it turns Dark once more…
    We are unconsciously aware that Light is not light, but we do neither think it over nor think it through, with causality in many areas of teachings, science, knowledge, wisdom and understanding.
    Implications:
    In a few areas, light is used as a tool:
    1) Medical Profession = For discovery and diagnosis.
    2) Chemistry.
    3) Geology = Optical Mineralogy (using light to detect the optical properties of minerals).
    4) Physics/Quantum Physics.
    5) Engineering.
    6) Astronomy.
    , and even has a few fields based upon it, such as there be the Science of Light and Vision (Optics or Optometry), which is the study of Vision Impairment, which has 4 specifying classes:
    1) Dispensing Optometry = the study of sight and the effect of lenses to help improvement in sight..
    2) Refraction Optometry = Study of sight and testing sight .
    3) Pathology Optometry = Study of the causes and causality of disease around, in and behind the eyes (nerves).
    4) Medicinal Optometry = Optometry based on the use of diagnostic drugs and a limited range of therapy drugs.


    The issue however is, that these use the concept of Light… as actual light.
    In the most fundamentalistic ways, this is a wrong, an incorrect, an error.
    Does this error has any impact on the fields where it is used or studied?
    This, I cannot yet answer, but I will eventually as I dig deeper into the matter…

    However: from a scholarly point of view, when one speaks of The Speed of Light, I begin to shiver, as it is so wrong in the deepest sense of it’s meaning and understanding: it is in it’s CORE ESSENCE literally SCIENTIFICALLY INCORRECT, and from a scientifically point of view unforgivable, hence I bring this matter to you.

    Righting the Wrong:Reasoning:While it may not have much effect on the practical side (at least for now), this error makes a precedent:
    As scientists we cannot be allowed to make mistakes, as mistakes can lead to devastating results.
    Imagine: a Nuclear Medical Scientist needs to cut out a tumour in a patient’s brain, by the use of a new type of radiation-based laser that is extremely accurate with a stronger beam to do the job three times faster, which causes less side effects on the patient over longer time.
    He sets the laser, pin-points it perfectly, but when he activated the laser, his arm sleeve slides a lever a tiny bit out of place, resulting in the beam missing the tumour by 1 millimetre.
    Now, I hear you ask: “What is one millimetre?”
    While burning away in someone’s skull, 1 millimetre can be the length between life or death… or worse: TOTAL paralysation while the patient keeps a perfectly sane and lively mind.
    In case you do not quite get it: put Metallica – And Justice For all CD in your CD player and listen carefully to One…

    What I am saying is: if we allow errors in naming concepts, then were will that lead to?
    The concept of Science is to be ABSOLUTELY 100% accurate, right?
    Even though it is in reality different, in mind it is about Absolutes, One either is, or is not.
    From a point of interpreting the concept Science, mistakes are not allowed: it’s a form of Asperger Perfectionism.
    And for us Asperger’s there’s only 0 or 1, no or yes, black or white: “Absolutes in Perfection = Perfect Absolutes”.


    Ah, the simplicity of that what is.
    Reply
  • Hayseed
    I thought you loved talking about theory. Would you like to see light blink? Acquire a dual port function generator. A digital capture scope, a short wave receiver with BFO. 3 BNC connected telescopic antennas. And a roll of insulated solid wire, #12 or #14 or bout anything will do.

    Attach a length of wire to each antenna and cut to resonant at 10 MHz.....at a 1/4 wavelength. Use the telescopic part to tune the wire. Connect 20-30 ft of wire to receiver.

    Connect antennas to generator and scope, all horizontal polarization. Do not use any feed lines. Set generator A channel to 10 MHz sine wave output, set channel B to same, but 180 out. This is how a conventional dipole is fed. At 100 ft away, tune in signal on receiver and set BFO for a tone. With the scope beside the radio, set scope to see the signal. Use separate antennas on radio and scope, scope antenna needs to be tuned.

    Now you can hear and see a regular radio signal. Light is the worse thing in this world, to try and measure light. Light is a flux. It's not singular. But a radio signal is just one singular light......that we can measure. We can't see it, but can measure it much easier.

    After establishing a conventional radio link, and noting the tone and the amplitude on scope.....set gen channel A to a full wave precision rectified positive signal. Set channel B to full wave precision rectified negative signal.

    The dipole is no longer alternating. Do you detect any difference in the radio tone or the amplitude of the scope?

    So, does a radio wave have to alternate? Now add modulation the the gen signals. Can you see or hear any difference?

    Now, for the good part. Set channel A for a one shot wave form. Use a precision positive 1/2 sine(180 degrees) positive output and channel B for one shot precision negative 1/2 sine(180). 10MHz.

    Now channel A has 180 degrees of positive at 10 MHz and channel B has 180 of negative at 10 MHz. Just one shot.

    This will emit one "photon" from the dipole......you have to catch it at the scope. Radio "waves" also blink. A continuous "wave" is actually blinking. It's intermittent. Not a wave. A strobe.

    I used a FeelTeck FY6600 generator, with isolation transformer, a Kenwood TS-570DG transceiver, and a SDS1000X/SDS1000X Series Digital oscilloscope. But, I became disabled and can no longer play.

    Let's see what you get.
    Reply
  • Xogroroth
    I'd really love to play slotin's Demon core game ... :(
    Got no Beryllium though.
    Nor any plutonium for that matter.

    Being a cripple, it's not quite a rich life.
    Wished I could yours too ...

    Man, I really need a LHC ... *sigh*
    Reply