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Science

Physicists Find That As Clocks Get More Precise, Time Gets More Fuzzy (sciencealert.com) 167

Posted by EditorDavid from the time-for-a-new-theory dept.
Physicists "have combined two grand theories of physics to conclude not only is time not universally consistent, any clock we use to measure it will blur the flow of time in its surrounding space." An anonymous reader quotes ScienceAlert: A team of physicists from the University of Vienna and the Austrian Academy of Sciences have applied quantum mechanics and general relativity to argue that increasing the precision of measurements on clocks in the same space also increases their warping of time... [W]hile the theories are both supported by experiments, they usually don't play well together, forcing physicists to consider a new theory that will allow them both to be correct at the same time...

In this case, the physicists hypothesized the act of measuring time in greater detail requires the possibility of increasing amounts of energy, in turn making measurements in the immediate neighborhood of any time-keeping devices less precise. "Our findings suggest that we need to re-examine our ideas about the nature of time when both quantum mechanics and general relativity are taken into account," says researcher Esteban Castro.
The article opens with the statement that "time is weird," noting that despite our own human-centric expectations, "the Universe doesn't have a master clock to run by."
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Physicists Find That As Clocks Get More Precise, Time Gets More Fuzzy More

Physicists Find That As Clocks Get More Precise, Time Gets More Fuzzy

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  • It's all a simulation (Score:4, Funny)

    by goombah99 ( 560566 ) on Saturday March 18, 2017 @10:38AM (#54065177)

    The think about time is we have no idea how long it really takes to go one second in the simulation we all live inside of. It could be years on the wall clock in the simulators universe.

    • I suspect it's the other way around: simulations look like the universe because the simulations are confined to the universe.

      • I suspect it's the other way around: simulations look like the universe because the simulations are confined to the universe.

        Or contained within a box [wikipedia.org], including the box itself.

      • Whut

        • As a concrete example: suppose P != NP. Then no simulation can solve NP-hard problems in polynomial outside time, so most simulations will have the same constraint as the parent universe (where we reside) and also be unable to solve NP-hard problems in polynomial inside time.

          The "hey, this universe looks like a simulation too!" argument would be: every simulation we make has P!=NP. Our universe has P!=NP... sure looks like what a simulation would be like. Obviously, every simulation's rules is heavily co

    • Re:It's all a simulation (Score:5, Interesting)

      by goombah99 ( 560566 ) on Saturday March 18, 2017 @11:09AM (#54065317)

      It's interesting that all the funny bits of quantum theory and relativity and light are infact identical to what you would expect to be the rules of any simulation.

      For example, if you aren't looking at something in a video game it doesn't get rendered, ergo schrodingers cat like phenomena. The moon in fact is not there if you don't look at it.

      Bells theorem rules out local hidden variables (that is variables that are in the game but are not coupled to you the observer) but it allows global hidden variables to explain all spooky action at a distance by means other that quantum entanglement. that is to say it's what should happen in any simulation in which you are part of the simulation too.

      diffraction and the heisenberg uncertainy relationships come from discrete binning. For example, in a pixelated universe you can'e actually resolve angles of far away objects since they are pixelated. hence there's a direction-position uncertainty.

      Likewise the more finely you allow a simulation to measure time the more finely you have to bin or divide the external clock requiring more energy.

      • Re: (Score:1)

        by Anonymous Coward

        Another thing I read mentioned that the size of the estimated universe (they provided some math which I don't recall) would actually fit almost exactly into a 64 bit unsigned integer for X,Y,Z.

        Lazy processing means time ticks only when something "happens to, observes, or changes" an object... Then we realize time ticks differently for objects in outer space moving very quickly vs something only updating less often which matches that behavior.

        I also think another logical idea is that we could just be very ve

        • Another thing I read mentioned that the size of the estimated universe (they provided some math which I don't recall) would actually fit almost exactly into a 64 bit unsigned integer for X,Y,Z.

          Measured in what units?

          • This is easily worked out. There is only one unit that would make any sense: The planck length. The smallest unit of length there can be in the universe. 1.6E-35 meters.

            Now you need the size of the universe. Unknown. But the observable universe is 8.8E26 meters across - and yes, due to expansion of space, that is a lot wider than the age expressed as light years.

            A little division puts this at... a crashed calculator. But a better calculator says that makes the universe 5.5E61 planck-lengths across. While an

            • The planck length. The smallest unit of length there can be in the universe. 1.6E-35 meters.

              Except it's not. It might be in some theories, but it may also have no physical significance.

      • Re: (Score:2)

        by Raenex ( 947668 )

        Bells theorem rules out local hidden variables (that is variables that are in the game but are not coupled to you the observer) but it allows global hidden variables to explain all spooky action at a distance by means other that quantum entanglement. that is to say it's what should happen in any simulation in which you are part of the simulation too.

        There's a difference between what we observe in quantum mechanics and a classical simulation using global hidden variables, and that's the no-communication theorem [wikipedia.org].

        • No you can have all of quantum mechinics in a classical world as long as you allow hidden variables. Bell's theorem just says there are no Local Hidden variable but it allows Global Hidden variables. Those are variables coupled outside the simulation.

      • For example, if you aren't looking at something in a video game it doesn't get rendered, ergo schrodingers cat like phenomena. The moon in fact is not there if you don't look at it.

        This is NOT AT ALL how quantum mechanics works. Schrodinger's Cat was a gedanken experiment developed by Schrodinger to show how absurd the Copenhagen interpretation of quantum mechanics was when applied to everyday objects. Absolutely no physicist believes that this is how QM actually works: the cat is simply either alive or it is dead and is not in a superposition of two states. The point was to show that the prevailing interpretation at the time was wrong. The same goes for the world: QM does not say th

        • Re: (Score:2)

          by myrdos2 ( 989497 )

          The point was to show that the prevailing interpretation at the time was wrong.

          It was an epic fail, then.

        • For example, if you aren't looking at something in a video game it doesn't get rendered, ergo schrodingers cat like phenomena. The moon in fact is not there if you don't look at it.

          This is NOT AT ALL how quantum mechanics works. Schrodinger's Cat was a gedanken experiment developed by Schrodinger to show how absurd the Copenhagen interpretation of quantum mechanics was when applied to everyday objects. Absolutely no physicist believes that this is how QM actually works: the cat is simply either alive or it is dead and is not in a superposition of two states. The point was to show that the prevailing interpretation at the time was wrong. The same goes for the world: QM does not say that things stop existing if they are not observed and nobody believes this. QM is strange and counter-intuitive, it is not crazy!

          While it was meant to demonstrate the absurdity of the Copenhagen interpretation, the Copenhagen interpretation still won.

      • The fact that we can't build a truly accurate clock is actually a safety mechanism built into the universe. As Professor T.Pratchett demonstrated in his groundbreaking analysis "The Thief of Time", the one thing we don't need is a perfectly accurate clock.

    • Re: (Score:2)

      by hey! ( 33014 )

      My wife did a physical simulation for her thesis of the ocean halocline by using an 8' wide rotating tank filled with water and sugar solution. Now the tank was a body of water rotating every 24 hours by virtue of being on the surface of the Earth, but the angular velocity was much too low to have an observable effect, so the tank rotated every few minutes on top of the 11.57 microradians/second rotation of the Earth.

      It was a real time experiment in which a short but fixed period represented a much longer

      • ... the tank rotated every few minutes on top of the 11.57 microradians/second rotation of the Earth.

        Or, at least, in oscillating directions tangent to the surface of the Earth.

      • the 11.57 microradians/second rotation of the Earth.

        So the earth only rotates one radian per day? 11.57 micrordians/second x 86,400 seconds/day = 1 radian/day.

    • There is no canonical universe to which all others are a simulation.

    • Re:It's all a simulation (Score:5, Insightful)

      by Greyfox ( 87712 ) on Saturday March 18, 2017 @01:15PM (#54065983) Homepage Journal
      Yes! And time is so problematic because the simulation is being run on a massively parallel system. While each processor is able to handle the physics and timing of a small area reasonably well, keeping time synchronized for the entire universe would slow the entire thing down far too much. Moreover, since the project was designed as a simple demonstration of how to convert hydrogen to plutonium over time, making an effort to do so was deemed unnecessary. We also had a problem with some particles being uninitialized upon creation and going off at a very high velocity, so the top speed in this particular universe simulation was capped to prevent anything too untoward from happening.

      The simulation has been running reasonably well for the amount of effort put into it, although there are still some issues of localized processors crashing when mass values in specific locations go too high, and some number of processors have been having to synchronize their timing signals across boundaries for reasons we do not currently understand. There is also the minor issue that eventually the plutonium degrades back to hydrogen, along with everything else, but we had no intention of ever allowing the simulation to run that long anyway.

    • Obligatory xkcd:

      https://www.xkcd.com/505/ [xkcd.com]

  • You see? (Score:4, Funny)

    by Jawnn ( 445279 ) on Saturday March 18, 2017 @10:39AM (#54065187)
    Yet another example of how science can't prove anything. No, wait. This is another example of how the science lobby is trying to protect their jobs by, you know, doing experiments and shit, and trying to understand how stuff works.

  • never (Score:2, Funny)

    by Anonymous Coward

    Is when I'll have time to give a shit about this.

  • Hmm... (Score:4, Funny)

    by Whooty McWhooface ( 4881303 ) on Saturday March 18, 2017 @11:10AM (#54065325)

    So if their clock turns out not to be accurate. it's the universe's fault?

    It's a poor scientist who blames the universe for their shortcomings.

    • Re:Hmm... (Score:5, Informative)

      by Anonymous Coward on Saturday March 18, 2017 @11:48AM (#54065537)

      Or it's Heisenberg up to his usual antics. Time and energy appear as conjugate variables in the quantum wave function solution to the Schroedinger equation for an oscillator (like a ticking clock), so the precision of your clock (delta-t) is inversely proportional to the precision of your energy measurement (delta-E), in the same way that the precision of position and momentum measurements are limited by the uncertainty principle.

      Energy curves its surrounding space under General Relativity. This would imply energy of whatever system does the ticking in your clock is constantly being "measured" by, at a minimum, the fabric of space-time, independent of how well you isolate it from the rest of the clock. So that puts a limit on the uncertainty in the energy measurement of whatever does the ticking. If delta-E is limited to be below a certain size, then delta-t is forced to be above some size, so you necessarily get some small variation in the time between ticks of the clock.

      This results in a tradeoff between precision and accuracy. Precision requires many small ticks, so delta-t makes up a larger fraction of the duration of each clock's tick. A clock which ticks less often becomes more accurate (delta-t is a smaller fraction of the total time between ticks), but fewer ticks limits the precision of your measurement.

      At least, as a physics grad student, that's how I've interpreted the result that TFA is utterly failing to convey properly.

    • Re: (Score:2)

      by Tablizer ( 95088 )

      poor scientist who blames the universe for their shortcomings.

      This fake universe won't run my fantastic experiments right. It's a low energy universe and has the worse ratings of all. I will defund it, build a sphere around it, that's a roundish wall by the way, and make God pay for it!

  • Schrodinger's clock? (Score:3)

    by zm ( 257549 ) on Saturday March 18, 2017 @11:10AM (#54065329) Homepage

    Or is it Schrodinger's time? Oh, sweet entropy...

    • It might not be Schrodinger's time. Or it might not be. We won't know until Schrodinger checks his watch.

    • I was going to ask: how is this any different from Heisenberg's Uncertainty principle? Time is just another dimension, measure it precisely enough and you disturb it too much to make an accurate measurement.

  • Forget time (Score:5, Insightful)

    by little1973 ( 467075 ) on Saturday March 18, 2017 @11:17AM (#54065363)

    https://arxiv.org/abs/0903.383... [arxiv.org]

    Time is just the sequence of events. And events on the smallest scale are particle interactions.

    What if there is an unknown quantum field which creates a barrier between particles? And particles have to "tunnel" through it in order to interact?

    When this quantum field is more disturbed (warped, etc) this barrier will be greater and it would be harder to particles to interact with each other. The end result is "time" slows down since the number of interactions drops.

    Note that an observer (in its own reference frame) will not notice anything (in the same way as in general relativity) since the observer just counts the number of interactions. To that observer the same number of interactions means the same amount of "time" passes.

    And yes, this means this quantum field would be a distinguished reference frame.

    • Indeed. Time is just a man made invention. How it's defined and "measured" is what can get wonky. Take out time from all physics to see the real core of how things work.

    • Re: (Score:2)

      by Calydor ( 739835 )

      So basically the Frames Per Outside Second drops, but the Frames Per Inside Second remains constant?

  • only man's devices for measuring the concept of time, the past goes on for eternity and the future goes on to eternity, it is just that we humans have the audacity to think we are smart enough to count it or measure it, we can make devices that do this but they will never be absolutely accurate as these scientists found...

    • Re: (Score:1)

      by Anonymous Coward

      The past most certainly does not go on for eternity. Thus far, current best understanding is that time had a definitive starting point, which you'd know as the big bang. It makes no sense saying "before that", as there was no before. This isn't just semantics or wordplay, time literally came into being at that point.

    • What do you mean by eternity?

    • the past goes on for eternity and the future goes on to eternity

      Prove it.

  • Makes sense (Score:5, Interesting)

    by Solandri ( 704621 ) on Saturday March 18, 2017 @11:40AM (#54065491)
    Einstein's theory of relativity tells us that time and space are the same thing (your perception of the two skews with your relative velocity, which causes all of relativity's time dilation effects). So I would expect there to be a time-corollary of Heisenberg's Uncertainty Principle [wikipedia.org]. Just as extremely precise measurements of position lead to poor measurements of momentum, extremely precise measurements of time should result in poor measurements of... something else.

    • Re: (Score:1)

      by Anonymous Coward

      Just clearing some pseudoscience: Uncertainty principle deals with VARIANCES OF MEASUREMENTS. It's Var(X)Var(P) >= hbar/2.

    • Re:Makes sense (Score:5, Interesting)

      by Baloroth ( 2370816 ) on Saturday March 18, 2017 @12:53PM (#54065845)

      So I would expect there to be a time-corollary of Heisenberg's Uncertainty Principle [wikipedia.org].

      There is, but it's probably not what you're thinking of. Technically speaking, the Heisenberg uncertainty pair applies to any two pairs of non-commutating quantum variables (or, depending on how you look at it, any two Fourier partners). Position and momentum happen to be one such pair. Another is time and energy. What that means, however, is that the energy of a particle in an unstable state (i.e. a state that can spontaneously decay into a lower energy state) is not perfectly well-defined, and the variance in energy is inversely proportional to the average decay time. In other words, the faster a particle (or state) decays, the wider the range of energies that particle/state is allowed to have, so that only long-lived states of physical systems have well-defined energies (by "long lived" I mean something like microseconds or even nanoseconds, which is long by quantum standards).

      In the case of time measurements, this would generally mean the energy of our clock becomes less well defined as we make more and more precise measurements of the time. That's not really a problem, though: we just have to be greater that 1/2 h_bar, which is ~3e-16 eV*s. That means if the uncertainty in our time is 1 part in 10,000,000,000,000,000 (modern atomic clocks are very roughly in that range), we have an uncertainty of about 1 eV in the energy of our state. That's decently large (in terms of atomic scale physics), but pretty negligible in terms of everything else (nuclear physics involves energies a million times greater than that).

    • Special relativity says that space and time are partially interchangeable. You cannot substitute a spacelike geodesic for a timelike one.

  • The article opens with the statement that "time is weird," noting that despite our own human-centric expectations, "the Universe doesn't have a master clock to run by."

    What, so God doesn't own a wristwatch? No wonder he's always late to the party. Or the rape, or robbery, or molestation, or murder. If only he had a watch he could've gotten there in time to stop that shit. Fuckin' slacker.

    • Re: (Score:2)

      by Nemyst ( 1383049 )
      I mean, he was three days late for his son's execution, had to resurrect him to make up for it. That's just rude.

      • I mean, he was three days late for his son's execution, had to resurrect him to make up for it. That's just rude.

        I know people who actually believe that fairy tale, but who swear the Moon landing was a hoax. Some of them aren't even sure whether or not satellites are real, but that doesn't stop them from using the GPS in their car.

        I've tried to find out at exactly what altitude their disbelief takes over but I've never gotten a good answer.

  • Perhaps the best thing to do when using this metric we call "time" is to constrain it within the boundaries of its inventors.

    Hell, I'm surprised that the concept of time is universally accepted on the planet, when we can't even come to an agreement on the metric system.

    • Re: (Score:3)

      by Greyfox ( 87712 )
      Well, the passage of time was universally observed by the same set of side effects; time passes and the sun rises and sets, the stars come out, the moon progresses along its course and the seasons change, which it was probably very useful to predict. What these things have in common is that they are questions of geometry, moreover questions of geometry that involve things happening in spheres. The planet rotates 360 degrees (approximately, depending on where you're standing) every 86400 seconds, and as it p

    • Re: (Score:1)

      by Anonymous Coward

      The world agrees on the metric system. There are only three backward third world hold-outs: Myanmar, Liberia and the United States.

  • Heisenberg (Score:4, Funny)

    by flargleblarg ( 685368 ) on Saturday March 18, 2017 @12:49PM (#54065827)
    "I am the one who clocks."

  • Semantics matter (Score:5, Insightful)

    by 93 Escort Wagon ( 326346 ) on Saturday March 18, 2017 @02:48PM (#54066333)

    "Physicists Find That..."

    Given that this wasn't a presentation of new research data, but rather an argument attempting to reconcile two theories - it is incorrect to claim that they "found" anything. Replacing that word with "argue" would fix that.

    Although perhaps there's a Slashdot corollary to all this stating the more accurate a headline is, the more fuzzy the linked article will be...

  • I can't say I understand it really, but I've always seen this as something that places limits on what we can measure. But can we use this phenomenon to force something to happen. That is, can we use precision clocks to force some weirdness to happen on a macro scale ? For example, can we make conservation of energy fail within a small volume if we measure time very accurately all around it ?
  • Written by the excellent (and sadly deceased) Terry Pratchett, Thief of Time is a story about a clockmaker who makes the perfect clock to measure time exactly. At that time, time stops. Luckily in the books of Pratchett creatures can exist outside of time, so the day is saved - in the end... By the Small Gods, I love his books and dearly miss him... :-(

  • I'm the one who knocks.

    M. White (Heisenberg)

  • If time is inconsistent according to location could we also say that physics is inconsistent according to location? That makes the entire observe and report method of study really shaky. If the laws of physics are indeed a variable we really know very little about what we observe in space. Try estimating the speed a star is traveling when you have no clue what time is doing in the area near that star.

  • the theories are both supported by experiments, they usually don't play well together, forcing physicists to consider a new theory that will allow them both to be correct at the same time...

    In relativity, the entire notion of "at the same time" depends on the observer. So I guess for some scientists, GR and QM play well together, for others not so well.

  • I think a good simple explanation is that to get higher and higher precision time measurements it takes more and more energy. At some point you're using too much energy in that it's having an effect on time itself. So there's probably some sort of limit on how far you can go.

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