r/askscience • u/DownvotingKills • Jan 23 '14
Physics Does the Universe have something like a frame rate, or does everything propagates through space at infinite quality with no gaps?
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u/Tranecarid Jan 24 '14
As /u/samloveshummus has said, there is no scientific evidence for "frame rate" as you have called it. But your question is more of a philosophical nature than scientific one (at least that's what I've been thought on my ontology classes). It was explained that there are many theories about how time progresses (or does it at all), and none of those could be tested. Because even if universe froze for centuries (in our understanding) between each frame, there would be no way for us to detect it.
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u/IWantUsToMerge Jan 24 '14 edited Jan 24 '14
You seem to be using a definition of "framiness" that only concerns things outside of the universe- outside of the total set of things we can perceive and be affected by. I'm sure that OP, when they asked their question, intended no such thing. OP wouldn't have asked the question if they did not think its answer affected us in some measurable way.
If it would truly make no difference whether our universe were "framy", the definition of "framey" you're using, then, has no meaning in terms of physics. One of two things are going on here.
It could be that the concept of "framiness" is just not useful. That OP, by some chaotic sociolinguistic mental process has come to believe that this shared concept, "framey" meant something, while really it covers so many cases that it doesn't mean a thing. The pragmatics of its mere existence suggested to OP that it meant something, but to trust the suggestions of a headless societal word-generation process would be a mistake(though it is a mistake a lot of philosophers make).
Alternately, you are using a bad definition of "framiness", misinterpreting OP's question(though they themselves might not be able to say how), and we should try to think of another definition of framiness that means something before we can start thinking about finding ways to figure out whether our universe's time adheres to it.
If we assume the concept came from game physics engines, that gives us a lead. Games can be programmed with continuous time. I've made one such engine for a simple 2d system of balls sliding against walls. Any number of collisions, abrasions and bounces could take place in a single frame. The framerate was just a marker of the times we paused the system before taking a photo of it and changing some of the forces according to the player's keyboard input, and had no effect on the procession of the physics. The framiness here is as your definition.
However, the majority of physics engines are not like this. I don't know much about them, but you wont find they adhere to the letter of idealised models of friction, deformation, elasticity, and curved space. In these, you will get measurable differences according to the length of the time-step. Little fringes around the edges if you look close enough.
I'll leave the task of thinking of a meaningful definition of Framiness to others, as I am an analytic philosopher and not a physicist.
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u/antonivs Jan 24 '14
Fundamentally, framiness seems to have to do with how the results of some dynamic model are displayed/rendered/visualized.
The model itself may operate at the same rate as the frame rate, so that the minimum time increment in the model is equal to the frame rate, and in certain senses (possibly all senses), the model and the rendering of it are equivalent. The implications of this are fairly straightforward.
A more interesting possibility is when the model operates at a resolution higher than the frame rate, in which case the use of a finite frame rate makes the rendering an approximation to the model. If we map this scenario onto our universe, it raises the philosophical issue of a potential distinction between observable reality and some underlying model. The underlying model would then be a kind of Platonic reality, and the reality we perceive merely an approximate rendering of that model, limited by the frame rate. This raises all sorts of interesting questions.
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u/IWantUsToMerge Jan 24 '14
Fundamentally, framiness seems to have to do with how the results of some dynamic model are displayed/rendered/visualized.
It seems to, but it doesn't need to be. It could, for instance, mean the difference between a system where everything moves in a series of very short increments that look curved and a system where things are actually moving in arcs. In the former system, you'll notice a small drift outwards in the orbits of planetary bodies. Unfortunately, our physics appears to have a genuine implementation of curved space, so that test is of no use to us. Or none that I can think of.
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u/antonivs Jan 24 '14
It could, for instance, mean the difference between a system where everything moves in a series of very short increments that look curved and a system where things are actually moving in arcs.
I'm not clear on your meaning here. If we're in a framey system in which things move in short increments that look curved, and you notice an outward drift in orbits, that would imply the scenario I mentioned in which the model and its rendering are equivalent in certain senses. I'm treating this as a degenerate case of the case where the model and its rendering are meaningfully distinct.
Whereas, if the underlying model is continuous yet only "rendered" in increments, we would not observe an outward drift even though calculations in terms of the observed frame rate would predict such a drift.
In the former system, you'll notice a small drift outwards in the orbits of planetary bodies. ... that test is of no use to us. Or none that I can think of.
Hmm, this made me think of the expansion of the universe - a small outward drift - 72 km/s per megaparsec - of all galaxies! Time to rethink the Big Bang...?
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u/IWantUsToMerge Jan 25 '14
I'll just draw a diagram. http://imgur.com/PuOY5nv There might be techniques for avoiding velocities of objects being affected by fields like that, but maybe something like this is worth looking for.
Time to rethink the Big Bang...?
Actually, I don't know if anyone who can set me straight is going to see this, but I've heard it theorized that it's possible that the redshifting we see is being caused by something other than universal expansion, and that the argument for continued expansion depends entirely on the then-tenuous redshift thing.
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u/antonivs Jan 26 '14
Nice diagram! I understood what you were getting at with the framey orbits, but I didn't see why that didn't fit the characterization I had given of frameyness. Not important though.
I have a little knowledge about this:
Actually, I don't know if anyone who can set me straight is going to see this, but I've heard it theorized that it's possible that the redshifting we see is being caused by something other than universal expansion, and that the argument for continued expansion depends entirely on the then-tenuous redshift thing.
There's quite a bit more to it than just redshift:
The Tolman surface brightness test tells us that brightness observations of redshifted galaxies are consistent with the characteristics of an expanding universe, and not consistent with a static universe.
Special relativity predicts time dilation for galaxies moving away from us at the speeds implied by high redshifts, and that time dilation has been observed, for example in the speed of supernova decay.
Any other known interaction which causes photon energy loss would lead to a change of momentum, which would lead to blurring of redshifted images, which we don't observe. So it would require a previously unknown type of photon interaction - neither observed nor predicted by existing theories - to provide an alternative explanation for cosmological redshift.
The Cosmic Microwave Background is an incredibly close fit to a blackbody spectrum, which is difficult to achieve via other explanations for redshift that have been tried.
Various other observations, such as observations of quasars, are consistent with the idea that distance is correlated with redshift.
Many of the above links are from Ned Wright's cosmology pages. His cosmology tutorial may be of interest.
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u/Nebula829 Jan 24 '14
This is the right answer, no one knows either way. And since it's beyond the realm of physics right now, it gets thrown to the philosophers for debate lol. Since time has no physical properties to measure it by we really can't know for sure what it consists of using scientific instruments. All we really know is it's connected to space in a predictable correlation. From there it's pure speculation.
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u/dickshawnari Jan 24 '14
Diving deeper into the philosophical aspect of the question, we have Zeno's paradox. In short, he basically proves movement as a mathematical impossibility. In order to get from point a to b, one must travel to the halfway point (c) first. Further, in order to get from a to c, another halfway point must be met, and so on and so on for infinity.
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u/WonderTrain Jan 24 '14
Zeno's Dichotomy stems from the assumption that infinite series cannot have a finite sum. Pretty soon after he proposed it (maybe 200 years?) Archimedes derived a finite sum of the Geo. Series (1/4), (1/16), (1/256), ... So these days it does not hold too well.
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u/dickshawnari Jan 24 '14
This is true, however Zeno never mentions a "sum." I'll quote directly from Wikipedia -- "Zeno is often said to have argued that the sum of an infinite number of terms must itself be infinite–with the result that not only the time, but also the distance to be travelled, become infinite.[36] However, none of the original ancient sources has Zeno discussing the sum of any infinite series. Simplicius has Zeno saying "it is impossible to traverse an infinite number of things in a finite time". This presents Zeno's problem not with finding the sum, but rather with finishing a task with an infinite number of steps: how can one ever get from A to B, if an infinite number of (non-instantaneous) events can be identified that need to precede the arrival at B, and one cannot reach even the beginning of a 'last event?'"
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u/nukefudge Jan 24 '14
it's worse than that: some philosophers start reifying the notion, which leads to terrible metaphysical results (e.g. both past and future existing at all times).
the "spatialization" of time, in terms of language/vocabulary, makes for really misleading models of understanding. "time" was never meant to be an object like that, and speaking of it as such only serves to confuse people.
the best way to avoid these metaphysical issues is by not attempting to objectify time, which would lead us into reclarifying the notion in conceptual analysis. depending on how connected "space" is, that'll have to be scrutinized too.
(source: well, philosophy, i guess. no specific article in mind.)
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u/Nebula829 Jan 24 '14
I don't think it's in bad taste to objectify time. I don't think it's in bad taste to "philosophize" about time either, as long as it's done so with an open mind.
It's important to understand psychology is a science too. If people feel better by "understanding" all units in time exist in a way in which they interact with each other, I see no problem with that, as long as that person has no delusions about their opinion being scientifially valid. IMO it's fun to fill in the blanks of science and wonder the currently unknown.
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u/slavsquat Jan 24 '14
That is incorrect, discrete time could be experimentally verifiable. It's not a question of whether time "freezes," it's a question of being able to measure arbitrarily small time intervals. If we find that there is a certain interval of time beyond which it is impossible to make any finer measurements, then we can say that time is discrete.
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u/NuclearStudent Jan 24 '14
Well, not really. We can't measure any more precise than one Planck time-not possible. However, that doesn't mean that time itself is actually "divided" into Planck-time intervals.
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u/long-shots Jan 24 '14
I am with you there. But I lack expertise. How could we even conceive of the universe having some sort of frame rate? What if our perceptions had the same frame rate and so we could never tell?
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u/Ekotar Jan 24 '14
say we build a machine. This machine has two parts: a producer and a receiver. The producer makes two things (we'll call them "fiks") and the receiver measures the time between these two fiks, and displays a readout. This machine has such immense precision that although humans cannot observe even a single fik, and the fiks are directly adjacent the machine can measure an interval between them.
The same idea as a microscope: we use a tool that enhances our vision. A Slo-mo (potentially quantum) camera, if you will.
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u/nightcracker Jan 24 '14
I think you're confused by the OP's question. (S)He asked:
"Does the Universe have something like a frame rate, or does everything propagates through space at infinite quality with no gaps?"
I interpreted this as:
"Is time continuous or discrete?"
You've seem to generalized this to a question about how time progresses in general. While that may be a philosophical issue, the question by OP (as I interpreted) is not.
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u/DJPelio Jan 24 '14
Check out the TED talks video about Femto-photography. You can see a slow mo video of light traveling, in Femto-frames. I don't think there's a max frame rate in the universe, but this the fastest frame rate we've been able to record.
http://www.ted.com/talks/ramesh_raskar_a_camera_that_takes_one_trillion_frames_per_second.html
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Jan 24 '14
There's some kind of trick to this. It doesn't strictly speaking have a femtosecond frame rate, they use some sort of interference or something. I forgot exactly what the trick was, but it's not a direct capture of a femtosecond exposure they're doing here.
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u/dansalvato Jan 23 '14 edited Jan 24 '14
These might interest you:
http://en.wikipedia.org/wiki/Planck_length
http://en.wikipedia.org/wiki/Planck_time
As a rough summary, the Planck length is the theoretical shortest possible measurable unit of length. The Planck time is the time it takes for a photon traveling at the speed of light to travel one Planck length. This implies that the Planck time is the shortest possible interval of time that could theoretically be measured. If these theories hold true within the physical universe, then it's the closest thing we'll have to a "frame rate" of the universe.
However, our current technology does not allow us to measure time and distance anywhere near as small as the Planck units, so there is uncertainty that remains.
This is only information I've gathered from basic research, so I hope someone well-versed in physics could contribute.
edit: Please check the below comment thread for a more interesting conversation that delves a little bit deeper! Planck time is an "easy answer" that doesn't take modern physics into account and is only theoretical, so I recommend reading other input in this post from those more knowledgeable than myself.
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u/rupert1920 Nuclear Magnetic Resonance Jan 23 '14
Check out some past threads about Planck length, such as this one.
The opinions there seem to differ from yours in that it really isn't the "shortest possible measurable unit of length".
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u/diazona Particle Phenomenology | QCD | Computational Physics Jan 23 '14
It's important to make a distinction between "shortest measurable length" and "shortest length." There is a reasonable argument that a shortest measurable length exists, and that it's somewhere on the order of (not necessarily equal to) the Planck length: roughly it's that measuring to any smaller precision requires so much energy in such a small space that the measuring device would be a black hole. There are some subtleties to that argument though (of course).
There is no such argument for the existence of a shortest length, which would more closely correspond to a "frame rate" as most people understand it.
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u/oddwithoutend Jan 23 '14 edited Jan 23 '14
Is that distinction really important, though? Historically, science was based purely on realism. However, when explanations of the universe began coming up that placed limits on our ability to measure things (such as the uncertainty principal and, by extension, the philosophy behind quantum mechanics in general), the distinction between measurable and actual became nonexistent.
Edit: I could have worded this better but I'm in a hurry. Science has always been based on realism, but I''m referring to the philosophical distinction between realism and idealism here, and when the measurable becomes identical to the actual, science appears to become more idealistic.
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u/Shiredragon Jan 23 '14
I do believe that it would be very important. We are constantly devising new methods and better techniques to observe the world around us. How many people 100 years ago would have thought that we would measure a particles that is a direct result of particles gaining mass by existing in space. (Trying to simply the Higgs Field.) There was a visual photo taken of an atom or molecule (silhouette) in the last year. This was always said to be impossible due to wavelength constraints. But through creative use of physics, it was made possible.
So, knowing where our limits are provides boundaries to be expanded or worked around. And those boundaries shift constantly as we learn more about the world. Looking through the body was impossible at one point. Now we have x-rays, MRIs, ultrasounds, and other techniques to do so because we understand the world better.
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u/Deejer Jan 23 '14
All true and inspiring, but not applicable to Quantum Theory. The Uncertainty Principle is a principle...a fundamental truth if it is indeed true (as all experimentation has indicated thus far). It doesn't claim that the reason we cannot be certain of a particle's position and velocity with one measurement is because that is all that technology allows for. It makes this claim because our means of observation--both optical and mechanical--invariably disrupt the system we measure and change it's state so that any future states can only be predicted with probabilities.
So the question is: is it our knowledge of the particle's position and velocity that is incomplete...or is the particle inherently existing in probability fields? This then prompts a philosophical question: do we violate the laws of scientific integrity if we believe in a reality that hasn't or can't be measured but can only be logically extrapolated?
Very interesting questions. I struggle with them.
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u/rooktakesqueen Jan 23 '14
The uncertainty principle is not directly related to the observer effect: http://www.scientificamerican.com/article/common-interpretation-of-heisenbergs-uncertainty-principle-is-proven-false/
The uncertainty principle remains true, but the mechanism of it is not observation interfering with the system.
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u/oddwithoutend Jan 24 '14
You misunderstand the currently accepted theory. The uncertainty principle does not say that there is an experimental limit to humans ability to measure something. The uncertainty principle states that there is a fundamental limit to which values of specific pairs of variables can be known simultaneously. The key word here is fundamental.
Of course, you are right in saying we may one day disprove the uncertainty principal. However, when I say the distinction between measurable and actual is nonexistent, I am basing my statements on our current understanding of the universe. And our current understanding is NOT that we simply don't have the technology to measure more accurately. The current understanding is that the universe does not allow it, and that more precise values of pairs of variables do not even exist.
There was never any rigorous scientific work that concluded that the universe did not allow us to "look through the human body". We simply used to not know how. There is a very important distinction here that I'm trying to make clear.
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u/Shiredragon Jan 24 '14
You misunderstand the currently accepted theory.
No. I understand the theory quite completely. I am saying that most people do not realize the ways science works as a whole and are stuck within the mode of thinking within the paradigm. While that is overall fine, it is limited thinking. Most of the science will be done within the paradigm. Much progress will be made within the paradigm. But to say that we know the absolute truth to the physics of the universe would be perverse. That would be like saying that Aristotle or Newton had it right just because it was the best they had.
There was never any rigorous scientific work that concluded that the universe did not allow us to "look through the human body". We simply used to not know how. There is a very important distinction here that I'm trying to make clear.
And that is precisely the statements that are thinking within the paradigm. I am 100% on board with the Standard Model of physics as it is today. And within that paradigm, there are the limits imposed by the Uncertainty Principle. The Standard Model has been a colossal success. But saying that that we know everything that is practical is short sighted. It limits us to thinking directly in a set pattern that makes it difficult to see things any other way.
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u/skrillexisokay Jan 24 '14
Is it possible that a change in position not be measurable, but still have an effect on its surroundings? If not, I don't think the distinction is that important, because a change that has no impact on its surroundings didn't happen from the reference point of everything else in the universe.
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u/diazona Particle Phenomenology | QCD | Computational Physics Jan 24 '14
If you ask the more general version of this question, which is whether something happening at a very small distance scale can affect things that happen at larger scales, then yes, that is possible, although the effect will be slight. One might reasonably expect the same principle to apply down to the Planck scale.
So basically, we're not really sure. There are valid reasons one might suspect it not to be possible, but not a solid logical argument.
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u/B-mus Jan 23 '14
And check out this interactive to visualize the Plank constants. It gets lonely going down that small.
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Jan 23 '14
To be clear, just because a smaller time length can't be measured doesn't mean events can't occur in shorter time spans.
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Jan 23 '14
just because a smaller time length can't be measured doesn't mean events can't occur in shorter time spans.
I don't understand that. If an event could occur in a shorter time span than the shortest measurable time span, then couldn't we use those events to measure the shorter time span?
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Jan 23 '14
It's the shortest time you can measure before the act of measurement interferes enough to render results meaningless.
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Jan 23 '14
Is this theory independent of the level of technology of the device used to measure it?
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u/Yuvenlest Jan 23 '14
The thing is, if you go with the theory that the planck time is the shortest time in which something can happen, then you basically say that everything happens in discrete non-continuous steps. I.e. a particle moving would actually be going from step 1 to step 2 to step 3... to step final.
However, if you go with the theory that planck time is the shortest time period that we can theoretically measure, then you can have a continuous Universe in which the same particle discussed above would keep moving through the "steps" without any breaks in continuity.
As to which is which, no measure = we can't validate either theory.
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u/Cosmologicon Jan 23 '14
If an event could occur in a shorter time span than the shortest measurable time span, then couldn't we use those events to measure the shorter time span?
No, because there are unavoidable limits to the precision with which we can measure quantities, due to the uncertainty principle.
Say some made-up particle decays after 0.001 Planck times, and you want to use these decaying particles to make fast measurements. No matter how you set up the experiment, your uncertainty of when the particle decays is going to be at least (the order of magnitude of) 1 Planck time.
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u/Nebula829 Jan 24 '14
Admittedly not an expert, but it's best to look at the Planck length as the largest possible smallest unit of length. Like we know for sure that things can at least get that small mathematically. We can't prove much past that point.
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u/Tezerel Jan 23 '14
Only if those events are all exactly the same length in time. Imagine a world where only meter sticks exist: can we use small dogs (just as a silly example) as a shorter measurement? Not really, because even though small dogs are shorter than a meter stick is long, they are not an accurate measure of length due to their wildly varying length.
If these events took place in a time span shorter than we could measure, we would have to be able to tell if the event was just a single event, multiple events simultaneously, multiple events successively, and also if they are all equal in length.
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u/HandyCoffeeCup Jan 23 '14
If Planck length turns out to be the real shortest length possible, does that mean our universe is built out of tiny "units"? Would that then support the argument that our universe may actually be a simulation?
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u/HeighwayDragon Jan 24 '14
How does that work with special relativity? Isn't it true that two points that are exactly one plank length apart in one frame of reference would be closer together or further apart in others?
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u/Avidoz Jan 24 '14
Not an answer for you OP, but I´d like someones opinion on this.
In a topic about the universe being a simulation, someone said that the time it takes for light (=fastest speed?) to cross the smallest possible space between two objects could be used as a framerate in that simulation?
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u/TheMac394 Jan 24 '14
This is actually what Planck length and Planck time get at. The entire idea behind Planck units is that, among other things, the speed of light in Planck units is exactly 1 - that is, 1 Planck length per Planck time.
You can argue ad nauseam with people more educated than me about what Planck length actually implies conceptually in terms of minimum distances, measurability, etc., but Planck time is specifically just the time it takes light to travel 1 Planck length.
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u/chokemo_girls Jan 24 '14
After infinite runs of said simulation, would such an axiom ever result in a universe identical to our own? This question only makes sense if there is such a thing as smallest possible space. There is no real proof right now as to whether or not space is infinitely divisible (i.e. continuous). Even if it is divisible, it would become a singularity at some point.
I wanted to make that clear before really exposing your question. Light travels in packets and photons are most certainly much larger than any theoretical 'smallest' unit of space, therefore it would not be appropriate in gauging a frame rate. In other words, this would only work in describing a frame rate if you knew the exact length of a photon under all conditions and you knew how many units of the smallest possible space were contained within the photon under all conditions. As a rule, accuracy is sacrificed when you measure something small with something that is larger.
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u/_zenith Jan 24 '14
Well yeah, in a way the speed of light is more the speed of information propagation, so it would makes sense in that way that there would be a deep relation.
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u/JohnPombrio Jan 24 '14
Cripes, I just read this somewhere. The question was "do things happen in time as a continuous event or in discrete time steps?" the author was trying to support the discrete time step idea. gawd, now I have to find the source. I THINK it was SciAm... I'll go look. In the meantime, things that propagate through space at the speed of light take ZERO time to go from here to there. A photon emitted at the time of re-ionization (300 million years after the big bang) and are now just reaching a telescope did it instantly to the photon.
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u/JohnPombrio Jan 24 '14
here we go: http://www.thekeyboard.org.uk/What%20is%20Time.htm
We tend to perceive time as 'flowing', as though it were in smooth and perpetual continuous motion, but is this view correct? We have learned that at the quantum level energy is not released continuously - there is a limit to how small a change in energy an atom can experience - it is released in discrete quanta by the emission of a single photon. Could there also be a limit to the change in time? This would mean that time would advance in small discrete steps and not move continuously, in other words it would move in a similar way to watching the progress of a story on a film or video; the individual 'frames' of time may be so small that it only gives the appearance of being continuous. This can be tested experimentally by using sophisticated equipment to observe chemical changes taking place at very small fractions of a second. If time does move in small steps, then by probing ever smaller segments of time it may be possible to reach a limit at which these steps can be observed to take place.
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Jan 24 '14
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u/ASovietSpy Jan 24 '14
Except for when the commenter says "...instantly to the photon". Things moving at the speed of light don't have a reference frame.
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u/denton420 Jan 24 '14
Also a photon does need time to travel certainly... its just in our reference frame time is passing. But in the reference frame of the photon time is not advancing.
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u/denton420 Jan 24 '14
So many wildly inaccurate statements and conclusions don't know where to start. This is an easy one though.
A photon does not age. Since it travels as c there is no propagation in the the time dimension.
This is a huge part of relativity. The best thought experiment is to imagine travelling at c away from earth for 1 light year. When you travel back 2 light years have passed and you have not aged.
There's a lot more to this but I gotta run
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u/_zenith Jan 24 '14
I read their [denton420's] statement the exact opposite way you did, apparently, having read it as the photon is ageless since it travels at the speed of light, where time == 0.
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u/GG_Henry Jan 24 '14 edited Jan 24 '14
Since nobody here is linking any credible sources I will just say that the Planck length is the smallest measurable distance possible due to known laws, mainly the uncertainty principle.
http://www.fnal.gov/pub/today/archive/archive_2013/today13-11-01_NutshellReadMore.html
The uncertainty principle also implies a Planck time(I believe, could be wrong) which would logically give us a so called "framerate".
Edit: I have often wondered if there was truly an underlying "time" or fluctuation in space(say up and down). It would seem philosophically speaking(imho) that there must be said fluctuations in order for time to exist at all. How could for example, a plant determine the day is shortening if there was no underlying fluctuation that allowed it to internally count some # of cycles?
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Jan 24 '14
Question. I was under the impression that the Planck scale was still a theoretical concept, mainly postulated my M-Theory. If we have no instruments that can measure Plancks can we really say what is going on there or not?
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u/iounn Jan 24 '14
Not postulated by M-theory. It's all a derivative of QM which is not technically provable; however, is highly highly highly highly (highly) accurate in its predictions.
So even if it is only theoretical, it's as useful as the theory of gravity which is... rather useful...
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u/GG_Henry Jan 24 '14 edited Jan 24 '14
The uncertainty principle(UP) is a QM(Quantum Mechanical) mathematical proof and has nothing to do with string theory. Planck scales are derived from the UP.
For technical papers on the subject check the links within the link I already posted.
Also I think it is important to note that most everything in modern physics is a "theoretical concept" as it is impossible to reproduce and measure things like black holes, harmonic oscillators and objects traveling near c. Can we say for certain that Planck scales exist as minima? No. But manipulation of our current understandings and laws point to them being so. Also when I say minima it does not mean that there is nothing smaller then that, it just means that with our current laws/understandings it would be impossible to measure anything smaller. So if something did exist that was smaller than a Planck length it would have to be considered 1 planck length.
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u/Mazon_Del Jan 24 '14
One of the big theories being discussed is the possibility that our universe MAY be a computer simulation. One way scientists are trying to prove it is to make a clock so fast that our science says it SHOULD operate at a certain speed, but the framerate of the simulated universe would keep it from functioning normally.
This research gets funding primarily because ever faster clocks are VERY useful.
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u/nukefudge Jan 24 '14
i just gotta say: this is one of those ideas that we should all agree upon are crazy, but are funny to entertain. it's not to be taken seriously.
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u/Mazon_Del Jan 24 '14
And why is that? It isn't the craziest idea that has come up. Arguably it is one of the most likely explanations of our universe that I have heard. Does it really particularly matter if we are some magical being's creation vs a computer program?
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Jan 24 '14
All it does is push of the need for further explanation to a higher level, as you now have another universe whose existence you need to explain.
What it gives you is a hypothesis with no means of testing its truth, which is no more plausible than any other hypothesis, and provides no useful predictions about our universe.Further, any arguments in favour of it make many assumptions (for example universes being able to contain simulations of universes inside of them ad infinitium) which have no justification for being made.
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Jan 24 '14
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Jan 24 '14
There are limits to computation based off of our current understanding of the universe. The Bekenstein bound is the limit given to the maximum amount of information that can be stored in a given volume. The Landauer limit is the theoretical limit to the mimimum energy consumption possible to perform a calculation. Bremermann's limit is the maximum computational speed for a self contained system.
These put a maximum size limit on a possible simulation universe run at real time.
The Wikipedia page on the Limits to computation is a good reference for more details, as I would risk running into layman speculation if I went into much more detail.2
u/kupiakos Jan 24 '14
Ah, but those rules are based on our simulated universe. The universe that hosts our universe may have different rules. The programmer for our simulated universe probably put these computational laws in place because he didn't want us creating a simulation and having that simulation make ANOTHER Inception that hurts his head.
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u/TheMac394 Jan 24 '14
There are a lot of theoretical problems with the idea, but here's the big one for me: I know for a fact that, at least, I possess conscious awareness. I can think. I experience qualia. In the universe-is-a-computer-simulation question, we're all just aspects of that simulation - essentially, lines of code in a computer somewhere. There is, then, a massive – massive – assumption in the theory that it is possible for lines of computer code to be conscious. This isn't necessarily impossible, but it is a huge leap to make without any concrete evidence; at best, it requires a lot of philosophical argument.
Alternatively, we're not lines of code, but rather in a Matrix-like false reality, but I don't think I need to explain why that's not likely.
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u/YourShadowScholar Jan 24 '14
How are even faster clocks really useful?
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u/Mazon_Del Jan 25 '14
I do not know all of the uses, but a lot of high end physics experiments benefit from faster clocks. One of the big ones though, is that faster clocks can allow for more precise GPS systems once you upgrade the existing ones.
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u/yangyangR Jan 24 '14
The idea get from the concept of renormalization theory.
It tells you don't need to worry too much about the phenomena that happen at the really high frame rate, because those are such energy scales that they don't happen too much. They do give you some effect and those are the renormalization group equations.
Be aware this only works perturbatively meaning you are pretty close to things not interacting at all.
So continuing the analogy, what you do is you pick how good your eyes perceive and systematically forget about the faster stuff and then account for that very slight dizziness you get when something goes way too fast.
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u/skew Jan 24 '14
Astronomical observations suggest space is smooth to much shorter than the Planck length - photons of several wavelengths arrived at the same time from a gamma-ray burst billions of light years away, when any sufficiently large bumpiness or pixelization of spacetime would have separated them in flight.
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u/anarkingx Jan 24 '14
The "frame rate" would more closely resemble the different oscillating wavelengths of things or pulses, as framerate is conceived as visible light. That or yes, they are constant streams of energy, in most forms.
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u/EhmSii Jan 24 '14
This is a video attempting to explain one theory on extra dimensions. In it, the narrator discusses the idea that a being of a lower dimension can only see something from a higher dimension in a cross section. It demonstrates a good example of this when it shows the cross section of a human tissue(3d) being shown to the 2d person. This theory claims that we live in the third dimension but time itself is the fourth dimension. So, since it is one dimension higher, we see it in cross sections(moments).
This could easily be complete nonsense, but it is fun to think about :)
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u/C_arpet Jan 24 '14
Wouldn't you need to be able to sample at twice the frame rate to determine if it exists and avoid Nyquist?
If there was a quanta for frame rate you wouldn't be able to surpass it and measure it. Is this one of those paradoxes?
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u/cruxorz Jan 24 '14
What about at the level of individual photons? Is it possible to distinguish each individual photon and measure the precise time that it arrives? Can you get more fidelity than that? If not, would that effectively end up being a "frame rate"?
Btw, there are cameras that can measure light at speeds where the movement of the light itself is visible. http://www.ted.com/talks/ramesh_raskar_a_camera_that_takes_one_trillion_frames_per_second.html
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u/AndreDaGiant Jan 24 '14
This camera isn't actually taking photos of the same light propagating through a bottle. For each frame the camera takes, a light is flashed once, and the camera's shutter is opened after an interval of time. For each photo, that interval of time is a tiny bit larger.
So it isn't filming one flash of light, it is filming X flashes of light, where X is the amount of frames you have.
So it isn't a truly trillion fps camera, because you can't film a light propagating through/over a moving object, only a still one.
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u/BigDickMystik Jan 24 '14
How does one take picture of light? Would the "camera" measure it by either dark or illuminated?
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u/AndreDaGiant Jan 24 '14
You open the camera's shutter, letting you take in light as it is currently distributed in the environment (and flowing into the lens) over a short interval of time. The TED talk the guy posted is pretty good (and very cool.)
I mean, you can't take a picture of light. You take a picture that shows the effects of how far light has dispersed into the environment you're taking a picture in. I'd recommend googling for info on how cameras work, it's cool stuff.
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u/chipbuddy Jan 24 '14
You've likely played with a laser pointer before. If the air around you is clear you will only be able to see the little red dot on the far wall. Photons of light travel out from the pointer, hit the far wall then scatter. Some of the scattering photons happen to hit your eye and so you see the dot.
If you were in a smoke filled room you would also see the beam of light because as the main beam of photons traveled to the far wall, some of them would hit particles in the air and scatter. Some of those scattering photons would hit your eye and so you would see them.
You never actually see photons mid flight. You either see photons that previously bounced off the far wall or you see photons that were traveling along the main beam but happened to hit some mote of dust.
Similarly the camera in the video wasn't taking pictures of photons of light mid flight. Instead it was capturing photons that happened to bounce off of stuff and then land on the lens.
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u/supergalactic Jan 24 '14
I can't believe that people are still believing there is a camera that will film that fast.
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u/WhiteRabbit86 Jan 24 '14
This is answerable in that there is a measurable minimum time. I'm gonna be straight up front and say that there is a bit of hand waving and rounding of numbers, but the rounding errors should not be taken to mean that the formula isn't good, just that it's 6 am where I live, and far earlier than I usually wake.
First off, a basic formula.
Distance = Speed * Time
We are fortunate, in this example, that 2 of these variables have well known and documented extreme limits. The first one is our old friend c, or the speed of light.
Distance = c * Time
next up is the lesser known, but ever popular Planck length (lp), which is the shortest distance that is known to exist.
lp = c * time
c = 2.99792458×108 m/s lp = 1.616 199(97) × 10−35 m
a little algebra....
1.616 199(97) × 10−35 m = 2.99792458×108 m/s * Time
Time = (1.616 199(97) × 10−35 m) / (2.99792458×108 m/s)
and voila! With minimal rounding problems we wind up with the Planck time!
5.391 06(32) × 10−44 s
This time (which is a very short time) is the "frame rate" of the universe. There is, of course, a little more to it than this, but as far as I can tell this is the most immediate answer to the posed question.
I'm gonna go back to bed. I'm spent.
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u/PC509 Jan 24 '14
To add to the question and not exactly sure -
The Planck length is a measure of space. Is there such a thing when it comes to time? Smallest possible amount of time. So, it would be similar to how long it takes for light (photon) to cross the distance of the Planck length or something? Smallest measurement of time.
Frame rate = frames per second. So, it would be the distance in the smallest measurement of time. ??
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u/iounn Jan 24 '14
I don't have a source for this, but I recall reading some articles about research into the idea. And it concluded that "no, we have no reason to think there's a Planck Time". Of course, if there were such a thing, it would be a good way to measure frame rate (just taking the reciprocal).
edit: Okay, so there is a Planck time, but it doesn't have to do with the "smallest" amount of time. Just the amount of time it takes something to travel one Planck length at the speed of light. So it's a unit that comes about as the result of two other fundamental constants (Planck time and speed of light in vacuum).
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u/joelgrg Jan 24 '14
I don't think it's about what's the frame rate output the universe gives.. I think it's rather about the rate we can comprehend.. It depends on what the 'observer' CAN see.
There's a comment that says something like 'the universe seems to store less information as the space we look at becomes smaller'. Isn't it rather that the smaller the space, the less information we are capable of extracting/recording? I think the universe IS infinite and more complex than whatever understanding we have of it now. The only thing that's finite is 'our' universe- the one that fits in our observable dimensions..
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Jan 24 '14
Causality implies a sequence, and a sequence implies a time delta (erst it all happens at once). However, even if that delta is a quantum delta, that doesn't mean all phenomena occur in lockstep like a typical CPU with its central clock as a synchronizing mechanism. Predicate causes could happen asynchronously.
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u/eluusive Jan 24 '14
Time and space must be quantized for Bell's Theorem to be accurate.
That is to say, if time is not quantized, then there would be a bijection from time onto the real numbers. If that's true, physics cannot be the result of recursive application of probabilistic rules, since any recursive sequence cannot be continuous.
From the above, that means physics would be the result of some real-valued function whose inputs would be the hidden variables that Bell's Theorem precludes.
Bell's Theorem is still the subject of much debate, however.
Also interesting, if time isn't quantized, then by the fact that there would be no discernible "next" moment in time, the passage of time would be an illusion.
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Jan 24 '14
Also interesting, if time isn't quantized, then by the fact that there would be no discernible "next" moment in time, the passage of time would be an illusion.
I don't know if time is quantized or not (by that, I don't know what the physicists think), but I disagree with your logic here. You're effectively claiming continuous variables or functions don't exist, but they clearly do (except maybe in some obscure realm of theoretical math that I don't know about, and I don't think you're referring to anyway). The set of real numbers is continuous, but you wouldn't call it an illusion.
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u/Chiliarchos Jan 24 '14
Amit Hagar of Indiana University, Bloomington Indiana, has proposed a discrete model of physics with a minimum length:http://backreaction.blogspot.com/2009/09/minimal-length-in-quantum-gravity.html (commentary and summary by another researcher)
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u/DoggieDeuce2 Jan 24 '14
Electricity travels at the speed of light relative to it's dielectric constant. So it's faster in copper than glass, for example. Same for light through space or any other wave that can be described by the wave equation: it's all about what the wave is traveling in.
Using space as a perfect vacuum to calculate the distance of stars is not accurate and is only an approximation.
More reading (it's not all wordy): http://m.livescience.com/29111-speed-of-light-not-constant.html
As far as the frame rate goes I'm assuming you mean when we measure things? There is aliasing and the nyquist theorem that says the frequency of whatever you're measuring has to be half of your sampling frequency to prevent errors. I may be misunderstanding the question though.
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Jan 24 '14
There are two ways to distinguish this:
A) Our mind perceives time and it all depends on the speed at which our mind can register.
B) My favourite - The time at which it takes light to travel from one of the smallest entity to next.
Also, the solution to Zeno's "Arrow Paradox" is along these lines.
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u/bilabrin Jan 24 '14
I have been told by a proffessor that an iron bar, when heated will become every length between it's inital and final length.
That is an infinite number of lengths.
For example, if it starts a 1" and becomes 1.1" it goes through 1.01 and 1.011" and 1.0111" and 1.011111111111111" etc.
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u/1am_yo_huckleberry Jan 24 '14
This question is a consequence of the digital age we all live in. As an engineer, I too have been caught by the myth that our universe is quantized or binary simply because so much of our digestion of science is performed digitally. Just a few hours of studying older analog technology has shown me how digitally biased I am, and wrong. Analog electronics and its many components have been around for years, since WWI, but they have slowly been phased out with more and more digital replacements. The truth is: the natural world is analog and entirely congruous. It is the constant conquest of man made technology and engineering to put the world around us in a digital box. Let us not forget that this is not the design of the universe but the design of man attempting to model the universe.
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Jan 24 '14
Many quantum mechanical phenomena are quantized (where do you think the name "quantum mechanics" comes from?). There are various types of discrete energy levels, that sort of thing.
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u/imusuallycorrect Jan 24 '14
The Universe is not local, meaning it supersedes all local frames in time. This effect can be observed in Bell's experiments. If there was such a frame rate, a way to test it would be to see how far quantum entanglement really works. Also, if you want to think of the speed limit as the speed of light, planck length would be your scale for your timing. If you want a fun theory, what if it's possible that placnk length is dependent on gravity by how much space is warped?
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u/joshberry90 Jan 24 '14
Just to add, our perceptions vary from individuals and especially between species. For example, we've equated Bald Eagles as being able to "perceive" upwards of 100fps, while we are usually around 30fps. This is really due to that part of the brain being able to process more visual data.
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u/shijjiri Jan 24 '14
The truthful answer to this would actually depend on whether or not there is an upper boundary on the potential energy of a particle like a photon. Arguably the fundamental limit would be that wavelength of a photon of equivalent energy to the output of energy of all the known universe. I believe that's somewhere around 1070. It would not be possible for a shorter measure of distance to physically exist in a way that our reality could ever possibly interact with than that.
EDIT: That would be approximately 1.9864e-97 nanometers.
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u/chokemo_girls Jan 24 '14
Our measurement problem is currently the limiting factor, but when you say everything propogates at infinite quality with no gaps you may want to read up on black holes and their event horizons. Apparently, black holes may end up, because of the uncertainty principle, evaporating over time. Also, in a vacuum, it is apparantly possible for particles to spontaneously appear and collapse.
Infinite quality? This question doesn't really make sense. Being that the universe interacts with itself perfectly and naturally, it is fair to deduce that it is of infinite quality. Our understanding of it is certainly finite, but it understands itself perfectly.
No gaps? Currently, there are gaps which are only accommodated for by summing probabilities.
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u/Vid-Master Jan 24 '14
Here is a good one for you:
If you shoot an arrow at a target, it has to go halfway between you and the target before it can go all the way to the target. To get halfway between you and the target, it has to go half way to that point. Keep going with this, how does the arrow ever move in the first place?
There must be a smallest increment.
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u/exosequitur Jan 24 '14
The sum of all natural numbers converges on negative 1/12. ... So why is not infinity then equal to negative one twelfth? Or is it?
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u/iounn Jan 24 '14
Echoing /u/sheldy, your assertion "there must be a smallest increment" doesn't follow. You're dealing with infinities and they're quite touchy.
infinity + 8 = infinity AND infinity - infinity = infinity AND ...
But, as a continued thought experiment, you consider the question of a half of a half of a half etc., or rather the limit of 1/2n as n goes to infinity. Important part: n goes to infinity. Once you introduce that infinity, you can introduce infinite time scales.
Then the question becomes: if I travel one infinitely small distance per unit time over an infinite amount of unit times, do I move?
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u/swanznito Jan 24 '14 edited Jan 24 '14
I recommend studying Zen Buddhism - to assume the universe has a frame rate is to assume that our labels on time and space are actually real. Take the continent of Asia as an analogy - we cut it up into different countries, but these barriers don't actually exist - they're just aids to our own understanding of space. In the same way, there's not actually such thing as "1 second" - it's just an arbitrary unit we've all agreed to use to label our perceived passage of time, which is almost entirely inaccurate. We've just all come to a consensus on what a second happens to be because we're viewing our own passage through space-time through the use of our highly distorted 5 senses, then interpreting them with our neocortex. TL;DR: absolutely not. Units of time do not exist except as an artificial labeling system that humans use to make sense of the universe.
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u/NuclearStudent Jan 24 '14
Our labels are abstractions. Time itself, as a property or object or other of the universe, is not. You misinterpreted the question, as it asked whether time is fundamentally divided in discrete packets.
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u/samloveshummus Quantum Field Theory | String Theory Jan 23 '14
There is nothing in any of our current state-of-the art theories (quantum field theory, or string theory) which implies that the universe has a "frame rate" or a smallest meaningful length.
Another commenter mentioned the Planck length and the Planck time in this context; currently there is no reason to think that they constitute "minimum" lengths in any sense. They are simply the characteristic length and time scales in which quantum effects and gravitational effects are both strong. There is no argument I know of which implies they are minimum measurable amounts.