An absolute measure of time?

[Dick Justice]

I don't have the familiarity to know if I'm asking the right question so check the spoiler if it sounds absurd to you.

Is there and can there be an absolute, constant, objective measure of time? While my great expertise at youtube videos about relativity suggests that's impossible, I don't see how it couldn't be tied to something that is temporally constant, such as the half-life of this or that element, or the time it takes light to travel the planck distance.

Spoiler: how I came to the question

I was listening to Feynman's Six Easy Pieces and he got to the point about leaving a message for aliens. You want them to come to you but you can't tell 'em to go west past the dipper, look for a galaxy named after a mars bar and if you hit the void you've gone too far. You need an absolute basis for direction. With that you can hope to just maybe build some kind of coordinates and give proper direction. So how do you find absolute up and down and such? Well apparently particle spin is universal. There's your direction. Perhaps there's some universal measure of time?

 

[Dom Cruise]

In daylights? In sunsets? In midnights? In cups of coffee?

 

[kūhaku]

Because of general relativity, no not really. Though from a different standpoint, anything that is consistent can be an absolute measure of time as long as you can account for time dilation when necessary. I imagine that if you wanted to make it "absolute" you would do something like the time it takes for some basic atom to rotate, because then any sufficiently intelligent race could measure it.

 

[FruitFighter]

I think what you might be interested in is Planck time, which is the smallest unit of time that would have any meaning. Relativity still applies, though, as always. If you're talking about a "universal" measure of time, you could always use the time on Earth as the set standard and just say that the time on planet X or whatever is a certain percentage faster or slower than it is on Earth.

 

[thick internet digit web]

Because of general relativity, no not really. Though from a different standpoint, anything that is consistent can be an absolute measure of time as long as you can account for time dilation when necessary.

General relativity doesn't stop the possibility of a measurement of time, it just would only be accurate for the measurer. I don't know if there is a possibility of a permanently accurate measurement of time, but i don't really see why it is absolutely necessary in the first place. It might end up becoming a huge problem for future historians but other than that i don't think it's something we need to worry about. Dilation also only comes into account if you happen to travel at thousands of miles per hour on a regular basis and even then it affects time by about a fraction of a millisecond so it hardly matters.

 

[Eris!]

Time is just an abstraction of distance and change.

 

[mindlessobserver]

This is actually a good question tbqh. Thinking about it, I would say that the most accurate measurement of time would be the time it takes an electron to move from one element to another in a molecule. We really have no way to measure that though. We know it has to take some amount of time, but we dont know how much.

 

[Un Platano]

What you're looking for are so-called natural units. These are units which are derived from the units present on fundamental constants in the universe, such as the speed of light, the gravitational constant, Planck's constant, and other such values. Alternatively some are defined using particles, such as the radius of a hydrogen atom at it's ground state. The units you can derive from these exist irrespective of human definitions because those numbers are the same anywhere in the universe.

There's a problem with this though: There's more than one way you can derive a time unit out of a set of universal constants. The most well known natural units are the Planck units, such as Planck time. These are based on Planck's constant, which is a fundamental constant relating the energy of a photon to its frequency. In fact, you gave a definition of the Planck time in the OP. There are also Planck units of length and mass, which means you can derive lots of other units from these.

It's not objective though, because it's not the only way we can define time in terms of universal constants. Another way to do it is with Stoney units, which are based off of the properties of charge-carrying particles. There are a lot of ways we could derive a set of natural units because there are a lot of physical constants out there. The problem with this, just like the problem with just calling it the half-life of an atom, or any other quantity, is how do you communicate how you derived the value of this quantity?

Setting up a coordinate system is an entirely different problem. To define a coordinate system, you absolutely must define an origin. That essentially means you have to define the center of the universe. This is hard not only because there's no objective way to decide where that center is, but also because everything in the universe is moving. There's no point where you can anchor a prime meridian to, especially since space itself can expand. A moving origin means the coordinates of everything are continuously changing. That's hard to deal with even if you know what the origin point is.

This is actually a good question tbqh. Thinking about it, I would say that the most accurate measurement of time would be the time it takes an electron to move from one element to another in a molecule. We really have no way to measure that though. We know it has to take some amount of time, but we dont know how much.

This wouldn't be a good way to set time because there's so many variables involved that change the time required for this to happen. In general, hotter electrons move faster, because that's what heat is. So you would have to decide a unit of temperature at which to define your unit of time, which is a frankly horrific use of units. And no, you can't use absolute zero, because then the electrons wouldn't move at all.

 

[Big Bad Wart]

Measurement is just taking something smaller in specific quantity you are measuring and using it as a unit. Eventually you get to the smallest possible. I haven't done physics in a while but theoretically I thinks its planck time.

basically there is no objective measurement and direction isn't a measurement its a scalar quantity of a vector

 

[NOT Sword Fighter Super]

I would think aliens capable of inter-galaxy travel would be able to somehow triangulate whatever signal our message is sent by for a general direction and would probably be able to gauge a distance based on the degradation of the signal itself.

 

[Eris!]

Anyway, most Aliens are psychic and they come to our planet by attuning to our vibrations. Traveling here is illegal so they have to be sneaky. Except the reptilians: They don't come from space. This is their home, we're the aliens.

 

[Μusk]

Time is a manifestation of the mind. This perception arises from the energetic expression and potential of existence.

To have time, you need A) change, and B) comparison. In the case of humans, we are able to differentiate change via our senses and with our memory determine the nature of this change. There is no past or future of existence, there only is.
Perhaps the most absolute measure of time that doesn't rely on theoretical physics would be to accelerate something to the speed of light, and determine the smallest "steppings" that the object/phenomena takes... Like a video game locked at 30FPS where, when recorded and played slowly, the car "jumps" from one position to another. With higher framerates, the "measure of time" becomes smaller, and even with slow speeds you are still able to witness more steppings inside of a block of time.

This is just my speculation, however. The most obvious change is kinetic energy. Witnessing an object change position.

 

[thick internet digit web]

Time is a manifestation of the mind. This perception arises from the energetic expression and potential of existence.

look who's taken /x/ seriously

 

[Μusk]

look who's taken /x/ seriously

When I say "energetic expression and potential of existence", I mean things like kinetic energy, thermal, chemical, etc. If you have a system with absolutely no energy within it, and no action whatsoever occurs inside as a result, does the system have time? I would say it does not, because it is imperceivable as there is no changes of its state. You can perceive a day progress, because you can witness the sun rise and fall. Even without this, your perception of time still exists because your brain provides such functionality. Being able to follow memories back in time.
"Time" then, is really your brains ability to comprehend state changes. Otherwise, the universe just exists "as is", and doesn't really maintain a past or future.

 

[mindlessobserver]

What you're looking for are so-called natural units. These are units which are derived from the units present on fundamental constants in the universe, such as the speed of light, the gravitational constant, Planck's constant, and other such values. Alternatively some are defined using particles, such as the radius of a hydrogen atom at it's ground state. The units you can derive from these exist irrespective of human definitions because those numbers are the same anywhere in the universe.

There's a problem with this though: There's more than one way you can derive a time unit out of a set of universal constants. The most well known natural units are the Planck units, such as Planck time. These are based on Planck's constant, which is a fundamental constant relating the energy of a photon to its frequency. In fact, you gave a definition of the Planck time in the OP. There are also Planck units of length and mass, which means you can derive lots of other units from these.

It's not objective though, because it's not the only way we can define time in terms of universal constants. Another way to do it is with Stoney units, which are based off of the properties of charge-carrying particles. There are a lot of ways we could derive a set of natural units because there are a lot of physical constants out there. The problem with this, just like the problem with just calling it the half-life of an atom, or any other quantity, is how do you communicate how you derived the value of this quantity?

Setting up a coordinate system is an entirely different problem. To define a coordinate system, you absolutely must define an origin. That essentially means you have to define the center of the universe. This is hard not only because there's no objective way to decide where that center is, but also because everything in the universe is moving. There's no point where you can anchor a prime meridian to, especially since space itself can expand. A moving origin means the coordinates of everything are continuously changing. That's hard to deal with even if you know what the origin point is.


This wouldn't be a good way to set time because there's so many variables involved that change the time required for this to happen. In general, hotter electrons move faster, because that's what heat is. So you would have to decide a unit of temperature at which to define your unit of time, which is a frankly horrific use of units. And no, you can't use absolute zero, because then the electrons wouldn't move at all.

My first choice was honestly the rate universal expansion from the big bang origin. But that sucks too because the universal expansion is accelerating. I wonder if black holes are the solution to this dilemma. The point at which a molecule on the far side of the event horizon touches it just enough to shear off an electron in the form of hawking radiation....


So that would mean the most accurate measure of time would be the rate of hawking radiation emission from a black holes event horizon at the point of observation being the exact delineation of the event horizon.

 

[Dick Justice]

I think what you might be interested in is Planck time, which is the smallest unit of time that would have any meaning. Relativity still applies, though, as always. If you're talking about a "universal" measure of time, you could always use the time on Earth as the set standard and just say that the time on planet X or whatever is a certain percentage faster or slower than it is on Earth.

I was trying to keep it abstract but to keep the thought train going here's two examples where simply setting a "master" clock in Greenwich or wherever wouldn't work, and I'm curious how you might tackle the problems.

1. We send out a probe that says "Hi! We're here, we existed!" for aliens to find, hopefully before we're dirt. The aliens will want to know when we existed so when they use their sci-fi universal translator to turn our glyphs into pleasant north american accents they're going to get a time of some kind, presumably big bang + N. What would N best be?
2. It is THE FUTURE and mankind has found many homes, but Earth is not one of them. A new galactic or perhaps intergalactic standard time is needed and people are too petty to simply let one planet be the master clock. Could a standard time be defined? How so?

When I say "energetic expression and potential of existence", I mean things like kinetic energy, thermal, chemical, etc. If you have a system with absolutely no energy within it, and no action whatsoever occurs inside as a result, does the system have time? I would say it does not, because it is imperceivable as there is no changes of its state. You can perceive a day progress, because you can witness the sun rise and fall. Even without this, your perception of time still exists because your brain provides such functionality. Being able to follow memories back in time.

These two posts imply that there can be no existence without observers, which is very much the tail wagging the dog.

 

[Mr. Skeltal]

When I say "energetic expression and potential of existence", I mean things like kinetic energy, thermal, chemical, etc. If you have a system with absolutely no energy within it, and no action whatsoever occurs inside as a result, does the system have time? I would say it does not, because it is imperceivable as there is no changes of its state.

What you described is the heat death of the universe or a state of total entropy. In that universe time would still continue to flow forwards. Causality is uniformitarian in its nature, it existed in the past thus must occur today and on into the future. The issue is in a universe of nothing but degenerate matter and photons what events can occur for causality to mean anything? What more entropy could be added to a system that's in a state of total entropy? Nothing much is the answer, so time loses its meaning but still passes. Time ends up governing the trajectories of remnant photons and other degenerate matter from a more ordered universe.

 

[Coleslaw]

With relativity, the fundamental quantity is speed/velocity. Everything else can change but the speed of light must stay the same.

 

[Un Platano]

Time is a manifestation of the mind. This perception arises from the energetic expression and potential of existence.

To have time, you need A) change, and B) comparison. In the case of humans, we are able to differentiate change via our senses and with our memory determine the nature of this change. There is no past or future of existence, there only is.
Perhaps the most absolute measure of time that doesn't rely on theoretical physics would be to accelerate something to the speed of light, and determine the smallest "steppings" that the object/phenomena takes... Like a video game locked at 30FPS where, when recorded and played slowly, the car "jumps" from one position to another. With higher framerates, the "measure of time" becomes smaller, and even with slow speeds you are still able to witness more steppings inside of a block of time.

This is just my speculation, however. The most obvious change is kinetic energy. Witnessing an object change position.

Let me start this out by saying that moving things at the speed of light is not the solution to this because you can't move things at the speed of light. It's not even open for hypothetical questions because there's no meaningful answer you can derive about the speed of light. It's like a nonexistent function such as sin(∞). We can't say "imagine if we could do it" because it's fundamentally a nonsense statement.

Another incorrect thing that you've stated is that change in position is kinetic energy. It isn't. Change in position is length. Change in position can imply potential energy, but only in the presence of an external force such as gravity. There is nothing about changing position that implies kinetic energy is necessary. You might argue that moving to a different position requires velocity and therefore energy, but at a quantum scale even that isn't necessary.

Anyway, this isn't a particularly meaningful argument. What's your point? That time doesn't exist and we only perceive a change of state as time? I could make much the same argument about length. Length doesn't exist, only the difference in the position of two points that we perceive as length. It doesn't matter what philosophical doubts you can come up with in your perception of things. If it does, you're going the route of Descartes and will eventually come to the conclusion that you don't know that anything exists. But while you go about arguing that nothing we know is real, everyone else will happily go about using this notion of time that lets us measure things to make very accurate predictions about how things happened in the past or will happen in the future.

 

[Chi-com Soldier]

there can be no existence without observers

This is true, though. There is no reality without conciousness.