I conjecture that time does not have any physical existence. It is more of a social construct, a mental construct, a perception, and a mathematical modeling construct rather than having any actual physical manifestation. More correctly, I would say that I am unconvinced that time has a physical existence. I concede that it may exist, but my intuition at this stage is that it does not exist in the physical world.

This informal paper will explore these and other aspects of the existence of time, or the lack thereof.

If time does not exist, what is it that we think we observe that we think of as time? That’s the right question to ask, and the one that this informal paper will explore as well.

To answer that last question directly, I would say that time as we experience it is a combination of:

  1. Discrete events — physical, social, and mental.
  2. Sequences of discrete events.
  3. Processes (physical, social, or mental) in which a system (physical, social, or mental) incrementally evolves, which can be broken down into smaller discrete events and sequences of discrete events.
  4. Counts of discrete events.

Generally, time is presumed or assumed to exist.

Generally, time exists by definition and by convention.

Can we directly measure time?

I would say, no, we cannot either directly observe or directly measure time.

Rather, we can observe and count occurrences of discrete events, singly, or in larger aggregates.

We can observe the transit of the sun through the sky, the shadow of the sun on a sundial, the rising and setting of the sun, phases of the moon, and changing of seasons, among many other events.

But time itself always seems to be hiding off in the shadows, always present but never seen directly.

Questions and topics covered in this paper:

  1. Yes, time exists — in our minds and in mathematical models.
  2. Time as a social construct.
  3. Time as a mental construct.
  4. Time as a perception.
  5. Time as a mathematical modeling construct.
  6. Events and processes.
  7. Time as an innocent bystander rather than a causal agent.
  8. Do events and processes depend on time?
  9. Is anything truly spontaneous, without any cause?
  10. Can time alone be the only cause of any event or process?
  11. What does science have to say about time?
  12. How much does science really have to say about time itself?
  13. What does science know about time?
  14. Physics — mathematical models vs. physical systems.
  15. Is time a force, a field, or… what?
  16. Is time an emergent property?
  17. Is time merely a conversion factor?
  18. Is time merely an accounting device, mere bookkeeping?
  19. Is there a proof that time exists?
  20. Time exists by definition.
  21. Time exists by convention.
  22. Time exists by presumption.
  23. Time exists by assumption.
  24. Nature and elements of time.
  25. The issue of velocity.
  26. How we experience velocity.
  27. The issue of acceleration.
  28. Time versus movement and position.
  29. Relation between energy and mass and velocity.
  30. Where else does time occur in physics besides velocity and acceleration?
  31. Frequency of electromagnetic radiation.
  32. How long does an event take?
  33. Does gravity require time?
  34. Does radioactive decay require time?
  35. Is time ever an observable in physics?
  36. Can time ever be measured directly in physics?
  37. Any evidence of time existing in physics?
  38. Nonetheless, time is central to much of physics.
  39. Does nature ever use time to synchronize events?
  40. Does time exist in a vacuum?
  41. Quantum foam.
  42. Rate.
  43. Impatience.
  44. Waiting.
  45. Delays.
  46. Aging.
  47. Relative temporal spacing of events.
  48. Time dilation under relativity?
  49. Arrow of time
  50. Entropy
  51. What physical properties does time have?
  52. Is time fundamental?
  53. Time travel?

Yes, time exists — in our minds and in mathematical models

My real question in this paper is whether time exists in a physical sense, comparable to energy, matter, forces, and fields.

But even if time does not exist in any strictly physical sense it certainly does exist in society, in the human mind, and in the mathematical models of science, including physics, chemistry, and astronomy.

Time as a social construct

Even if time does not exist in a physical sense, it certainly does exist as a social construct, governing social interactions.

Time as a mental construct

Even if time does not exist in a physical sense, we certainly have a sense of time in our minds as a mental construct.

Time as a perception

To the human mind time does feel as if it existed.

We perceive that time exists.

How could we have a perception of time existing if it didn’t actually exist?

Of course, there are illusions, hallucinations, delusions, imagination, misperceptions, and other ways that the human mind can be deceived, so mere perception is no guarantee of existence of that which our minds believe to have been perceived.

But the perception of time is persistent and widespread, so the perception certainly seems real.

But are we really perceiving a physical quantity in the real world, or an ephemeral quantity within the human mind and social experience?

And we are culturally programmed with clocks and expressions of time that continually reinforce the notion of time existing.

But all of those reinforcements are social and mental.

But time clearly does exist as a social and mental construct that can indeed be perceived, regardless of whether there is any actual underlying physical quantity for time.

Time as a mathematical modeling construct

There are certainly plenty of mathematical formulas, equations, and models which depend on time in physics and other sciences.

But there is a distinction between a model and the physical reality that is being modeled. Just because a variable or quantity exists in a model does not mean the corresponding quantity exists in the real physical world.

Models can have both real and nominal variables.

Real variables are supposed to correspond to quantities that are observable or measurable in the real physical world.

Nominal variables are part of the model, but do not necessarily exist in the real physical world.

So, the open question is whether time is a true, actual real variable, or is merely a nominal variable.

At this stage, I fully accept time as a quite reasonable nominal variable, but I’m having great trouble accepting time as a true real variable.

Events and processes

An event is a discrete phenomenon which is observable, detectable, or measurable, or can be experienced, whether directly by the human eye or other senses, or using some scientific instrument.

A process is a phenomenon which is either not so discrete or has some degree of complexity. As a general proposition, a process is some sequence or complex set of interacting sequences of smaller events.

A process might also be a discrete event to the degree that it is easily observed or measured.

A chemical reaction is a process. It might also be an event if it happens very quickly and has some visible or palpable effect such as color change, heat generated, or precipitation from a liquid. Or possibly even an explosion.

Some classic examples of processes which wouldn’t normally be considered events per se:

  1. Waiting for a watched pot to boil.
  2. Waiting for paint to dry.
  3. Watching grass grow.
  4. Evaporating water in a pan or glass.
  5. Freezing water. Although once ice has formed it is distinctly visible.
  6. Setting of concrete.
  7. Setting of glue.
  8. Melting of butter.
  9. Formation of a new star.
  10. Formation of a new planet.

Each of these processes has a clear end state, but other than bringing water to a boil, none would be a palpable event per se other than waiting for the end state.

But in all cases, every process tend to involve some potentially enormous number of discrete events, event sequences, or interacting events to finally get to the desired end state.

Time certainly appears to be involved in all of these processes, and frequently a relatively large amount of time, but is time involved in any causal sense, or is it the causal interactions of many tiny events that causes the result, and time is merely an innocent bystander?

Time as an innocent bystander rather than a causal agent

I haven’t yet been able to identify any situations where time itself is the causal agent in an event or process. Rather, time seems like more of an innocent bystander, an observer, a mere spectator while the real action is occurring within the matter, energy, forces, and fields involved in the events and processes of the physical world.

Although, in a social or mental setting the elapse of time can feel palpable, as if it were indeed active. But, in reality, it is more likely that individuals are experiencing biological and mental processes rather than time itself directly.

Do events and processes depend on time?

Could or do events and processes occur without time as a causal agent?

Or, once again, is time more of an innocent bystander to the events and processes as they proceed at a physical level?

Does a cake truly require time to bake, or is it chemical and physical processes that proceed sequentially that cause the cake to bake?

Is time an ingredient to the cake or simply a count of the events that must transpire for the cake to bake?

My tentative conclusion is that events and processes do not require time per se to proceed at the physical level.

Is anything truly spontaneous, without any cause?

Does any event ever happen truly spontaneously and solely as a result of time, or is it always some combination of either external or internal events or processes?

Again, can time be a cause, or is time always never more than an innocent bystander?

My tentative answer is no, there is always some physical cause.

Can time alone be the only cause of any event or process?

Same question, basically.

Does every event or step of every process need to have some physical cause other than time, or can time alone cause an event or progress in a process?

My tentative answer is that no, time is never the only cause of any event or process. And not even a cause at all.

What does science have to say about time?

Physics has a lot to say about time.

Actually, I would say that physics has very little to say about time itself. It does have some important things to say, but the total volume of knowledge about time itself is amazingly small, and more assertions and assumptions than actual observable facts.

Most of what physics has to say about time relates to the modeling of time, or I should say modeling using time, rather than about any physical aspects of time itself.

I won’t cover the full scientific background on time here. The Wikipedia article on Time in physics has a semi-decent narrative, or is at least a semi-decent starting point.

I concede that time has a role in the math of physics, but I remain unpersuaded that time exists in a physical sense.

How much does science really have to say about time itself?

I keep looking, but my search so far has uncovered amazingly little about time itself.

Time is mostly defined and assumed rather than being an object of direct study.

Scientists define and measure many physical quantities, in terms of time, but time itself hasn’t gotten that level of scrutiny.

Sure there is time dilation in Einstein’s theories of relativity, and the space-time continuum, and wild speculation about quantum foam.

But not a lot more.

This is amazing, really.

But I’ll keep looking.

What does science know about time?

That’s an interesting question, but as far as I can tell, scientists know very little about time itself.

After all, you can’t know much about something if you cannot observe it, measure it, or run experiments that tell you something about it.

Physics — mathematical models vs. physical systems

As a general proposition, physicists work with mathematical models of real-world physical systems.

The theory is that the models very closely parallel reality.

In reality, mathematical models will tend to approximate physical reality.

The general idea is that the approximations of the models will be close enough for most purposes.

In the case of time, the issue is not accuracy per se, but whether the physical system actually has some physical quantity called time, or whether our notion of time is merely approximating whatever is actually occurring in the physical world.

The general approach in physics is that if the calculated results from the mathematical model closely match the measured results and observations of the actual physical system, then the model is presumed to be correct.

But, the model may not be absolutely correct in that there may be more than one underlying fundamental quantity in play such that collectively they sum up to what we call time.

In any case, it is the mathematical models in which time definitely exists, regardless of whether or not time exists in the underlying physical world.

Is time a force, a field, or… what?

What exactly is time, anyway? From the perspective of science.

Is it a force?

Is it a field?

Is it a form of energy?

Is it a particle?

Is it a wave?

Does it have a wave function, with eigenvectors and eigenvalues?

Does it have a gauge particle?

There are no positive answers here, as far as I can tell.

Interesting. Very interesting indeed.

Is time an emergent property?

Maybe time is simply an emergent property rather than being a fundamental quantity or force of nature.

What might time be emergent from?

We certainly perceive time, but is that more illusion than reality?

Perception rather than physical existence.

Is time merely a conversion factor?

In most equations that include time one could solve for time in terms of other, more fundamental quantities. Time could be considered simply a conversion factor between fundamental quantities.

Is time merely an accounting device, mere bookkeeping?

Many measurements of time are simply counting of some designated marker events.

As such, time would appear to be more of an accounting device or mechanism, mere bookkeeping, rather than necessarily a fundamental quantity of the physical world.

Is there a proof that time exists?

Has any serious scientist or mathematician actually constructed a proof that shows that time must exist? None that I am aware of.

Technically, they can probably show that a given model of reality only works if time exists, but that still wouldn’t necessarily prove that the model and its assumption of the existence of time are both necessarily universally valid, even if such a model seemed to work in all known situations.

People could argue that time must exist, but that wouldn’t constitute a proof.

Time exists by definition

Generally, time exists by definition.

We simply define it as existing, regardless of whether there is any physical evidence of its existence.

Time exists by convention

Generally, time exists by convention.

We’re simply very used to treating time as if it existed.

Time is simply a convention that we have adopted.

The convention seems to work, so that is treated as good enough.

But, that’s not good enough for me. I have higher standards.

Time exists by presumption

Generally, time is presumed to exist.

We may not have physical evidence or proof that time certainly exists, but we are so comfortable with the notion of its existence that we have no trouble with a presumption of its existence.

After all, nobody has ever proved that time does not or cannot exist, so the presumption of its existence has not been invalidated.

But that’s too weak a standard, for my taste.

Time exists by assumption

Generally, time is assumed to exist.

All of the math and evidence of other phenomena do seem to work out when we assume that time exists, so it makes perfect sense to accept the assumption that time exists.

The basic logic is that if the assumption works, it must be true.

Granted, we haven’t yet discovered or explained all known phenomena, but so far the assumption of time existing hasn’t hit any real obstacles, yet.

But, to me, that’s a very weak logic. I’m looking for a stronger form of logic, coupled with actual, real, hard, physical evidence of time’s existence.

Nature and elements of time

I intend to write a separate paper on the more detailed nature of time — Elements of Time.

Whether or when I get around to writing that paper is uncertain.

This paper already covers a fair fraction of the aspects of time of interest, but that future paper would cover more, such as:

  1. How do we talk about time? Terminology, vocabulary, concepts, euphemisms, principles.
  2. What makes time tick?
  3. What specifically do physicists have to say about time?
  4. What are the elements of time as a social construct?
  5. What are the elements of time as a mental construct?
  6. What are the elements of time as a mathematical modeling construct?
  7. What are the elements of time as a physical construct?
  8. Fabric of time and space.
  9. Space-time continuum.
  10. Relationship between time and space.
  11. Time as a dimension.
  12. How come space gets three dimensions and time gets only one?
  13. Arrow of time.
  14. Linear progression of time.
  15. Can time every leap?
  16. What prevents time from looping?
  17. Time travel.
  18. Elements of time.
  19. Nature of time.
  20. Qualities of time.
  21. Aspects of time.
  22. Essence of time — observables, qualities.
  23. Units of time.
  24. Planck time.
  25. Is Planck time the true fundamental unit of time?
  26. Is there no shorter interval of time than Planck time?
  27. What happens to time during the middle of a Planck time interval? Does a photon jump by the Planck length or transition smoothly?
  28. Beginning of time.
  29. Origin of universe.
  30. What terminology should be used to refer to time before the Big Bang?
  31. End of time. What would define it?
  32. Could time even have an end?
  33. What happens to time if the expansion of the universe ends, reverses, and leads to a collapse to a new singularity?
  34. How does time relate between universes in a multiverse?
  35. Timelines.
  36. Smallest time interval in the natural world.
  37. Longest time interval in the natural world.
  38. Smallest time interval in the human or manmade world.
  39. Longest time interval in the human or manmade world.
  40. Time in a vacuum.
  41. Time beyond the outer reaches of the universe, beyond all matter and energy.
  42. How does time behave in and near a black hole? Does time have a singularity? Does time lose its arrow? How and by what mechanism is time distorted by a black hole?
  43. Relationship between entropy and time.
  44. What does entropy tell us about time?
  45. How does time affect entropy?
  46. Absolute, relative, local, and observer-dependent time.
  47. Invariance — time invariance.
  48. State change under time — velocity, position, chemical reaction, radioactive decay, fusion, pair production, etc.
  49. Nature of clocks.
  50. How do or can we measure time?
  51. Can we ever observe or measure time directly?
  52. What exactly do we measure with time?
  53. How do we experience time?
  54. How do machines experience time?
  55. How does a clock experience time?
  56. Is time a human invention?
  57. Why did we invent time?
  58. What benefit did we get from the invention of time?
  59. What purpose does time serve?
  60. Social interaction as a need for time.
  61. Time-based social events.
  62. Does society need time?
  63. Could society exist without time?
  64. What would society be like without time?
  65. What would games, sports, and athletic events be like without time?
  66. What is time good for?
  67. Can the universe proceed without a notion of time?
  68. Regularities of time in nature.
  69. Ordering of events and steps within processes.
  70. Use of time to synchronize events and activities.
  71. Light cone of photon — past, present, future.
  72. Does time itself heal all wounds or is there some other causal factor(s) doing the healing and time is merely coincidental with the actual causal factor(s)?
  73. Does time have a cause? What causes time?
  74. Is time a phenomenon? A single phenomenon?
  75. Are time and space independent phenomena or a single phenomenon?
  76. When did man first become aware of time and how?
  77. What biological process allows us to be aware of time?
  78. What does it mean to be aware of time?
  79. Does time happen? How can we tell?
  80. Can time be stopped or paused and resumed?
  81. Time as a metaphor.
  82. What does it mean to say that a force acts in time?
  83. Why is it easier to imagine moving in space than moving in time?
  84. Do any forces act on time?
  85. Does time exert any force on anything?
  86. Does time stand still for a photon, other than its frequency? Does a hypothetical observer within a photon experience time or frequency at all?
  87. Does free will apply to time?
  88. Time as a rhetorical or literary device.
  89. Can time be curved in a comparable manner as space?
  90. Would light (photons) be possible without time?
  91. Is time a causal factor for photons?
  92. Does the existence of energy depend on time in any way?
  93. Is time a causal factor for energy?
  94. Does time in any way depend on energy?
  95. Time as a process.
  96. What does Stephen Hawking have to say about time?
  97. What does Einstein have to say about time?
  98. Escalator or conveyor belt as metaphor for the inexorable flow of time, as opposed to stairs or a sidewalk, where action is required to move.
  99. Is time chiral?
  100. Is time polarized?
  101. Does time have spin?
  102. Does time have charge?
  103. What assumptions do scientists make about time? Uniform, a constant?
  104. Time as an artifact.
  105. Time as an effect.
  106. Time as a consequence.
  107. Does time have an intensity?
  108. Does time have a frequency or sense of oscillation and a sense of states?
  109. Time as a sequence of state transitions. Each state transition pair being one unit of time. Time at a micro level. Some physical processes have state transitions that are reasonably uniform in duration, while others are more widely varying in duration. Duration only being measurable by comparing and counting state transitions of two parallel systems.
  110. Is time itself an event or sequence of events?

Questions and topics covered by this paper aren’t necessarily on that list. The full list would be the union of this list and all topics and questions from this paper.

The issue of velocity

My main unresolved concern here is the role of time in motion of particles or bodies.

With bodies or systems at rest, we can observe many ongoing processes and discrete events. Time is not needed, and is simply an analog for counting of events.

But with a body in motion, even light itself, time manifests itself as a change in position with no intervening events, or at least no readily apparent events.

For an object moving through space at a constant velocity, its position is changing without any apparent connection to external events, interactions with other bodies, or processes of any kind.

The position changes, with only time being what changed.

A single photon with a fixed amount of energy and no apparent processes, events, or interactions with other bodies can change its position from A to B, with the distance between A and B measurable based on this thing called time, using the math that distance equals velocity times time, or velocity equals distance divided by time.

As far as I can tell, there is nothing else going on physically with that photon, subatomic particle, or even macroscopic object (pick your metaphor — bullet, baseball, missile, or frisbee.)

Distance doesn’t depend on time, but velocity is completely dependent on time. Or so it seems.

Or is velocity an illusion as well?

Maybe.

How we experience velocity

Or, does it even matter how long it takes to travel from point A to B?

It only matters if the events transpiring during that interval matter in some way.

You may be impatient that it takes too long — your mind has too much time to ponder annoying thoughts.

You may get very hungry during the trip. You may even starve.

Or the trip may take longer than your natural life.

But in all of those cases we are back to discrete events and sequences of events.

We could use time as a conversion factor to calculate how many books to take on the trip, or how many meals, or whether cryogenic sleep may be needed to keep us alive.

Yes, we experience the time needed for the trip, but it is the events and even sequences that we experience, rather than the time itself.

You could also say that we experience the distance travelled.

But our experience of that same distance would be very different at different velocities.

So we’re back to time having an impact on the experience even though the events and sequences of events are what we directly experience.

It would seem that some notion of rate of events still has significance even if time itself is not the observable factor.

But is rate necessarily directly related to time?

Or, is rate itself merely a conversion factor from distance to events?

Also, velocity is related to mass and energy — kinetic energy. Impart an impulse of a given amount of energy to a given mass and that gives it a velocity.

Again, maybe time is simply a conversion factor, connecting energy and mass.

So the travel problem relates to distance, mass, and imparted energy. Those are the three things that are real. Time is simply the conversion factor.

Yes, that conversion factor will impact our experience, but it remains true that only the distance, mass, energy, and events that transpire while travelling are truly real.

The issue of acceleration

Even if the issue of velocity is addressed, where does that leave acceleration?

Acceleration is the change in velocity per unit of time. There’s time again.

Acceleration can occur in several ways, such as:

  1. Gravity.
  2. Sudden impulse, accelerating from zero to some terminal velocity.
  3. Deceleration or negative acceleration due to drag such as a body moving through a gas or a liquid. Or even through a solid, such as a bullet through wood.
  4. Continual change in direction of velocity even though the magnitude of velocity remains unchanged, such as one body orbiting another.
  5. Sudden change in velocity due to impact and reflection of one body by another.

It sure seems to me that most of this involves events rather than time.

Most. But maybe not all.

Orbiting involves time, but there is some sequential and mathematically deterministic change in the direction of motion, which seems more of an event than time per se. That’s an oversimplification of orbital mechanics under gravity, but still seems somewhat event-driven.

Time does seem involved for deceleration due to drag, but once again maybe it is a large number of small events rather than time per se.

Gravity? That seems somewhat more complicated. Certainly magnitude of velocity when a smaller body accelerates towards the larger body at least superficially seems dependent on time, but more analysis seems warranted. Again, maybe time alone is more of a conversion factor masking the underlying physical phenomenon.

Time versus movement and position

Position, movement, and time seem related, at least superficially.

Position is maybe the ultimate and most useful aspect of physical reality. Objects as they are, where they are, right at this moment.

Time doesn’t seem relevant to position per se.

Movement or change of position does seem dependent on time, at least superficially.

But, I’m trying to be careful to avoid falling prey to the trap of committing to belief in what may only be superficial appearance.

Relation between energy and mass and velocity

Kinetic energy is calculated based only only mass and velocity.

Time doesn’t directly show up in the calculation of kinetic energy. You can safely say that kinetic energy is invariant with respect to time — presuming velocity is constant.

Time does indirectly show up in the calculation of kinetic energy in the sense that velocity is measured or calculated or given as distance travelled per unit of time.

But unit of time is really more of a scalar conversion factor than some variable quantity.

And since velocity can be calculated based solely on kinetic energy and mass, for a given energy and a given mass there is no relevant notion of time per se in this picture.

Time will enter the picture if we want to calculate (or measure or observe) the position of a body as it moves.

On this particular point I do have to concede that it does feel that time has some physical significance.

But, more thinking and research on my part is warranted before I can come to a firm conclusion.

Where else does time occur in physics besides velocity and acceleration?

Here are a few other places I know where time appears in physics:

  1. Frequency of electromagnetic radiation.
  2. Radioactive decay. Half-life of a radionuclide. But once again, that seems more like events than time, but how does half-life come about?
  3. Rate of chemical reactions. That’s nominally chemistry, but certainly there is physics involved.
  4. Production and destruction of particles from electromagnetic radiation, such as pair production. Time is involved somehow, but those seem more like events to me.
  5. Time for fission of a nucleus.
  6. Time to fuse two nuclei.
  7. Time for a neutron to be absorbed into a nucleus.
  8. Time for an electron to absorb energy and go to a higher state.
  9. Time for an electron to emit energy and fall to a lower energy state.
  10. Time for an atom to capture a free electron.
  11. Time for an atom to lose an electron.
  12. Any others? Probably many, but do they introduce any new factors that the preceding examples don’t cover?

Clearly time seems at least superficially relevant, but once again the key question is whether it is simply masking underlying events.

Frequency of electromagnetic radiation

Photons, which include radio waves, wireless communications and data transfer, microwaves, x-rays, and gamma radiation in addition to visible light and infrared and ultraviolet, all travel at exactly the same speed in any given medium, the so-called speed of light, c.

But all of these various forms of electromagnetic radiation have different levels of energy, with radio waves and microwaves having less energy than visible light, and x-rays and gamma rays having much higher levels of energy.

The level of energy of a photon is determined by its wavelength or frequency (inverse of wavelength.) A longer wavelength or lower frequency has less energy, while a shorter wavelength and higher frequency has more energy.

Wavelength of a photon is simply a distance — the speed of light divided by the frequency. The latter is dependent on time.

Frequency of a photon is a count of full cycles in the oscillation of the electric and magnetic fields of the photon for a single second. Very dependent on time.

The energy of a photon is calculate by multiplying its frequency by Planck’s constant.

Unlike a body with mass where the time to travel a given distance can be calculated from mass and kinetic energy, neither mass nor energy can be substituted for time to calculate the time to travel a given distance without reference to time.

So, the speed of light seems to be one place where time seems to be required to have a physical existence.

At this stage I would say that one of the following has to be true:

  1. Either there is some more fundamental, undiscovered force or phenomenon that drives frequency, wavelength, and even the speed of photons.
  2. Or time itself must have some sort of physical manifestation which is driving the frequency and wavelength of photons.
  3. And maybe both are true.

In any case, I will continue pondering photons and their relationship, if any, to time.

At the moment, it does indeed feel that at least the traditional conception of electromagnetic radiation requires a physical conception of time. But I’m not thoroughly convinced of that either.

How long does an event take?

Obviously many events take widely varying amounts of time to occur.

But the key question there is whether time itself is the determining factor, or whether the observed events are really composites of significant numbers of smaller events, each of which in turn can be decomposed into smaller events.

All of those smaller events add up to the larger interval of time, but once again time can be modeled as simply a count of events.

Where does that decomposition into ever-finer events end?

We have:

  1. Smaller bodies.
  2. Smaller, but still macroscopic particles of matter, possibly still visible under a microscope or able to be trapped by a high-efficiency filter.
  3. Discrete molecules.
  4. Discrete atoms.
  5. Subatomic particles.
  6. Quantum interactions.
  7. Quantum foam.

What happens down at the atomic, subatomic, and quantum levels can get very mysterious indeed.

There is something called Planck time, which is the time it takes a photon to travel the distance of a single Planck length. That is theoretically the shorted time interval and the shortest distance, but this is somewhat speculative at best since it cannot be observed or measured.

I personally can’t go much further down at that atomic level, but it seems fairly obvious that the duration of an event is dependent on the complexity of the event.

The duration of the event also seems dependent on the energy involved in the event and all of its sub-events. A bunch of fissioned uranium atoms release a bit more energy in a more rapid burst than a sharp object piercing a balloon. Or even a firecracker compared to dropping and breaking a small piece of glassware of comparable mass.

Does gravity require time?

Once again, is time more of a conversion factor than an active physical quantity the way mass and gravitational force are?

An analysis of gravity with respect to time is well beyond the scope of this informal paper.

Maybe gravity requires time, or maybe not.

I’m content to leave it as a potential stumbling block for my conjecture, but I also don’t feel confident enough to assert that gravity definitively requires time.

Does radioactive decay require time?

Even if time is involved in radioactive decay, where does that come from? How is it derived?

Alternatively, what events are transpiring inside of a nucleus that sometimes and in a quasi-random manner lead to radioactive decay?

What actual physical quantity or quality suppresses decay most of the time but occasionally allows it to happen?

And how exactly is it that various radionuclides of the same atomic number have such wildly varying half lives? Like uranium-238 with a half life of 4.5 billion years while uranium-235 has a half-life of only 700 million years? And then plutonium-239 with a half life of only 24,000 years. And iodine-123, 131, and 125 having half lives of 13 hours, 8 days, and 59 days respectively.

And some radioactive isotopes have half lives of only very tiny fractions of a second.

What physical processes and qualities can account for such wide variance?

Is time necessarily a required driver of that process?

I concede that radioactive decay is a potential stumbling block for my conjecture, but by the same token I cannot state with confidence that radioactive decay is definitively driven by time.

Is time ever an observable in physics?

Does time have a wave function?

Does time have eigenvectors with eigenvalues? After all, eigenvalues of a wave function define exactly what is observable in physics, or at least in quantum mechanics.

How else could time be observable in physics?

Can time ever be measured directly in physics?

Measurement is the same as asking whether time is ever an observable in physics.

As far as I can tell, physicists are not able to directly measure time.

The best they can do is to simply count discrete events or stages of a physical process.

Cesium (caesium) fountain atomic clocks such as the NIST NIST-F1 and NIST-F2 are among the most accurate time measurement devices in the world, but even there, scientists are simply counting discrete events that they believe are closely paralleling time, but are not time itself.

Atomic clocks are counting the electromagnetic emissions when electrons transition between energy levels.

Of course, scientists are presuming that these transitions are occurring at incredibly precise regular intervals.

How close to time itself are these regular intervals? Good question. In theory, that would require specific knowledge about the nature of time itself, which they do not appear to have at this time.

Any evidence of time existing in physics?

Are serious scientists, notably physicists, able to marshal any evidence, other than hand-waving, that time exists?

None that I know of.

For the most part, the belief in time is based on:

  1. Hand-waving.
  2. Assumption.
  3. Presumption.
  4. Definition.

I am unaware of any past or proposed experiments or tests that could confirm the physical existence of time.

That’s not to say that experiments or tests cannot be imagined or proposed, but simply that to date none has been put on the table.

I personally find that very interesting indeed.

Nonetheless, time is central to much of physics

Even though physicists know very little about time itself, it remains central to much of physics.

Physicists speak of the time evolution of quantum systems, such as the Time-Dependent Schrodinger Equation (TDSE.)

Granted, a fair fraction of physics is invariant with respect to time, but the remainder of physics is dependent on time.

But, that said, I have my doubts as to whether time is an actual, physical, fundamental quantity or whether time is more of a conversion factor with respect to whatever true, real, physical, underlying fundamentals, such as events and processes, are being manifested when we refer to time.

Does nature ever use time to synchronize events?

A critical purpose for time in human society is to synchronize activities.

An example would be scheduling a meeting, game, or performance.

But does nature ever have any need to use time to synchronize events?

Does nature ever intentionally synchronize events?

Or is any synchronization of events or processes in nature purely coincidental?

I suspect the latter. Synchronization of events and activities seems to be more strictly a human social phenomenon.

Although, the steps in natural processes do have a clear sequential nature to them.

But even that sequencing appears more a natural consequence of preceding events and interactions of bodies and forces than anything resembling an intention to sequence the events in some artificial sense.

The whole point of synchronization is that the events would not have naturally followed each other had explicit synchronization not occurred.

The use of time to synchronize events seems more of a human, social construct.

Does time exist in a vacuum?

Does time require mass or energy for us to discern its existence?

Does time exist in regions in which there is neither matter nor energy?

Are there any places in the universe where time (or space) do not exist?

Does time suddenly pop into existence when matter or energy enter a region in which there previously was no matter or energy?

And does time just as suddenly vanish from that region when all remaining matter and energy have exited that region?

Does time collapse?

Interesting questions.

It’s rather difficult to say much intelligently about time without definitive answers to questions such as these.

Welcome to the world of time.

Quantum foam

Far below the size of scale of atoms and even subatomic particles lies what the scientists speculate is something called quantum foam.

This is down it the scale of the Planck length and Planck time, the shortest intervals of space and time that scientists believe is possible.

But this is all (100%!) speculation on their part.

Lack of certain knowledge down at that fundamental level makes it rather difficult to theorize or even casually discuss the true nature of time and space.

The secret of whether time truly exists in any physical sense will remain locked up in that quantum foam for the indefinite future.

The good news is that more rigorous speculation might be able to come up with models for quantum foam that enable predictions at a more macroscopic level which can actually be observed and measured, so that models and assumptions about space and time at the quantum foam level can finally be validated.

Rate

Many processes in life and nature appear to have a rate — quantity per unit of time.

But once again, is time a fundamental quantity or merely a derived conversion factor dependent on a true fundamental such as energy.

For example, the reaction rate for a chemical reaction. We may perceive it as based on time, but in reality it may simply be based on the energy stored in chemical bonds that are broken or formed. Time may simply be derived from the heat of reaction, the net change in energy.

Impatience

Human impatience can certainly seem related to time, but once again, that can be more a matter of perception, a matter within our minds, and maybe more dependent on events and processes within our minds and bodies than requiring that time have a physical existence per se.

Waiting

Waiting for event can certainly seem dependent on time, but once again seems more related to events and processes rather than requiring that time necessarily have a physical existence.

Delays

A delay in the occurrence of an expected event can be disquieting for impatient humans (or algorithms), but once again that seems more related to biological and mental or social functions rather than requiring that time necessarily have a physical existence.

Aging

Aging would certainly seem related to time, at least superficially, but once again the main driver seems to be events and processes rather than time as a causal factor.

Whether people, wine, cheese, trees, birds, or stars, there are very clear biological and physical processes involved with aging.

Once again, time appears to be more of an innocent bystander, a mere spectator, rather than a causal agent.

Does we feel the passage of time?

Besides the explicit notions of impatience, waiting, delays, and aging, can we indeed actually feel the passage of time, in a way comparable to feeling water and wind run over our skin?

Again, we can certainly feel the physical effects of water and wind, but do we physically feel any effect of the passage of time per se?

Well, maybe in some superficial sense. Try holding your breath. Very quickly you become very acutely attuned to the passage of time. But even then, it is a physical process that you are experiencing — build-up of carbon dioxide — rather than time per se.

And maybe in a mental sense, but once again that may simply be more of a build-up of emotional stress, a physical process rather than strictly a mental process, and not feeling time per se.

Time as an emotional crutch

Whatever the physical reality may be, we clearly have some emotional association with time.

Whether time actually exists, we appear to have some sort of emotional need for something like time. As a crutch of sorts. An emotional crutch.

Time seems to help us organize our lives and our activities, in much the same way that space helps us organize physical objects.

But, once again, are we simply organizing things relative to actual physical processes rather than raw time itself?

Relative temporal spacing of events

Whether in physics or in the realm of human activity, the notion of the spacing between events is significant. Relative temporal spacing of events.

Are two (or more) events very close in time?

Or are two (or more) events very separated in time?

We seem to need time to judge the distinction.

On the other hand, the distinction may not matter or have any true physical significance.

In fact, if the distinction of relative spacing in time has no actual physical effect on any other event or process, it may as well not have existed at all anyway.

Time dilation under relativity?

Einstein’s theories of special and general relativity predict time dilation. I don’t dispute that.

But whether time itself is dilating or physical events are changing the way clocks and observers measure or perceive time is unclear, to me.

I think it could be argued either way.

For the moment, I would suggest that motion and gravity are somehow affecting the measurement of time rather than changing time itself.

Here’s an interesting question: are all locations in the universe at this moment at the same time? Or, is every location in the universe by definition at a different time?

I guess it depends on how you define time.

Which leads me back to my conjecture that maybe time isn’t a true physical quantity or quality.

Especially if time is different everywhere.

Maybe, for a clock orbiting the earth the motion introduces some additional physical effect so that the sequence of events involved in the clock is expanded, slowing down the apparent measure.

Plenty to ponder on this front.

A more careful definition and treatment of time dilation is needed to resolve this matter.

For now, I will leave it and accept it as a matter which prevents me from asserting a strong belief that time can’t have a physical existence. But I do consider the matter still open.

Arrow of time

Just a brief mention of the notion of an arrow of time which physicists like to talk about, as if it existed. I won’t go into any detail here, other than to simply note that nothing in the discussion of an arrow of time actually proves that time does or must exist, separate from actual physical processes from which time seems to be more of a derivative concept.

Entropy

Another brief mention, which I won’t delve into deeply here, of the notion that entropy progresses in parallel with the presumed arrow of time.

The progression of entropy seems more associated with physical processes than flowing from time per se.

In fact, if you simply observe a single, isolated particle, would you notice any change in entropy? And if you did observe changes, then once again there is some physical process at work, so it’s the effects of the process you are observing rather than time per se.

What physical properties does time have?

Although people do speak of time as having a direction, the so-called arrow of time, I am not aware of any evidence or reasoning to support the notion of time having any physical properties, such as:

  1. Mass.
  2. Energy.
  3. Length.
  4. Size.
  5. Geometry.
  6. Topology.
  7. Momentum.
  8. Velocity.
  9. Acceleration.
  10. Frequency.
  11. Wavelength.
  12. Wave number.
  13. Force.
  14. Field.
  15. Spin.
  16. Density.
  17. Color.
  18. Flavor.
  19. Charm.
  20. Gauge particle.

Did I miss any?

I mean, if time has a physical existence then it should have some measurable properties.

Is time fundamental?

If time does exist, is it fundamental, with no underlying composition, structure, or process, or merely an emergent manifestation of something even more fundamental?

Time travel?

Sorry guys, but one of the implications of the nonexistence of time in the physical world is that the possibility of the concept of time travel would not exist either.

That said, you can of course travel through time by going to a museum, a movie, or a virtual reality theater or headset. Or just watch some old YouTube videos.

Absent time as a true physical phenomenon, a true dimension of reality, there is no way to reverse or accelerate the events or processes that pass for what we refer to as time.

We can accelerate events and processes by changing the amount of matter or energy involved in the event or process, but we can’t do that for all simultaneous events and processes in the universe, and we can arbitrarily skip over events and get the same effect as if they had not been skipped over.

Conclusion

I have no firm conclusion at this stage, although I retain my conjecture that time does not exist in the physical world as a weak to moderate belief, even though I readily acknowledge that I am unable to fully justify my conjecture as a strong belief.

The flip side is that I also cannot justify a strong belief that time does have a physical existence.

I do strongly believe my proposition that events and processes are where the real action is at, regardless of whether time has a physical existence.

And I do strongly believe that time is primarily a social construct, a mental construct, and a mathematical modeling concept.

And it does appear to me that time is more of an innocent bystander than a causal force in both events and processes.

That said, there are still issues in areas such as movement of objects and frequency of electromagnetic radiation that require significantly more information before any strong conclusions can be drawn, either way.

In short, the matter is still unresolved, in my view.

But I still lean towards the notion that time is more of an artificial, invented construct than a physical reality.

What’s next?

Only time can tell! Okay, that was just a small joke, very small.

Seriously, I’m waiting for serious physicists to shed more light on the nature of time.

Meanwhile, I’ll continue my speculation.

And hopefully I will get around to writing my Elements of Time paper, although it would be a shame to write that paper without a clear and convincing resolution to this issue of whether time is a physical reality. I may have to do a first pass as a partial paper, or a paper restricted to the non-physical aspects of time.

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