What is time?

[CraigD]

In various forms, this question seems to come up a lot on scienceforums, stirring considerable debate.
Answers include:

• time is something defined by any clock
• time is something defined by only certain kinds of clocks
• time isn’t defined by clocks of any kind
• time is a dimension that cannot be translated into other dimensions
• time is a dimension that can be translated into other dimensions
• time in quantatized (eg: can only be measured in multiples of 5.391 × 10-44 sec)
• time has something to do with increases in disorder/information/entropy
• there is no such thing as time – it’s just a psychic construct to prevent everything from being perceived at once
• Zeno’s paradox
• time exists, but can’t be meaningfully discussed in any natural language

Perhaps this discussion would benefit from if it left its various parent threads, and continued here. What’s do you believe time is, or is not, and why?

[infamous]

Originally Posted by CraigD

In various forms, this question seems to come up a lot on scienceforums, stirring considerable debate.
Answers include:

• time is something defined by any clock
• time is something defined by only certain kinds of clocks
• time isn’t defined by clocks of any kind
• time is a dimension that cannot be translated into other dimensions
• time is a dimension that can be translated into other dimensions
• time in quantatized (eg: can only be measured in multiples of 5.391 × 10-44 sec)
• time has something to do with increases in disorder/information/entropy
• there is no such thing as time – it’s just a psychic construct to prevent everything from being perceived at once
• Zeno’s paradox
• time exists, but can’t be meaningfully discussed in any natural language

Perhaps this discussion would benefit from if it left its various parent threads, and continued here. What’s do you believe time is, or is not, and why?

One answer that I've heard a couple of times, little pun there, is that time is really only the passage from one universal existence into the next and following universal existence. What this preception does is eliminates not only time but also all observed motion. I personally don't buy into the idea but I thought I would just throw it out there for discussions sake.

[EWright]

It's a funky Minneapolis band from the 1980s. Duh.

[Southtown]

Originally Posted by infamous

One answer that I've heard a couple of times, little pun there, is that time is really only the passage from one universal existence into the next and following universal existence. What this preception does is eliminates not only time but also all observed motion. I personally don't buy into the idea but I thought I would just throw it out there for discussions sake.

Ya, that's quite a stretch. And good question/topic, Craig. I have a large curiosity for this subject at the moment. (another pun 4u haha)

Richard D. Stafford, Ph.D describes it as the division between the past and the future, or in my mind, the known and the unknown.

http://home.jam.rr.com/dicksfiles/flaw/Fatalfla.htm

[infamous]

Originally Posted by Southtown

Ya, that's quite a stretch. And good question/topic, Craig. I have a large curiosity for this subject at the moment. (another pun 4u haha)

Richard D. Stafford, Ph.D describes it as the division between the past and the future, or in my mind, the known and the unknown.

http://home.jam.rr.com/dicksfiles/flaw/Fatalfla.htm

Cool link Southtown, going into my favorites.

[EWright]

Originally Posted by Southtown

Ya, that's quite a stretch. And good question/topic, Craig. I have a large curiosity for this subject at the moment. (another pun 4u haha)

Richard D. Stafford, Ph.D describes it as the division between the past and the future, or in my mind, the known and the unknown.

http://home.jam.rr.com/dicksfiles/flaw/Fatalfla.htm

If you didn't know, that's DoctorDick's paper, who is making his argument in the 'Arguing Einstein' thread.

[Southtown]

Ya, I just figured I'd give his full title for credibility purposes, but shoulda added his handle for all here, too. Oops.

And, to the topic, the question still begs if time is the division between past and future, why is it moving?

[Jay-qu]

time could be considered to be the passing of events, if nothing is happening who is to say that time is passing? even the thought of 'is time passing' takes up time, so time must have past its fun to play little time games in your head but man it can be wierd!

heres an interesting view on it.
When thinking back to a point in time, say this morning, how can you be sure that that event actually occured? sure your mind says it happened becuase you remember it, but at any one point in time the universe could be created or altered with those memory's 'preloaded' into your mind...

[alxian]

thanks to eintein and his time warping model of gravity time is reckoned locally and cannot be expressed as a metric even a theoretical one on a universal scale.

time is defined as a local constant (or pseudo constant) by which local events can be measured with reasonable accuracy.

once a constant is defined and tested its 'good enough' to judge local events with great accuracy, getting further away from that point of reference (light years) where synchronizing those local constants becomes difficult is a problem we'll have to resolve once we start travelling beyond our solar system.

a good question would be how much gravity distorts local time and can civilizations prosper in very high gravity fields that are 'accelerating' much like a ship would travelling through space. one way to find out is by visiting the moons of jupiter. the loss of synchronicity may be noticable, and means found to synchronize chronological constants between bases in orbit around jupiter and ones around earth.

another question is relative to observers would that civilization in a gravity field several tie stranger than earths, say on a planet several times as massive as earth, age noticeably faster than we do?

and would peeps on a generation ship (ship carrying peeps from on star to another) with very little gravity (1/6 enough to get by on, or peeps living on lunr bases) age slower than terrestrial humans since they'd have less local acceleration being applied to them?

since we are being affected ourselves by several local gravity fields, earth, the moon, jupiter and the sun, it is possible we are losing time relative to a beacon with a chronometer floating in interstaller microgravity (where the micro in that sense is much nearer to nothing than satelites in orbit around earth). another question is how far does a galaxies gravity field extend? are there regions of space that have no more local gravity than the static energy of motes attracting or repeeling each other? if you set off a repulser type energy pusle and voided nearby space of such particle could you achieve zero gravity?

that beacon, if it were not accelerating and if it could compensate for the pull of local galaxies (should their magnetic influence overlap to neighboring galaxies) and anomalies would represent as close to perfect "time" keeping we could hope for. if we had ansibles (FTL communications) to communicate with it, and a need to keep perfect universal time, then several such clocks could keep several local systems synchronized.

[CraigD]

Circa 1980, I was quite passionate about a personal belief in the nature of time. I can’t call my belief a theory, or even a hypothesis, because I couldn’t wrap any of the mental tools at my disposal around it well enough to make any testable predictions not in agreement with orthodox Physics. It would be most accurate, I think, to call it a Math student’s campfire tale (I particularly liked to tell it at night, deep in the woods of southern West Virginia, preferably in the presence of lotsa tequila).

Try to build the appropriate mental image. The story teller is 20 year old, 6’0”, 165#, an obsessive runner, with long brown hair and matching beard. It’s a summer night, too warm for a fire, really, but there’s a fire nonetheless. Look up from the fire far enough, and the WV sky is so free of light pollution you can see stars down to the 4th and 5th magnitude, so many stars you can’t truly find a place in the sky that doesn’t have one. The story goes like this:

Imagine that mass is not what we think it is – a property of certain fundamental particles, electrons and quarks mostly. Instead, imagine it’s a periodic phenomena, something that comes and goes like a moving wave. The frequency of mass is very high, some ten to the several tens cycles per second
”hertz,” someone interjects. “don’t sit on it, then,” someone else rejoinds
Macroscopically, what we measure is an average, the square root of the sum of the squares of the wave’s amplitude, measured from its mean. Like ocean waves, we only get a measurement where there’s some particle to manifest the wave. The wave doesn’t do any work, doesn’t have any energy. It just confers mass to massed particles, allowing them to have, averaged over these incredibly short periods of time, energy.
”what about magnetism?”
Magnetism’s same as always. So’s gravity, and everything else. On average, nothing’s detectably different.
“what good is it, then?”
For that, you gotta ask, “where is the past?”
(looks of incomprehension on firelit faces) “wadda you mean, where is it? Should that be ‘when it it?’” someone finally says
What makes you believe there’s a “when?” Did you ever see one?
“you don’t ‘see’ when. Time’s measured by changes in position – you see where, then, later, a where that’s a little different. Tee equals dee times vee.”
We all see space all the time. I mean, we’re all sure that any given volume has at least some proper distance from any other, even if we’re vague on the exact measurement.
(West Virginia woods are mostly 4th or later growth, logged for centuries - lots of medium to big trees, mostly deciduous at this altitude, a few coniferous, with a lot of small trees between. To a bunch of students in a college too small for the physics majors not to know the fine art majors, it suggests a sort of sloppy graph paper)
Think how much harder it is having a universe with everything always moving around. All those vectors and magnitudes, all those insoluble en body equations. Time makes physics so damn complicated.
“kinda seems obvious, though,” says someone, “motion happens.”
(it’s a still night, but notice now that there’s still a breeze, leaves and tree limbs moving against the starfield more ways than you can begin to describe)
Well, maybe. Unless the past isn’t somewhen, but somewhere.
“where?” several voices simultaneously
Further away than we can ever see. Outside of our light cone. Out there. There’s no reason to believe space isn’t infinite, even if observable space is clearly finite.
“like a flip-book,” somebody says, getting it.
“doesn’t look like a flip-book”
“a three dee flip book at ten to the fiftieth frames per second”
You can fit a lot of visible universes in an infinite three dee space. Even at ten to the fiftieth per second, that’s only about ten to the sixty-eight so far.
(to kids who doodle in their paper notebooks numbers like 10^(10^(10^(10^10))), this seems a tiny number indeed)
“but how you gonna make a flip book outa ten to the sixty-whatever spherical volumes the size of the visible universe? Even if the first few seconds worth are really small?”
(The story teller smiles, resembling for a moment a satyr from Greek mythology)
If mass is a zero-centered wave, then, whatever its average square-square root amplitude, it has to, for an instant, pass through zero. And what does a particle with zero mass do?
“it moves the speed of light”
And what’s the time dilation for an observer moving at the speed of light? How far does he go in an instant of his time, no matter how brief?
“its indeterminant”
(the science and engineering majors favor the speaker, a very prim and proper looking female math major with a lifetime 4.0 GPA, with a withering look. They’re having none of that as-i-approaches-zero nonsense, rather, they’re calling an infinity an infinity)
It’s infinite – or close enough to it to get outside of the visible universe. Any timer on a ship moving at the speed of light is incapable of dropping the ship out of lightspeed soon enough to have moved a finite distance.
“Okay, but how does this flip-book space-time give us the observed laws of physics? Wouldn’t everything be random, particles just appearing and disappearing according to no pattern?”
You’re saying it isn’t? At least on a sufficiently small scale?
(that shuts up the critic – these are all undergraduates, not a PhD candidate among them. Quantum weirdness is, to a math/science/fine art student circa 1980, without bounds, indistinguishable from magic)
The distance-at-lightspeed function may not be any kind of continuous, but it can obey statistical scattering laws. On average, the quantum-scale fluctuations in observed particle position give way to nineteenth-century macroscopic Newtonian mechanics. Everything’s works out the same. The only difference is, the past, the future, everything, is (gestures to the woods and sky) out there.

Somebody should mention Karl Popper, or experimental falsifiability, but it’s 1980, and it’s a cabal of drunken undergraduates at a school best known for producing band teachers, not physicists or mathematicians. Our teachers are Doctors of Education and unemployed spaceflight engineers and astrophysicists, and really haven’t done as thorough a job as a major university. Nobody has even heard of Popper. Somebody should whip out Occam’s razor and flay this story to ribbons, but the night is warm and magical, the tequila half gone, and the thought never crosses anybody’s mind. In the firelight dimly, one can make out the symbols of a derivation of Heisenberg uncertainty principle on someone’s tee-shirt, but nothing said seems to disagree with that.

The story teller should recognize the effect that his second dayjob is having on his perception of the universe. He’s carrying 15 semester-hours, working in sessions of a state-funded job tutoring introductory math, then getting down to serious programming after 6:00 PM weekdays and all day weekends. The hardware of the day are Apple 2 home computers. Getting them to render graphics in anything approaching a smooth manner involves drawing multiple pages in their 48 kilo-bytes of main memory, swapping it into one of the 2 pages of memory-mapped video, before the program switches to that page. His affection for a universe consisting of 10^68 pre-rendered, unchanging copies of the observable universe bears an uncanny similarity to his affection for pre-rendered pages of Apple 2 color graphics.

On some level, he does recognize it. Somehow, it just didn’t feel wrong.