Talk:Time

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[edit] Discussion

New page, previous talk moved using TW. —Yamara ✉ 09:01, 18 February 2008 (UTC)

user Neverquick deleted my changing, he does not believe our in time machine, but the science is not a religion, so please do not delete if You are not agree, it' s not a reason to delete it a reason to reasearch and try to understand.Ryururu (talk) 06:42, 16 March 2008 (UTC)

If there is research needed such as you indicate, the reports cannot be cited as reporting matters of fact regarding time.
Wikipedia has an explicit policy against publishing original research. It also has high standards regarding the factual content of articles. Statements need to be supported by reputable sources. In the sciences, this typically means that at minimum a statement has been made in a peer-reviewed journal and credible dissenting views are also reported. P0M (talk) 07:00, 16 March 2008 (UTC)

[edit] Dogmatic assertion

Within science, the only definition needed or possible is an operational one, in which a procedure is given for defining the base unit of time (the second).

The above statement is dogmatic. It is also indefensible and unscientific. Even the presumed "fact" that only an operational definition (or, actually, operational definitions) are currently acceptable among scientists is stated dogmatically. Anytime one makes a statement using the word "only" as it is used above, an incredible burden of proof is loaded onto the writer. And, besides, the statement is contradicted by what is well attested in other, competent, writing within Wikipedia (not to mention standard physics books).

An operational definition of time says, basically, "Time" is what we call the measurement or quantity we get when we compare the beginning and end of one operation (or some number of cycles of some regular operation like the swinging of a pendulum under standardized conditions) with the beginning and end of some other operation. But the number associated with "t" in such a case does not even have a direction. Working with devices like clocks, which incorporate an operational definition of time, researchers are puzzled by the direction of time. (I can establish a line from New York to D.C., start laying my meter stick along the line at a point in NYC and stop counting when I get to a point in D.C. Or, I can start in D.C. and end up in NYC. So why can't I start laying out cycles of my stop watch with the birth of a hamster in my lab and stop the clock when the hamster dies of old age, but also start the stopwatch when the hamster dies and lay out cycles of its operation back to the moment of its birth?) Then, around the beginning of the 20th century, people begin to realize that identical clocks do not measure identical numbers of cycles if one of them takes a fast trip to Pluto and back. The measurement of time becomes inextricably implicated in the measure of space and movement in space. Then the question arises, "Why?" There is no answer for that in the operations used. To the contrary, the measurements and the operational definitions of "space" and "time" suggest that something is going on to link the two, and from that point some researchers have asked whether there is some realm of experience (perhaps at quantum measurement range) in which space and time "collapse" into something more basic.

"Space-time" turns out to have more explanatory value than just "space" and just "time." The operational definitions for the measurement of time are profitably brought into cojunction with the operational definitions for the measurement of space, for motion in space, etc. It is not clear whether space is nothing but the relationships among things, or whether space has characteristics of its own. Similarly, it is not clear yet whether considerations of entropy and use of the operational definition of time will be sufficient to exhaustively delineate the nature of time.

If science can discover something about time that is not a function of the operations by which we make what are called "time measurements," then on what grounds can the writer preemptively exclude that knowledge from the definition or the understanding of time in the sciences?

The "Within science" part is clearly argumentative. Why start the article by taking a dogmatic and argumentative stance? P0M (talk) 04:56, 20 February 2008 (UTC)

I've had my qualms about the sweeping scope of the phrase "within science": ie geology and palaeontology use relative dating, so a precise chronometric unit may be of less importance than a sequential placement of events. The adjective "only" and the verb "needed" are problematic and presumptive. But I don't find the sentence forwarding an "argument" so much as a rough attempt at categorizing the many perspectives on time in the opening of the article. The opener demands a conciseness and clarity that is also useful to the reader. And it has to be accurate, of course. Can the sentence be replaced with a more perfect description in thirty words or less? Don't forget to preserve a mention of the SI second. —Yamara ✉ 07:11, 20 February 2008 (UTC)
I don't think it needs anything more than tweaking. I've started to take a look at the whole article, so I may wait until I've gotten a better grasp of the whole and then tweak the top. No use in making a change topside that will mess us something later down. P0M (talk) 04:55, 21 February 2008 (UTC)

[edit] Hourglass analogy

Trying to take a wikibreak, but we know how that is; as soon as you announce it something you've been wanting to address moves to the fore.

The caption under the hourglass pic describes the analogy—("The flow of sand in an hourglass can be used to keep track of elapsed time. It also concretely represents the present as being between the past and the future.")—and I believe it was placed there by JimWae on January 9.

It's a truly brilliant analogy, and one that ought to have been seen before. I'd been working on Hourglass before my break, but never got to ask—where did JimWae get that phraseology? It would very sad if it were OR, since "concretely represents the present as being between the past and the future" is very insightful and helpful to readers (IMO).

BTW - It's a philosophical analogy, but is describing the hourglass appropriate for the religion & mythology section? I haven't found references yet suggesting the hourglass is older than the 11th century AD, and would be unknown to the early Greek philosophers. —Yamara ✉ 20:44, 26 February 2008 (UTC)

I took out the part in the text about the famous third century hour glass analogy. I thought it would be easy to find by Googling it, if it were indeed a famous analogy. Unfortunately most of what I found were in clones of Wikipedia, and no indication of a real locus classicus.
The hourglass is a very good way of talking about time "flow" or "the arrow of time" as something closely related to entropy and/or probability. First, for the hourglass to work we have to supply energy by lifting the sand above the level of the tiny gap in the middle. Second, when a grain of sand falls it can hit just about anywhere below, and then it will probably bounce a couple of times. So that is at least two or three low probability events and their joint probability is X x Y x Z, i.e., extremely low. The probability that some blow coming from beneath the same grain of sand would launch it in the correct trajectory to drive it back up way it came is almost infinitestimal. Getting a string of luck that would drive all of the grains of sand up the way they came down (and against gravity) is not an event that one should bet the family farm against.
So getting "time" requires an energy source to drive things along, and a universe that has probabilities. Getting a universe that would permit the reverse "flow" of time would demand our getting into a very different kind of universe (or maybe restricting ourselves to considering only individual quantum events in this universe). The next question is whether one could imagine a sequence of events in which the outflow of the hourglass would go through some kind of warp and become the inflow at the top of the hourglass. That's only a rough analogy, but it suggests one idea of time travel (or at least communication backwards in time) in which a signal is sent from one intertial frame to another, and eventually gets bounced back to the first inertial frame before it was sent out. But, if I recall correctly, that scenario would only work if signals could have a velocity greater than c.
But regarding a grain of sand in the hourglass, all one really can say is that its passage from wherever it starts in the upper chamber to where it ends up is a process that occurs in time. "The present" is not at the neck of the hourglass. The nearest we could get to that is to look at the path of the grain of sand in a movie and stop the projector on the frame where the grain of sand is in the neck. The movie film that has already passed through the projector would record the "past" from the point of view of the frame that is currently being paused in the gate of the projector, and the movie film yet to be shown would represent its "future" from that arbitrary definition of what the present is.
In a sense, the person standing outside the "universe" of the hourglass can see the past and future of a grain of sand, at least in general terms. If the grain of sand is near the neck, the observer can be pretty sure that it was originally higher up, and the observer can predict that it will end up somewhere in the bottom chamber. But then the real master experimenter beams the hourglass into outer space, gravity ceases to pull sand from one chamber to the other, and its future is suddenly to stay just where it is. P0M (talk) 02:51, 27 February 2008 (UTC)
By the way, if anybody can supply the warp then we have an inexhaustible energy supply. We just put a little paddle wheel in the outflow and connect it to a generator. P0M (talk) 03:02, 27 February 2008 (UTC)

[edit] Semi-protection

I think it is about time for this page to be Semi-protected as it is constantly being vandalized by IP's. N.B. This is the first time I am in need of Admin. with the exception of Speedy deletes. Zginder (talk) (Contrib) 23:19, 26 February 2008 (UTC)

[edit] When do we start measuring time?

An open question,"When do we start measuring time?" Some scientists agree that we start measuring time after the "Big Bang". I disagree. Time begins at the point of observation. Everything else is computer model of what our modern concept of time could have been millions of years ago. What do you think?

Who is the "we" of whom you speak? Who was around to measure the time at which life on Earth began?
Without getting into the argument of that time is (relationship or something real in itself), measuring time implies that there are processes of sufficient regularity to make counting their cycles useful to some lifeform, and that there is a lifeform around to do the measurement. Of course that doesn't mean that the moon wasn't circling earth before the first oyster started timing its ovulation to the times and the tides.
We can measure things like how long it takes to lay down an inch of sediment in a lake and then work backwards to date things not according to current observations of clock cycles but according to inches of sediment (and what was caught in it) in existing lake beds. When we go back to the earliest times in the Universe we have the advantage of the natural "time machine" presented to us because it because things that we see that are the farthest away in space are also the farthest away in time. So by panning from near to far we can pan from nearby times to far back times, and we can measure the progress of events that happened long ago. P0M (talk) 14:47, 8 March 2008 (UTC)

[edit] "Is time worth measuring if there is no organic life?"

TIME. An Open Question for Discussion. "Is time worth measuring if there is no organic life?" After all it is organic life which came up with the concept of time and how it relates to the beginning, size and evolution of what we call, "The Universe". —Preceding unsigned comment added by 64.231.14.90 (talk) 23:47, 7 March 2008 (UTC)

Does time exist if nobody is there to experience it? Does a tree that falls generate noise if no-one listens? Does a comment exist if no-one reacts? Can anyone tell me why the heck I rendered above comment existent..? ;) JocK (talk) 07:53, 8 March 2008 (UTC)

[edit] 'Time as a measure of resistance'

One thing I wonder is if it possible to think of time in terms of resistance to force. That if A has no resistance in reaching state, or location, B then the dimension of time is not present, yet there is still space dimensional change. Also, what would that type of a change be defined as? I know this is a metaphysics question, just curious as to what people think. It would be a singularity would it not? --99.225.10.18 (talk) 09:39, 11 March 2008 (UTC) Now that I think about it, I doubt there could be space without time. XD --99.225.10.18 (talk) 11:23, 11 March 2008 (UTC)

There is a long history of working out such logical connections, etc. Is space a thing (does it exist?), or is it only something that appears within a context of the relations that exist among things? Is Euclid's geometry the only geometry?
Suppose that all actions occurred instantaneously, or that light traveled instantaneously. If things traveled instantaneously they would be everywhere at once -- whatever that means. If light traveled instantaneously that would mean that inter-atomic events would occur in a radically different way. (Just look at how many fundamental formulas contain a c or a c squared factor.) (fixed omission P0M (talk) 10:42, 15 March 2008 (UTC))
If you want to start on the ground floor, look for a library that has a copy of Gottfried Martin's Kant's Metaphysics and Theory of Science. It's a very useful book because, while it centers on Kant, it covers the history of the concepts of space and time from the early Greeks, through Leibniz, into Kant, and beyond to Einstein. P0M (talk) 15:23, 12 March 2008 (UTC)
That sounds like something I'd enjoy reading. Thanks for suggesting it. I'll look for it this weekend. --99.225.10.18 (talk) 07:39, 15 March 2008 (UTC)

[edit] Time as an observable set of wave-function collapses.

It seems to me that the fact that we humans can only observe one history of the universe needs some mention. Theories of the history of the universe that do not necessarily agree with that we can observe and/or experience abound. That we cannot observe those histories is a point that seems to be omitted when those theories are discussed. This is an important omission. I could repeat similar criticisms about many physics-related topics. A stress toward exactness seems to be overwhelming encyclopedic-style writing.Wildspell (talk) 08:14, 8 April 2008 (UTC)

I'm not sure what you mean. First, you imply that there is some "history of the universe" that we cannot observe. How can we do other than imagine or speculate about something that nobody can observe? Second, you imply that there is one account of the "history of the universe" when in fact one of the problems is that accounts of what are going on can so easily differ if stringent controls are not maintained and differences in perspective, e.g., people in different inertial frames, are not taken into account.
Different models to account for the development of the universe exist. One of the frontiers of our knowledge is the very earliest time after the big bang. As scientists recover evidence of earlier and earlier periods by detecting radiation from farther and farther away, the models we have that will fit with the evidence will change.
The difference between what we can observe and what we theorize is always in play. We take whatever we do see and whatever remains in the natural black box is something that we have to make up our own models to explain. Then maybe we make one more observation and see something that strongly suggests that our model is the wrong one. Two things tend to happen at these points: (1) We have trouble giving up on something that has been enormously helpful, e.g., Newtonian mechanics. So the first thing that people are likely to do is to explain away the difficulty, or, if that doesn't work we can just paper over the defect and continue to use the model -- just keeping away from the places that it doesn't work. Sometimes we have discovered that a theory such as classical physics is a special case of a more general theory, and that if we apply the more general theory we get the same answers except in special ranges of experience (speeds that are substantial fractions of the speed of light, for instance). At other times people may be forced to admit that the old model just was not right, and they have to be abandoned.
Are you possibly referring to subjects like the search for previously undocumented animals, or subjects like ball lighting that seem hard to make jibe with physics?
What does your topic have to do with what your wrote below? One group of people who theorize in the area of quantum physics speak in terms of the collapse of wave functions, but nobody actually observes the phenomenon. What we observe is the appearance of a photon or other particle at some specific time and place. Or, to avoid circularity, we might say that we observe events that some postulate are due to the collapse of wave functions, and we are somehow convinced that they are serially related and that the series is not reversible.
One of the problems with that kind of account would be that in quantum entanglement versions of double-slit experiments, a photon that is detected at t=3 can determine how a photon is detected at t=2, so the idea of sequence mentioned above no longer holds. P0M (talk) 19:27, 8 April 2008 (UTC)
I am not sure that there is only one history that we can observe. I have had many instances where I remember specific events that those who were involved will later tell me happened in a completely different way. I would chalk this up to faulty memory except that a rare few remember things the same way I do which indicates that some of us are changing parallel universes where the flow of history is not as it seems to those around us who did not come from our universe (^_^)Jiohdi (talk) 19:16, 17 April 2008 (UTC)
One of the consequences of Special Relativity is that events that observers in one inertial frame identify as simultaneous will be observed to occur at different times by observers in another inertial frame. So even if one uses the most complete recording devices, there are problems with the "one history" idea.
Then there is the problem that may occur if two or more observers have very complete recordings. If it really happened that my neighbor and I recorded a view of the street from our security cameras and when we compared tapes one showed that there had been a mugging and the other showed there was not even a single person on the street at the same time, then maybe the multiple universe idea would have merit. But we'd also have to ask why somebody with no history of interest in burrs and stick-tight out of nowhere invented Velcro. I.e., there are generally antecedents to discoveries like that which make sense, so if there were many cases of such "spontaneous attacks of genius" we'd probably have noticed by now.
One of the things that psychologists have determined about witness reports in crime cases is that people's memories are very selective and not very reliable. One of the most glaring problems with memory is that if someone is led somehow to visualize an event as if s/he had perceived it in person and in fact, then it becomes a memory that "replays" in no way distinguishable from the "replay" of an event the person really saw. A similar thing can happen when someone reviews an old memory over and over again. There may well be an active component, a sort of mental editing, involved, and each time the memory is reviewed it gets changed a little more.
I'll let you know if the wife I never had meets me at the doorway of my spick-and-span cottage. It will be too bad for the me in whatever universe she comes from. But, wait... How will I recognize her? And then there is the loutish teenager who demands to know where his heavy metal posters, etc., have gone to. But I'll be sure to let you know... P0M (talk) 20:51, 17 April 2008 (UTC)

[edit] Time as a World Standard

Since time is essential to history and chronology, a short section might address when the present seconds, minutes, and hours became universal. Perhaps it's unknowable but I suspect that most of Asia and Africa must have adopted the Western standard c. the 18th century.

B Tillman 15 April 2008 (Tax Time!)

Good question. There were interactions between Egypt and the Middle East (particularly Judea) very early on. Their ideas on time have determined many of our ideas on time, particularly the division of the day into 24 periods, the idea that each of the planet-gods had charge for a time period in regular rotation, and the resulting way that the days of the week got their names.
At least the major outlines of these ideas were known in China around 50 a.d. The Chinese divided the day into twelve watches, i.e., into two-hour periods. I suspect that as a practical matter the division of the day into hours must have coincided with mechanical clocks, and they may have been imported by Catholic missionaries around the time of Leibniz.
When the further division of the hour into 60 minutes came about must be recorded somewhere. There is apparently a practical connection between the number of days in a year and the division of the circle into a rounded version of that number, 360 degrees. All over the world at the dawn of civilization people were aware of the five planets. (Astrologers are still fascinated with some of the ideas that drove lots of early interest in the planets, so it's an enduring idea.) There are 12 months, which is an idea we get from lunar cycles, 12 * 5 = 60, human heart rates average out to something close to 60/minute (particularly for shepherds and other people in good physical condition), and 60 * 60 gives the number of seconds in an hour and the 360 degrees in the circle and approximates to the 365.25 days/year. So all of these numbers hang together. Also, we see traces of numeration base 12 in things like our idea of the dozen (12) and the gross (12*12).
So my guess is that time to the base 12 must have been a common idea throughout Eurasia very early on. I have no idea about pre-Muslim Africa or the pre-Columbian Americas.
Probably the best one could do would be to find the earliest mentions of "24 hours in the day," "60 minutes in the hour," and "60 seconds in the minute." Linguistic traces suggest to me that the Chinese, before missionary-led calendar studies, divided the hour into quarters. Books on technology might tell us when the first mechanical clock was made. It's pretty hard to imagine dividing the hour into standard units with tools like the water clock or the hour glass. On the other hand, a big enough sun dial would have probably encouraged people to divided the dial into degrees, so maybe that could have led to the definition of a minute.
Joseph Needham's Science and Civilization in China might have the information somewhere in one of its many volumes. If you are around a library that has the whole set you might give that source a try. There are also encyclopedias of technology. P0M (talk) 01:29, 16 April 2008 (UTC)

[edit] Archaic systems of time measurement

 Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion.

This article is lacking discussion of systems of time measurement other than the current international one, for units smaller than a day. There are many different units listed in the particular articles linked from Systems of measurement, such as Chinese units of measurement. History of measurement could potentially be expanded to provide an overview of this topic, with a very short summary in this article. -- Beland (talk) 17:45, 5 May 2008 (UTC)

Ideally, archaic systems of time measurement would be collected in an article demonstrating their creation, period of use, and obsolescence. A chronology of chronometry, as it were. History of calendars and History of timekeeping devices both have useful information, but how the clock and the calendar interact across history is little explored.
That being said, the main Time article needs to remain a broad and relevant overview, and has little room for more than a summary of any approach to understanding Time; indeed, I think it would be useful to have most of the detailed information on the history of clocks moved off to be handled by History of timekeeping devices. The timekeeping methods (and reasons) of other major cultures should certainly be mentioned in the main Time article, but even notable details belong in other articles. The subject is simply too vast, and finding the balance between the extremes of too much detail and being a glorified List page is where the article will achieve its goal of being informative. --Yamara ✉ 20:42, 5 May 2008 (UTC)
As I've indicated above, the subject is universal (as far as I know) in the ancient past (days, moons, years being obvious, but dividing the day into shorter periods -- except the variable units day and night -- has no natural unit. Providentially (or maybe due to cultural transmissions) the two ends of Eurasia settled on 12 watches and 24 hours. Anybody know what the Muslim world worked on? India? But as soon as mechanical clocks came into existence they had a pervasive influence. Technology drove language, for instance. The Chinese "hour" is "little time unit" (xiao shi) because it is half a "normal" time unit. Nobody figures time in the old 12 unit system anymore. As far as I know, there are no base-16 time systems, base-10 time systems... Maybe the Mayans had a different system. Those brief determinations ought to do it for this article. P0M (talk) 21:07, 5 May 2008 (UTC)
I did a preliminary survey of Mayan time ideas. They divide the day into four periods, according to some sources. But then if you look farther you will find indications that they divided the daytime hours into four periods, and the nighttime is not divided. Anyway, they do not seem to have ever divided the day into small units. The Muslim societies were quite well aware of Greek philosophy during the dark ages when that stuff had been forgotten in Europe. So they probably took over the 24 hour day from them if not more directly back to Middle Eastern sources. P0M (talk) 23:22, 5 May 2008 (UTC)

[edit] Boldness strikes: Shake up in religion & mythology

I've removed the following from the "Time in religion and mythology" section, following a sentence about Greek philosophers:

One analogy compared the time of life to the passing of sand through an hourglass (a common measuring device for time in the past). The sand at the top is associated with the future, and, one tiny grain at a time, the future flows through the present into the past (associated with the sandpile at the bottom of hourglass). The past: ever expanding, the future: ever decreasing, but the future grains become amassed into the past through the present.

My work on Hourglass suggests ancient Greeks didn't have hourglasses. Also, looking in the history, this statement was tagged "citation needed" in February 2007, but never got one. I've said before that I like the image, a lot, but there's simply no cite for it.

Finally, I've moved the opening of this section down to "Time in philosophy", since it's, well, philosophers talking philosophy. There are plenty of gods one might mention under the "religion & mythology" header, but these ain't it. --Yamara ✉ 22:25, 5 May 2008 (UTC)