Time

Time is a physical size type. The symbol of the time t, its SI unit is s, the second

The time describes the sequence of events has thus, in contrast to other physical quantities a unique, irreversible direction. With the help of the physical principles of thermodynamics this direction can be seen as increase of entropy, that is, of disorder in a closed system can be determined. From a philosophical perspective, the time coming describes the progression of the present from the past to the future hinführend. According to relativity theory, the time with the space forms a four-dimensional space-time, in which time plays the role of a dimension. The term of the present is defined only at a single point, while other points of space-time that are neither in the past nor the future of this point be referred to as " spacelike separated " from this point.

The SI unit system, the time of a plurality of basic parameters from which other values ​​can be established.

The civil time ( UT, CET, etc. ) depends approximately on the Sun and by state regulations within a certain time zone uniform.

In philosophy has always asks about the nature of time, which also touches on issues of belief. For the physical, the biological and human sciences, the time is a key, also detectable by measurement parameter, including all moving bodies (dynamics, development ) in chronobiology or the sociology of time. The psychology examines the perception of time and the sense of time. The economy considered time as a valuable asset. In linguistics means " time " the grammatical form of the verbs, the tense.

• 4.1 The perception of time
• 4.2 The perception of simultaneity

Introduction

The most striking feature of the time is the fact that there always seems to be a current and excellent location, in a sense, we call the present, and that seems to be inexorably moving from the past into the future. This phenomenon is referred to as the flow time. However, this flow eludes scientific observation, as explained below. The humanities can not clearly answer the question.

The time used in physics in the same way for the description of the events as space. The physics simply implies that under all possible structures, only those observed in three-dimensional space in combination with all possible time sequences that obey the laws of physics. This could just as well involve immovable structures in a four-dimensional space, which are subject to the laws of physics certain geometric conditions. Something that could be interpreted as the flow of time, does not occur in physics. On closer inspection it turns out to actually be totally unclear how a flow of time could be precisely described in the physics or mathematics or any other language of science.

For example, the statement that the time flowed, only makes sense if one of them distinguishable alternative is feasible. However, the obvious alternative to the notion of a time allotted for example, leads to a contradiction, since it is conceivable only from the perspective of an observer, for the time continues to elapse so that the standstill adopted as such is noticeable at all (see also Critique of Pure Reason by Immanuel Kant). If we could stop time, for how long " would " then the time?

The apparent flow of time is therefore considered by most physicists and philosophers as a purely subjective phenomenon or even as an illusion. It is believed that it is very closely linked to the phenomenon of consciousness, which, like this a physical description or even defies explanation and is one of the greatest mysteries of science and philosophy. To ensure that our experience of time would be comparable to the qualia in philosophy of consciousness and would consequently with reality as little to do as the phenomenal content of consciousness in the perception of the color blue with the associated wavelength of light.

Lapsed would be that our intuitive notion that there is independent of the person 's own instance of the manner of a cosmic clock, which determines at what time we all experience the moment together, and thus the presence of connecting all makes an objective us now.

Time as a physical quantity

In physics, time is (symbol: t or τ, from Latin tempus (time )) is the fundamental quantity that can be determined on the along with the space, the duration of tasks and the sequence of events. Since they can not so far be traced back to more fundamental phenomena, it is defined on methods for their measurement, as is the case with space and mass. In the SI unit system time is measured in seconds ( unit symbol s ). From this derive directly from the units minute and hour, indirectly (via the earthmoving and statutory leap seconds ) and day and week, plus (depending on the calendar) month, year, decade, century and millennium.

Timekeeping

The time measurement is one of the oldest tasks of astronomy. There, between a solar day ( civil time ) and a sidereal day is distinguished, which differ by one day a year. The solar day is not a whole number of seconds after SI; the difference was made by leap seconds. These problems led to the introduction of different time scales:

• Ephemeris Time (1960 ) to compensate for the irregularity of the earth's rotation;
• TDT (Terrestrial Dynamical Time, "Earth atomic time " ) from 1984; it is based on the SI second;
• TCB ( Barycentric Coordinate Time), the proper time of the barycenter of the solar system.
• Geocentric Coordinate Time ( TCG), the proper time of the Erdmittelpunktes.

Astronomical data and times are often useful as a Julian date ( JD) or modified as specified MJD.

Now is the time in physics, such as other measures too, operational, that is, a measuring method, defined. Time-measuring systems are mainly used, the return to the same periodic state. The time is then determined by counting the number of periods. Such a device is called a clock. However, repetitive movements that can be based on time measurement, eg in the earlier sand and water clocks.

A clock is the better, the more accurate the periodic process is reproducible and the less he can be influenced by external conditions, such as mechanical disturbances, such as the temperature or air pressure. Therefore, quartz watches are much more accurate than mechanical watches. The most accurate clocks are atomic clocks based on atomic vibrational processes. So that a relative speed error of 10-15 is reached, corresponding to a second variation in 30 million years. The time and the frequency, its mathematical inverse of, the physical quantities that are with the highest precision at all measurable what has led to the definition of the length in the meantime at the time is fed back by the meter as the jenige route defined, traveled by light in vacuum during 1/299.792.458 seconds.

Newtonian physics

Isaac Newton describes the phenomenon of time with the following words:

" Absolute, true and mathematical time elapses in itself and from its own nature is uniform and without reference to any external object. "

The term " absolute time " was in physics to formulate the special theory of relativity in 1905. He is still the everyday human understanding of the phenomenon time basis.

Quantum mechanics

Although the energy-time uncertainty relation, at first glance, has the form of the Heisenberg uncertainty principle, it is of a different nature. In quantum mechanics, the time is a parameter. An operator for the time there is not. In attempts to introduce him one encounters contradictions.

Relativity theory

Through the discoveries in connection with the theory of relativity the Newtonian concept of absolute time had to be abandoned. To assess observer moving relative to each other, timing different. This applies to the simultaneity of events that take place at different locations, as well as the time period between two meetings of two observers moving relative to each other between the meetings ( time dilation ). Since there is no absolute coordinate system at rest, the question is, which observers judged the situation correctly, does not make sense. One therefore assigns to each observer to his so-called proper time. Furthermore, the presence of mass effect on the course of time, so this passes at different rates in different places in the gravitational field. This is Newton's assumption that the time verfließe without reference to external objects, no longer tenable.

Time and space appear to be almost entirely equivalent to the basic equations of the theory of relativity together and leave unite to form a four-dimensional space-time therefore. In three-dimensional space, the selection of the three coordinate axes is arbitrary, so that terms such as front and rear are the left and right, up and down relatively. In the special theory of relativity now turns out that the time axis is not absolute. To change the state of motion of an observer and the orientation of its time and space axes in space-time. It is a type of shearing movement of these axes which is closely related to the mathematical rotation. Thus, space and time can not be separated clearly, but depend in some way from one another. The results are phenomena such as the relativity of simultaneity, time dilation and length contraction. These discovered in connection with the theory of relativity, properties of time and space beyond the largely human intuition. However, they are mathematically precise written and - if experimentally accessible - also well confirmed. However, the time axis can be explained by a movement not turn around, that is, past and future can not be interchanged.

Time is not necessarily unlimited in the general theory of relativity. So many physicists expect that the Big Bang is not only the beginning of the existence of matter, but also represents the beginning of space and time. After Stephen W. Hawking has a date " one second before the Big Bang " nor given as a point on the earth, is 1 km north of the North Pole.

Time travel

The above-mentioned relativistic effects can be interpreted as time travel in principle. On the curvature of space- time and other phenomena also travel into the past are possible in principle to what extent, is not fully understood. Possible candidates are called wormholes could link the areas of space-time with a different time as well as special trajectories in the vicinity of a sufficiently rapidly rotating black hole and build the environment of two cosmic strings that pass sufficiently fast to each other. The effort required for a practical use of these potential opportunities, however, would present the means of mankind exceed by far.

The paradoxes that occur when traveling to the past could be avoided in the context of Plenty by Everett worlds theory. After that would be the past, in which one travels, settled in a parallel world. The original sequence of things and modified through time travel would play both parallel and independently.

Time travel is a popular theme in literature and film → time travel # time travel in literature and film.

Time and causality

The concept of time is closely related to the concept of causality. So we take it for granted that the cause occurs before its effect, more specifically any observer of correlated events will describe the process so that in his model of the process, the effect is due to the cause. The past is immutable, it can not be influenced by current events. The future, however, depends upon the presence from causal, so it can be affected by events or actions in the present.

In the theory of relativity is the chronological order of some events that take place at different locations and are perceived differently by observers moving relative to each other. This is exactly the case if the two events could contact only by a signal faster than light. Could an interaction to take place faster than light, then you could send a message with the following system in the past:

Therefore, the principle of causality would be violated. Mid-20th century has been suggested that there could be superluminal tachyons. Should they be ordinary matter can interact, the causality would be violated. The hypothesis of the existence of tachyons therefore has little trailer.

For the symmetry of the two directions of time

The laws of physics that underlie the fundamental forces of the phenomena of our everyday lives, are invariant with respect to inversion of time. This means that for every operation, which obeys these laws, and the time-reversed, in principle, possible. This statement is in stark contrast to our everyday experience. If a ceramic cup to the ground, it breaks into pieces. That reversed these shards of itself back to an intact cup together, on the other hand has never been observed. However, such a process would not in principle contrary to the laws of nature. He is just extremely unlikely.

The background of this circumstance is a likely consideration which is formulated in the second law of thermodynamics. After taking the entropy, which indicates the degree of disorder of a closed system to keep and thus its order from. A transient increase of order is in principle not excluded, but depending on the size more or less unlikely. To provoke the spontaneous reunion of broken glass into a cup, you would have to create more than astronomical number of shambles and watching.

The second law of thermodynamics - and the associated friction phenomena - that violate the symmetry with respect to the two directions of time. It can therefore not be derived from the basic laws of physics, but has the property of a postulate. The two directions of time lose their equivalence, and one speaks of the thermodynamic arrow of time. He is regarded as a potential basis for the flow of time from the past to the future, as we experience it in our everyday world.

Often talk in this context of a reversibility or irreversibility of time. However, it is a linguistic and logical inaccuracy. Could someone turn back the time, then he saw all processes run backwards. This reversed the course of time would be only from the perspective of an observer recognizable, which is subjected to a kind of personal time, which is still running forward unchanged. Such division of time into one that is subjected to an experiment or thought experiment, and another unchanged, but has no meaning.

The laws of physics that describe the phenomena of weak and strong interactions are not invariant with respect to a time reversal. To a process in the field of nuclear and elementary particle physics is the time-reversed therefore not necessarily compatible with the laws of physics. The CPT theorem states that the process is again in accordance with the laws of nature when it is not only time- reversed, but additionally considered a mirror image and is composed of antimatter. Follows from the CPT theorem that processes which constitute a so-called CP- injury, as is the case with some Teilchenzerfällen may be a time reversal is not invariant.

In the formalism of the description of antimatter antiparticles are equivalent to ordinary particles that move in a sense backward in time. In this sense, the pair annihilation of a particle with its antiparticle, a formal similarity with a single particle begins to move back at this point in time so that it does not exist there twice and in the future.

Boundaries of the physical concept of time

There is strong evidence that the phenomenon of time loses its properties as a continuum in the Planck time of 10-43 s. So leads the consistent application of the known laws of physics to the conclusion that every process that is shorter than the Planck time, can only be assigned to an object, which must immediately collapse into a black hole (see Planck units). This consideration shows that the known laws of physics break down beyond the Planck time. A clarification of the issues involved it is hoped that a yet to be developed theory of quantum gravity that would unite the two fundamental theories of physics, the theory of relativity and quantum physics. In such a theory, the time might be quantized in the Planck time. So you go for example in loop quantum gravity, a candidate for the theory of quantum gravity, assuming that the structure of space-time is a four-dimensional, foam-like spin- network with "bubbles" of the order of the Planck units. However, one must be this " foam " not imagine embedded in space and time, but the foam is in this theory, space and time.

Philosophy

In ancient times, inter alia, the philosopher Plato, Aristotle and Augustine have dealt with the concept of time, in modern times, especially Newton, Leibniz, Kant, Heidegger, and Bergson.

For Plato, time and space have no essence, but are just moving images of the actually existent ( theory of ideas ). For Aristotle, the concept of time is inextricably linked to changes, time is the measure of every movement and can only be measured by these. They can be divided into an infinite number of time intervals divided ( continuum ).

Augustine distinguishes between a physically accurate ( measurable ) and a subjective, experiential time for the first time. Time and space emerged only through God's creation, for whom everything is a present. The mystery of time summarizes Augustine as saying together: " So what is 'time'? If nobody asks me, I know it; I want to explain it to a questioner, I do not know. " ( Confessions, XI, 14)

For Isaac Newton make time and space, the "container" for events, they are as real as representational objects for him: "Time is, and it is ticking smoothly from moment to moment. " In the natural philosophy of Newton dominated view because it allows time to describe and space independent of a reference point or observer.

In contrast, Gottfried Wilhelm Leibniz says that time and space are only mental constructions to describe the relationships between events. They have no "essence" and that there was therefore no " flow" of time. He defines the term as follows: " Time is of the order of not yet existing. It is therefore the general order of the changes is in fact not seen on the particular type of change. "

According to Immanuel Kant, the time is just like the space a "pure form of intuition " of the internal sense. Be our approach to the world, that belonged to the subjective- human conditions of knowledge of the world, human consciousness experienced in the form of sense impressions.

Kant, however, you write to an empirical quality for time measurements and remote events. We can not think away time from our experience and not tell whether they are a - plays world itself - whatsoever. Similarly, describes Martin Heidegger's main work " Being and Time " the latter as a reality that profoundly shapes the human condition.

Psychology

Subjectively perceived between the time and the objectively measurable often exist significant differences. The following sections will briefly describe these and clear.

The perception of time

The perception of time depends on what happens in time. An eventful period appears briefly, " Flies ". In contrast, take uneventful periods sometimes agonizingly long. From this observation, the terms Kurzweil and boredom derived.

Paradoxically, one feels, in retrospect, the times just the opposite: In busy times it has stored a lot of information, so this time period seems long. Conversely appear shortly uneventful times in retrospect, there is little information about them is stored.

The perception of simultaneity

Simultaneity in perception is more complex than it at first glance seems. There are different thresholds:

• The threshold, two events are detected as separate from the on your particular sense organ dependent. Thus optical impressions have 20 to 30 milliseconds apart, to be separated in time, while for acoustic perceptions suffice three milliseconds in humans.
• The threshold at which the order of two stimuli can be distinguished, is independent of the kind of perception about 30 to 40 milliseconds, but is always oriented according to the slowest stimulus transmission.
• In addition, the perception of the present is indicated by a three-second period, this period is called the present time.

Biology

Almost all living things, to the protozoa, have a biological internal clock that synchronizes with the day - night cycle and other natural cycles. However, the internal clock to the daily rhythm runs even without daylight, as demonstrated on plants in the dark, but also to people in the bunker experiments in which lived the volunteers without any reference to external rhythms. Here, a constant sleep-wake rhythm in the middle of about 25 hours presented itself after some time. It is called the circadian rhythm (from the Latin circa, about, and lat this day).

Comparative Cultural Studies

The comparative cultural studies and philosophical reflection on lead more and more to the conclusion that it does not exist at the time as an anthropological constant that belongs to all people equally, but only several culture-specific concepts of time with various structures such as the cyclical pre-Socratic and the Naturethnien which is documented in the acceptance of the eternal recurrence of the same, the eschatological, that has a beginning and is directed to a final destination and also the pre-modern conception of history determines the straight - continuous, coming from the past and the present into the future continuous, the maximum rate in the traditional physics and we usually assume today as universal, but which is a Western cultural product, the dilating that spreads in every moment and to explain the concept of time in quantum theory can (see Everettsche More World theory).

Sociology and Society

Time in the literature

" Human existence is realized in designing the future, Keep of what has been and Entspringenlassen the present. Therefore, it is to be understood by the process of their maturation ago. A preferred form of Zeitigens is telling. When and how the process of Zeitigens insert on how it unfolds and how it ends -. Everything that is creation of the narrator "

• Walter Biemel examines in his book maturation and novel structure. Philosophical analysis in the interpretation of the modern novel (Freiburg, München: Alber, 1985, ISBN 3-495-47548-6 ) the example of the five novels Indian Summer by Adalbert Stifter, Madame Bovary by Gustave Flaubert, The Magic Mountain by Thomas Mann, A Fable by William Faulkner and La Casa Verde ( the green house ) by Mario Vargas Llosa, the diversity of Zeitigens, with a different emphasis, a different interpretation of reality is visible in every novel.
• In the novel The Magic Mountain by Thomas Mann time is a central motif interwoven with the life / death issue. In it is discussed, inter alia, the extent to which " interestingness and novelty of content drive away the time, that is, shortening, while monotony and emptiness complain their gear and hemme " (short ). Is also discussed the problem of " narrate " of time, the relationship between the duration of a report and the length of the period to which it refers ( narrative time, narrative time ). The last two chapters gather six embossed for the fictional hero of routine and monotony years. In this process man Arthur Schopenhauer, the " timeless now ", Latin nunc stans. The asymmetry in the novel structure corresponds to the narrative level a distorted perception of time by the protagonists themselves
• In the novel In Search of Lost Time by Marcel Proust noted the novel's protagonist, that the past is preserved only in his memory. He realizes at the end of his life that a novel of his memories is the last opportunity to create a work of art, which he had set out to do. Thus ends the book by the author begins to write it. The " lost time " is ambiguous: Time that has wasted the narrator,
• Time that is lost if it was not preserved in the memory or in a work of art,
• Evoke memories or imaginations, the names or objects.

Tense

As tense is called the tense in grammar. There are different tenses that are formed differently in different languages. In the High German language, the time is shown in three ways.

• The tense of the verb allows the distinction of presence ( present tense) and past ( preterite ). Example: I go and I went.
• The provision of auxiliary verbs ( have, be ) allowed the distinction of past forms such as perfect and pluperfect. Example: I went and I was gone. In addition, auxiliary verbs are used (in this case be ) to display the future ( future tense ). Examples: I'll go. I'll be gone.
• Possible is an explicit indication of the time or period. Examples: Now I am going to school. Tomorrow I am going to school. Tomorrow I will go to school. It was yesterday, I go there just down the street, I see a twenty euro note.

A temporally persistent course you can also specify participle. Example: the flowing water.

One extreme case is the allegation of Benjamin Lee Whorf, who claims to have found in a study of the language of the Hopi that the Hopi language possessed no concept of the notion of time. This led to the linguistic relativity principle known as the Sapir -Whorf hypothesis that thinking depends on the spoken languages ​​.