Vrijeme (fizika)

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Vrijeme je fizička veličina i jedna od sedam osnovnih veličina SI sistema. Prema istom sistemu mjernih jedinica, jedinica za vrijeme je sekunda (1 s) dok je oznaka za vrijeme t.

Kroz historiju, pojam vremena je dugo bio važan predmet proučavanja u različitim oblastima ljudskog djelovanja, u religiji, filozofiji i nauci ali je definisanje jedinstvene definicije vremena koja bi se koristila u svim oblastima konstantno predstavljala probem naučnicima.

Vrijeme je kontinuirani slijed postojanja i događaja koji se dešavaju u naizgled nepovratnom slijedu iz prošlosti, preko sadašnjosti, u budućnost.^[1][2][3] To je komponentna količine različitih mjerenja koja se koristi za slijed događaja, za poređenje trajanja događaja ili intervala između njih i za kvantificiranje stopa promjene količina u materijalnoj stvarnosti ili u svjesnom iskustvu.^[4][5][6][7] Vrijeme se često naziva četvrtom dimenzijom, zajedno sa tri prostorne dimenzije.^[8][9]

Vrijeme je jedna od sedam osnovnih fizičkih veličina u Međunarodnom sistemu jedinica (SI) i Međunarodnom sistemu veličina. Osnovna jedinica vremena SI je sekunda, koja se definira mjerenjem elektronske prijelazne frekvencije atoma cezijuma. Opšta teorija relativnosti je primarni okvir za razumijevanje kako prostor-vrijeme funkcionira.^[10] Kroz napredak u teorijskim i eksperimentalnim istraživanjima prostor-vremena, pokazalo se da vrijeme može biti iskrivljeno i prošireno, posebno na rubovima crnih rupa.

Tokom historije, vrijeme je bilo važan predmet proučavanja u religiji, filozofiji i nauci. Mjerenje vremena okupiralo je naučnike i tehnologe i bilo je glavna motivacija u navigaciji i astronomiji. Vrijeme je također od značajnog društvenog značaja, ima ekonomsku vrijednost („vrijeme je novac“) kao i ličnu vrijednost, zbog svijesti o ograničenom vremenu u svakom danu iu životnom vijeku ljudi.

Sekunda je prvobitno definisana kao 86400-ti dio prosječnog sunčevog dana. Danas se prema SI sistemu sekunda definiše kao: trajanje od 9192631770 perioda zračenja, koje odgovara prijelazu između dva hiperfina nivoa osnovnog stanja atoma cezijuma 133Cs.

1. ^ "Oxford Dictionaries:Time". Oxford University Press. 2011. Arhivirano s originala, 4. 7. 2012. Pristupljeno 18. 5. 2017. The indefinite continued progress of existence and events in the past, present, and future regarded as a whole
2. ^ * "Webster's New World College Dictionary". 2010. Arhivirano s originala, 5. 8. 2011. Pristupljeno 9. 4. 2011. 1.indefinite, unlimited duration in which things are considered as happening in the past, present, or future; every moment there has ever been or ever will be… a system of measuring duration 2.the period between two events or during which something exists, happens, or acts; measured or measurable interval
   • "The American Heritage Stedman's Medical Dictionary". 2002. Arhivirano s originala, 5. 3. 2012. Pristupljeno 9. 4. 2011. A duration or relation of events expressed in terms of past, present, and future, and measured in units such as minutes, hours, days, months, or years.
   • "Collins Language.com". HarperCollins. 2011. Arhivirano s originala, 2. 10. 2011. Pristupljeno 18. 12. 2011. 1. The continuous passage of existence in which events pass from a state of potentiality in the future, through the present, to a state of finality in the past. 2. physics a quantity measuring duration, usually with reference to a periodic process such as the rotation of the earth or the frequency of electromagnetic radiation emitted from certain atoms. In classical mechanics, time is absolute in the sense that the time of an event is independent of the observer. According to the theory of relativity it depends on the observer's frame of reference. Time is considered as a fourth coordinate required, along with three spatial coordinates, to specify an event.
   • "The American Heritage Science Dictionary @dictionary.com". 2002. Arhivirano s originala, 5. 3. 2012. Pristupljeno 9. 4. 2011. 1. A continuous, measurable quantity in which events occur in a sequence proceeding from the past through the present to the future. 2a. An interval separating two points of this quantity; a duration. 2b. A system or reference frame in which such intervals are measured or such quantities are calculated.
   • "Eric Weisstein's World of Science". 2007. Arhivirano s originala, 29. 11. 2017. Pristupljeno 9. 4. 2011. A quantity used to specify the order in which events occurred and measure the amount by which one event preceded or followed another. In special relativity, ct (where c is the speed of light and t is time), plays the role of a fourth dimension.
3. ^ "Time". The American Heritage Dictionary of the English Language (Fourth izd.). 2011. Arhivirano s originala, 19. 7. 2012. A nonspatial continuum in which events occur in apparently irreversible succession from the past through the present to the future.
4. ^ Merriam-Webster Dictionary Arhivirano 8. 5. 2012. na Wayback Machine the measured or measurable period during which an action, process, or condition exists or continues : duration; a nonspatial continuum which is measured in terms of events that succeed one another from past through present to future
5. ^ Compact Oxford English Dictionary A limited stretch or space of continued existence, as the interval between two successive events or acts, or the period through which an action, condition, or state continues. (1971).
6. ^ * "Internet Encyclopedia of Philosophy". 2010. Arhivirano s originala, 11. 4. 2011. Pristupljeno 9. 4. 2011. Time is what clocks measure. We use time to place events in sequence one after the other, and we use time to compare how long events last... Among philosophers of physics, the most popular short answer to the question "What is physical time?" is that it is not a substance or object but rather a special system of relations among instantaneous events. This working definition is offered by Adolf Grünbaum who applies the contemporary mathematical theory of continuity to physical processes, and he says time is a linear continuum of instants and is a distinguished one-dimensional sub-space of four-dimensional spacetime.
   • "Dictionary.com Unabridged, based on Random House Dictionary". 2010. Arhivirano s originala, 5. 3. 2012. Pristupljeno 9. 4. 2011. 1. the system of those sequential relations that any event has to any other, as past, present, or future; indefinite and continuous duration regarded as that in which events succeed one another.... 3. (sometimes initial capital letter) a system or method of measuring or reckoning the passage of time: mean time; apparent time; Greenwich Time. 4. a limited period or interval, as between two successive events: a long time.... 14. a particular or definite point in time, as indicated by a clock: What time is it? ... 18. an indefinite, frequently prolonged period or duration in the future: Time will tell if what we have done here today was right.
   • Ivey, Donald G.; Hume, J.N.P. (1974). Physics. 1. Ronald Press. str. 65. Arhivirano s originala, 14. 4. 2021. Pristupljeno 7. 5. 2020. Our operational definition of time is that time is what clocks measure.
7. ^ Le Poidevin, Robin (Winter 2004). "The Experience and Perception of Time". u Edward N. Zalta (ured.). The Stanford Encyclopedia of Philosophy. Arhivirano s originala, 22. 10. 2013. Pristupljeno 9. 4. 2011.
8. ^ "Newton did for time what the Greek geometers did for space, idealized it into an exactly measurable dimension." About Time: Einstein's Unfinished Revolution, Paul Davies, str. 31, Simon & Schuster, 1996, ISBN 978-0-684-81822-1
9. ^ Bunyadzade, Konul (15. 3. 2018). "Thoughts of Time" (pdf). Metafizika Journal (jezik: azerbejdžanski). AcademyGate Publishing: 8–29. doi:10.33864/MTFZK.2019.0. Arhivirano (PDF) s originala, 5. 4. 2019. Pristupljeno 15. 3. 2018.
10. ^ Rendall, Alan D. (2008). Partial Differential Equations in General Relativity (illustrated izd.). OUP Oxford. str. 9. ISBN 978-0-19-921540-9. Arhivirano s originala, 14. 4. 2021. Pristupljeno 24. 11. 2020.