Uhusianifu maalumu

halisi ya Albert Einstein ya mwaka 1905 hivi, ambapo alichapisha kitabu "Annus Mirabilis" yakiwemo maandishi kuhusu *Zur Elektrodynamik bewegter Körper* (yaani "On the Electrodynamics of Moving Bodies") yaliyounda nadharia ya uhusianifu maalumu.]]
**Uhusianifu maalumu** (kwa Kiingereza: *special relativity*) ni nadharia muhimu sana ya fizikia iliyoundwa na Albert Einstein mwaka 1905. Ilichapishwa katika jarida la fizikia la Ujerumani liitwalo *Annalen der Physik* chini ya kichwa "Zur Elektrodynamik bewegter Körper" (Kwa Kiingereza: "On the Electrodynamics of Moving Bodies") . Nadharia hiyo ilileta mapinduzi makubwa katika uelewa wetu wa nafasi na wakati.

## Nadharia hiyo kwa ufupi
Nadharia hiyo husema:
* Wachunguzi wakiwa na mwendo tofauti, huona wakati na umbali kubadilishwa, katika fomula γ=(1-v2/c2)-1/2.
* Inayolingana nishati na tungamo katika fomula E=mc2.
* Kasi ya nuru huwa sawa kwa wachunguzi wote.

Majaribio mengi yamethibitisha nadharia hiyo na ile ya uhusianifu wa jumla, kama vile majaribio wa Michelson-Morley na majaribio wa Ives-Stilwell (nadharia ya uhusianifu maalum), na majaribio wa Pound-Rebka (nadharia ya uhusianifu wa jumla).

## Misingi Mikuu 
Nadharia hii inategemea misingi mikuu miwili:

# **Kanuni ya Uhusianifu (Principle of Relativity):** Sheria za fizikia ni zile zile kwa waangalizi wote walio katika mwendo wa kasi isiyobadilika (inertial frames of reference). Hii inamaanisha kwamba huwezi kutofautisha kati ya wewe umesimama au unatembea kwa kasi isiyobadilika kwa kufanya majaribio yoyote ya fizikia ndani ya chumba kilichofungwa.
# **Kasi ya Nuru ni Isiyobadilika (Constancy of the Speed of Light):** Kasi ya nuru katika ombwe (vacuum) ni sawa kwa waangalizi wote, bila kujali mwendo wao au mwendo wa chanzo cha nuru . Kasi hii ni takribani kilomita 299,792,458 kwa sekunde (mita 300,000,000 kwa sekunde), na inawakilishwa na herufi 'c'.

## Matokeo Muhimu 
Kutokana na misingi hii, Einstein alihitimisha matokeo kadhaa ya kushangaza na yanayokwenda kinyume na uzoefu wetu wa kila siku, lakini yamethibitishwa na majaribio :

* **Uhusianifu wa Wakati (Time Dilation):** Saa zinazotembea haraka huonekana kwenda polepole kwa mwangalizi anayesimama. Kadiri kitu kinavyokwenda haraka kuelekea kasi ya nuru, ndivyo wakati unavyokwenda polepole zaidi kwake.
* **Mkunyuko wa Urefu (Length Contraction):** Vitu vinavyotembea haraka huonekana kufupishwa katika mwelekeo wa mwendo wao kwa mwangalizi anayesimama.
* **Usawa wa Misa na Nishati (Mass-Energy Equivalence):** Huu ndio msingi wa fomula maarufu ya Einstein, **E=mc²**, ambapo 'E' ni nishati, 'm' ni misa, na 'c' ni kasi ya nuru. Fomula hii inaonyesha kwamba misa na nishati ni pande mbili za sarafu moja na zinaweza kubadilishana. Kiasi kidogo sana cha misa kinaweza kubadilishwa kuwa kiasi kikubwa sana cha nishati.
* **Nafasi-Wakati (Spacetime):** Nadharia hii iliunganisha nafasi (vipimo vitatu) na wakati (kipimo kimoja) kuwa kitu kimoja kinachoitwa nafasi-wakati, chenye vipimo vinne.

Uhusianifu Maalumu unatumika kwa matukio yote ya kimwili ambayo hayahusishi mvuto (gravity). Kwa matukio yanayohusisha mvuto, *Uhusianifu Mkuu* (General Relativity)'* wa Einstein, uliotolewa mnamo 1915, unaeleza jinsi mvuto unavyopinda nafasiwakati.

## Marejeo 
## Vitabu
* Einstein, Albert (1920). Relativity: The Special and General Theory.
* Einstein, Albert (1996). *The Meaning of Relativity*. Fine Communications. 
* Logunov, Anatoly A. (2005) Henri Poincaré and the Relativity Theory (transl. from Russian by G. Pontocorvo and V. O. Soleviev, edited by V. A. Petrov) Nauka, Moscow.
* Charles Misner, Kip Thorne, and John Archibald Wheeler (1971) *Gravitation*. W. H. Freeman & Co. 
* Post, E.J., 1997 (1962) *Formal Structure of Electromagnetics: General Covariance and Electromagnetics*. Dover Publications.
* Wolfgang Rindler (1991). Introduction to Special Relativity (2nd ed.), Oxford University Press. ; 
* Harvey R. Brown (2005). Physical relativity: space–time structure from a dynamical perspective, Oxford University Press, ; 
* 
* 
* Silberstein, Ludwik (1914) The Theory of Relativity.
* 
* Taylor, Edwin, and John Archibald Wheeler (1992) *Spacetime Physics* (2nd ed.). W.H. Freeman & Co. 
* Tipler, Paul, and Llewellyn, Ralph (2002). *Modern Physics* (4th ed.). W. H. Freeman & Co. 

## Makala
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* 
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* Special Relativity Scholarpedia
*Special relativity: Kinematics Wolfgang Rindler, Scholarpedia, 6(2):8520. 

## Viungo vya nje
### Maandishi asili
* *Zur Elektrodynamik bewegter Körper'' Einstein's original work in German, Annalen der Physik, Bern 1905
* *On the Electrodynamics of Moving Bodies* English Translation as published in the 1923 book *The Principle of Relativity*.

### Ufafanuzi rahisi
* Einstein Light  An award-winning, non-technical introduction (film clips and demonstrations) supported by dozens of pages of further explanations and animations, at levels with or without mathematics.
* Einstein Online  Introduction to relativity theory, from the Max Planck Institute for Gravitational Physics.
* Audio: Cain/Gay (2006) – Astronomy Cast. Einstein's Theory of Special Relativity

### Ufafanuzi rahisi kiasi
* Greg Egan's *Foundations* .
* The Hogg Notes on Special Relativity A good introduction to special relativity at the undergraduate level, using calculus.
* Relativity Calculator: Special Relativity  – An algebraic and integral calculus derivation for .
* MathPages – Reflections on Relativity A complete online book on relativity with an extensive bibliography.
* Special Relativity An introduction to special relativity at the undergraduate level.
* , by Albert Einstein
* Special Relativity Lecture Notes is a standard introduction to special relativity containing illustrative explanations based on drawings and spacetime diagrams from Virginia Polytechnic Institute and State University.
* Understanding Special Relativity The theory of special relativity in an easily understandable way.
* An Introduction to the Special Theory of Relativity (1964) by Robert Katz, "an introduction ... that is accessible to any student who has had an introduction to general physics and some slight acquaintance with the calculus" (130 pp; pdf format).
* Lecture Notes on Special Relativity  by J D Cresser Department of Physics Macquarie University.
* SpecialRelativity.net - An overview with visualizations and minimal mathematics.

### Maonyesho
* Raytracing Special Relativity Software visualizing several scenarios under the influence of special relativity.
* Real Time Relativity  The Australian National University. Relativistic visual effects experienced through an interactive program.
* Spacetime travel A variety of visualizations of relativistic effects, from relativistic motion to black holes.
* Through Einstein's Eyes  The Australian National University. Relativistic visual effects explained with movies and images.
* Warp Special Relativity Simulator A computer program to show the effects of traveling close to the speed of light.
*  visualizing the Lorentz transformation.
* Original interactive FLASH Animations from John de Pillis illustrating Lorentz and Galilean frames, Train and Tunnel Paradox, the Twin Paradox, Wave Propagation, Clock Synchronization, etc.
* lightspeed An OpenGL-based program developed to illustrate the effects of special relativity on the appearance of moving objects.
* Animation showing the stars near Earth, as seen from a spacecraft accelerating rapidly to light speed.

Jamii:Fizikia