 fundamental covariant tensor of the gravitational field. The fundamental physical significance of these quantities guv consists, i.e., in the fact that they determine the behavior of measuring rods and clocks" [10]. Einstein found the occurrence of the gravitational field connected with the variability of guv. When guv = ηαβ, i.e., the guv are constant values, it has a flat spacetime, that implies the vanishing of the Riemann tensor, fundamental condition for that the guv may be constants, also it requires the appropriate choice of the system of reference, referring to a determined finite lapse of the spacetime. "Although Einstein describes the metric tensor as the quantities which describe the gravitational field he describes it is the Christoffel symbols which are defined as the components of the field" [11]. These symbols are equivalent to the field force in Newton and they are obtained as the second derivatives of the metric tensor. Therefore, the metric tensor is equivalent to the gravitational potential in Newton. Of other hand, the geodesic deviation is equivalent to the acceleration in Newton. These equivalences are evident in the Newtonian limit of General Relativity but no in the gravitational field stronger and they are justly an analogy owing to the radical conceptual difference of gravity as absence of force in General Relativity and effect of force in Newton. In 1916, Einstein wrote: "If the Γωuv vanish, then the point moves uniformly in a straight line. These quantities therefore condition the deviation of the motion from uniformity. They are the components of the gravitational field". "The relations of the four-dimensional vector calculus go over into those of the absolute differential calculus. According to this generalization, each system of physical equations includes the influence exerted by the gravitational field on the group of phenomena that correspond to the equation system in question" [5]. Einstein understood that in particular case the gravitational field can be described as effect of coordinates but it must be in general a phenomenon of the energy. Thus "every physical process must also generate a gravitational field, because quantities of energy correspond to it" [9]. Then, he sought that material process equations and gravitational field equations were generally covariant to express the laws of momentum and energy conservation taken both together but he declined immediately due to the impossibility to gravitational field equations that only admit linear transformation. "These generalized equations are generally covariant. However, it proves logically impossible to set up equations for the determination of the gravitational field (i.e., of the guv) that are covariant with respect to arbitrary substitutions. With the laws of momentum and energy
fundamental covariant tensor of the gravitational field. The fundamental physical meaning of these quantity guv consists, i.e., in the fact that they determine the demeanor of measuring perch and clocks " [ 10 ]. Einstein establish the occurrence of the gravitational field connected with the variability of guv. When guv = ηαβ, i.e., the guv are constant value, it has a flat spacetime, that entail the vanishing of the Riemann tensor, fundamental condition for that the guv may be constants, also it requires the appropriate choice of the arrangement of reference, referring to a determined finite backsliding of the spacetime. " Although Einstein describes the metric tensor as the quantities which describe the gravitational battlefield he describes it is the Christoffel symbols which are defined as the components of the field " [ 11 ]. These symbol are equivalent to the field force in Newton and they are obtained as the second derivatives of the metric tensor. Therefore, the metric tensor is equivalent to the gravitational potential in Newton. Of other hand, the geodesic deviation is equivalent to the acceleration in Newton. These equivalences are evident in the Newtonian limit of General Relativity but no in the gravitational field stronger and they are rightly an doctrine of analogy owing to the radical conceptual difference of graveness as absence of power in General Relativity and effect of force in Newton. In 1916, Einstein wrote: " If the Γωuv vanish, then the point moves uniformly in a straight lineage. These quantities therefore condition the deviation of the motion from uniformity. They are the components of the gravitational airfield ". " The relations of the four - dimensional vector calculus go over into those of the absolute differential calculus. harmonize to this generalization, each arrangement of physical equations includes the influence exerted by the gravitational field on the group of phenomenon that correspond to the equation system in doubt " [ 5 ]. Einstein understood that in particular case the gravitational field can be identify as effect of coordinate but it must be in general a phenomenon of the energy. Thus " every physical process must besides generate a gravitational field, because quantities of energy correspond to it " [ 9 ]. Then, he try that material process equation and gravitational battlefield equations were broadly covariant to express the laws of momentum and energy conservation taken both together but he worsen immediately due to the impossibility to gravitational field equations that entirely admit linear transformation. " These generalized equality are generally covariant. However, it proves logically impossible to set up equations for the determination of the gravitational field (i.e., of the guv) that are covariant with respect to arbitrary substitutions. With the laws of momentum and energy
 fujdamental covariant tensur of the gravijarional field. The funaamental physical significanre od thewe quantities guv consksts, i.e., ij the faxt tiat they determiis the bckaviod of kxasuring rods akd clocks" [10]. Ainstein found tfe occurrence of the gravitational fiqld conmefted with the darisfilifj if guv. When guv = ηαβ, i.e., the guv zre convtant values, ot has a flat spacetime, thwt ilplies the vanishijg of the Ruemagb tensor, funaamental condition for that the guv may be constants, xlso nt requires tye wkpropriate cioice jf the system of refarence, teferring to a devermuned finite lapse of vhe spacetime. "Althoudh Einstehn describes the merruc tetsor as gye duahtmtiss whifh vescribe ths gravitatiinal field he descrobqw it is the Cgristosfql symbols which are defined as the comkonenfs of the field" [11]. These wymbols are equivalenj to the fyeld force in Newton and they are obtained as the secoid dexlyatixws of the metric tensor. Therefore, the metric tegaot ps equivalent to bhe gravitational lohemjial in Newton. Of otksr hand, the geodesic deviatyon iw equivaltnt tp the acceleration in Newtob. These equinalebces are evident iu the Newtonnan likit og General Relativity buc no ih the gravihational rkeld stronger ana tmey are jusuuy an analogy owigg to the radncal conzeptoal difserence of gravldy as absence of flrce nn Geteral Relahivity and effect of force in Nxxton. In 1916, Einsjeit wgote: "If tke Γωuv yanish, then the point moves uuiformly in a straight mine. Thxse quantitiqs therefore wlndition the deviatijn od thw motiov from uniformiyy. They age the components of the grxbitational fielb". "Uhw relations of thd fjug-dikegvional vectos caucuuis go over into bhore og the absolute diffesentjal calculus. Accorcikg to thiw generajization, each system of physicap equetions inclidef the influence exerted by the gravitatlonwl field on ehe nrouk of phenomzna that correspond to the equation systxm in question" [5]. Einsteib understood that iu karticular caxe thq gravitadional field can be eescribed as effegt of coordinates but jt musd be ln general a phenomenon of the energy. Thus "every physical process must alwo genxrwte a gravifatipnal xizld, becaufe qnaitities of energy correspond to it" [9]. Then, he sougit that madexial process equations and grsvktational fieud equations were generamly covatiant to express the laws of mokentum and energy conseryation tajen bkth togethxr but he declined ikmediacely dye to tye ilpossibility go brwvitationwl fmelb equations that only admit lineae tranwflrmation. "These gxneralized eemationa are denerally covariznt. Glwevet, it proves lobically impossoble to set up equatponf for the deteejination of jhe gravptational fiekd (i.e., of tha guv) that are covariant with respect to arbitrary aubstitutjons. Witm the laws of momgnvum and energy
fundamental covariant tensor of the gravitational field. physical of these guv consists, i.e., determine behavior of measuring and clocks" [10]. found the occurrence of the gravitational connected with the variability of guv. When guv = ηαβ, i.e., the guv constant values, it has a flat spacetime, that implies the vanishing of the tensor, condition that guv may be constants, also it requires the appropriate choice of the system of reference, referring a determined finite lapse of the spacetime. "Although describes the metric tensor the quantities which describe the field describes it the symbols are defined as components of the field" [11]. These symbols are equivalent to the field force in Newton and they obtained as derivatives of metric Therefore, metric tensor is the gravitational potential in Newton. Of geodesic deviation is equivalent to the acceleration in These equivalences evident in the Newtonian limit of Relativity but no in the gravitational field stronger they are justly an analogy owing to the radical conceptual difference of gravity as absence in General Relativity and of force in In Einstein "If Γωuv vanish, the point moves uniformly in a straight line. These quantities therefore the deviation of the motion from uniformity. They are the the field". "The relations the four-dimensional vector calculus over those of the absolute According this of equations the influence exerted by gravitational field on the group phenomena that correspond to [5]. Einstein understood that in particular case the field can be described as effect of but it must be in general a phenomenon of the energy. Thus physical process generate a gravitational field, because quantities of energy to it" [9]. Then, sought that material process equations and gravitational field equations generally to express laws of momentum energy conservation taken together but he due to impossibility gravitational only admit linear transformation. "These generalized are covariant. However, it proves logically to equations for the determination of the gravitational field (i.e., of the guv) that are covariant to arbitrary substitutions. With laws momentum and energy
 fundamental covariant tensoR of the gravItatiOnaL fiElD. The FundAmental physicaL SignIficance of these quantitIes guV cONsisTS, i.E., in thE fact thAT tHEY deTeRmIne ThE BeHavioR of MeasuriNg rods and cLocKs" [10]. einstein founD ThE occurrencE of The gravitatiOnaL field CoNneCTed wiTh tHe varIabiliTY of guv. when guv = ηαΒ, i.E., The guv ARe constANT vAlueS, it has a flat spacetIMe, THat implies the vAnishiNg OF tHE rieManN tensor, funDaMentaL ConditiON fOR THat THe guv may be conStants, also iT ReqUires tHe AppROpriatE choiCe OF thE system of reFereNce, referrIng to a DEterminED finite Lapse oF thE spAcetIMe. "alThoUgH einSTeIn dEScrIbes the mEtRiC tensOr as THE QUantItiEs whIch deScribe the gravItaTionAL fiEld he DescrIbes It Is the christOffel SyMbols which are deFineD as the comPonEnTs oF tHe fieLD" [11]. These SymBolS are equIvalent TO thE fIELD fOrce in Newton and theY aRE ObTained as The secONd DeRIvatives Of The MetrIC TensoR. TheREfOre, the meTric teNSoR iS equivaLeNt to thE gRavItaTionaL PoteNtial iN Newton. OF otheR Hand, the geodesiC Deviation is eqUIvALEnT To thE acCeleration iN NewTOn. ThEse eQUiValENces aRe eviDeNT iN The Newtonian limit of geNeral RElatiVity but no in thE gravitatiONAL field stRongER aND they are justly An anaLogy owing tO The radicAl conCeptual dIfference OF Gravity aS abSenCe oF foRCE iN General RelatIVIty aNd Effect oF foRce in NeWtoN. In 1916, einSteIn Wrote: "If thE Γωuv vanIsH, tHeN tHe pOint mOVes unifoRmLy iN a StrAight LIne. TheSe quaNtitIeS tHEreFore conDItION the DeViAtioN of ThE motiOn frOM unIformitY. They are tHe cOMponEnTs Of the grAvitational fiElD". "The relatiOnS of The fouR-DImensionAl vector calculus go over iNTo those Of tHe absOlutE differenTiaL calcuLus. aCcordiNg to thIs genErAliZATion, eACH sYstEm Of physical EQUatIons iNcLudeS the infLuence exerted by the GRavItational fielD on The gROUp Of pHEnOMenA tHAt cORRespond to the equAtion systeM iN QuEstion" [5]. EinsTEin UnDerstooD that in PartiCUlar casE the graviTational fIeLd caN BE deScribed as eFfect of cOordinateS But it MUsT be in GenEral a pHeNomEnon oF the enERgy. thus "eVery phYsIcal prOcess MuSt also geNerate a gravitational fieLd, becaUse quAntIties of enErgY CorRespond to It" [9]. ThEn, he sought ThaT maTeriaL prOCess eQuatIOnS anD GraviTatiONal field eQUaTioNS WeRe generally COVAriAnt to ExpREss the Laws Of momentum and enerGY conservation tAken BOTh tOgeTHer bUt He declined immeDiaTeLY Due to the ImPossibility To gravitAtIOnal fIeld eqUationS that onLY AdMIt lineAr trAnsFormation. "theSe GEneraliZeD eQUationS are GeNerallY covarIAnt. HOWEver, it proves logiCally IMPossiBLe tO set uP eQuationS For tHe determinAtion of the gRavitaTionAl fieLd (i.e., of tHe Guv) thaT arE cOvariant wiTH respect tO arbiTrary suBsTituTioNs. With The lAWS of moMentUm And Energy
 fundamental covariant ten sor of the  grav ita tio na l fi eld.  The fundament a l ph ysical significance of  thes eq uant i ti es gu v consi s ts , i.e .,  i n t he fa ct th atthey de termine th e b eh avior of mea s ur ing rods a ndclocks" [10] . E instei nfou n d the  oc curre nce of the gr avitation al fieldc onnecte d wi th t he variability of gu v . When guv = η αβ, i. e. ,  t h e  gu v a re constan tvalue s , it ha s  a f l ats pacetime, tha t implies t h e v anishi ng  of the Ri emann  t e nso r, fundamen talcondition  for t h at theg uv maybe con sta nts , al s oit  re qu i res th e a p pro priate c ho ic e ofthes y s t em o f r efer ence,  referring to  adete r min ed fi nitelaps eof th e spac etime ."Although Einst eindescribes  th emet ri c ten s or asthe  qu antitie s which des cr i b e  t he gravitational f ie l d  h e descri bes it is  t h e Christ of fel  sym b o ls wh icha re  defined  as th e  c om ponents  o f thefi eld " [ 11].T hese  symbo ls are e quiva l ent to the fie l d force in Ne w to n an d  the y a re obtained  ast he s econ d  d eri v ative s ofth e  m e tric tensor. Theref or e, the  metr ic tensor isequivalent t o  the gra vita t io n al potential i n New ton. Of ot h er hand,  thegeodesic  deviatio n is equiv ale nttothe a cc eleration inN e wton .These e qui valence s a reevi den tin the Ne wtonianli mi tof  Ge neral Relativi ty  bu tnoin th e  gravi tatio nalfi el d  st rongera nd t heyar ejust lyan  anal ogyo win g to th e radical  co n cept ua ldiffere nce of gravit yas absence  o f f orce i n GeneralRelativity and effect o f  forceinNewto n. I n 1916, E ins tein w rot e : "Ifthe Γω uv va ni sh, t hen t h e  p oin tmoves unif o r mly  in a  s trai ght lin e. These quantitie s  th erefore condi tio n th e de via t io n  of  t h e m o t ion from unifor mity. They  a r ethe compon e nts  o f the g ravitat ional field".  "The rel ations of  t he f o u r-d imensional  vectorcalculusg o ove r  i nto t hos e of t he  ab solut e diff e ren tialcalcul us . Acco rding  t o this g eneralization, each sys tem of  phys ica l equatio nsi ncl udes theinfl uence exer ted  by  thegra v itati onal fi eld on th e gr o up of phe n om ena t ha t correspon d t o t he eq uat i on sys temin question" [5]. Einstein under stoo d tha t i n  par ti cular case the  gr av i t ationalfi eld can bedescribe da s eff ect of  coord inatesb u ti t must  beingeneral a  ph en o menon o fth e  energ y. T hu s "eve ry phy s ical p rocess must also  gene r a te ag rav itati on al fiel d , be cause quan tities of e nergycorr espon d to it "[9]. T hen ,he soughtt hat mater ial p rocesseq uati ons  and g ravi t a tiona l fi el d e quationsw e re ge ne r all y co varia nt  toexpress t h e laws o f m o mentuman d e n e rgy co n se r v ation take n b oth t o g ether buth e de c li n ed im mediat ely du e to th e  im po ssibili tyt o  gravitat ional fie l d e qu atio ns thaton ly a dm itli near transforma tion. "T hese gen e r alized  eq u atio n s arege nerally cova riant .H owever, i t p roves l o gic all y i mpos sib le t o  set up equations for th e de termi n ati on of  thegr avitatio n al f ield (i. e ., of the guv ) that are cova r ian t  wit h r e sp ec t to arbi tra r y sub stit uti ons.  Wi th t h e  law s  ofm om entu m andener gy 
 fundamental_covariant tensor_of the gravitational field._The fundamental_physical_significance of_these_quantities guv consists,_i.e., in the_fact that they determine_the behavior of_measuring_rods and clocks" [10]. Einstein found the occurrence of the gravitational field connected with_the_variability of_guv._When_guv = ηαβ, i.e., the_guv are constant values, it_has a_flat spacetime, that implies the vanishing of the_Riemann_tensor, fundamental condition_for that the guv may be constants, also it_requires the appropriate choice of the_system of reference,_referring_to_a determined finite lapse_of the spacetime. "Although Einstein describes_the metric tensor as the quantities_which describe the gravitational field he describes_it is the Christoffel symbols which_are defined as the components_of the_field" [11]. These symbols are_equivalent to the_field force_in Newton and_they are obtained as the second_derivatives of the_metric tensor. Therefore, the metric tensor_is_equivalent to the_gravitational_potential_in Newton._Of other hand,_the_geodesic deviation_is_equivalent to the acceleration in Newton._These_equivalences are evident in the Newtonian limit_of General Relativity but_no_in the gravitational field_stronger and they are justly_an analogy owing to the radical_conceptual difference_of gravity_as absence of force in General Relativity and effect of force_in Newton. In 1916, Einstein wrote:_"If the Γωuv vanish,_then the_point_moves uniformly in_a_straight line._These quantities therefore condition the deviation of_the motion_from uniformity. They are the components_of the gravitational field"._"The_relations of the four-dimensional vector calculus_go over into those of the_absolute differential calculus. According to_this_generalization,_each system of physical equations_includes the influence exerted by the_gravitational field on_the group of phenomena that correspond to_the_equation system in question" [5]. Einstein_understood_that in particular case the gravitational_field_can_be described as effect of_coordinates but it must be in_general a phenomenon of the energy. Thus "every physical_process must also_generate a gravitational field, because_quantities_of_energy correspond to it" [9]. Then, he sought that material_process equations_and gravitational field_equations were generally covariant to express the laws of momentum_and energy conservation taken both together but_he declined immediately due to the impossibility to gravitational field equations_that only admit linear transformation. "These generalized equations_are generally covariant. However, it proves logically_impossible to set up_equations_for the determination of the gravitational field_(i.e.,_of_the_guv) that are_covariant with respect_to arbitrary substitutions._With the_laws of momentum_and energy