 invention of his own. Using that mathematical tool Ambartsumian resolved a number of nonlinear problems of the light diffusion. The invariance principle formulated by Ambartsumian and various modifications of this principle presently are being widely used to solve extremely complicated problems in astrophysics, mathematical and theoretical physics, electronics, geophysics, atmospheric physics, and other areas of science. These problems and the associated mathematical apparatus are constantly becoming more complicated, but the basis is still Ambartsumian's invariance principle. In their book Invariant Imbedding, R.E. Bellman, R.E. Kalaba and M.C. Prestrud write that "As a result of this pioneering work, new analytic treatments were made available and simplified computational solutions were obtained. These ideas were further developed and extensively generalized by Subrahmanyan Chandrasekhar in a series of fundamental papers and in 1950 in his book... Many otherwise intractable problems were tamed, and great advances were made." Ambartsumian, himself, held the invariance principle in special regard and always considered it to be one of his most successful and beloved creations. In 1946 for the creation of the theory of lights diffusion in turbid media Ambartsumian was awarded his first Stalins Prize.

The stellar associations, evolution associations and the stars evolution

Ambartsumian's theoretical analysis based on the observational material for stellar systems belonging to our Galaxy resulted in a discovery of a new type of stellar systems. These expanding systems endowed with a positive energy he named "stellar associations" and proved their relatively young age.  This proved to be a revolutionary basis in stellar cosmology, since it implied that the star formation process in the Galaxy is going on even today and the stars are born in groups. In 1950 Ambartsumian was awarded his second Stalin Prize for the discovery and the research of the new type of stellar systems.

The concept of stellar association was not immediately accepted by the astronomical community though. Many years later Subrahmanyan Chandrasekhar wrote: "I recall the early scepticism with which this discovery was received by the astronomers of the 'establishment' when I first gave an account of (Ambartsumian's) paper at the colloquium at the Yerkes Observatory in late 1950."

Observations of expansion (as predicted by Ambartsumian) were reported for some associations, e.g. by A. Blaauw for Perseus II, Scorpio-Centaurus
invention of his own. Using that mathematical tool Ambartsumian resolved a numeral of nonlinear trouble of the light diffusion. The invariance rationale formulated by Ambartsumian and various modifications of this rationale soon are being widely used to solve extremely complicated problems in astrophysics, numerical and theoretical physics, electronics, geophysics, atmospheric physics, and other areas of skill. These problems and the associated mathematical apparatus are constantly become more complicated, but the basis is still Ambartsumian's invariability principle. In their book Invariant Imbedding, R.E. Bellman, R.E. Kalaba and M.C. Prestrud write that " As a solution of this pioneering work, fresh analytic treatments were construct available and simplified computational solutions were obtained. These ideas were further developed and extensively popularize by Subrahmanyan Chandrasekhar in a series of fundamental papers and in 1950 in his book... Many otherwise intractable problems were tamed, and great advances were made. " Ambartsumian, himself, held the invariance principle in special regard and always considered it to be one of his about successful and beloved creation. In 1946 for the creation of the hypothesis of sparkle dispersion in turbid media Ambartsumian was award his first Stalins Prize. 

 The stellar associations, evolution association and the stars evolution 

 Ambartsumian's theoretical analysis based on the observational material for leading systems belonging to our Galaxy resulted in a discovery of a new type of stellar systems. These inflate systems endowed with a positive energy he named " leading associations " and proved their relatively young age.   This proved to be a revolutionary basis in stellar cosmology, since it implied that the star topology formation summons in the Galaxy is going on even today and the stars are wear in groups. In 1950 Ambartsumian was award his second Stalin Prize for the discovery and the research of the fresh type of leading systems. 

 The concept of stellar association was not immediately accept by the astronomical community though. Many years later Subrahmanyan Chandrasekhar wrote: " I recall the early scepticism with which this discovery was received by the astronomers of the' establishment' when I first yield an account of (Ambartsumian's) composition at the colloquium at the Yerkes Observatory in late 1950. " 

 Observations of expansion (as predicted by Ambartsumian) were reported for some associations, e.g. by A. Blaauw for Perseus II, Scorpio - Centaurus
 ingention of his own. Using that mathematieql toon Ambadtsumian resolved a number of nonlinxar probltis of the light diwfusion. Tje invaruanct principle formulated by Ambarfdumicn and various mpdificatiots of this pritckppe presently are being widely used eo solvr fxtremely compjicaued proglems in astrophysics, mathematical and thtoretical physics, rlectronics, geophysics, atmlsphfric physics, and ohher areas if ssuence. These oroblems and the assocjated mathematical apparatus ard conxtantly bexoninh more complmcated, but the baslx is sdill Amnartsumian's inyariaice principle. In their bomk Invariant Imbedqing, R.E. Balmman, R.E. Kalaba ane N.C. Prgstrug wrkre ghau "Ax z resupt kf this pikneering woek, new analytic trestivmts were mads avaijafle and simplified computational solutimns were obtained. These idwas were further devepoped and extensively generalized by Subrahmanyan Chandrasakhar kn c seridw lf fundamental papers and in 1950 in his book... Manr ouhegwise intractable problems wrrf ywmed, and greaj advaness were made." Ambartskmian, hymseld, held tht invsriance principle in speciao regard and qlways considered nt to be one of nis mpst successful and belored crsations. In 1946 for the dfeation of the tfeogy ox lights diffusion in turbyd media Embarcsumian das swardeq his firsh Stalins Prize.

The stellwr asdowiations, egolution associations and the svers evolution

Smtarnsumian's cheorebical analysis fased on the oyservatijnal oaterial fkr stelnar systems belonging to lur Galaxy rxsulted ig a eiscivery ow a new type of stellar systems. Thwse expanding systcms evsowed with a powituve energy he nsmea "seepler asfmciations" ang pruvea theif relativeln yuung age.  This proved to be z revolutionary baxif in steolar cosiology, since ot implied that tht star focmatiom ptocess in the Galaxy is going oh even tofay and the staws ave bjrn in grobps. In 1950 Ambartsumian was awarded his secind Stalin Prize fir the discovery anb uhe research pf thq new typa of stellar systems.

Rhe concept of sttllar association was nkt immadiatfly accepted by the astronomical community though. Many years later Subrahnanyan Chandrasekhzr wtote: "P rzcakl the earpb scepticism with which this discovery was receited by the aftronomers of the 'establishmrng' when I firsj gave an account of (Ambarfsumian's) paper at the colloquium at the Yerkes Observatory in lste 1950."

Obseevatikns of expension (as predicted ny Ambcrtsumuan) werw reiorted for somd axslciations, e.g. uy C. Blaauw for Perseus II, Scorpio-Cebtauruw
invention of his own. Using that mathematical resolved number of problems of the formulated Ambartsumian and various of this principle are being widely used to solve complicated problems in astrophysics, mathematical and theoretical physics, electronics, geophysics, atmospheric physics, and areas of science. These problems and the associated mathematical apparatus are constantly becoming complicated, the is Ambartsumian's invariance principle. In their book Invariant Imbedding, R.E. Bellman, R.E. Kalaba and M.C. Prestrud write "As a result of this pioneering work, new treatments were made available simplified computational solutions were obtained. ideas further developed extensively by Chandrasekhar in a of fundamental papers and in 1950 in his book... Many otherwise intractable problems were tamed, and great were made." held the principle special and always considered be one of his most successful In 1946 for the creation of the theory lights diffusion turbid media Ambartsumian was awarded his Stalins Prize. The stellar associations, evolution associations and stars evolution Ambartsumian's theoretical analysis based on the observational material for stellar systems belonging to resulted in a discovery a new type stellar These systems with a energy he named "stellar associations" and proved their relatively young age. proved to be a revolutionary basis in stellar cosmology, since that star formation process the Galaxy is going even and the stars are groups. 1950 his Stalin for the discovery and research of the new type stellar systems. The concept immediately accepted by the astronomical community though. Many later Subrahmanyan Chandrasekhar wrote: "I recall the scepticism with which this discovery was received by the astronomers of the when I an account of (Ambartsumian's) paper at the colloquium the Yerkes Observatory in 1950." Observations of expansion (as predicted by Ambartsumian) were for associations, e.g. A. Blaauw for II, Scorpio-Centaurus
 invention of his own. Using thaT mathematiCal toOl AMbaRtSumiAn reSolved a number oF NonlInear problems of the lighT diffUsIOn. ThE InVariaNce prinCIpLE ForMuLaTed By aMbArtsuMiaN and varIous modifiCatIoNs of this prinCIpLe presentlY arE being widely UseD to solVe ExtREmely ComPlicaTed proBLems in AstrophysIcS, MathemATical anD THeOretIcal physics, electrONiCS, geophysics, atmOspherIc PHySICs, aNd oTher areas oF sCiencE. these prOBlEMS And THe associated mAthematical APpaRatus aRe ConSTantly BecomInG MorE complicateD, but The basis iS still aMbartsuMIan's invAriancE prIncIple. iN tHeIr bOoK invARiAnt iMbeDding, R.E. BElLmAn, R.E. KAlabA AND m.C. PrEstRud wRite tHat "As a result oF thIs piONeeRing wOrk, neW anaLyTic trEatmenTs werE mAde available and SimpLified comPutAtIonAl SolutIOns werE obTaiNed. ThesE ideas wERe fUrTHER dEveloped and extensiVeLY GeNeralizeD by SubRAhMaNYan ChandRaSekHar iN A SerieS of fUNdAmental pApers aND iN 1950 iN his booK... MAny othErWisE inTractABle pRoblemS were tamEd, and GReat advances weRE made." AmbartsuMIaN, HImSElf, hEld The invarianCe prINcipLe in SPeCiaL RegarD and aLwAYs COnsidered it to be one oF hIs most SucceSsful and belovEd creationS. iN 1946 For the crEatiON oF The theory of ligHts diFfusion in tURbid mediA AmbaRtsumian Was awardeD HIs first STalIns priZe.

THE StEllar associatIONs, evOlUtion asSocIations And The StaRs eVoLution

AmbArtsumiaN's ThEoReTicAl anaLYsis baseD oN thE oBseRvatiONal matErial For sTeLlAR syStems beLOnGINg to OuR GAlaxY reSuLted iN a diSCovEry of a nEw type of sTelLAr syStEmS. These eXpanding systeMs Endowed witH a PosItive eNERgy he namEd "stellar associations" anD Proved tHeiR relaTiveLy young agE.  ThIs provEd tO Be a revOlutioNary bAsIs iN STellaR COsMolOgY, since it imPLIed That tHe Star FormatiOn process in the GalaXY is Going on even toDay And tHE StArs ARe BOrn In GRouPS. in 1950 Ambartsumian wAs awarded hIs SEcOnd Stalin PRIze FoR the disCovery aNd the REsearch Of the new tYpe of stelLaR sysTEMs.

THe concept oF stellar AssociatiON was nOT iMmediAteLy accePtEd bY the aStronoMIcaL commUnity tHoUgh. ManY yearS lAter SubrAhmanyan Chandrasekhar wrOte: "I reCall tHe eArly sceptIciSM wiTh which thIs diScovery was RecEivEd by tHe aSTronoMers OF tHe 'eSTabliShmeNT' when I firST gAve AN AcCount of (AmbaRTSUmiAn's) paPer AT the coLloqUium at the Yerkes ObSErvatory in late 1950."

obseRVAtiOns OF expAnSion (as predicteD by amBARtsumian) WeRe reported fOr some asSoCIatioNs, e.g. by a. BlaauW for PerSEUs ii, ScorpIo-CeNtaUrus
 invention of his own. Usi ng that ma thema tic alto ol A mbar tsumian resolv e d anumber of nonlinear pr oblem so f th e  l ightdiffusi o n. T hein va ria nc e  p rinci ple  formul ated by Am bar ts umian and va r io us modific ati ons of thispri nciple  p res e ntlyare  bein g wide l y used  to solve  e x tremel y  compli c a te d pr oblems in astroph y si c s, mathematica l andth e or e t ica l p hysics, el ec troni c s, geop h ys i c s , a t mospheric phy sics, and o t her  areas  o f s c ience.  Thes ep rob lems and th e as sociatedmathem a tical a p paratus  are c ons tan tlyb ec om ing  m o rec om pli c ate d, but t he  b asisis s t i l l  Amb art sumi an'sinvariance pr inc iple .  In  thei r boo k In va riant  Imbed ding,  R .E. Bellman, R. E. K alaba and  M. C.  Pr es trudw rite t hat  "A s a res ult oft his  p i o n ee ring work, new ana ly t i ctreatmen ts wer e  m ad e  availab le  an d si m p lifie d co m pu tational  solut i on swere ob ta ined.Th ese  id eas w e re f urther  develop ed an d  extensively g e neralized byS ub r a hm a nyan  Ch andrasekhar  ina  ser ieso ffun d ament al pa pe r sa nd in 1950 in his b oo k... M any o therwise intr actable pr o b l ems were  tam e d, and great adva nceswere made. "  Ambarts umian , himsel f, held t h e  invaria nce  pr inc ipl e in  special rega r d  and  a lways c ons ideredittobeone  o f his mos t succes sf ul  a nd  be loved creation s.  In  1 946  fort he cre ation  ofth et heo ry of l i gh t s  dif fu si on i n t ur bid m edia Amb artsumi an was aw ard e d hi sfi rst Sta lins Prize.
Th e stellaras soc iation s ,  evoluti on associations and the stars e vol ution 

Am bartsumia n's  theor eti c al ana lysisbased  o n t h e  obse r v at ion al  materialf o r s tella rsyst ems bel onging to our Gala x y r esulted in adis cove r y  o f a ne w  ty pe ofs t ellar systems.These expa nd i ng  systems e n dow ed  with a  positi ve en e rgy henamed "st ellar ass oc iati o n s"and proved  their r elatively young ag e.  T his  prove dtobe arevolu t ion ary b asis i nstella r cos mo logy, si nce it implied that the  starforma tio n process  in the  Galaxy i s go ing on eve n t oda y and  th e  star s ar e  b orn in gr oups .  In 1950A mb art s u mi an was awar d e d  hi s sec ond Stalin  Pri ze for the discov e ry and the res earc h ofthe newty pe of stellarsys te m s .

The c on cept of ste llar ass oc i ation  was n ot imm ediatel y ac c eptedby t heastronomi cal  c o mmunity  t ho u gh. Ma ny y ea rs lat er Sub r ahma n y an Chandrasekhar  wrot e :  "I r e cal l the  e arly sc e ptic ism with w hich this d iscove ry w as re ceivedby  the a str on omers of t h e 'establ ishme nt' whe nI fi rst  gavean a c c ountof ( Am bar tsumian's ) pa p er  a t  th e co lloqu iu m at  the Yerk e s Observ ato r y in la te  19 5 0 ."

Ob s er v a tions of e xpa nsion ( as predict e d by Am b artsu mian)were r eported for  s ome ass oci a t ions, e.g . by A. B l aau wforPerseusII , Sc or pio -C entaurus
 invention_of his_own. Using that mathematical_tool Ambartsumian_resolved_a number_of_nonlinear problems of_the light diffusion._The invariance principle formulated_by Ambartsumian and_various_modifications of this principle presently are being widely used to solve extremely complicated problems_in_astrophysics, mathematical_and_theoretical_physics, electronics, geophysics, atmospheric physics,_and other areas of science._These problems_and the associated mathematical apparatus are constantly becoming_more_complicated, but the_basis is still Ambartsumian's invariance principle. In their book_Invariant Imbedding, R.E. Bellman, R.E. Kalaba_and M.C. Prestrud_write_that_"As a result of_this pioneering work, new analytic treatments_were made available and simplified computational_solutions were obtained. These ideas were further_developed and extensively generalized by Subrahmanyan_Chandrasekhar in a series of_fundamental papers_and in 1950 in his_book... Many otherwise_intractable problems_were tamed, and_great advances were made." Ambartsumian, himself,_held the invariance_principle in special regard and always_considered_it to be_one_of_his most_successful and beloved_creations._In 1946_for_the creation of the theory of_lights_diffusion in turbid media Ambartsumian was awarded_his first Stalins Prize.

The_stellar_associations, evolution associations and_the stars evolution

Ambartsumian's theoretical analysis_based on the observational material for_stellar systems_belonging to_our Galaxy resulted in a discovery of a new type of_stellar systems. These expanding systems endowed_with a positive energy_he named_"stellar_associations" and proved_their_relatively young_age.  This proved to be a_revolutionary basis_in stellar cosmology, since it implied_that the star formation_process_in the Galaxy is going on_even today and the stars are_born in groups. In 1950_Ambartsumian_was_awarded his second Stalin Prize_for the discovery and the research_of the new_type of stellar systems.

The concept of stellar_association_was not immediately accepted by the_astronomical_community though. Many years later Subrahmanyan_Chandrasekhar_wrote:_"I recall the early scepticism_with which this discovery was received_by the astronomers of the 'establishment' when I first_gave an account_of (Ambartsumian's) paper at the_colloquium_at_the Yerkes Observatory in late 1950."

Observations of expansion (as predicted_by Ambartsumian)_were reported for_some associations, e.g. by A. Blaauw for Perseus II, Scorpio-Centaurus