# Best fit curve for a list of data

I am kinda new to Mathematica and I have some basic questions. I need to find the best fit curve for a set of data. Here's the data:

    data1 = {{5.095394399615566*^-11,
221592.93606333656}, {5.175438872751551*^-11,
1418.2592685868801}, {5.255483345887536*^-11,
180.36535785522187}, {5.335527819023521*^-11,
57.78186440272107}, {5.4155722921595055*^-11,
28.471203122045367}, {5.495616765295491*^-11,
17.64444756164996}, {5.5756612384314755*^-11,
12.479906758697593}, {5.65570571156746*^-11,
9.574931076706036}, {5.7357501847034454*^-11,
7.7461647030921075}, {5.81579465783943*^-11,
6.498661228416742}, {5.895839130975415*^-11,
5.595759399624425}, {5.9758836041114*^-11,
4.912245837241986}, {6.055928077247385*^-11,
4.376431621076272}, {6.135972550383369*^-11,
3.9446016652474}, {6.216017023519355*^-11,
3.588694947456349}, {6.29606149665534*^-11,
3.289917393392387}, {6.376105969791324*^-11,
3.0352250485945325}, {6.456150442927309*^-11,
2.8152869327067567}, {6.536194916063294*^-11,
2.6232528415371474}, {6.616239389199278*^-11,
2.4539797111397714}, {6.696283862335264*^-11,
2.30352986792074}, {6.776328335471249*^-11,
2.1688362159395167}, {6.856372808607233*^-11,
2.047473128812804}, {6.936417281743218*^-11,
1.937496127951711}, {7.016461754879204*^-11,
1.8373274283575256}, {7.096506228015188*^-11,
1.7456727467120015}, {7.176550701151173*^-11,
1.6614598423826141}, {7.256595174287158*^-11,
1.5837924397392111}, {7.336639647423142*^-11,
1.5119152153834552}, {7.416684120559128*^-11,
1.4451868646156196}, {7.496728593695113*^-11,
1.3830591481970886}, {7.576773066831097*^-11,
1.3250604217076631}, {7.656817539967082*^-11,
1.2707825640480017}, {7.736862013103067*^-11,
1.2198705112768415}, {7.816906486239053*^-11,
1.1720138073421555}, {7.896950959375038*^-11,
1.1269397306544722}, {7.976995432511022*^-11,
1.084407662577183}, {8.057039905647006*^-11,
1.0442044425779882}, {8.137084378782993*^-11,
1.0061405131879546}, {8.217128851918977*^-11,
0.9700467016695216}, {8.29717332505496*^-11,
0.9357715184024515}, {8.377217798190947*^-11,
0.903178877236555}, {8.457262271326931*^-11,
0.8721461624747224}, {8.537306744462916*^-11,
0.8425625821904257}, {8.617351217598902*^-11,
0.814327759321539}, {8.697395690734886*^-11,
0.7873505212046772}, {8.77744016387087*^-11,
0.7615478555071276}, {8.857484637006856*^-11,
0.7368440063159101}, {8.93752911014284*^-11,
0.7131696887869516}, {9.017573583278826*^-11,
0.6904614044939441}, {9.097618056414811*^-11,
0.6686608426391558}, {9.177662529550795*^-11,
0.6477143547458817}, {9.25770700268678*^-11,
0.6275724924597701}, {9.337751475822766*^-11,
0.6081895997337226}, {9.41779594895875*^-11,
0.5895234520290247}, {9.497840422094735*^-11,
0.5715349362892934}, {9.57788489523072*^-11,
0.5541877663779555}, {9.657929368366704*^-11,
0.5374482294495846}, {9.737973841502688*^-11,
0.5212849593747402}, {9.818018314638675*^-11,
0.5056687338959169}, {9.898062787774659*^-11,
0.4905722926381131}, {9.978107260910644*^-11,
0.47597017350513315}, {1.0058151734046629*^-10,
0.4618385653145305}, {1.0138196207182613*^-10,
0.4481551748099921}, {1.0218240680318599*^-10,
0.4348991064305685}, {1.0298285153454584*^-10,
0.42205075342260656}, {1.0378329626590568*^-10,
0.40959169905744197}, {1.0458374099726553*^-10,
0.3975046268704663}, {1.0538418572862538*^-10,
0.3857732389687203}, {1.0618463045998522*^-10,
0.3743821815681021}, {1.0698507519134509*^-10,
0.3633169770199247}, {1.0778551992270493*^-10,
0.3525639616723639}, {1.0858596465406478*^-10,
0.3421102289870661}, {1.0938640938542464*^-10,
0.3319435773964021}, {1.1018685411678448*^-10,
0.3220524624439043}, {1.1098729884814433*^-10,
0.31242595280043206}, {1.1178774357950417*^-10,
0.30305368979253045}, {1.1258818831086402*^-10,
0.2939258501180877}, {1.1338863304222388*^-10,
0.2850331114584601}, {1.1418907777358372*^-10,
0.27636662072630314}, {1.1498952250494357*^-10,
0.2679179647150094}, {1.1578996723630341*^-10,
0.25967914293917227}, {1.1659041196766325*^-10,
0.25164254247648143}, {1.1739085669902311*^-10,
0.24380091464004972}, {1.1819130143038298*^-10,
0.23614735332675174}, {1.1899174616174282*^-10,
0.22867527490191852}, {1.1979219089310266*^-10,
0.22137839949398197}, {1.2059263562446253*^-10,
0.21425073358439706}, {1.2139308035582237*^-10,
0.20728655378885152}, {1.221935250871822*^-10,
0.20048039173513388}, {1.2299396981854207*^-10,
0.19382701995170093}, {1.237944145499019*^-10,
0.18732143868849516}, {1.2459485928126175*^-10,
0.1809588635985957}, {1.2539530401262162*^-10,
0.17473471421543652}, {1.2619574874398143*^-10,
0.1686446031659563}, {1.269961934753413*^-10,
0.16268432606513406}, {1.2779663820670116*^-10,
0.15684985204196078}, {1.28597082938061*^-10,
0.15113731485103488}, {1.2939752766942084*^-10,
0.14554300452775681}, {1.301979724007807*^-10,
0.14006335954856963}, {1.3099841713214055*^-10,
0.13469495946069543}, {1.317988618635004*^-10,
0.12943451794878147}, {1.3259930659486026*^-10,
0.12427887630835555}, {1.3339975132622007*^-10,
0.11922499729839053}, {1.3420019605757994*^-10,
0.1142699593473977}, {1.350006407889398*^-10,
0.10941095108945076}, {1.3580108552029964*^-10,
0.1046452662083297}, {1.3660153025165948*^-10,
0.09997029856958628}, {1.3740197498301935*^-10,
0.09538353762188789}, {1.3820241971437919*^-10,
0.09088256405032613}, {1.3900286444573903*^-10,
0.0864650456659457}, {1.398033091770989*^-10,
0.08212873351489902}, {1.4060375390845873*^-10,
0.07787145819775398}, {1.4140419863981857*^-10,
0.07369112638033126}, {1.4220464337117844*^-10,
0.06958571748851083}, {1.4300508810253828*^-10,
0.06555328057416032}, {1.4380553283389812*^-10,
0.06159193134217045}, {1.4460597756525798*^-10,
0.057699849328957775}, {1.454064222966178*^-10,
0.05387527522349567}, {1.4620686702797766*^-10,
0.05011650832249526}, {1.4700731175933753*^-10,
0.046421904111937806}, {1.4780775649069737*^-10,
0.042789871967679804}, {1.486082012220572*^-10,
0.0392188729683185}, {1.4940864595341708*^-10,
0.03570741781395004}, {1.5020909068477692*^-10,
0.03225406484486637}, {1.5100953541613676*^-10,
0.028857418154628167}, {1.5180998014749662*^-10,
0.025516125792270028}, {1.526104248788565*^-10,
0.022228878048787593}, {1.534108696102163*^-10,
0.0189944058232685}, {1.5421131434157617*^-10,
0.015811479064405276}, {1.55011759072936*^-10,
0.012678905283348474}, {1.5581220380429585*^-10,
0.009595528134082265}, {1.5661264853565571*^-10,
0.006560226057792828}, {1.5741309326701558*^-10,
0.003571910987858473}, {1.582135379983754*^-10,
0.0006295271123315516}, {1.5901398272973526*^-10, \
-0.002267950309073008}, {1.598144274610951*^-10, \
-0.005121516076247445}, {1.6061487219245494*^-10, \
-0.007932136130866407}, {1.614153169238148*^-10, \
-0.01070074859192438}, {1.6221576165517465*^-10, \
-0.013428264746988106}, {1.6301620638653449*^-10, \
-0.0161155700013369}, {1.6381665111789435*^-10, \
-0.01876352478710208}, {1.6461709584925422*^-10, \
-0.021372965434321767}, {1.6541754058061406*^-10, \
-0.02394470500581125}, {1.662179853119739*^-10, \
-0.02647953409753967}, {1.6701843004333374*^-10, \
-0.028978221606220878}, {1.678188747746936*^-10, \
-0.03144151546563778}, {1.6861931950605344*^-10, \
-0.03387014335319316}, {1.694197642374133*^-10, \
-0.03626481336809828}, {1.7022020896877312*^-10, \
-0.03862621468248584}, {1.71020653700133*^-10, \
-0.04095501816674396}, {1.7182109843149283*^-10, \
-0.04325187699022637}, {1.726215431628527*^-10, \
-0.0455174271984653}, {1.7342198789421253*^-10, \
-0.04775228826797795}, {1.7422243262557237*^-10, \
-0.0499570636396478}, {1.7502287735693221*^-10, \
-0.05213234123165833}, {1.7582332208829208*^-10, \
-0.054278693932880095}, {1.7662376681965192*^-10, \
-0.05639668007758303}, {1.7742421155101179*^-10, \
-0.05848684390228964}, {1.7822465628237163*^-10, \
-0.06054971598554415}, {1.7902510101373147*^-10, \
-0.06258581367135108}, {1.7982554574509133*^-10, \
-0.06459564147697883}, {1.8062599047645117*^-10, \
-0.06657969148579657}, {1.8142643520781104*^-10, \
-0.0685384437257901}, {1.8222687993917085*^-10, \
-0.07047236653434741}, {1.8302732467053072*^-10, \
-0.07238191690991425}, {1.8382776940189056*^-10, \
-0.07426754085104426}, {1.8462821413325042*^-10, \
-0.07612967368338897}, {1.8542865886461026*^-10, \
-0.07796874037510193}, {1.862291035959701*^-10, \
-0.07978515584116819}, {1.8702954832732997*^-10, \
-0.08157932523706046}, {1.878299930586898*^-10, \
-0.08335164424221064}, {1.8863043779004968*^-10, \
-0.08510249933366465}, {1.8943088252140952*^-10, \
-0.08683226805033817}, {1.9023132725276936*^-10, \
-0.08854131924823072}, {1.910317719841292*^-10, \
-0.0902300133469831}, {1.9183221671548906*^-10, \
-0.0918987025680833}, {1.926326614468489*^-10, \
-0.09354773116508674}, {1.9343310617820877*^-10, \
-0.09517743564611703}, {1.942335509095686*^-10, \
-0.09678814498900357}, {1.9503399564092845*^-10, \
-0.09838018084928457}, {1.958344403722883*^-10, \
-0.09995385776138122}, {1.9663488510364815*^-10, \
-0.10150948333319665}, {1.97435329835008*^-10, \
-0.10304735843438673}, {1.9823577456636786*^-10, \
-0.10456777737853873}, {1.990362192977277*^-10, \
-0.1060710280994881}, {1.9983666402908754*^-10, \
-0.10755739232200678}, {2.006371087604474*^-10, \
-0.10902714572703642}, {2.0143755349180725*^-10, \
-0.11048055811171276}, {2.022379982231671*^-10, \
-0.1119178935443319}, {2.0303844295452693*^-10, \
-0.1133394105144725}, {2.038388876858868*^-10, \
-0.11474536207843089}, {2.0463933241724663*^-10, \
-0.11613599600015156}, {2.054397771486065*^-10, \
-0.11751155488780496}, {2.0624022187996634*^-10, \
-0.1188722763261767}, {2.0704066661132618*^-10, \
-0.1202183930050067}, {2.0784111134268604*^-10, \
-0.12155013284343985}, {2.0864155607404588*^-10, \
-0.12286771911069971}};


I have used FindFit with the functions of the form:

FindFit[data, {b*x^a}, {a, b}, x, MaxIterations -> 1000]


and

FindFit[data, {a/x^2}, {a}, x, MaxIterations -> 10000]


But I still can't find the best fitting curve for the data. Any help is appreciated. Also is there a way to measure the accuracy of my fitting to the data using Mathematica commands? Thank you!

The scaling of your data1is very poor( x-values O[10^-10])!
Logarithmization (y==b x^-a-> Log[y]==Log[b]-a Log[x] helps to find a numerical solution:
logxlogy = Map[{Log[#[[1]]], Log[#[[2]]]} &, data1];