30105.對在光錐上模擬lambdacdm的不均勻宇宙學模型的年齡檢驗

1、中國科學技術大學碩士學位論文對在光錐上模擬LambdaCDM的不均勻宇宙學模型的年齡檢驗姓名：蘭迷香申請學位級別：碩士專業(yè)：理論物理指導教師：李淼20110415AbstractⅡABSTRACTABSTRACTIntheusualevolvingcosmicmodelscosmicageisdefinedtobethescalefactgoingfrom0toitspresentvalue.Fsomecosmologicalmodel

2、fexampleNewton’scosmologicalmodeltherankmodelthesteadycosmologicalmodelthecosmicageisofnosense.UsuallyHubbleageisthereliableupbofthecosmicageitcanbeusedtoestimatethecosmicage.Ifwelookbackintimethecosmicdensityisincreasin

3、g.Bysomefinitetime0tthecosmicdensityisincreasingtobeinfinite.Ifwesetthecosmicagetobe0whenitsdensityisinfinite0tisthecosmicage.Soouruniversehasafiniteage.Differentcosmologicalmodelswillgivedifferentcosmicage.Whichcosmolog

4、icalmodelisbetterindescribingouruniverseWemustcomparethepredictionofthemodelswiththeastrophysicalobservation.Themodelwhichcanmatchtheastrophysicalobservationwellisbetterthanothers.Cosmicageisonekindofquantitieswhichcanbe

5、usedtocomparewiththeexperiment.Sincecosmicagecannotbemeasureddirectlywhatismeasuredistheageoftheoldobject.Ifweassumetheobjectisfmedattimeof1titsageatpresenttimeisτ.Sothecosmicageisτ=10tt.Theobjectisveryoldsoτ1t.Wecanuseτ

6、toestimatethecosmicage.SinceRutherfdpeoplebegantouseradioelementtomeasuretheageoftheremnantoftheoldobject.Sincethecosmicageisabout10Gasothelifeoftheradioelementthatwereusedtomeasurethecosmicagemusthavethesamedimension.Th

7、eradioelementthatwereusedtomeasurethecosmicageareTh233（lifetimeτ=20.3Ga）；U235（τ=1.02Ga）；U238（τ=6.45Ga）.Since1980sthecoolingoftheneutronstarisusedtoconcludetheageoftheMilkWay.Atthebeginningoftheneutronstarfmationthetemper

8、atureintheneutronstarisstillveryhigh.Soitcangiveoffthelight.Withthetimepassbythetemperaturefalls.Theluminosityoftheneutronstarisdepressed.Sothedimmertheneutronstaristheolderitis.Asthecoolingoftheneutronstarisslowerthanth

9、eburningofthenucleitheageofthedimneutronstaristheageofthestar.FthisreasontheageoftheMilkWaycanbeestimatedbythedimmestneutronstarinit.Themeimptantthingistheageoftheglobularcluster.Theglobularclusterisoneoftheoldestobjects