Download The Study of Outer Space Astronomy History of Astronomy

TheStudyofOuterSpace
Astronomy
HistoryofAstronomy
• Astronomyisthebranchofsciencethatdealswithcelestialobjects(objectlocatedoutsideof
theearth’satmosphere),space,andthephysicaluniverse.
• Astronomyisconsideredtheoldestofthenaturalsciences.
• Manycivilizationslookedtotheskytounderstandtheirworld.
• WhenStoneagepeopleturnedtoamoreagricultural(farmer)wayoflife,theirinterestlikely
turnedtotheheavens.
• Theseasonsbecameimportant.Peoplenoticedthatdifferentstarpatternsappearedat
differenttimesoftheyear.
• Howcouldthisbehelpfultothem?
• WehavelearnedaboutsomesocietiesthatbelievedthattheSunGodwouldneedtobe
honoredinorderforthesuntoriseeveryday.
• Imaginethefearthatwouldexistduringasolarorlunareclipse.
• Predictingeclipseswaspossiblytheearliestastronomicalactivity.
• Stonehengeisaparticularlyinterestingastronomicalsite.Itisestimatedthatitwasconstructed
between3100BCE-2000BCEinSalisburyPlain,England.
• ManystoriesexistaboutthisstructureincludingthepossibilitythataliensbuiltStonehenge.
• Amorerealisticviewofthisstructureisthatitwasbuilttokeeptrackofthemovementofthe
sunandmoonaswellasmarkthechangingoftheseasons.
• Astronomershavenotedthatthe“heelstone”isindirectalignmentwiththerisingsunonJuly
21(thesummersolstice).
• Stonehengeistiedtothewintersolsticealso.
• AroundDecember20,thesunsetsinthemiddleof3stonesknownastheTrilithon.
• ThereislittleagreementonthesignificanceofStonehenge.Inrecentyears,scientistshave
suggestedthatitisanancientburialground.Perhapsitisacombinationofboth.
EarlyAstronomers
• AncientChinesecivilizationskeptcarefultrackofeventsintheskies….particularlywhatthey
called“gueststars.”
• Agueststarwouldbeaneworunusuallightinthesky.
• Asearlyas1059BCE,theChinesekepttrackofagueststarthatwenowcantracetobeHaley’s
comet.
• Pythagoras(580-500BCE)-wasaGreekmathematicianwellknownforhistheoremregarding
triangles.a2+b2=c2
• Healsoiscreditedwithrecognizingthatthe“morningstar”and“eveningstar”areboththe
planetVenus.
• Aristotle(384–322BCE)cameupwithatheorythatearthwasthecenterofthesolarsystem.
Hebelievedthattheearthdidnotmoveandtheuniversemovedaroundplanetearth.
• HisfindingswerepresentinthewritingsofSt.ThomasAquinasandbecamethefoundationof
Churchbeliefsformorethan14centuries.
NikolasKopernig(Copernicus1473-1543AD)developedanideathatputthesunatthecenter
oftheuniverse.Healsoestablishedtheproperorderoftheplanetsoutwardfromthesun.
• GalileoGalilei(1564-1642)designedhisowntelescopesandmademanydiscoveriesin
astronomy….
• Sunspotsonthesunandcraters/mountainsonthemoon.
• MoonsofJupiter
• RingsofSaturn
• GalileoalsoconfirmedthatCopernicus’ideathatthesunisthecenterofthesolarsystem.
• ThiswentagainstwhattheCatholicChurchtaughtandhewasputontrialin1633.
• Hewasforcedto“disavow”hisworkandwassentencedtohousearrestfortheremainderofhis
life…8moreyears.
• IsaacNewton(1642–1727)isprobably2ndinimportanceofearlyastronomerstoGalileo.
• NewtondevelopedtheLawsofMotionandusedittounderstandgravity.
• TheLawsofMotionareasfollows:
• Anobjectatresttendstostayatrest,andanobjectinmotiontendstoremaininthat
stateofmotion,unlessanexternalforceisappliedtoit.
• Aforcecausesaccelerationofanobject.
• Foreveryactionthereisanequalandoppositereaction.
• HowdotheLawsofMotionrelatetotheSolarSystem?
• Newtonconcludedthatwithouta“force”(gravity)pullingonplanets,theywouldshootoffinto
outerspace.
• Thisideahelpedastronomersunderstandhowandwhyplanetsorbit.
ToolsofSpaceExploration
• Telescopesarethefirstinstruments,otherthanthenakedeye,tostudythesolarsystem.
• ProbablythefirsttelescopewasinventedbyaDutcheyeglassmakernamedHansLippershey.
Heappliedforapatentin1608.
• WehavelearnedthatGalileoimprovedonthisideaandusedhisimprovementstofurtherthe
developmentofspaceexploration.
• Telescopeshaveadvancedsomuchthattherearenowhugebuildingsthathouse
observatories….whicharegianttelescopesthatcanlookatthesolarsystem.
• Mostofthesetelescopesusemirrorstoenlargeobjects.
• ThelargestradiotelescopewasjustfinishedinJuly2016inChina.Thistypeoftelescope
measuresradiowaves.
• Thedishofthistelescopemeasures1,650feetthatisbeingusedtosearchforsignsoflifeand
otherdiscoveries.Thisisalittlemorethan5footballfields.
• Radiotelescopesmeasureradioormagneticwaves.
• Planstobuildtheworld’slargestvisualtelescopetodatewasintendedforHawaii.This
telescopewillhaveamirrorthatmeasures127feet.
• Controversyaroundthistelescopehasoccurredsothemostrecentplansaretomovethe
buildingofthistelescopetoChile.
• OneofthemostimportanttelescopesinourhistoryisthelaunchoftheHubbletelescopein
1990.ItisconsideredthemostimportantadvanceinastronomysinceGalileo’stelescope.
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TheHubbletelescopeisnamedforEdwinHubblewhohelpedtoprovethatothergalaxies
existedoutsideoftheMilkyWay.
HeisconsideredtobeoneofthefoundersoftheAndromedagalaxy.
Byshowingthatothergalaxiesexisted,EdwinHubblehelpedastronomersbegintograspthe
sheersizeoftheuniverse.
TheHubbletelescopefloatsinthethermospherelayeroftheatmosphere.Ittakesdigital
picturesasitorbitstheearth.
TheHubbletelescopetravelsataspeedof17,000mph.
Itispoweredbysolarrays.
TheHubbletelescopeisaboutthelengthofaschoolbus.
TheHubbletelescopeisanexampleofaspacesatellite.
Satellitesaremachinesthatarelaunchedintospaceandorbittheearth,moon,orotherplanet.
Therearemorethan4500satellitesinouterspace.Someofthemaretakingpicturesbutsome
ofthemareprovidingcellphonesignalsandtelevisionsignalsthatweuseeveryday.
ThefirstsatellitelaunchedintospacewastheRussianSputnikIin1957.Thiswasthefirsthuman
madeobjectlaunchedintospace.Wewilltalkmoreaboutthiswhenwediscussspace
exporation.Itwasthestartofthe“racetospace”betweentheU.S.andRussia.
Robotsareanothertoolthatastronomersusetogatherinformationaboutouterspaceand
otherplanets.
Wewilltalkmoreaboutthiswhenwegetintospaceexploration.
1976iswhenthefirstspacerobot,VikingIlandedonMarsandcollectedsoilsamples.Since
then,manyotherrobotshaveexploredourplanets.
Robotshavebeenthepreferredtypeofspaceexplorationbecauseitisextremelydangerousfor
humanstotravelthatfarintoouterspaceandreturntoearth.Manytimes,scientistsexpect
thattheirrobotsorsatelliteswilldisintegrateonthereturntriptoearth.
Roboticarmshavebeenusedformanyyearstolaunchsatellitesandassistastronautswiththeir
missions.
OthermorerecentspacerobotshavebeenusedtoexplorethesurfaceofMars.