SKY & SOLAR SYSTEM
SKY & SOLAR SYSTEM ASTRO 120
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This 256 page Class Notes was uploaded by Solon Leuschke on Sunday September 27, 2015. The Class Notes belongs to ASTRO 120 at Iowa State University taught by Staff in Fall. Since its upload, it has received 21 views. For similar materials see /class/214520/astro-120-iowa-state-university in Astronomy and Astrophysics at Iowa State University.
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Date Created: 09/27/15
Reading Chapter I l Section ll L3 l l56l4344 Am mmlmsmwl p g l Midterms posted onWebCT please check with us with grade questions Observing SessionTomorrow if clear stay tuned to the website Brief review of last time Mars I m I General properties size orbit moons I Hemisphere dichotomy I Tharsis Bulge features volcanos and tectonics 0 climate changes I evidence of liquid water 0 results from Mars Exploration Rovers Overview of Planetary Atmosph el els jupiter Saturn Uranus H 75 85 74 g He 24 I4 24 cH4 lt 0I lt 0I lt I 2 NH3 lt0 lt0 lt0 avg T C 50 85 20 Clouds NHa H20 NHa NH4 SH NHa CH4 Venus Earth Mars Tu Surf Pressure 92 0007 3 C02 96 trace 95 E N2 4 77 3 3 02 0 2 0 39 avg 39r C 470 IS 50 Clouds H2504 H20 C02 H20 Am an Hilms Luau mag Planetary Atmospheres gasvapor ice 0 Primordial Atmosphere composition mostly H2 He 0 trace elements tied up in molecules C02 CH4 N2 H20 NH3 0 Hydrogen largely lost from inner planets very early T l d 21 k av mo spee ms gtlt 4273K gtlt mmol gas will escape if this is greater than l6 vesc 39 R 16 l esc 19 kms X m X m MEarth R WW I outgassing volcanism release of gas from interior C02 N2 H20 CH4 02 I impacts of icy bodies H2O CH4 CO2 I chemistry I 02 bound up in oxides very fast I C02 bound up in carbonate rocks surface H20 I H20 bound up in rock I geology I H20 trapped beneath surface permafrost I BIOLOGICAL ACTIVITY I photosynthesis C02 gt 02 methane from cows I Human Activity CO2 complex organics CFCs ozone depletion Am an Hilms Luau mag 4 Atmospheric Pressure and Temperatilir i em 0 Pressure vs height Hydrostatic Equilibrium 0 gas pressure upwards balances 0 gravity weight downwards 0 pressure highest at surface drops with altitude 0 density also highest at surface drops with altitude 0 Temperature vs height thermal equilibrium 0 warm if layer absorbs solar energy 0 cool if layer is transparent to solar radiation 0 temperature depends on composition of atmospheric layers as well as pressure and density 0 IR absorbers C02 H20 0 UV absorbers N2 02 O3 Am an Hum Luau Mag 6 Earth s Atmosphere 0 80l l0 kmthermosphere 0 UV absorption by N2 02 0 5080 km mesosphere 0 02UV gt O OOOzUV gtO3 0 03 great absorber of UV 0 l050 km stratosphere 0 cold 0 0 l 0 kmtroposphere if 0 ground heating 0 H20 Am an Hllms Luau Mag 7 The Greenhouse Effect some gasses are transparent in visibleUV wavelengths but are opaque absorbers in the Infrared MAIN GREENHOUSE GASSES C02 H20 0 solar energy arrives at Earth heats up ground 0 ground radiates energy in far IR 0 far IR trapped by Greenhouse gasses 0 ground heats up more radiates in near IR 0 greenhouse gasses allow near IR to escape sets up a balance with incoming energy Am an Hi zms Luau Mag 5 The Greenhouse Effect 77777 A New with no ampms Inme vadio39ulon a Planmm an alm pim Inhaled Ndh lo ls 5ng im min mi Imusth I thplanail mbaamm r m m tapinglnlnxpocn Temperature Structures in terrestrial pl anets Venus a runaway greenhouse Global Warming e cts of mankind on our atmosphere 0 CO2 is up 5 this century from burning fossil fuels 0 complicating factors warmer more cloudx blocked xun w quot m39r l illizlisisis consequences possible e on l an glelaa nan lcezggi effects of mankind on our atmosphere h minimumw 0 Ozone 03 critical for life 39 shields land from bad UV 0 is very fragile o destroyed by trace chlorofluorcarbons CFCs 0 complicating factors we 0 mutations etc Ozone Depletion a JV m 5n 5n 33 SQEWVZ g 963ng gi g mg a g 3ng Voyager39s Journey V3 g Wb g VOYAG E R l VOYAG E R 2 Launch Launch VOYAGER 2 5 Sept 77 20 Aug 77 Nep une 25 Aug 89 12 N no VOYAGER 1 Saturn 25 Aug 31 Voyager39s Or biTs 100 AU Sep r 2005 d Bow Shock quot V V 7 Heliosheath j39 iVoyagen Q Termination Shock Voyagarz Helim 39 quotg Heliosphere Kepler39s F i rs r Law Afn ellipSe has Two foci Minor axis in 939 3r Major axis Kepler39s Second Law Perihelion Perigee Kepler39s Third Law 132 N 33 P2 Ka3 is a constant of proportionality 1 if a is in AUs and P is in years Generalization of possible or39bi rs Physical Basis P2 47I53a3 5m1m2 Total Orbital Energy is Cons ran r Change Orbi r Mus r have energy gain or loss Ge r ring To Or39bi r No r To scalell MM I 1725lsec 1mm 559 lgnllhn All 11nml 194395 P My All 915 4231555 v 2 697lp5 vs VI 25625 fps 56 xs m nml mu Fairing Jemsan 25241 sec 655 nml An 64 I VI usurp f 111 nml l 39v 1566 4 20110 sec Ah 31414 lus Inc 2541 de Dr Perigeeah 55 rum 4 151 kasecz aux 5126 deg RLA 526590 deg W v 24 a 5610 sec 1193 um 3343 I 3153 n snmmpm 39 p Open M 4 Figure 34 MERA Ge r ring To Or39bi r gt VB ltlt VG C Pa rh is ellipse wi rh Ear39Th of one focus No r To scalell Ge r ring To Or39bi r gt VB lt VGquotC B Apogee her39e Pa rh is ellipse wi rh Ear39Th of one focus Per39igee her39e Ge r ring To Or39bi r gt VB VGquotC B Pa rh is cir39cle wi rh Ear39Th a r cenfer Vcirc 8 kms 28 800 kmhr39 LEO 90 min Ge r ring To Or39bi r gt VB gt VGquotC B Pa rh is ellipse wi rh Ear39Th of one focus Apogee her39e Ge r ring To Or39bi r gt VB V6SC B Pa rh is parabolic V6SC 11 kms 39 600 kmhr39 Rocket Science How fas r does a safellri re go in low Earth orbit Fi r39s rj we equate gravitational and cen rr39ie ral forces F9 mvw39Z r39 r GMm r39z approximate 39versfiio n v GII 12 no rice that v is independent of set mass Iinse39r39 ng number39s v 6167 x 10 1 1598 x 1024 6500 100101 239 v 78 kmsec 28000 kmhr39 Rocket Science AT 0 given dis rance from a massive body The escape velocityquot is 212 Times The circular veloci ry Thus The escrape veloci fy from low Earth orbit is 1414 78 11 kmsefc ye bye Ge r ring To Or39bi r gt VB gt V6SC I As VBT The spacecraff will have a higher veloci ry once if is far39 from EarTh Pa rh is hyperbolic Modifying Or39bi rs Ini l39ial or39b adds energy Apogee her39e Modifying Or39bi rs Rocke r bur39n To slow down Geosynchr39onous Or39bi r h 34000 km No r To scalell LANDSAT I a O a x D m m a MEO Example GPS Safelli re 650 Example Communica rion Safelli re In rer39plane rar39y Or39bi rs Things To considerquot 1 Required Av 2 Time how long when To launch 3 Arrival Or39b i r or39 flyby 4 Refurn Are you coming back Lec rur39ei Question Given P2 13 If The yellow or39bi r has a land P 5 1 And The green or39bi r has a 15 and P 19 Wha r can you say about The period of The whi re oval or bif Lec rur39ei Question Semimajor axis of white orbi r is i1510 2125 AU Thus i rS H39per39iod must be be rween land 19 years More specifically or39bi ral period 14 years Transfer Orbi r Geome rry Hohmann Transfer Orbi r Vemh 30 kms Vineri 33 kms Thus required Av 3 kms Travel Time abou r 7 mon rhs Alignment Occurs every 26 mon rhs 2001 Odyssey Interplanetary Trajectory Earth at arrval Launch mv mmm Asg s r Voyager 2 Jimpf fca VOVAGER JUPITER JUPITER 9JUL79 5MAR79 SATURN 2 NOVE O V SATURN v 25 AUG 81 Mummy quotj kaiqum w URANUS 27 JAN 55 NEPTUNE 01 SEPT 59 o o iii 1 4 my 39 Gr39GVI ra rlonal From The Assis r Jupiter POWr 01 view quot3ij of Jupi rer39 T63 16 LQ 0 ltmNltlt S6 6 ma Gravitational assis rs 4 3L 9 iEarth Saturn quot 32 Neptune E39I I Jupi t8 U39aknus VOYAGER 2 VELOCITY KM 039 S I Tl h VE LOC ITY Z H 1U L SOLAR SYSTEM ESCAPE VELOCITY HELIOC IT1 l llllllllIJlllllllllllllIlllllllllIII 5 n 1 35 an I 39 RADIAL DISTANCE FROM SUN AU Same process can modify plonefor y or39bi rs Jupifer familyquot comeTs or39biT befween Sun amp JupiTer new orbit after Jupiter encounter comet orbit before Jupiter encounter Ar39r39ival Unless The mission is a flyby Need To lose orbital energy Rocke r To slow down mos r orbi rer39s Dir39ec r En rr39y eig Mars EXplora rion Rovers Aerobraking Magellan Odyssey Aer39ocap rur39ej 2007 ESA mission Aer obr aking 1 Probe capTur ed 2 Ini rial orbiT 3 Passes Through aTmosphere lower39 apoapsis 4 5 Periapsis raised 6 OrbiT circularized Aerocapfure Is aer obraking in one pass No r as Time consuming Uses even less propeHanT Fr39om Ear39fh To Mars httpmarsroverrsjpl nasagovgalleryvideoanihma tion htm l Lecture 9 History I Ancient Greek astronomers Aris rofle Er39a139os139hanes Aris1 archus of Samos Hippar39chus PTolemy 7 VLF 9 A L I 44 39 J v 3 1m We 1ng m W wcj l wa 23 y w 3 J L wv mm 59 M WW 1 Jmm WW if m o jrn Mlmdgmmif Hi 1 5 0 0 new fwj EJLQ UWUIF TU L x x 12 5 I7 X 2 2 Mquot tray 31 L iiy L m o V G n 7 Adi r UM C U 93 E J w m f j JW r r f L V MUQEEWCQ E f gz a 7 g V V 4 VV QMquot m kl QM l Una Ancient Astronomy Many cultures throughout the world practiced astronomy They made careful observations of the sky Over a period of time they would notice the cyclic motions of Sun Moon planets celestial sphere stars hcamgg mama 5 1 3 57 Mg Miami Em LEde mg MM is 111 mmmya o E g mm rm ng md ka A Hm dimmmg f ammng sunrise I J 1 r A summel it Wquot m m whmm g WEE 621mger f A f wk mama 913 E 553 mm dbwy 1mm chez 39szd fray beg gm mlbg whim l sunset v extreme moonset nset winter moonrlse D 7 kchalk banks Aubrey holes EsmngM mm We ay Lr r 5 v y39 Why did mew d r o Wh g i 6 miFhWpgtHg ir wmigcaa a if Ragga mea a few gw w mm pr a ow mca g wg pwgcag o A 1 5 mg mm mm mm f mama m mf Mj mmg lw ead m bam d phyg m MQDCQ C H b m mm b W gt m o o EW FL WW mccmmd myfhg m xp ca m m mm mg f hcg b g M m 5W0 Ma 4 V W q H M v H r mm 1 K33 2 LEquot quot 1quot V IL K WW3 V173quot WE 1 quot V V F KS xg f 6 i quot 4 Warm r A 5 Qt WHH WQI VUJ a U zr39xxc zA kw V K h I w T I quot7 Vquot 33quot F V39S quot quot quot A 9 vs r r39 v 4392 7 3 x m J r117 Vr j 131 r WUMEU b39ww 49 37 w QCQJMW r WW If WM ziLJLQJ H mm H GL3 1quot I vamp mm H A Jvm Spmw m EQWh f M wmg 6633 LEE We r g m gwggagg 65 gaajmc h mg fhcaw mm EUng H62 pmmgw i yH mdrgm W mgwcqg f S mg WSW 3amp6 the fit g i pmrgm m Emh ES 1 5 ifc gd v dmw We d mppmmmw f bi fmeg aw ppmmd as p m 0 md rm WMMS mm f mgi U ma ycad gmm f Eng gmdm m fm M Wo Aw gm ea Am k 32 C is m f meg mg f r f We Wk ph pm He dv pd WW mf mm d hi Wmd f m m vcama ii mdm w m f w mg dmgs 211 fwm b E Hm m Egal fhg wmgm m f m mm mwmg g fhc iw mmgmm Hmeagwa DWEQ th g gma gphca a m Emdy fh m w m m gjmm f geaw cag f mm m gphcagma 9W6 Umw Uwcg g ch mm wbjw m gmmgeao m9 highwf WQ mwfcgcc mdt Jimdmmg mgo Slam 9 lane r m 39F l 173 epvhaes WWW E f if mm W mbGnWmmo Moon Earth Venus Sun Mars Am mk g fmmg y 1 a quot hW g an ECQWM ng am his f a7dc v g b w ffwm p ccmga GA 19 PRIMA PARS Ha Schema dcma nnrat mmm cn c globcfnm mu lb L1 I quotIllquot Shem rm Iciragonavmbra ququ tarragon gurzln ccllpfmiont luxmri appnrurcr Si term crru trlganaymbra quoq rriangulao run habcrzr formulam sirena hexagonm cheI guri us qunq vmbrz in defc u lunnri hmagonn apparcrurqua lilmt n mmnda cunilur mmmk L 9y Sunlighl Zen ilh al Alexand ria 7o Well at Syene Em mf mca WEZW CJ mm Few mmwmg m 1 A mmm ammg v m Emith gawk F A Zlcaxm r lm 9 L wz w 15m 51 wogmb ce Ib f rnm 139 W011 i Sygma d Egg E E 2 83me 3 mm Ex Qm w ME Eggg mi 0 Qggggggg Mgt 3E3 m mm 3me 9 EA 335 wggmgg Q 0 ggm gig E WE k ma Ewgwawax E5 EEQE mgww wggw O EEE Qmwgmg wggm Aristarchus of Samos 250 BC 111e most original of the Greek astronomers Beieved Earth moved around Sun Derived geometric methods to determine distances to Moon and Sun though he didn39t follow through with the calculations rdmg my film 4 MT CZL Mg hm f Ami Anstarchus tried to me sure this ang e m determme the distance tu me sun Arisrar39chus found A 87 deg n d rm n n n I Modern value 8985 deg Me rhod of Ar is rar chus To find dis rance ro Moon arm s mummy ms pan on moon 5 acmaHy vmbre Bummer Dummy M Moon of 5am Hipparchus 400 BC Possibly The grades astronomer of antiquity Produced earliest cafalog of brightesf stars Refined ArisTarchus39 methods Discovered precession of The equinoxes Precession of The equinoxes discovered by Hippar chus To Polaris mom EvoomDo erThomson Leammu Ptolemy 450 AD The last great astronomer of antiquity Produced great book called The Almagesf Inven139ed terrestrial coordinate system Produced geocen39l39ric model of Solar System based on circular motion His ideas remained unchanged for 1500 years Pir my mill mdca BEEF 1 g r m milw oSm Wbll lfg EQth ol km g l b l L l 55mle f Wl a mifwg WEE lm E l h m ngm m gg a li hw lm 2mm M2 m lbrdl chag J Movemem 01 small ciIcIes upon larger circles explained rewugrade mnlion comngnm Audan wml P rolemy s geocen rric model 39 Explained retrograde motion 39 Inferior planet epicycles were fixed To The EarthSun line 39 Explained why Mercury 5 Venus never strayed far from the Sun Ancient Greeks summary Ancient Greek astronomers figured out The shape and size of the Earth The distance to the Moon The distance to the Sun though not accurately Ti meline Reading Chapter 9 Sections 91 94 96 8 2i 38 ExtraCreditMakeup Assignment OPTIONAL Final Exam Monday Dec 12m 430 am630 pm Last Time The Sun Vital Statistics Si Structure photosphere chromosphere corona the solar cycle Energy Source Combustion 10 000 years zwsuzouwim Contraction 100 000 000 years Nuclear Fusion Converts H to He 10 billion years 07 of mass to energy E mc2 lemma Planet luvizm rlawl Orderly Motions mm mm large moon Small Objects OddballsquotExceptions Am 22 m 2225 mm 25 pa 2 The Solar Nebula Theory One sentence version The planets formed in a dustfilled disk of gas surrounding the early Sun The Timing Am 22 m 2225 mm 25 pa Age 46 01 billion years Age 455 002 billion years Carbonaceous Ch ondrite m m nuns m as pg 5 Sun amp oldesT me reori res formed from The same ma rerial m m nuns m as mu From diffuse gas 1390 0 s rar disk pressury39 gravity Hon Image mm mm uwmisvzs We see disks around other young stars mm mm uwmisvzx Clump fla r rens and spins up n uh I q x gt I a E a 3 S 25 iy Enwwnm V 54 tadM 7 Cen rral regions of disk k are The mosT hoT amp dense W J 1 quot quot 39 WNW A few hundred AU mmunrauz Mmsz Disk gas sTarTs To cool off solids dusT form AccreTion dusT planeTesimals planeTs I clump PO v4 A few million yearS K 1 WWW k Tammi 1 A few hundred AU CenTral regions of disk are The mosT hoT amp dense Mmimraizn uwu wun Role of TemperaTure amp Abundance mm in m M w i 02 l 04 14 98 mm in mm M 2m So you can define a disTance wiThin which only rocks amp meTals can condense This frosT line was around 3 5 AU from The early Sun WWW Wm Jovian planeTs creaTe Their own miniaTure solar nebula Moons formed ouT of The disk Why More maTerial larger planeTesimals cooler gas M m rauznns mu Dive u quot kR Or erly Motions Two distinct planet types Strong solar wind sweeps gas Planets Si planetesimals I from solar system interact Kmnevaen mggmm encounters change orbits Planet growth largely ceases collisions Small Objects OddballsquotExceptions M m rauznns mu Dive 5 A m m Inns lam 25 pm in Two Types of Planets Arise from forming solids in a nebula that cools off with distance from the proto Sun Nepuuna jamiar quot 7 y l Orderly Motions f Arise naturally from objects forming k l in a spinning flattened disk 139 Expected from collapse of initially slowly rotating clump Small Objec rs inm mummu Solar wind doesn39T remove lefTover plane resirnals munw Wm laughs mm mm In rerac r wi rh plane rs mummmmm lax Amman Hagan asiemms Trojan asterolds amii al Jupiier Mmiznfaiznm unm vz a OddballsquotEgtltcep rions Do These exceptions disprove The Nebular Theory or can They be accommoda red This is a common Eailh39 problem in science WWW FirsT 100 million years heavy bombardmen r period Clementine Topographic Map oi the Moon mm mum excep rions quotexplainedquot by encoun rers wi rh plane resirnals during This period Reading Chapter I3 I36 Chapter 9 Sect 94 A mums mm W Am imHilmS Lumveli page 1 NOTE for next time read Chapter 3 Sect 36 andWWW reading C i 8 Ex 2 Th d N b 0 m U ayeven39ng mm er IOOO objects whose orbIts cross I au Brief review of last time Meteors Meteorites and Asteroids 0 Aten asteroids 0 Meteorites 0 perihelion inside I au 0 meteors burning during brief fall to Earth 0 aphelion beyond I au o showers and radians 0 nearly circular orbits O mos y very small about IOO known 0 falls types Irons stones stony Irons APC llo aSterO39dS 0 Ancient all are over 45 billion years old VEF elllPtlcal orblts 0 some show evidence that there was no heat processing Perihelion Well inside l au O Asteroids 0 aphellon well beyond I au 0 all lt 8km across 0 location Sizes and types normal and Earth crossers 0 compositional families correlation with meteorites 3753 Cruithne 2302 r Types of AsterOIds 5 composition rom re ectance and spectra 0 Ctype common in outer asteroid belt 0 extremely dark low reflectivity 0 75 of all asteroids 0 no evidence of high mineral content Durat39 0 carbon rich 595 0 Stype silicates inner belt 0 spectral evidence for olivine a silicate mineral 0 Mtype rare 0 metallic ironnickel Asteroid origins total mass much less than a small planet 0 some evidence of differentiation N Am an Hum Lumvell pig 5 Impacts in the Inner Solar System 0 Collisions have played a key role in the past 0 formation of planets by accretion 0 fragmentation formation of the Moon 0 sustained planetary melting 0 global surface structures 0 atmospheric composition 1 0 Collisions have play a key role in the present 0 continued modi cation of planetary surfaces 0 meteor storms 0 large and small extinction events 0 Collisions will play a key role in the future 0 the threat of future mass extinctions on Earth Am an Hum Lumvali pig 6 Catastrophic impacts in past 0 formation of planets by accretion of smaller bodies more later 0 High density of Mercury toolarge an iron core 1 r39 3amp9 v1 I i 0 Formation of the Moon the Giant Impact theory 0 Huge impacts basins on Moon Mercury 0 Anomalous rotation of Venus Uranus 0 Bizarre Moons Phobos MirandaTriton Am an Hum Lumvell pig 7 Craterinz rates then and now 0 Lunar Results 0 high rate in past 4 Gy ago 11 Hm mm mm W l maximum 0 now nearl stead Moon39s y y Eaponulimlly decaying Imlm39n mmpunnnl us History mm pmduullun 0 recent impacts 0 Tycho IOO My ago 0 Coperni us 600 My ago Ml emerzrg crygum Innum am U39rcmlcxruscls mm m of mm Flequ umlers me a copsmuuc RATE OF MPACT CH1E FURMATIQN Iona Y wmynnenl oi Ema nmuucmn 4 a 2 1 TIME ti ions w yDars beiare now Current Impacts Energetics 0 unit we ll use Megaton Mton Ioooooo tons ofTNT 54 X Hiroshima Abomb impactor Energy Crater size 20 m 5 02 km 00 m 00 0 km km 0 km 0km 0000000 00 km Okay but how often on Earth WMecaum rm 5113mm I I mmm mmm m Meteor Crater Wm gnu mm 0 mum x Tunguska waer a 7 Amara 7 some yr ago 9 no man 3 kmdmmuu mm mm zmvanmzm Wm uncuum g n rmsuk n a 5 mo sq um km 7 nudu Mas mde Swazi am markmgs asungmanyym s mm m a7kmnazuanE The KT Impact gt Death to all Dinosaurs umli lShuomlknLIV II HUI y 0 Global iridium layer at KT boundary 65 Myr ago ml 4 0 iridium is extraterrestrial 0 global layer 2 cm thick 0 parent body size gt l3 km taller than the atmosphere 0 crater diameter gt I30 km 8 39 impact energy gt IO Mton 0 Results of this impact 0 A global NuclearWinter lasting years 0 major disruption of climate Mmequot mum WW ll 39 J 0 major disruption of food chain v o mm smsm 139 I 0 large scale extinctions 90 of all species extinct AMI 73m mntm was some Am izn Fall zms Lumvell pg 5 T h e I m H ems izn Fall zms Lumvell pg l6 cm vsnis Size of Howoften Energy Crater body once every Mton size consequences local devastation 20 m 50 yr 5 02 km 39 other severe local effects similar to Tunguska damage to ozone layer 39 local incinemtion 00 I km local dewstation other severe local effects societal chaos if populated area IOO m IOOO yr suspended dust for months lower global temperature agricultural failure i km 00000 yr ioooo l0 km Nahum mass starvation comparable to SL 9 on Jupiter creiaoeous e suspended dust for years total darkness for a year l0 km IO7 yr IO7 00 km massive dieoff ofvegetation ITIsz extinction m ie KT dinosaur extinction g 8 geologically signi cant impact 30 km yr 3X o km relax not likely any more Aswa mu FallQEIEI Lemme l page 5 A Scale Model Solar System Distances the Sun a softball l au ID meters Jupiter agmpe Earth a poppyseed i each step you take l0 million miles Aswa mu FallQEIEI Lemme l Page 7 W mm 7mm 1 mu l mm 1 mg 2W r 39 quotN l mum mm l l um i mmmmmi I um i mm mum mm H nvnrur wam TH nuvzxs 0quot DNer Lecture 10 History II Renaissance astronomers and their discoveries Copernicus Brahe Kepler39 Galileo Las r time Ancient Greek astronomers 39 The spherical Earfh Aristoer Aristarchus of Samos 39 Erafosfhanes 39 Hipparchus 39 P rolemy Pm egmy g gm w mdH H g mg mcairmmmm gmmwm mm ea 5392 M d m mb md pmd cg my hmg mg mwm p tm F fm SW00 m Hmcai go ff mg m phygim WWW Pm my d pifd Aw g m gg M fphy md phyg m WUyo Haa m5 m 0 ifd Em gcgw mg m pcacammgow W HEEWQWWQJJW g m 2ka f wd 1 Wm a m p colmmm wm g WWW mv mimgo Gwyngm mmquot mm Qameag m WM d 37 ifh mk pwmp ad Sfr mmwg m bmdm WHmy mm cg 15m ymmg WW NM gm Cdil y WWW fr mww Pm myg meww cg macadca wwkcgd WEN ma gh m macme e am b W W f we p mca go A mmmc w W WF mwca y m m y pdmg his Md Fm mm y 35m ymwgo me Pm egmy m gm Amb cg mmgs mg f g eg fwmd mm m Emmy m midd cg gqjo AUWMWh Uibm y W md ifmmgfwmz my g cagm ca M pifm Qghdm md Mm g gwwq i aw byzmif m mp g m mm mpv cal Emmg m f Meg mr kg m 1453 m gm m f h m m Wmcgm wmmo WIN m w y H g mmmm m ggmgg andmmg Swamicays i mm 39 2d in Silh m kiim WU am mm 5 in W3 mmxfrlhamxmmdk M1 Jamaal Lam 3 mlbgju 61 Fatal mamm 1m T x d m rwmm 1211 wf rrg war39u n hw Hm waa a mm afmmg fag air a g m w mm ja Copernicus39 heliocentric model Sun is at center Earth orbits Sun like other planets Inferior planet orbits are smaller Retrograde motion occurs when we lap Mars amp the other superior planets N h M pm f Mg ngmfrg Fm Wig maid m m ws 6 Humming EQW fh mltd mmea mwcmgb cg Mm gmw g h mm mmm WW 2 Emma DFHJ mg dwcad mag mm d mm Ug imam WHmy Cccczmmcad 1 WWgmd mf m f nes WCQW p mcgifg m g mp c z wwbg aH g m ea Hcam fd We gmmg f We EWh a if bm lt2 9pm 2 wbiamm Lm ne Ramdlmr ms Ma LEMWWJHV c d i meI MWV W 39 Lmp txx39 r M yy Kuhn ru Wampgu as annular0 6039 lcam u g HLEL39SSEJF 1 5162 LHW mama 39239 Mm mgx ca IQUF T WQJF galy I 33 A Hui 3 m How does one explain refrograde motion Over a period of 10 weeks Mars appears To stop back up Then go forward again megmdcg Mmm North 0 L kea rhea 31M Hm g gummy 1691 mm mm Md m w wg We rm gm go O 041 g mg magma by in W mb m ifhcgy mv m7 b f m fr mg wg e 339 W lt P mmirha v Nb weab ea 1 P m gmg m m1g ca might Hmcg W rm md gcgfg Em ww rm East Copyright 0 Addison Wesley Nkm wg gm LBW aH g Wanda d d m bez w f md cg f mg hea p f rm pu ccim fg if m W Hcgm f m wm m U m md by pmccz gg m bgmmfr mg r ung mcg W irh rm E h Em momma we p f m f rm gmw ghw d h f mm m ff i o hm ii mi b W 93qu H m md by mgo WHWEM Tycho Brohe d 1601 Danish as rronomer from wha r is now 5 Sweden Es rablished an observatory on Hven or Ven an island be rween Sweden and Denmark T3 mm Wi lmf mm mmkxa Emar m t 15mm am 1m 3 a ff a bgf lkamima gv of Rmmk m itm ydm mme M am mc b gh mimlramm 11 r m am a im rm22m i g i g l aging m3 ELI i 3113 if 22 Em Wig m 5111mm 17 m 1er wall53mg 23ml m mm E mjg 3mm my m3 i Wham milimgii 6h e 1 i 1pm Thub 1mm ammm am m mi BL a u vim m ifmmm an if mi Mmfg mil w l mm Ltm ka SEE 23 m1 me Mma mm Trim i iaxmm mini mm mm mmmmm Tm ng main rm mml m m E egg E g2 miwwg wn 39533 9ng 8g gagg gasgggw gquot E Q E E9 gm 5 Emgggg 58 g Et 8 Egg 5 E ggmgggw Egg W gg Egg i wg a mmgg giwmg EEEQMED E omgg E gg mg gmgng Egm ggmgg mmggg g mpg ggg mE W6 obmvimvmg ESQ Egg Wm 3mm Th Wm b WiF m Wmd We Aw m m mgm gyo WC QWQ mam mi M if baa mfgw bjw g m pr f md mhmmg mg rac cq m f ifhea p mc mmf and m w gph g ago mm h Lagc wcc r mg d mi W Hmy0 mm e z o mm pmco megd W mmpmm gea mco ca o mam gpcg g f 1th 13m W Hhm ccz and gm m mdca gm 5 quot 1quot 5 girmmfa x META ANN D E co 1 5 NOVA fVTVDANKYSTE til4 fl HTPOTTFOSIS all AK THO I 7 PI l 4quot TrquotMy ulLlrlr714quotIuwuvgnmg pfllluux Cabm A mr 1 4 x K VL L J1 L Ewmlm v dzMW mawmva r J 7 n vr 1 m Twmd Slum mm 519m 4 x N m l39rE iVQDHRVL zs Jrfxf lgllnkql E a Wh D Q 1 y t 22 k l g pt 57 Z K33 hm 5M L1 PD 39 d j o t i 35 nga Kim Lt v5 mm 45 3A A W x K W Kgpj k W1 wrycam jr J a J V n 38 A 7 LHJQJO U i fa g agi Lnwr UHF J W12 ch 39 QWQLLM JF gtK 1 NHL 5 4 mf A V N mo 391 gt 1 3 CLWDWKQEFJMQ U H mg 1153 u f NAMES WU W H md 1va ihm fm tm gzd m mm U rfm l j 3 gt I39 J x v W 3 V V 391 a z GC 1 Thug mm a mmgw guwk mu m 1 t KL Km 3 7 er 3 A 74 quotL d fig y 1 15quotw in gjw mwctym u 9 J W 13mm in U HJL y FM W quot 7 gJL J LJ ff 02bquotmflf39QUU 311 5A iz f 1F JHCCJM 4 h 633 lm h C A Van a WWW LtV w HWSU m gm1g 9W MHLHUQM m EM 9 EM fwd u W 39 A 1 CL r x gt 790 1 V f w mu Ma Ma AL M g ff i Sl jlpl j may 7 ch y a 4 So 51lt33PLJU W W5Cny U3 JJ inf cw J rm 53m i5 aim SW1 v wags Nothing lies at me other focus aphelion perihelion semimaior axis JA quot L Cwyngmam wnwu iy 77W 7 7 Wm m Qq wg mm m WQ XIF kamn a H m g k a P b y rm f g WW phy s ih H2 ghwcad Weft Am gm ca g Hmwg 1 WWW mm mmwo 1 mg rm f m f if mm a if p Ema g fmmm m bgrgwm r mgo H WdQE dfr d d am mgcs f rm Mmmn quot gmgm gg mg f39 Mama mm wmd pr mm mg hw nga H W U m xpegw mm am mwmmm md 5ng 2 W6 Emwmv EH 2 E SEE 2 E3 Ea gw mgg gmgg f g Egg 22 Egg 6 ggg mvmge min mgmp m Emmgm gg 583 2 2 5 E w gw gm g g mggmggm ng gng min E Emggg EU E5 mggiww g maggghg 3 wgw gg Egmgm wg E 3339 wggkwggwwg gamg w mm 3ng EE Venus in Ptolemy39s model Ear39rh Which phases are impossible in This model Where does Venus appear Full in heliocentric model gm mm L MQMJ l 413Eth i er b Q mm 2 JC r 9 1118 pd Q U J j 71 VH 5W Renaissance astronomers summary They figured out The correct geometry of fhe Solar Sysfem The shapes of The plane39rs orbits Kepler The laws of planefary motion Kepler Anaxgmmann VAZSEC ngnxmsauur 35 EC Mammazzaq E prpmmsogu m P R E WGIEIUV HEAD v up Tychna Kemumm n 39Ga11a156471542 gt Newtm064271727 l Comet Ikeya Seki 39 39V C1965 51 39 I Jama W Yang4965 W 39 3223 9 mm m l m mm mm walk muff 39 imamiwk am mm mz awemm rib mm a grasse ewm mmmam mxmgmm o a V a I 39l 3 b A v mamaW E JUWWW a M mmgew am 0 dwf s u k quot JWWEXWEEGJW39 W 39 Anatomy of a Comet ComeT Tails can ex rend more Than 100 million km Coma is abou r 1 million km in diameter Nucleus is only a few km across Nuc aus warm and Gas coma begms m mm 939 MW avound nucreus when camel vs about 5 Au lmm Sun Tall toms Pushed aux by sub wmd and vsdia nmdimnw 393 now abnut Au was ung nolvlsxble are Sam neahng mmmlshas com u M 1 una ec m and xail msappaur hemeen sun 9 Sand 5 AU Item Sun Tall new way mm sun 55912321153 How a comet ge l39s H39s fail A Poi of quotConfusiion Haleop 28 97 HaleBopip 22497 Ciome r s move slowly from nigi39h r To nigh f r39ieil a ri ve To The background sr r ar39si And meteors move quickly Edmmd Ham Ek hmmd JHKQWcW 2m 5 er f w g k m mm 121 Lam a b i mg mg 332 Mm p m gg Ug mg ag mm fMd Eswrcalk r fadi lb 13 gag Nan39mm i MQ iZ7 a HQ 4mi gt4u Mb if Raw 24L O JL Hg cit g caw g msz b i f ag f cam may s Cfcom d frfmw mg mm mg umxumdt m gm m Ham 11hLa rlhma WM Camila WWW Em 1 my Tm W ii aw Ifna 39xuum rrggd maq tg mdf HhIL g mmad IiFiFF JF Hrg dl wg 1mg digu Th Come r Holley 1PHolley Firs r recorded in China in 240 BC ClosesT To EorTh 837 AD 003 AU Los r re rurn To inner solar sys rem 1986 Nex r re rurn To inner solar sys rem 2062 Curren r orbi rol period is 76 years Jupller s Orbit Mars39s Orbit Earth39s Orbil HaleBopp Come r HaleBopp 61995 01 Kr39eu rz Sungr39azing Come rs 1QQBJOSIU1 0400 9290 15gquyg 59 Gas Phase Sublimation SublimaTion occurs when a solid conver39Ts dir39ec rly To a gas wi rhou r going Through a liquid s rage first NASA s Deep Space 1 photographs the gas amp dustjets of Comet Borrelly on 92201 ESA s 601391390 spacecraff pho rogr aphs Come r Halley on March 13 1986 of a disfance of 600 km from The nucleus Potatoshaped Halley has a nucleus That is roughly 15 km across Come r BorreHy from Deep Space 1 92201 Size 8 x 4 km F r39om Sfardusf Comet Orbits Hyperbola Orbit Type Eccen l r icify Total Energy KE PE Elliptical 005 e lt 10 TElt0 Parabolic e10 TE0 Hyperbolic egt10 TEgt0 Shor f LongPeriod Period fCometOrbits Comets Come rs T I 1 Hyaku rake empe Halley Origin of The LongPeriod Come rs Dun ChmdA swarm 5F mums amz nudm m a huge mu surmundlng Sun and p una s Appmx A0900 Au Kmpev BED 39 mc RW 3 W md 6622 62 Sedno OrbiTs beTween 76 AU and 000 AU OrbiTol period gt 12000 yr Kuiper BelT No Oor39T Cloud Inner Edge Asteroids Inner Solar System Saturn Solar System Sedna 8001 I 00 miles in diameter 3 Guaoar Pluto Moon Earth 800 miles 1400 miles 2100 miles 8000 miles Kuiper Belt Objects GKBOs aka TransNeptunian Objects Over 1000 have been discovered since 1992 Six of theSe have diameters of 1000 km or greater They orbit b et Weeri 30 I 7 mam andi5o ammu ailAU a sun mnA39u Meieor39oids meteors me39reor i39res Mefeoroid small body in orbit around The Sun prior to encounter with Earth Manor The visible sfreak in The atmosphere produced by the small body entering The Earth39s How big are most meteors That afmospherg we see Most are the size of sand grains rarely The size of a pm or a marble Mefeorife wha t the small body is called if it reaches The ground If m1mmaomll1hmhowm nem nm mqm cmmmapudi 10701mm leavingmexpanding glowing ioniadcohmofuinud cmpkthmmeOmmmm Origin 99 mt dcbris 17 mm fragrant Me reor39s More Plen riful Af rer39 Midnigh r 1 am Dayligh r Time Direction of Earth39s orbital dawn motion F few meteoroids I 4 catch up with more meteoroids are Earth swept up near dawn On any clearquot dar39k n igh r away from ci39Ty ligh rs you39ll see 610 meTeors per39 hour bu r some rimes during a 39 you39ll see many more Mg f wm SWQW r 1 fn g v L n 3r 3 Mcawgszmw SUMWWS 5mm Md 6 in m 1 77w w m 1r E Qx ng iami aq US b i f mm h m fmw ubgt ghd mammal a U r 1 C63 Tum give ng gmwm mmeacc fh a G m m m vquot r C quotx I a m quotw a u v fjrnr f ln x v 1 11mm W1ch Persemds MWng ElliL54 gmch Leonids r F J C A me reor39 shower occurs where a come r39s or39bi r in rer39sec rs Ear rh39s or39bi r 6me WE gag g Em n 63 5 EEEWQ a FE gmg g 90 QB ME h 3 2amp3 g g E 293 29 EE Eggmgg mk g 9E g3 bm gm Egng 55 amp LecTure QuesTion MeTeor showers occur aT specific Times each year such as The Perseids around AugusT 12Th and mosT meTeors boTh shower members and sporadics are seen from July Through December MeTeoriTe falls however occur aT random Times ThaT are evenly disTribuTed ThroughouT The year WhaT does This imply abouT The origin of meTeoriTes Am an an m Luau wag i Reading Chapter l2 through IZ5 Midterms submitted please check with us with grade questions Brief review of last time Planetary 39 0 Overview of PlanetarxAtmospheres o composition differences between JovianslTerrestrials o terrestrial planet differences 0 PrimarxAtmosphere 0 SecondaryAtmosphere alteration 0 loss by thermal velocity evaporation o outgassing impacts chemistry geology biology 0 Atmosoheric Pressure and TemDerature 0 Pressure vs height Hydrostatic Equilibrium 0 Temperature vs height thermal equilibrium 0 Earth s Atmosphere 0 thermosphere mesospherev stratosphere troposphere 0 Venus and Mars Atmospheres 0 The Greenhouse Effect and Ozone DeDletion Am an an zms Luau mag 1 Temperature Structures in terrestrial planets ms Venus a runaway greenhouse lupiter 0 The Basics 0 Mass 38 X Earth View through small telescope 0 Diameter I I2 X Earth 0 Surface Gravity 253 X Earth 0 Moons 4 major many minor I 0 Rotation very fast P l0 hours HST39m ge 0 view from Earth cloud belts no surface 0 visits 0 flybys Pioneer ID l I973Voyager l 2 I979 0 orbiter Galileo l 9952003 0 atmosphere probe Galileo I995 lll lulwhler Am iZDHilmS Lunm l7pag a The ovian Atmosphere 0 75 Hydrogen 25 Helium 0 trace compounds all H rich ammonia NH3 methane CH4 0 water vapor 0 composition of clouds F 0 ammonia high level 0 ammonium hydrosul de ice middle level 0 water ice low 0 colors of clouds only small amt needed In general 0 high clouds are white ammonia 0 lower clouds are dark amm hydrosul de 0 other coloring agents still unknown complex organics Atmospheric Features m W 0 Zones 0 upwardly moving material 0 high cool cloud bands 0 Belts 0 falling gasses 0 low warm and dark 0 Spots 0 updrafts white spots 0 holes in cloud decks dark spots 39 0 Winds and CirculationZonal Winds 0 belts and zones rotate at different rates 0 lots of shear from band to zone 360 kmhr 0 circulation at interfaces Example the Great Red Spot Winds and Circulation 0 Zonal Winds 0 belts and zones rotate at different rates 0 lots of shear from band to zone 360 kmhr 0 Circulation at iterfaces 7 lt Am il HilmS Lunm mag 9 The Jovian Interior 0 Clouds and atmosphere Er 39 0 temperature increases with depth WWW 9m mm 0 pressure increases with depth WW 0 Deeper pressure liqui es hydrogen 0 liquid molecular hydrogen mantle 0 then metallic liquid hydrogen electrons free to roam 39 quot i 0 starts where P 2 3000 X Earth s 0 root ofJovian magnetic eld 0 Finally a rocky core Ml 5XEarth 0 T 20000K P 50000 X Earth s Am il HilmS Lunm mag in Sat urn 0 The Basics 0 Mass 95 X Earth a 0 Diameter 95 X Earth 0 Surface Gravity 07 X Earth small telescope view 0 Moons 5 major many minor 0 Rotation very fast P 06 hours 0 view from Earth ball with big beautiful rings 0 visits 0 flybys Voyager 2 l98l 0 orbiter Cassini arrived summer 2004 HST Image Samm Am il HilmS Lunml7pagl1 Saturn Atmosphere 0 lt 0 less vivid coloration than Jupiter 0 stronger zonal winds 3 X higher than Jupiter 5 39 k 0 deeper cloud layers 3 7 0 less helium thanJupiter a r r 0 helium sinks down in cooler atmosphere 0 Jupiter too hot Helium stays up 0 H20 220 50 400 wind Valarin Jmsi Clouds on lupiter and Saturn Jupiter w Saturn ammmum Wampum Am an an zms Luau wage is Jupiter W Am iZDHilmS Lunm l7pag H 0 thicker liquid molecular H mantle 0 smaller metallic H interior 0 similar rocky core to preserve mean density vlsibie clams cure ui rack me c s and hydrogen nnmpnum ls Jupiler Salurn napymmomu f nnlmn WWW p W M mummm Uranus and Am iZDHilmS Lunm mag l5 Neptune The Basics Mass l45 X Earth Diameter 40 X Earth Surface Gravity 090 X Earth Rings several thin dusky rings Moons 5 major 0 minor view from Earth dusky blue disk discovered in 78 visit flybyVoyager 2 I986 The Basics Mass l7 X Earth Diameter 39 X Earth Surface Gravity Li 2 X Earth Rings several partial ring arcs Moons l major 7 minor view from Earth dusky blue disk discovered in l846 visit flybyVoyager 2 I989 HST IR Images Am an Hi zms Luau mag it Possible Interior Structure of Uranus and Neptune visible gum 39 1lciidhylrugn gaseous Warmerquot ame r Md mam nyu ugen gasems Hyavogen cove oi ruck meiex s and hydrogen vtnrrnmm s 39 Juplle Uranus Nemlme 2003 G Gonzalez Lec rure 7 Lunar phases Phases of The Moon What causes Them and what doesn39f Phases of The Moon and rime of day Lunar eclipses I Lec rur e Challenge A What do you Think causes The Moon To 90 Through its phases uses of The Moon Names of The lunar phases Phases of The Moon39s 295 day cycle new crescent first quarter waxing gibbous fu gibbouN last quarter wamng crescen Lunar Eclipse The Movie Lunar Eclipse mm Th MVWMWW mg bmmdmry m and dark 39 Draw what you see 5h Now indicate which picture looks most like what you saw 09999 IR r39 125 m 15 N 5339 MTG W2 QE hwgm Im lt 33 w m 9 p 3 1 H O A YV V 31 hgmgu WM m alcqil sn w mm mg pix bu hw IL 1 r V W Vf s yhcsa M30 gm LWQ EF h Mg 10 quot J m w M 15 Nx vLe m a r 4 airbag mm om wm m on two 394 va A 3 w c v quot O 4 f hag25 xyCQW 54in LOLGA wkvz v 924 x J 0V Ma Sm M J1 V t w rm Mmm 739 39 Lan Quarter Waning Cresceht 1 39 39 New Mbqh Waxing CfeScent 39 1 3 I Waxihg Gibbons First Qua er L Ea h Diagram above shows EarthMoon sysfzm drawn To scale View 0 the Mann I seen l mm an Sidereal v5 Synodic months Test your understanding Is There a dark side of The Moon The Moon always presents rhe same face To us What does rhis imply Why do we see The same face Ro ra rion period or39bi ral period Copyright a Addison Wesiey Moonrise amp MoonseT aT 1ST QuarTer39 Where is The Moon in The sky aT sunseT Sunrise A A V V NoTe ThaT The illuminaTed half of The Moon faces The Sun Waning Crescanl asse 3 A u Menmar 9m Set a m 0 s New Moon 07 a u s m s Mend an noun 55 a w Mnnd an 1 M 5m 0 0 Hrs auaner Waxing Crescem H v 8 Fuse naan mas and sat limos Mendwen e w ale appraximme 3m mmmgm DavwgmOZWA mnnmvEmcmm WW mmamwm The phnxas snow how she would see me lunar phases quotom Eath as she Iurns to face ms Mann in each Fashion is il orbils Eanh Third Quarter Fuse mamgm Mendwan 5m Sex roan We 39 gsvhhcus Rise 9 m Mendwaw 3 w Sm 9m to Full Moon Waxing einhaus R se am Menwaw am Sex 3w Fuse ow Mondxan maan Set 6M1 39 SUREmfmiparent I quot a The New Moon39s apparent path on the sky i x Test your unders randing Wha39r does if mean To say That The Moon39s path closely follows The ecliptic 1 L U Wquot k a U L The Moon on The celestial sphere Diurnal motion What time of year is shown What phase is the Moon Is if visible from The North Pole on Earth v m Ear rh39s shadow a r The Moon m5 53 U 0 I by E rs AS 7 001 Em ole PublishingWP Penumbra Cross section of Earth s shadow Orbit of moon total eclipse Not to scale Uneclipsed Moon The eclipsed Mann loaks red for fhe same reason The settingrising SunMoan look red The blue light is absorbed by the afmosphere Eclipses occur where the two curves cross x nP The Habitable Zone 0 water essential to life as we know it 0 liquid water has to exist on or in the planet 0 must be right distance from star heat from star maintain 32 F ltT lt 22 0 too close runaway greenhouse Venus 7quotquot too far CO ice no greenhouse Mars 2 0 BUT 0 life exists in extreme environments on Earth 0 liquid water a constraint for normal life only Planet Size and Habitability Planets form by accretion from a disk of gas and dust Too small about lt05 M69 0 Can t hold onto a life sustaining atmosphere Mercury Mars 0 no tectonics no carbon regulation 0 surface gravity g lt 08 G Too big about gtl0 M69 0 Can hold onto the very abundant light gases H2 and He 0 turns into a giant jupiter Saturn or ice giantUranus Neptune 0 surface gravity g gt 22 G Habitable planet search guidelines Stellar type gt stars not too unlike our Sun 0 HZ gt Orbital periods of U2 to 2 years 0 set by the planetstar distance Planet sizes gt 005 to 02 x jupiter 0 much smaller mass and radius than those found in reflex motion studies 0 Current searches are INEFFECTIVE for nding habitable planets A better way the Transit method Radial Velocity variable Eel orbits along our lineofSIght M069005 MJ SO gt planet tl aI39ISItS across P 3524738 2 0000015 0 the star b o relative flux 0 to on i Killlllllllllllllllllllllll 015 010 005 000 005 010 HJD v Tcduys Depth 100 ppm Aii 7 i 0 JupiterSun transit 00l magnitude dip easy i ii Time hours The rst transiting extrasolar planet HD209458 Hubble Space Telescope light curve Discovery by Charbonneau et al I999 Detection of the ATMOSPHERE of the planet around HD 209458 f 1 39 39 Charbonneau et al HST November 2001 Ame no PAHIOOS Lemurel page 31 39 l E Muvs I i E l l quot szws 1 mums l 1 I I umm ammo at math man i l l p E v c D 0 1 umul dlmmnet of mam llum uuum 4ng 39 what about Earthlike planets compare with JupiterSun transit EarthSun transit 0000034 magnitude this is not so easy mu rm uA E ma Looking for Earths in all the right places the 200920 3 Kepler mission U A Searchfur Habitable Planets 0 Kepler Mission is optimized for nding habitable planets 05 to 10 M in the HZ near 1 AU of solarlike stars Continuously and simultaneously monitor 100000 mainsequence stars 0 Use a onemeter Schmidt telescope FOV gt100 deg2 with an array of 42 CCD Photometric precision Noise lt 20 ppm in 65 hours V 12 solarlike star gt 40 detection for Earthsize transit Mission Heliocentric orbit for continuous Viewing 2 3 year duration Kw r A Searchfur Habitable Planets rx ng EARTHTRAILINQ HELIQQENTRIC ORBIT a Spacecraft orbit Eanh a h Earth a Vernal Winter orb E d Y 1 equ nox solstice n ear A End Year 4 K E p L E R 1 AU Summer Launch June 2008 Autumnal solstice equmox End Year i Sun Heliocentric m m SunEarth Coordinates Per ddays 36525 37250 Fixed Coordinates End Year 4 Semimajor AU 100000 101319 eccentricity 001675 003188 Delta 11 292510L Kayla 39 A Search for Habitable Planets Kgplgr PHQTQMETER Photometer CCDs sensors Telescope Kepler will be 9th largest Schmidt ever built and the largest telescope launched beyond earthorbit Proto Tvne CCD y A Search for Habitable Planets Views of a prototype module composed of two CCDs mounted to a common carrier Each CCD is 2200 columns by 1024 rows thinned backilluminated antire ection coated 4phase devices manufactured by e2v Each CCD has two outputs With the serial channel on the long edge The pixels are 27 mm square corresponding to 398 arcsec on the sky lilh Hm Miami 4 a 3 v s 39039 39 a tv 39 u 7394 3 b 7 quot quoti T EXPECTED Fianna v a A Searchfur Habitable Planets A Searchfur Habitable Planets r quot M Hypothes1s all dwarf stars have planets and monitor 100000 dwarf stars for 4 years Transi s of erres rial plane 3 V About 50 planets if most have R10 R M10 M quotc b q About 185 planets if most have R13 R6 M22 MG a 439 quot About 640 planets if most have R 22 R M10 M 3 W l About 70 cases 12 of 2 or more planets per system 39 39 Transi s of housands of erres rial plane S It most have orbits much less than 1 AU r A V Modula ion of reflec ed Iigh of gian inner plane 5 About 870 planets with periods s1 week 35 with transits OWEI m j Albedos for 100 giants planets also seen in transit at i 39I Transi s of gian plane 5 7 f I About 135 inner orbit planet detections Densities for about 35 giants planets from radial velocity data I I39l Oquot t t I PVT cmquot 39 A A About 30 outer orbit planet detections Astra no Fall 2005 lemme 5 page 1 Reading Bennett Chapter 2 Sections 25 Help Room New Open 7 Schedule soon on website Problem Set 1 Available NOW on the Astro 120 Website Due 99712 Print from your browser Brief review of last time Time and The Seasons 0 The Sun on the Meridian Diagram altitude at noon at equinox altitude at noon at summerwinter solstice 0 The Ecliptic sun moves eastward along the ecliptic inclination of the ecliptic 235 degrees to celestial equator 0 crossing points are equinoxes extrema are solstices 0 The Seasons azimuth of sunrisesunset at various latitudes length of time above the horizon in summer and winter angle of sunlight shallower in winter than in summer distance is NOT a factor 0 The Motion of the Moon eastward motion in orbit around the Earth 0 eastward motion with respect to the caused by 0 orbit of the Moon around the Earth Astra no Fall 2005 lemme 5 page 2 The Motionls of the Moon sta FS Rate of motion is about 13 degreesday Complete circle in one sidereal month 273 days BUT V Time between successive full moons is 295 days This is the synodic month start After I siderial month 27 3 days later 29 5 days later After I synodic month 51m lZO Fall 2005 lemme 5 page a it IIA T JKUA39UAIHJ ma 4 kmumuuuh ewe he uuml u arnuuiqli The Phases of the Moon 0 1stQuarter GIEEOUS 39 Waid ng 6PM noon 6AM Wawi ng 3rdQuarter O midn t 51m lZO Fall 2005 lemme 5 page 4 llllll name no Fall 2005 Lecture 5 page 5 Appearance of Moon from Earth Phase crosses New Moon noon waxing crescent lst sunset Full Moon 3rd sunrise Crescent name no Fall 2005 Lecture 5 page 5 why not ECLIPSES every new and full moon The Moon39s Orbit is Tilted TheMoon s orbit is tilted5 tothe ecliptic 39 ecliptic Mocn39scrbll Angle 53w N 0 d e S crossing points of lunar orbit with ecliptic 7 line of nodes Line of Nodes connects lunar nodes name no Fall 2005 Lecture 5 page 7 Nohh ascending node Declination 0 I r descending 393939i1 node South I 12h an 0h 18h 12h Need the Sun to lie at a node at new or full moon for an eclipse to occur name no Fall 2005 Lecture 5 page x Regression of the line of nodes Line of nodes circles WESTWARDS in 187 years Appruxlmnlaly 2 years later 4 4 935years d later a smallest lunar HigheStLOWeSt M00quot altitude variation Astra iZEI Fall zms Datum s rage 9 Earth and Moon Shadows 0 The UMBRA region of total obscuration of Sun 0 narrow coneshaped 0 finite length 0 The PENUMBRA region of partial obscuration of sun 0 broadening coneshaped 0 quotinfinitequot length Jorgensen 2005 Lecture 6 Coordinates II More on The equatorial system Combining coordinate systems Using a star wheel Last time Seasons Coordina res I What does not cause the Seasons 39 What does cause The seasons 39 Equatorial coordinates 39 SUREmfmiparent I quot a gt Summer Winter Solstice Eclip ric another view Eclip l39ic plane DR b 3 XNT Plane formed by Earth s orbif around The sun Terrestrial coordinates on the Earth North Pole Latitude N or 5 from the Equator Longitude E or W from Greenwich related to time difference HORIZON sys rem The Observercentered view Al fude up from fhe horizon Only true for a particular observer Azimuth around from North through East SoufhWes139 S 180 Zeni rh A Ia mde 39 E 90 Horizon W27O Meridian diagram based on Horizon coordina re sys rem Bu r NCP and CE are par r of ano rher coordina re sys rem 71 quot39x KWrJ39L CSUCQD 4 V j 2 J 3 E7 The North Celestial Pole is a special point in the sky and it stays in one place With respect to the stars 90 from the NCP is the Celestial Equator Diurnal daily motion is parallel to the CE CE also stays put in the sky The Equatorial coordinate system This coordina re system is pasted on The sky Thus if doesn f depend on The position of an observer on The Earfh like The Horizon sysfem does The equatorial coordinate system is named affer the celes al eqtmfor A few key facts declination To make star maps we need coordinates fixed on the sky The North Celestial Pole and the Celestial Equator are fixed so we start there 90quot from the NCP is the Celestial Equator gt Count declination N 5 from here Declination DEC or d is measured in degrees N or 5 It is a lot like latitude on Earth 90 the star is Polaris 90 2 the South Celestial Pole What star is close to 90 declination Where s 90 declination A wigth o m fhcgr W mif m d gm mg u f m m W64 U lt01 Eco mad 1 m mo Agirmmmwg m where the Sun is on March 21 The Vernal equinox 0 TM gamma g QUU Riga m umo I if its 1 MW Hm H ngdi cam E j i ha 1 me iwdCQ m g g m a quotmm mma RA Hgsco k md f mo mm Em hrgammg m m r gg Lmdl Longitude is measured E W from Greenwich We need a special point in The sky To measure quotaroundquot from We use The apparent motion of The Sun To pick our special pointquot March 21 the Vernal Equinox the Sun passes the Celestial Equator heading N It is here A9 South North V ptiatteooIrolmate V A V39 A l t 32 1 I r x L I l 5 X CCnSIOnTk39 What are the Equatorial 3 coordinates of the Sun on 1 1 The sun on March 21 On March 21 the Sun is at the Vernal Equinoxquot It is also on the Celestial Equator Its declination is 0quot Its right ascension is also zero Special note Longitude relates to time and so does right ascension For convenience really we count RA in hours minutes and seconds We use the same name for the place in the sky and the date Sometimes confusing Aros of a circle time 360 1 circle 24 hours 1 day 15 1 hour of time 60 minutes of time 1 60 minutes of 4 minutes of time arc 15 1 minute of time 1 4 seconds of time Our39 eye can resolve one minute of are 139 How long would you have to watch before you could see the apparent motion of the sky without 9 a lelescoPe39 You would have to wait for39 at least 4 sec with a very accurate and stable line of view to detect a change in position 39 Vhaiigfejthe of the on sol Declination235 h 39 a 7 fujf39gne Why not 0 39quot 139 a v 33944 1 39 quota 42 s 1 V V I I IV 14 of the way around I 14 of 24 hours c 6 hours quot i right ascension of the Sun on June 21 39 l I J n l Putting everything Togefher39 summary 2 N What is The declination of the Sun on June 21 Wha r is The altitude of the Sun cf noon on June 21 What is The RA of the Sun on June 21 if EccaWWg b w w Wf f mm Wm mm rm QW0 Wit mif be m Wm 21 if m E m h mi f md w iFh re mg wb mm h 3 mm m Sm mw d b am am r c g Eqmmw UH WW mmd U m m a D Em i h g mseg mad mm m f md m mgw p png m m ght gsmg m fmm 3de m m mimi Em rm 5W KFC QQWWEW Why mm mm Amww Ag mes Km mm eagg mg mm W mg hmg mgg 631 M20 In the Sumerrio is up in the sky 39 mostly When the Sun is up too WhaT if you don T have a sTar wheel HinT For a given daTe figure ouT where The Sun is STar39T aT 0h RA on March 21 Add 2h for every monTh STars near The Sun on The sky will noT be visible aT nighT STurs wiTh RA 12h difference from The Sun will be visible all nighT Problem The bright star Vega has the following equatorial coordinates RA 18h 35m DEC 39d Who par of The year is it visible from Ames in The early evening Winterspring Springsummer SummerFall Follwinfer E Summing up coordinate systems Terrestrial system of Earthquot Latitude Longitude Equator Greenwich Horizon system Altitude azimuth horizon meridian 39 Equatorial system Declination Right Ascension Celestial Equator Vernal Equinox Lecture Question A What do you think causes the Moon to go through its phases B Fact the Moon passes through the Earth39s shadow only during a lunar eclipse once or twice a year Does this change your answer to part A How Reading 5mm I437l44ch2pur l2 hmugh I25 Midwmumm piesunccitwm uswnngodscmmns Temperature Structures in terrestrial planets Brie4 review of last time Planetag Atmospheres 0 Overview of PlanetzzxAtmosph eres c mpmmn dMelmwa human imnsrrmmmis mmmaipumdmmm o o lax by harmll vdunty r mpmmn w m mpmmhsmmmmiegnmieg 0 Atmospheric Pressure and Temperatur view height demsiancgguinnum WW 0 Earth39s Atmosphere nymph mumpiurtsmmspnmmam o The Greenhouse Effect Venusa runaway greenhouse Global Warming eiiects of mankind on ouratmosphere Ozone Depletion e ects of mankind on our atmosphere own co2 is up is this century 1 39 010m 03 critic 0 rom burning lossil luels o increased greenhouse eilect al for life 0 shields land 4 ad UV 0 is very lragile o excess global warming de m yed by quotm o complicating lactors mm mums u had 7 L 0 complex chem l min 5 imwmn o consequences possible ginai mm rumquot in humans assimimi massivuuudmm glubzk aimg nmimgu o mumtions etc JAM Mm momma Mm quotpig 5 0 The Basics 0 Mass 38x Earth View through small telescope 0 Diameter l 2 x Earth 0 Surface Gravity 253 x Earth 0 Moons 4 major many minor 0 Rotationvery fast P IO hours HSTImage 0 view from Earth cloud belts no surface 0 visits 0 flybys Pioneer l0 l l I973Voyager 2 I979 0 orbiter Galileo l9952003 0 atmosphere probe Galileo I995 Mm momma Mm quotpig 7 The ovian Atmosphere 0 75 Hydrogen 25 Helium U 0 trace compounds all H rich l ammonia NH3 i h w L I o methane CH4 39l 39 39 0 water vapor w 39 39 quot quot 0 composition of clouds 0 ammonia high level 0 ammonium hydrosulfide ice middle level 0 water ice low 0 colors of clouds only small amt needed In general 0 high clouds are white ammonia 0 lower clouds are dark amm hydrosulfide 0 other coloring agents still unknown complex organics Mm momma Mm quotpig 9 Atmospheric Features Zones 0 upwardly moving material 0 high cool cloud bands Belts 0 falling gasses 0 low warm and dark Spots 0 updraftswhite spots 0 holes in cloud decks dark spots 39 Winds and CirculationZonalWinds 0 belts and zones rotate at different rates 0 lots of shear from band to zone 360 kmhr 0 circulation at interfaces Example the Great Red Spot Winds and Circulation l I Zonal Winds O belts and zones rotate at different rates 0 lots of shear from hand to zone 360 kmhr I Circulation at interfaces Example the Great Red Spot The ovian Interior 0 Clouds and atmosphere mm 0 temperature increases with depth 0 pressure increases with depth 0 Deeper pressure liqui es hydrogen 0 liquid molecular hydrogen mantle I then metallic liquid hydrogen electrons free to roam quot39quot 0 starts where P 23000 x Earth39s 0 root ofjovian magnetic eld 0 Finally a rocky core Ml5anrth O T 20000K P 50000 x Earth39s Saturn 0 The Basics 0 Mass 95 x Earth 0 Diameter 95 x Earth 0 Surface Gravity l 07 x Earth 0 Moons 5 major many minor 0 Rotation very fast P l0 6 hours 0 view from Earthzball with big beautiful rings 0 visits 0 flybys Voyager l2 l98l O orbiter Cassini arrives summer 2004 small lelesoope view HSTlmage Looking down ori Cassini39 24 Got 2093 0 00 GMT Saturn Atmos here mwmw Clouds on u iter and Saturn WWW Jupimr w Saturn 1 less vivid coloracicm chan Jupiter 7 stronger zonal winds 3 x higher than Jupiter deeper cloud layers less helium chanJupicer o helium sinks down in cooler atmo o Jupimrtoo hot Helium my up Saturn s Interior thicker liquid molecular H mantle I smaller metal ic H interior I similar rocky core to preserve mean density new elm F all Semester 2007 Learning Community Team S130 LAS Connections The Heroes and The Heavens Name Students in this learning community register for the following courses Reference I I 7975130 I L TM 5130 Learning Team ID I a twopart course Students must register for a numbered section rst then register for one of the Basic Time Grid for Students in Learning Community S130 am am am am pm p m p m pm Coordinators Jane Jacobson Zora Zimmerman Director of Student Academic Services Associate Dean 102 Catt Hall 202 Catt Hall Phone 2944831 Phone 294 7740 Email jzy39acobiastate edu Email zdzimmeiastate edu Web Site httpWwwlasiastateeduadmissionsconnectionsshtm1 Fall Semester 2007 Learning Community Team S131 LAS Connections Guns Gods and Gold American Values in the 21 Century Name Students in this learning community register for the following courses I Reference I I I 7982131 I L TM 5131 Learning Team 1D I Note For this learning community students will registerfor eitherHIST 221 orRELIG 210 Basic Time Grid for Students in Learning Community S131 am am am am pm pm pm Coordinators Jane Jacobson Zora Zimmerman Director of Student Academic Services Associate Dean 102 Catt Hall 202 Catt Ha11 Phone 2944831 Phone 294 7740 Emailjn39acobiastate edu Email zdzimmeiastate edu Web Site httpWWW1asiastateeduadmissionsconnectionsshtm1 F all Semester 2007 Learning Community Team S132 LAS Connections Roots of Con ict Name Students in this learning community register for the following courses Reference I I 7993132 I L TM 5132 Learning Team ID I Basic Time Grid for Students in Learning Community S132 am am am am pm p m p m pm 205 Coordinators Jane Jacobson Zora Zimmerman Director of Student Academic Services Associate Dean 102 Catt Hall 202 Catt Hall Phone 2944831 Phone 294 7740 Email jzfacobiastate edu Email zdzimmeiastate edu Web Site httpWwwlasiastateeduadmissionsconnectionsshtm1 F all Semester 2007 Learning Community Team S133 LAS Connections Ethics and the Economy Name Students in this learning community register for the following courses Reference I I 8000133 I L TM 5133 Learning Team ID I Basic Time Grid for Students in Learning Community S133 am am am am pm p m p m 230 230 Sec B Sec C Coordinators Jane Jacobson Zora Zimmerman Director of Student Academic Services Associate Dean 102 Catt Hall 202 Catt Hall Phone 2944831 Phone 294 7740 Email jzfacobiastate edu Email zdzimmeiastate edu Web Site httpWwwlasiastateeduadmissionsconnectionsshtm1 Lecture 4 ecliptic calendars 39 Apparent motions of The Sun on the sky 39 Eclipfic Calendars LasT Time 39 LaTiTude and longiTude RelaTing longiTude To Time 39 Time and Time zones EarTh39s revoluTion 39 Sidereol Time LasT Time We learned ThaT The Sun moves easTward relaTive To The sTars This causes sTars To rise 4 minuTes earlier each nighT WhaT does The Sun39s annual moTion look like on The sky Sun in Pisces Plsces Aqua us Capricom Sagittarius m O scorpius Libra S September Sun in Virgo Taurus Ades Prsces Aquanus GMQNS Cancer k Capricom Sagittarius Scorpius m0 Leo Libra Virgo June Sun in Gemini P39 1sces Aquanus Tm Camcom Sagrttanus Cancer k Virgo Leo Libra December Sun in Sagittarius W W A Xxx 45 Leo Pisces Aquanus W Capricorn Sagittarius Scorpius m0 The Analemma Take a picture of The Sun every few days a The same Time for a full year What do you get You get a figure called The analemma Puzzle The Analemma Sun39s diurnal pa rh on our sky Where is The Celes rial Equa ror39 on our39 sky Meridian diagramquot N 5 All The angles on This halfcircle mus r add up To 180 degrees Summer versus Winter Ames Summer versus Winter New Zealand Does Earth39s axis wobble 39 If it did what would the apparent motions of the stars look like 39 Simple observational test Monitor the altitude of Polaris over the course of a year Its position apart from diurnal motion does not change appreciably over a year Sun39s altitude and Earth39s orbit Celestial Celestial sphere March sphere 7 Sun south Sun north 39 39 of celestial at celestial equator equator equator 39 R I r t l Celestial quot September X equator c J Decem r Note Not drawn to scale Astro term obliguitx is angle between the rotation axis and the perpendicular orbital plane Amy June 21 Summer solstice Nbr fher n Summer Sou rhar nWin rer December 21 Win rer sols ri39ce Nloer n Win rer 39 Sou rher n Summer Equinoxes March 3920 amp Sept 22 Nor rher n SpringFall 39 Squ rHarn FallSpring CE N DecemVv quotWha r Ifs WhOT if Ear39Th39s obliq ui ry were 0 degrees 90 degrees 39 SUREmfmiparent I quot a Calendars r WhaT are They good for They Tell us whe n39To planT crops harvesT prepare for coldhoT WeaTher eTc IT is convenienT To divide up The year inTo quarTers demarcaTed by imporTanT poinTs in The Sun39s moTion across The sky demarcaTe seasons more nexT week r The ideal calendarwould have precisely The same lengTh as The Tropical Year The Time iT TakesThe EarTh To make a comp leTe circuiT abouT The SLIn BUT Tropical year is noT an inTeger number of days IOng Why would This be a problem Calendar design This has been a problem Throughout hisTory because people like To reckon The passage of Time by counTing days and They like To have The same sky evenTs an d fesTivals in The Seasons occur on The same calendar daTe Clock errorsquot accum ulaTe wiTh The passage of Time Some culTures also like To coun T lunaTions buT There are MT 0 whole number of These in a year eiTher Synodicquot monTh is abouT 295 days long gt 172 of TheSe is 354 days noT quiTe a year HisTorically popular calendar year lengThs 360 365 36525 True value 3652422 days up mom i r xm r 12 39E I39ZIp39 i39 c39V 5 mm Julian and Gregorian Calendars Prominen r calendars in The Wes r Julian Gregorian Julian calendar 365 days excep r every four rh year leap year which is 366 days Average 36525 days Bu r Tropical year is 3652422 days Sol Julian Calendar isgood bu r no r gOod enough Over a long Time period HOW much error accumulates in 100 years wi rh Julian Calendar Answer 02502422 x 100 078 days Gregorian calendar By 1582 11 days error h ad acciumula r39ed in Julian calendar Gregorian calendar was ins ri ru red in rh a r ye ar wi rh The following change Leap year rule same as Julian calendar excep r rha r cen rury years no r divisible by 400 are no r leap years Thus 2000 was a leap year 1900 was no r a leap year Me an year leng rh 365 x 400 100 34 OO 3652425 d39ays Lec rure Challenge Question Why do you Think it is hotter in Ames in June Than if is in January Readng Chapter i0 emon i0 34 0 s Homework 2 Posted onWWWdue WM and iUi 7 Brief review of last time Ages of Planetary Surfaces the 0 O on Relative Ages via Crater Density I more craters worndown craters older surface I relative ages I Absolute ages via radiometric dating I halflife of unstable isotopes I relative number of par ntdaughter time since formation I Need to calibrate relative crater ages with absolute I The Moon I Highlands old and Maria young I impact history of inner solar system through Apollo I History of lunar surface impacts and lava flooding I m act histor of the inner solar s stem I Lots of impacts in lst Gyr smaller since Lunar Surface History I 46 Gyr ago formation via Giant Impactquot I impact of a Marssized object with primitive Earth I debris accretes to form molten Moon I differentiation and solidi cation I 46 38 er ago intense bombardment I continuing impacts obliterate original surface form terrae I some huge impacts form basins ie future maria I 38 32 Gyr ago lava flows ll maria I lava wells up from below to flood basins I ie maria form with denser rock I 32 Gyr ago to novw continued cratering I lava flows ceased 32 Gy ago I further surface changes from impacts 33 Gyr ago 32 Gyr ago Impact History of the Inner Solar System used on the lunar chronology maria form n ow 1 2 3 4 46 Age Gyr crateri n 9 rate The cratering rate has been the same for the Earth then and now Thls chronology also applles to Mercury Venus and Mars m W apnnavarbe mg Mme m m u39 mm M e rc u ry 0 The Basics I Mass 006 X EarTh I Diameter 038 X Earth I Surface Gravity 04l X Earth I Atmosphere almost none I View from EarTh at best like Moon w naked eye I visits flybys by Mariner l0 l974 and l975 Mariner l0 39 Moon to scale View from Earth 0 Mercury s Surface I Dominated by impact craters I Ejecta more compact than Moon higher gravity I Some flooded basins I largest visible is Caloris basin multiringed I focus terrain opposite Caloris I some fresh intercrater plains possibly old I Scarps relatively recent crustal shrinkage m Calorls Ringed Basin Focus Terrain opposite Caloris m TheVenusian Surface I The Basics I Mass 082 X Earth I a few mostly large impact craters I recent and continued volcanic activity I Diameter 095 X Earth Shield velcanoes I flooded plains and craters 39 surface GmVltY 09l X Earth I relatively young surface ler or so I Atmosphere 92 x denser than Earth39s I Minimal erosion or weathering I view from Earth surface obscured byVenus clouds 0 Unusual tectonic activi visits I coronae collapsed magma domes I ai39achnoids circular regions connected by web fractures 39 flyby by Mariner lo 974 I crustal distortions but plate tectonics I orbiter Ma ellan l990 radar ma in under vegan M 982 PP g I surface composition basalt where landers were Reading Chapter 3 Sections 33 35 Chapter 5 Sections 51 53 A Brief Review of Last Time plane i ary mo i ions eas i ward mo i ion re i39rograde loops near eclip i ic Venus Si Mercury near Sun plane i ary alignmen i s conJ39unc139ions opposi i ions synodic perio 139ransi i39s Reading Chapter 3 Sections 33 35 Chapter 5 Sections 51 53 Today AncienT Greek Asi39ronomy The geocen rric model Copernicus The heliocen rric model mm mm imam Spherical Ear39ih Py rhagoras of Samos 5OO BC Firs r person To sugges r The Ear rh is a sphere Amiznraiiznns mum Spherical Ear39ih ships disappeared before They appeared as poin rs The shape of The EarTh39s shadow during lunar eclipses 1540 Tebeook ArisToTle c 350 BC ArisToTle argued sTrongly for a spherical EarTh One of his argumenTs considered The visibiliTy of sTars aT differenT places N ArisToTle c 350 BC m He developed a very influenTial philosophy model of The universe The four basic elemenTs EarTh waTer air fire Tend Towards Their naTural placesquot The EarTh is a small spherical body aT The cenTer or boTTom of a series of concenTric spheres The lower levels are mosT subjecT To change The highesT ones are perfecT and unchanging Sun Moon planeTs and sTars locaTed 3H concenTric spheres wiTh EarTh aT cenTer Moon Eorlh Venus Sun Mar l l y Spheres roTaTe aT differenT raTes w moTions passed down Through The spheres Moon Eorlh Venus Sun Mars Why did The ancienT Greeks rejec e noTion ThaT The EarTh orbiTs The sun IT ran conTrar39y To Their senses If The EarTh roTaTed Then There should be a greaT windquot as we moved Through The air Greeks knew ThaT we should see sTellar parallax if we orbiTed The Sun buT They could noT deTecT iT Parallax Angle ApparenT shifT of a sTar39s posiTion due To The EarTh orbiTing The Sun If you don39T observe an apparenT shifT Then a EarTh is noT moving or b STars are very far away WiTh The conquesTs of Alexander The GreaT Greek asTronomy meeTs Babylonian observaTions Focus sTarTs To shifT To geomeTric based models wiTh predicTive power Ledme paw EraTosThenes39 c 200 BC meThod for measuriangegThe Arisfarchus of samos c 250 circumference of The EarTh x Described meThod To find EarThSun disTance xquot 90 at half moon Alexandria Aristarchustnedlo 39 7 hesu WNW 39 39Syene So This disTance is 7360 of The EarTh39s circumference STick aT Alexandria casTs a shadow buT also believed ThaT The EarTh was in Sun is visible aT boTTom of well aT Syene moTion and moved around The Sun Asmzmuzms Ledme vivel Apollonius c 200 BC Apollonius c 200 BC Developed more flexible forms of circular moTion Developed more flexible forms of circular moTion PlaneT on epicycle The eccenTric circle Allows for reTrog rade moTion of planeT PlaneT Allows for uniform moTion of planeT buT differenT apparenT speeds as seen from EarTh
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