RegionalGlobal Enviro Science
RegionalGlobal Enviro Science HNRS 228
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This 97 page Class Notes was uploaded by Velda Bode on Monday September 28, 2015. The Class Notes belongs to HNRS 228 at George Mason University taught by Harold Geller in Fall. Since its upload, it has received 57 views. For similar materials see /class/215058/hnrs-228-george-mason-university in Honors Program at George Mason University.
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HNRS 228 Astrobiolo 5y The Habitab ty of Earth hap4 Earth Bennett 8 Shostak IGeology and Life 41 IReconstructjng the Hismry of Earth and Life 4 2 ElRodlts radronretrrc daong ge ologlcal record tossrls geologlcal ume scale Earths a e Ledme quotMes kquot Chap e39 4 IThe Hadean Earth and the Dawn of Life 43 some quot03911 quotNR5 227 ocans heavy borrbard enls Dr H Geller Atmosphere IIGeology and Habimbility 44 E lEath s rrrerror plate Ectorllcs magnetosphere The Habitab ty of Earth Some Guiding Questions r Ahat rs the greenhouse ette39ct7 How does rt affect Fe 39 39 ICIimate Regulation and Change 45 quotV3395 ewe ame l 75 Earn Greenhouse effect carbon cycle ice ages Snowball Earth long term habimbility o H7 ow rs rt possrble for mure corrunt to move across e face or the Eath7 IIThe Procss of Selence ln Acton r ow does our planets rnagneuc eld protectlrte on Formation ofthe Moon 46 l 39 41y rs Earth the onlyplanet wrth an oxygenrrch Elsismr model capture model sainoff model o hee7 y are prevallng wlnds generallr trorn the West ove most or North Amerlca out genera ly trorn the east rn Hawall7 what are global Warmng and the ozone holequot7 Why snould they concern us7 I Plate tectol39llcs ls lnvolved rn the tormao on or the I three naro Tel ing Rocks Apart SGHow geologis13 tell apart different minerals and rocks Elcolor luster texture Elhardness test msoatchrrrg one aga nst another 7 dammd rs hardest ler lgnmuuutunuln tereed andsd nererer rern ad ilr Qeie ellai Dac39 test musrng weak hydrochlorlc acrd to Elstreak test mform a streak across a ceamlc ule emene heat and pressure ls Munmnmhxndulmnlnmltu The Rock Cycle Surface Bu ding Processes mum astr S 21 stress is a force that tends m compress pull apart or deformquot Edifferent types of stress W Strain the adjustment m stress Stress and Strain Surface Bu Processes x Folds Ebends in layered bedrodlt Z xAnticline lSyncline V Surface Building Processes Mounlams Faumng I elevated pars of Elformatlon ofa crack caused by relatlve m Earmrs crust movement of rock on either side of a fracture mat rise 6erde ove srrrounding srrfacequot auses Elfo dmg taumng vocaruc acu mty Volcanoes I hill or mountain formed by the extrusion of lava or rock fragments from magma belowquot I Different types Eshield cinder cone composite composite shown TearDown Processes XWeathering Elmechanical wathen39ng Echemical weathering xErosion Emass movement mass wasting Erunning water oodplain delta acner Elwind de ation and abrasion Elimpact cratering Earthquakes Defined as quaking shaking vibrating or upheaval of the ground I Earthquake causes Eelasuc rebound theor I Intensity measue ERichter Magnitude Enot linear scale Earth s Interior and How We Know It nmum l NMJ u m mnmmmm mm mlmmt law ma Mt m 1mm r Earth s Inside Story m n fquot Ulhostteve Yunch 39939 FULL nergy transfer in the mantle similar to that of a pot of boiling water um cm woupmuwm ml quotMahmouwm 74mm mm um um Earth s Interior Then and Now mid Solid ilon mm armquot can a Durlnydi u onlmn unkw r and less dense material mm b As may uldltkreminlondhe um um mm In m layuvadnmnurz outd u that we seuodIy I39llI W Lam from Solontumour f f Crustal Rumb ngs i Earth39s rnner and cuter coves i aiettmDU o non th some nitkei and otha rneais mixed n r 1 a e w eman eis emposed orrrcn nth mineiais arm rfmml t i n Hath ta39nuaamve and Dessuie steadiiv increase with math rnsrde the Earth t with igt rtmtrrrmrm Wat lt1 mii rt nurturrmnttr tntrrtrmrtrr mm n no mum norm Hum m with menu iuxutw rtrrrtrttrmm rnrum Minimum trnrr trrtt Plate Tectonics 8 The theory that the Earth39s crust is made of rigid plates that oat on the asthenos herequot RConsider the scienti c evidence for plate tectonics and what forced scientisis in accept the theory as fact Plate teetnnies nr mwemeht of the plates is driven by enmeethm within the asthennsphere r nr dn rnn sea oor spreadrng and rs returned to the asthenosphere ii i adbducuon zones I As one end of a piate is abducted back into the as wmosphere rt heips m puii the rest of the piate aiong mrra own mm mm d aw r Plate Tectonics Tire mm u The Earths oustanda smaii partofiB Lpper rnande form a ngrd iayer caiied the irthoephere x The ii pnere rs dvided rnm huge piates that move aboutover the piasnc iayer caiied the asthenoephere rn the upper rnantte FOSSI S across an ocean The continents jigsaw puzzle u 137 million yealsagnzlhesupumminent Pangaea Development of Geologic Time IIFoss Zation Rmding the Rocksquot Elprinciple of uniformity Elprinciple of original horizontality Elprinciple of ilperposition Elprinciple of crosscut ng relationships principle of faunal ilccession Elradiometric dating GGeologic Time Scale Geologic Time Scale Earth s Atmosphere IComposition ENUogel l 78 Oxygen 21 Argon vvate Vapor co Methane othe lAtmospheric Pressure apressure exerted by atmosphere lWarming 215m 7 solar constant is not really cohstaht Bgremhouse e ect T Wavinan due in the vanSDalmEv cf 2 slbslarlte m ladlannn at visible WavdEmlhs and DDSEW m lrlflalad ladlannn The Ea h s atmosphere has changed substan Ily overtime I The Ear atmosphere differs from mose of lhe 0 er terrestrial planets in is cherncal corrposmon orculauon patten and terrperamre pro le I The Earth39s atmosphere chahged from pemg most wate yapor to behg rtch m capoh dl0gtltl de I A strong greenhouse effect kept the Earth Warm mough fcgr Water to remam liquid and to permit the eyolutoh of l e The appearance of I photosynthetic r urnmm x tt A 1 t IlllllmMynlsbzhtelherM Structure of the Atmosphere Circulation I our atmosphere results on and the Earth s ratat h Because of ihe Earih s rap id rotation ihe c39rculation in is a re is complex wiih ihree circulation 39n eac cells i hem isphere Weather Producers Winds xLocel winds p leAir Masses Ewmd chlll 312 leEvaporation factor I 4 W EAbsolute humidity KGlobal Wind 393 ElRelative humidity patterns 39 r inmikapimicmivszm ME a t 39 xWavs and cyclons i s Emundersm rms mmadoes hurricanes Aime mu An idealized cold front An idealized warm front a an M it quoti Warm air mass Animus mi a mu 400 600 mu ioooizoo ma Aikn cirms Air Haw Weather Forecasting Climate xPredictions based upon aracteristics location and rate of movement 0 air ma es and associamd fronts and pressure sysmmsquot Elchaotic dynamic systems I general pattern of the weather that occurs for a region over a number of yearsquot lMajor climate regions The principal climate zones Ocean currents in uence temperatures The hydrologic cycle Tidai rurces neip puwertne mutiun urtne uceans Distribution of the Water Watersheds of three rivers The path of groundwater Permeable soili sediments andror lOll llECl lDClK Lake Waler table S 1i In permeable layer Rl 397 lvel39 Swamp lmpelmeahle layer Oceanography 8Waves and tides Elchanges coastal structure Eltransport of material along term and short term changes 8A Climate control mechanism ocean conveyor belt Elmajor control of climate l 39 Onewaveienglh l l l Awe passrng In E t e open E 9 ocean Eg gt cg Nu movement below depth at one hall wavelenglh A wave becoming breaking onshore ln Surl zone Breakers Beach Ocean Conveyor Belt Major Climate Control Id The Earth s Magne IElectric currents 39n the liquid outer core generate a dipole magnetic eld as rnia to a coil ofwlre around an lrol i nail lThis magnetic eld produces a magnetosphere that surrounds the Earth and blocks the solar wind from hitting the atmosphere ITraps particles from the solar wind in regions EProduang Van Allen see I aticles of the solar wind are de ected around the Earth by the magnetosphere magnetosphere An increased flvw nf charged part cles frnm r the Sun can overload the Van A en belts and Energy sources and e Ea h 5 cascade toward the Earth produ 39ng aurorae a m 5phe39es 069339 and 5u ace table grz The Earlh39s Energy Sources Motion ol vm t39r in nconm Sular unrrgylld1 mrL39ux i rs lokct r Vt Some charged parocles from the solar wind are trapped in two huge doughnutrshaped rings called the Van Allen has Mnnnn oi the almasphrm Snlnr cnrrg Ilcwha ping rll39 uirfnm Fa nit mtmal hm Llfc Snlnr vllclgy in tow puciu rhml m rlro n in tloor inth l ot the E rt li39s imcnml lwml The Greenhouse Effect g a W tumor ms gm So a mergvis ie 5539 as More 39gxro mg energy source for the E 2 v i mm atmosphere 33 quot3 i l in the greenhouse E E or l A m effecsome otthi 531 um loo139 39 i rm energylsh apped by 3 2 3 mar i trared absorbl 4h mom gases in the 5 gt o l t iaiiitii ampere a l i 39 quotmmr the Earth39ssurtace 5 39 l 3735 39immmhumio terrperature aaove mo wan mm ma mo woo won 20 i nation I momma what it would belt gighszg m la Changes in the Earth39s average temperature The Science of Life in the Univrse Chap 2 Benntt et al 30 January 2007 Lecture 3 HNRS 228 Astrobiology Prof Geller Vf 3Ancient Debate about Life Beyond Ealth 21 Greeks and Geocentrism 3 The Copernican Revolution 22 Copernicus Tycho Kepler Galileo Newton 38The Nature of Modern Science 23 The scienti c method remember 227 Ovrv 38The Process of Science in Action Understanding Gravity 24 Newton s view of gravity Einstein s view of gravity String theory View ofgra Vity not in text r iting Scece swer But Fir 38Regarding answering science questions Complete sentences Science reasoning Specific examples Mathematics Use all information given Answer with question Exe 38Evaluate the given statement and decide whether it makes sense Explain your reasoning clearly Even if we discover a civilization around other stars we will never be able to talk with them with the same ease with which we carry on conversations with people on Earth Sample Ans 3 Given that we discover a civrllzatIon around other stars let s examine the closest that such a civilization could be from the Earth The nearest star is 43 light years distant from Earth This means that a twoway conversation would take at least 86 years since no information can travel faster than the speed of light While this is well within a human lifetime of say 75 years it is a long time for a conversation There would be a delay of at least 86 years for any twowa conversation between any civilization ever discovered This does not represent an ease with which we carry on conversations with people on Earth The maximum distance between any two points on Earth is about 26000 miles the approximate circumference of the Earth much less than the speed of light travels which is approximately 186000 miles per second Therefore the given statement makes sense Anhr 38Evauate the given statement and decide whether it makes sense Explain your reasoning clearly If the universe did not contain stars more massive than our Sun we couldn t be here Sample Ans Relatd to ar 1 38 The chemical elements upon which all life on Earth is based upon includes many elements heavier than lithium such as carbon nitrogen and oxygen All elements heavier than lithium were produced in stars that died as supernovae long before our Sun was formed A star like our Sun can only form elements up to carbon Elements beyond carbon require stars that are greater than about 38 solar masses Therefore the statement given makes sense since we need heavier stars to make the chemical elements upon which our lives are based In fact only the most massive stars reater than about 10 solar masses will ever form the c emical elements of iron and those more massive than iron up to and including uranium 38 Now back to Chapter 2 Universality of Chemistry an cs 3 Are laws of physics universal What do we mean by universal What do we mean by Laws of Physics How do we know they operate in the universe S Are laws of chemistry universal What do we mean by universal What do we mean by Laws of chemistry How do we know they operate in the universe Usit or 7 38Characteristics laws of biological systems universal What do we mean by universal What do we mean by characteristics of biological systems How do we know they operate in the universe 3Reasons for optimism 7 Early Earth s innate constituents formed complex carbonbased organic molecules eg carbohydrates lipids nucleic acids etc Observation of comparable organics on meteorites Step from chemistry to biology not difficult thermodynamically Life arose very early on Earth first 10 of time Conditions on Earth were right even though extreme Success of extremophiles 3 High probability that principle characteristics of life are universal Science of Astrobiology 3 Exobiology 38 Bioastronomy 3Astrobiology NASA National Aeronautical and Space Administration Study of life in the Universe 3 Generally accepted components Beginnings of life on Earth and its evolution Life elsewhere in the Universe Future of life on Earth and elsewhere The Beginnings of Astrobiology 3 Thales and Pythagorus N600 BC 500 BC Geocentric view of earth and solar system Composition of nature water fire earth and air 88Atomists N600 BC 400 BC Universe composed as noted above Multiple worlds with life 38 Key ideas of Atomist Random events elsewhere as on Earth Geocentric view Atomlike chemistry Really not science more intuition and philosophy Historical Debate on Life in ts 3 Myt oogy s 600 quot 38Atomists N600 BC 400 BC 3 Aristotelians N400 BC 300 BC 3 Christianity Middle Ages 88Transition Speculation to Science 3 Copernican Revolution 8 Revolution in the Life Sciences and Geology 8 Summary role of science versus speculation S eca W w 7 77 38Aristotelians N400 BC 300 BC Plato 400 BC and Aristotle 350 BC Rejected atomists Tenets 4 elements plus aether Geocentricism Uniqueness of the Earth Integration into Christianity in 1250 AD by St Thomas Aquinas 3Pluralism and Christianity Middle Ages Plurality of worlds many worlds in the Universe Christian scholars problem Jewish scholars no problem Islamic scholars no problem Eastern Religions scholars no firm position 3 From Speculation to Science Key to all of the above speculation not science Why What events trigger the transition from speculation to science 1450 Co eian Ro lutio W 7 3 Key models of how nature operates Define model conceptual mechanistic mathematical Outline approach observation followed by construct Models fail and this is Ml 3 Ptolemy Model of the Solar System 1150 AD Geocentric circleuponcircle tricks all paths circular Reasonable accuracy of model Coeis 7 38Copernican Model planetary motion explained by suncentered solar system Circular orbits and circleuponcircles Reasonably accurate 8 Tycho Brahe Quality data Via nakedeye observations for 3 decades No model KePquot39s of tiquot 38Kepler s First Law of Iatary Moton 7 planets orbit sun in an ellipse with sun at one foci 38Kepler s Second Law of Planetary Motion planets sweep out equal areas in equal times travel faster when closer slower when farther 38Kepler s Third Law of Planetary Motion orbital period squared is proportional to semimajor axis cubed P2a3 Sequel to Kepler Galileo ann 3 Observations with telescopes 1600 Observations of Brahe Multiple models circles ellipses etc Define ellipses oval with 0 eccentricity two foci 3 Galileo observations and Kepler model Strong evidence against a geocentric view 3Newton closing chapter 1700 Mathematical formulations to explain Kepler Laws Newton s Laws of Motion andiy 38Newton s First Law of Motion body at rest tends to stay at rest and body in uniform motion will stay in straight line uniform motion unless acted upon by an outside force 38Newton s Second Law of Motion the acceleration of a body is proportional to the force being applied oFma Newton s Laws of Motion andiv 38Newton s Third Law of Motion for every force there is an equal and opposite force action and reaction 38Newton s Law of Gravitational Attraction force is proportional to masses and inversely proportional to the distance squared FGmMr2 Revolution in the r amiw 77 3 Historical concept of a static Earth crustal antiquity 88Wegener 1920 Theory of Continental Drift 3 Hess 1960 Theory of Plate Tectonics 3 Emergence of climatology as a science 1960 s Past paleoclimatology to current to future 38Dynamic Earth and affect on living organisms Rise of the Life Science 38 Darwin s Theory of Evolution 8 Struggle for survival natural selection and origin of species 38 Mendel s Theory of Particulate Inheritance 1860 Traits are inherited from generation to generation 36 Watson and Crick 1950 s Discovery of DNA Molecular explanation for Mendel s theory looking back ElCatapulted life sciences into new dimension and prominence forward looking 38 Metabolism and molecular biology 19702002 ElGene regulation affects the chemistry of cells 86 Genetic engineering and bioinformatics new frontier 2000 and beyond Revolution in the Sciences and 0quot Iife iUi 3 The process of change speculation to science 3 Change in human perspective stars are just not lights but other worlds 3 Idea of extraterrestrial life 3 Universality of Laws of physics 3 Universality of Laws of chemistry 3 Dynamic state of Earth s geology 3 Rise of the life sciences from Darwin to bioinformatics 3 Universality of characteristics of living systems Hallmr of S 38Driven by observations 38Foundation in logic S No special circumstances no miracles in science 380ccam s razor KISS principle 3 Falsifiability things not tested are not scientific The Senific SSObservations 38Hypothesize 3 Test hypothesis what does hypothesis predict beyond current observations Maxwell s demon 3More observations Nonscience and Pseudoscience 7 r 7 7 3 UFOs 3 Astrology 3 Psychics Mediums 3 Big foot 3 Levitation 3 Teepathy 3 Crop circles 38Gemstone cures 3 Tarot cards 38 Nessie 3 Fortune telling 88 Nostradamus 3 Channeling 2 Magnetic cures 3 Teekinesis Some Science fees 8 Committee for the Scientific Investigation of the Paranormal httpwwwcsicoporg ElThe Skeptical Inquirer 8 The Skeptics Society http wwwskepticcom Skeptics magazine 38 Books Demon Haunted World Sagan Why People Believe Weird Things Shermer Flim Flam Randi Fads and Fallacies in the Name of Science Gardner The Universal Context of Life Chap 3 Benntt amp Sht 77w 1 February 2007 Lecture 4 6 February 2007 Lecture 5 HNRS 228 Astrobiology Prof Geller 0v of cpter 3 The Universe and Life 31 Age Size Elements Laws 3 The Structure Scale and History of the Universe 32 Planets Solar System Galaxy Local Group Supercluster Universe Big Bang Theory of creation of universe Evidence for expansion age and composition 3 The Nature of the Worlds 33 The solar system and its formation remember 227 0quot f 38A Universe of Matter and Energy 34 Atoms Energy Electromagnetic Radiation Spectroscopy 38Changing Ideas about the Formation of the Solar System 35 Nebular Condensation Model F 39 z A 88 The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest number of hypotheses or axiomsquot Albert Einstein 1950 The Following Slides are from HONORS 227 1st 7 Thm 8 In an isolated system the total amount of energy including heat energy is conserved 38ENERGY IS CONSERVED 2nd Th V z w w A7 8 Two key components heat flows from a warmer body to a cooler body entropy increases remains constant or increases in time Phases and Phase Diagram Pressure Condensation Gas Triple point a Deposition Temperature Plancsie v 38A way to depict frequency inverse of wavelength versus intensity Intensity Frequency Wien L r 7 3 Peak wavelength is inversely proportional to the temperature of the blackbody Cooler Body Peak W avelengm Hotter Body Intensity Frequency SteaB 3 Energy radiated by blackbody is proportional to the temperature to the 4th power 0EGT4 38A change in measured frequency caused by the motion of the observer or the source classical example of pitch of train coming towards you and moving away wrt light it is either redshifted away or blueshifted towards Snurce Stz nnary nhserver 039 039 Static G39JVVVVVVVVV aning QNW anplex mm The Bih of 5 Like Ou un 88Gas cloud 88 Fragmentation 38 Protostar 38 KelvinHelmholz Contraction 88 Hayashi Track 8 Ignition 3 Adjustment to Main Sequence The 3 Core 88Radiative Zone 3 Convective Zone sePhotosphere 8 Chromosphere 3 Corona How right is It 8 Apparent Magnitude from Earth 8 Absolute Magnitude Sun Moon Venus Vega bagg gfl lggg t I I I u s 10 15 20 25 Sirius faintest VGTY faint naked eye star i i t E 25 2o 15 1o 5 o varybrighi Apparent brightnesses of some objects In the magnitude system Luminosity solar units 10mm 7 75 100 D I 5 001 10 0001 15 mmmm Palm mu mu m Absomte magmmae quot39 t 7 Wien s Law moan Wavelength nm Classes for Spectra 80BAFGKM There are also subclasses 09 4000 K 3000 K 30000 K WI ml m I 806 um quotMagIesl m h oxygen 6000 K 700 nm Lm neg Titanium wide u Omen 4 I s Hellum HE u Mal n 33ng j 9 HR Diagram Death of Stars like Sun 8 Hydrogen Core Depletion 8 Hydrogen Shell Burning 39 Red Giant Branchquot 8 Helium Flash 8 Helium Core BurningHydrogen Shell Burning quotHelium MSquot quotHorizontal Branchquot at Helium Core Depletion x Helium Shell Burning x Asymptotic Giant Branch at Planetary Nebula a White Dwarf Lumlnndly high nau i Avwrwwwt rum 9 10R 0 lireadm Vacuum mm 0 am 0 300110 21mm moon 5 moon Loon urhcc tnrnp39 vt Spud il dmm mtiun Galaxies F r l Elliptical Galaxies SO Ienticular Galaxies Spiral Galaxies BarredSpiral Galaxies Irregular Galaxies The Big Bang Murglow Light mum Dark Ages anopnn yrs um Energy Accelerated Expunsinn Development av G l XleS Planels em quot in Inuauon 9quot 4 mln aw Gull Flumumiulll Big Bang Expansion 137 hlman years The Big Bang Summary Timescl 7 sec lt10 10 sec sec bosons 10394 sec Epoch Decoupling helium 1 sec 1 month years Epoch birth billion years yrs Dark Era Black Hole 100 billion 7 Th Evdce 38Evidence for a Big Bangquot expansion of the universe Distant galaxies receding from us everywhere the same remnants of the energy from the Big Bang a very hot body that has cooled 27 K cosmic background radiation the primordial abundance of chemical elements Cosmic Ba 3 How hot would the cosmic background radiation be l close to 3 K first noticed by Penzias and Wilson Elconfirmed byCOBE satellite Mather and Smoot won 2006 Nobel Prize for this What CMB means 8 Remember Wien s Law 8 Remember Doppler 3 Taking the perspective of the universe with you at the center The ema w 77 38Using COBE DIRBE data for examining the fine differences fine structure of the universe led to the galaxies and their location Gut r bhk 7 7 8 What is a light year and how is it defined 8 The light year is a unit of distance It is de ned as the distance traveled by light in a year about 6 trillion miles or 10 trillion kilometers Gust r 38Why are astronomical distances not measured with standard reference units of distance such as kilometers or miles 8 Because astronomical distances are so large 1 ly 95 x 1012 km 38Which stars have the longest life span 3 The lowest mass stars have the longest life span Red dwarfs can live 100 billion years Stars like our Sun live about 10 billion years Gut r 38What is the HeltzsprgRussell diagram 7 What is its significance and how can it be used 8 Basically a plot of temperature vs luminosity You can determine the approximate age of a star cluster with an HR Diagram You can follow the life cycle of a star with an HR Diagram Question fr Tught 3 es e n gene c ceo a star wit a mass similar to our Sun 38 Gas cloud Fragmentation Protostar KelvinHelmholz Contraction Hayashi Track Ignition Adjustment to Main Sequence Hydrogen Core Depletion Hydrogen Shell Burning quotRed Giant Branchquot Helium Flash Helium Core BurningHydrogen Shell Burning quotHelium MSquot quotHorizontal Branchquot Helium Core Depletion Helium Shell Burning Asymptotic Giant Branch Planetary Nebula White Dwarf Question for Thought What is the Hubble classification scheme of galaxies Ell cals E7 5 039 39 Irregulars 550 a 53 Lenticular galaxy l I 33 SBb Barred spirals Qutio for Tht 38What is a no r 8 The explosive outburst of a star that is part of a binary star system A white dwarf can accumulate hydro en on its surface until it builds up so much hydrogen around the car on core that it ets ot enough to cause fusion This fusion explosion of the s ell of a carbon white dwarf blows as a nova a very high increase in the luminosity of the star The star can undergo a nova explosion many times as it is not destroyed in the process Qquot r 1 1 if 8 What is a supernova 3 The catastrophic explosion of a star It can be a star that is part of a binary star system or a standalone star In the case of a standalone star it is a star that is so massive that it goes through all of the fusion steps possible up to iron Supernovae explosions result in the formation of either a neutron star or black hole Qquot r 1 8 Describe the forces that keep a star in a state of hydrostatic equilibrium S Fusion generates energy that pushes out from the center of a star Also gas pressure maintains a push out from the center The weight of the star gravity keeps pulling the stellar material to the center of its mass Qquot 039 88What is the source of the chemical elements of the universe 88Hydrogen helium and little lithium and berylium were made in the big bang formation of the universe All other chemical elements ufp to Uranium 92 were formed in stars E ements up to iron are formed in stars during their life cycle Elements beyond iron are born in supernovae explosions Gut r 3 How do you explain that a red giant is very bright with a low surface temperature 3 While the surface temperature of a red giant is relatively low 3000 K the star is so large that it is emitting a lot of light in accordance with StefanBoltzmann s Law and the surface area of a star Gut r 38Describe the structure of the Milky Way Galaxy 38 The Milky Way galaxy consists of a core or central bulge region and spiral arms The spiral arms are engulfed in gas and dust of what is referred to as the disk of the galaxy The Milky Way Galaxy also has a bar It is a barred spiral galaxy The Following should help with the stay of the formation of the Solar System Quto 38How did the solar system evolve 3 What are the observational underpinnings 3 Why are some elements like gold quite rare while others like carbon are more common 3 Are there other solar systems What evidence is there for other solar systems to be discussed later in semester Obss 0 lei 38 Each radioactive nucleus decays at its own characteristic rate known as its halflife which can be measured in the laboratory This is key to radloactlve age datlng which is used to determine the ages of rocks 3 The oldest rocks found anywhere in the solar system are meteorltes the bits of meteoroids that survive passing through the Earth s atmosphere and land on our planet s surface 88 Radioactive agedating of meteorites reveals that they are all nearly the same age about 456 billion years old 38 Radioactive dating of solar system rocks EIEarth 4 billion years EIMoon 45 billion years Obstis 0 be 38Most orbital and rotation planes confined to ecliptic plane with counterclockwise motion 3 Extensive satellite and rings around Jovians 8 Panets have more of the heavier elements than the sun Abundance of the Cheial Elents SSAt the start of the Stellar Era there was about 7590 hydrogen 1025 helium and 12 deuterium 8 NOTE WELL Abundance of the elements is often plotted on a logarithmic scale this allows for the different elements to actually appear on the same scale as hydrogen and helium it does show relative differences among higher atomic weight elements better than linear scale Abundance of elements on a linear scale is very different Log Plot of Abundance Logarithmic Plot of Chemlcal Abundance of Elements Relative Abundance Relative Abundance A LinarView o nance Rdzllve mundznm Another Linear View Chemlcal Abundance vs Atomic Number LInearFlot Relative Anunuance 15 Alarm Murrher Planet Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Mass Earth1 082 100 011 318 95 14 17 Density 9 cma 13 17 Major Constituents Rock Iron Rock Iron Rock Iron Rock Iron Ices H He Ices H He Other I equot 8 Terrestria planets are closer to sun Mercury Venus Earth Mars 8 Jovian planets furthest from sun Jupiter Saturn Uranus Neptune 38Panets formed at same time as sun 38Panetary and satellitering systems are similar to remnants of dusty disks such as that seen about stars being born eg T Tauri stars 3 Panet composition dependent upon where it formed in solar system Neb nde 38Energy absorbed per unit area from sun energy emitted as thermal radiator 3 Soar Flux Lum Sun 4 x distance2 38FUX constant X T4 StefanBoltzmann 38Concuding from above yields T constant distanceo5 Nebular Condensation Cht Molecule Freezing Point Distance from Center H2 10 K gt100 AU H20 273 K gt10 AU CH4 35 K gt35 AU NH3 190 K gt8 AU FeSO4 700 K gt1 AU SiO4 1000 K gt05 AU Nebular Condensation Pref of 3 Most remnant heat from collapse retained near center seAfter sun ignites remaining dust reaches an equilibrium temperature seDifferent densities of the planets are explained by condensation temperatures 3 Nebular dust temperature increases to center of nebula A Pictorial ew HST Pictorial Evidence HST Prictorial Evidence More Pictorial Evidence Disk ofgasand dust Central s ar blocked o telesmpe to make disk VI ble G Size of Pluto39s orbit
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