Elementary Astronomy PSC 203
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This 76 page Class Notes was uploaded by Melyna Mayert on Tuesday October 20, 2015. The Class Notes belongs to PSC 203 at South Carolina State University taught by Jennifer Cash in Fall. Since its upload, it has received 20 views. For similar materials see /class/225407/psc-203-south-carolina-state-university in Physical Science at South Carolina State University.
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Date Created: 10/20/15
Overview I In this section conStellatIons I What is a constellation I How do we show the constellations I What about other patterns PSC 203 Constellations Constellations I What are they definition I Examples I Groups of 23 I Recognized grouping of stars 39 llSt 5 You want to see tOdaY I Officially recognized grouping of stars I Class list on board Of cial Constellations Asterisms I Who is responsible I Unofficial groupings of stars I IAU I How many are there 39 88 I Examples I Big dipper I Pleiades Cultural Hlstory Many scmes ivtm many Cannes Many names Ema ivtm anan mymes Many stay names cm Alstn mystic Representaums Hep m see names Boundarles Of ma vEgms in each mnst anun y Induces ymde sky Star Chem scavs snmm as dms can be ham u see uamans sack gares 39 vay basyt DIME Take same ymaeynancn Naman Of ua name an Man em Abbamama ettas am an Cummm name Eyg D09 Haney Plane anum somzre Law WWW an m m am am W 2nd mm m Vm want mm mm the kkuu d mkhkg 5m m be huwrv m Dhmunum 5m m be hnwrv m mam Corml anms Gravity PSC 203 Theory of Gravity IGravity is the force of attraction between any two masses I Sir Isaac Newton IAIbert Einstein Law of Graviy I Force is I directly proportional to product of masses I inversely proportional to distance squared Gmlm2 2 FG g I H I I Mass I More mass more force I Less mass less force I Distance I Large distance less force I Small distance more force G I Universal Gravitational Constant I found by experiment I assumed constant throughout universe G 67x10 kg I Don t need to memorize this number ualitative Exam Ie F GmAm2 FG2mAm2 A 2 BT F2F Example 2 Gm1m2 Gm1m2 A r2 3 3r2 1 FB 6FA Quantitative relationships I Need to look at full equation I You need to make sure that your units are the standard mks meters kilograms and seconds I Then it is just plugging into the calculator I For astronomy masses and distances are often found in the tables in the book Example Earth and Moon Gravity Fields I Around multiple objects 67x1041 Nmz6x1024kg7xlozzkg I Look at effect from each object F kgz I Amount and direction 6 4x108mZ I Add or subtract to get total F r 1 75 WW G i X Tutorial Visual picture of Gravity field I Page 29 I Einstein39s view I Class discussion of 1 2 3 I Setup for 410 I Small group work I Wrap up I Treat each object as a dent I More mass gt deeper Visual picture of Gravity field Orbits are like objects sliding around rim Example Question I If the mass of the Earth were twice as large as it currently is then the force of gravity between Earth and the Sun would be u A Larger B smaller I C doesn t change Example Question I If the distance between Mercury and the Sun was half the distance it currently is the force of gravity between Mercury and the Sun would be u A Larger B smaller I C doesn t change Surface Gravity Surface Gravity Measures the affect of gravity at the surface of an object G 1 I Depends on mass and radius of planet R 2 Qualitative relationships Mass More mass more gravity Less mass less gravity Radius Large radius less gravity Small radius more gravity Give and bke The Jwan genes have more mass man mrresmak But they a so have a arger radLs So What s me resut mug imm mhev cexmmk Example question Example Question Example Question mm mass m ou d Amvgev Amygav a smaHa a smaHa IOGDESH39IEHEFEE c duesn39t Charge Gas and Dust in interstellar space PSC 203 Overview I What is interstellar space I What is out there I What do those things look like Interstellar space I what do you think this term means I the region between the stars I Distances between stars are large I That s a lot of space Interstellar space I the region between the stars I is it empty I almost but not completely I so what is out there I gas I dust Almost empty I empty is really a description of density I empty would be density 0 Typical Densities I water I 1 gcm3 I air I 000125 gcm3 I in 1 g of water or air there are a lot of molecules I water 33 x 1022 moleculescm3 I air 26 x 1019 moleculescm3 Deng es I Interstellar gas I Hydrogen 001 atomscm3 I 1 Hydrogen atom in 100 cm3 I Interstellar dust I dust IX 10 12 particlescm3 I 1 dust particle in 1000000 m3 Densities I space is not empty just a very low density I compared to air I space is almost empty Higher density regions I air can have clouds of higher density I interstellar space also has clouds Nebulae I clouds of dust and gas in spacequot I one is called nebula I more than one is called nebulae Composition I What are the clouds made of I Mostly hydrogen I Trace amounts of other gases I Dust is mainly carbon Nebula Sizes I smaller I 10 light years across I larger I 200 light years across Locations Some nebula are associated with stars We have already talked about 3 Star formation regions Planetary nebula Supernova remnants Star formation Planetary Nebula Supernova remnant Crab Nebula 39E E h Ialini39Pa 5331 2 Appearance types Nebulae are also categorized based on appearance Three main types I Dark Reflection Emission Dark nebulae dense cloud of dust and gas blocks out light coming from behind the cloud can block out stars or another nebula W Visible vs IR Infrared light can pass through the dust Re ection I light from a nearby star reflects off nebula toward us I reflection is diffuse or scattering blue light scatters best Rflection Emission light from a nearby star causes nebula to emit light emission can be many colors Hydrogen emits in reddish purple light I but blue is scattered so mostly red is left Emission Emission Combination quite often you can see more than one type of nebula in the same region reflection nebula from gas behind star emission nebula from gas in front of star dark clouds higher density regions in front Combination In Class Activity In small groups discuss For each of the following images does it show dark nebula emission nebula re ection nebula Combination identify which types Then we will discuss as a class Overview TOOIS Of I In this section I How do we observe light I How does a telescope work I What tools can we use with a telescope PSC 203 Observational methods Parts of the Eye VWk Iris I To observe light we need tools I Brainstorming l A fmmea I What type of tools do we use 39 Cmea 39 pupll I eyes I IrisPupil Ema I telescopes I Lens I cameras 39 Reuna Iris I I Optic nerve I Support structure What does each part do Parts of telescope I Cornea protects eye amp starts to focus I Support structure I Iris restricts how much light comes in I Collecting aperture I Pupil opening where light comes in I Focusing optics I Lens focuses light onto retina I Detectors I Retina detects light I Filtersgratings optional I Optic nerve sends signal to brain Support Structure I Hoids aii pieces in piace I Moves to point in different directions I Protects sensitive parts Focusing optics I Tvvo main types I Retiectos and Retractors I Retractors use ienses I Re ectors use mirrors Re ectors I Ligtt bounces oft mirros I Severai common arrangements I Generaiiv aiso goes through iens evepiece Collecting aperture I Where the iignt comes in I Bigger apertures aiiovv I Brighter images I Better resoiubon I Smaiier apertures aiiovv I Easrer manufacturing I Easrer operatmuse Refractors I Light is bent bv ienses I Objective and evepiece ienses Detectors I Must sense the iignt I Sbouid convert it into a measurabie form I Piaced at tocai point of teiescope Examples of Detectors I Eve I Photographic Film I Photon counting devices I ChargedCoupled Devioe CCD Gratings GratJrlgs to breakllghtlnto spectrum ant plans l l zemmy I Hands on demos Telescopes in space I Why would we want to put one in space Vour mougm CCD39s I Started in astronomy now everywhere I Each pixel detects light that hits 39t I Megapixels million pixels Filters Fllters letthough onlyselectwavelengths Allow you mum lnformatlon more carefullv I Hands on demos Atmospheric Transmission I Some regions of EM Spectrum blocked by atmosphere e Twinkle Twinkle Little Star Why Have a Telescope in Space I A moves I Above weather I Shifts star Image I No Minklingstars I Twinkling to eye better spatial I Blurring to camera ris llggquot by funquot 0 I Regions of spectrum UV IR Xray Ga mma Rays SPACEBASED OBSERVATORIES In Class Acti x HST UV Optical R I Brainstorming and discussion Chan ra erav I 5 RE 1255 er I Ideas for outside projectsquot related to light Op 5 and tools Groundrbased Still have role Field oNeW Large insuumene Lots ofo 9 me Mdupie sites slmulbanesously 21 PSC 203 7 Elementary Astronomy Name Spring 2008 Prelecture Assignment Due February 5 Reading Assignment textbook sections 53 71 72 73 1 Stars on the celestial equator rise and set 2 South Carolina s Eastern Standard Time EST is hours different than Universal Time UT 3 What are they are the names of the four time zones in the continental United States 4 Which time period is longer The mean solar day or The sidereal day 5 There are solar days in a solar year Other announcements 0 Class on Tuesday meets in the regular classroom 0 Make sure that you bring your Lecture Tutorials book to class on Tuesday 0 next Thursday Feb 7Lh we will meet in the planetarium at 930am Work on your WAC constellation papers Links to a star chart maker can be found on the course website at httpphysicsscsueduNjcashastro OO Structure of the Universe PSC 203 Overview I In this lecture I Nearby galaxies I Clustering of galaxies I Overall distribution of galaxies Review I What galaxy do we live in I What type of galaxy is ours I What are the other types of galaxies Nearby Galaxies I Closest galaxy I Sagittarius dwarf I Dwarf elliptical I Other very close galaxies I Large and Small Magellanic clouds I Irregular galaxies Large Magellanic cloud Small Magellanic cloud local subgroup What types of galaxies are in local sub group Us a spiral Mostly dwarf ellipticals Some irregulars Local Group I The full local group is larger still I about 3040 galaxies about 1 Mpc across biggest I andromeda galaxy Andromeda l mlllllal i l Clusters of Galaxies Clusters I galaxies are found in groupings clusters I very few galaxies in between clusters Galaxy Clusters I A group of galaxies I Located together in space I Mutual gravitational attraction I distances across measured in Mpc I 1 Megaparsec Mpc 326 million light years Cluster types I Rich clusters I 1000 or more galaxies I Poor clusters I less than 1000 galaxies I sizes range from 1 10 Mpc across The local group I What type of cluster is the local group I Rich or poor I Local group has 3040 galaxies I So we are POOR Virgo Cluster I a nearby galaxy cluster I 55 million light years away I towards constellation of Virgo I 2500 galaxies I rich cluster Vi rg Cluter o Supercluster I Definition l a cluster of galaxy clusters Our Supercluster includes Local Group Virgo Cluster u 160 groups of galaxies total gt 25000 galaxies 2550 Mpc across not exactly known centered on Virgo cluster Other superclusters We see other Superclusters near us Map them out by using distance and direction Create a picture of the local universe Virgo Sumrcluster Known Universe I superclusters are connected to form great walls and filaments I voids in between have virtually no galaxies In Class Activntz I list two of the astronomical examples of the nonuniform distribution of matter clumpiness I list one example from normal life on Earth where things are found in clumps and not evenly distributed over the surface Seasons PSC 203 Overview Why do we have seasons Misconceptions about the seasons Sun Earth geometry during the seasons Seasons terminology PreIecture questions I Turn in now if you haven t already Question 1 page 28 Question 2 fig 17 I Question 3 page 30 and fig 113 Question 4 page 25 and glossary Cause of the seasons The tilt of the eaith on its axis relative to the sun I 235 degrees Maintains direction over the year Visual example I Norlh Pole a 235 7 Equator September K North Pole r H 9 December Solar Heating The sun or any light heats a surface most effectively when it is shining directly onto the surface In Summer tiah in aft 0 t l 0 Em in W39Inmr lmmr in silty will gm thu Ixnnlth North Pole Equator l d Ellis 68 Sunlight gt nl 1quotmmtfi mmfmlb quotIIIIIIIIIIIIIII III f gt 239 Less heat IS received because the surface is tilted anaemia ham to u st of q Ianm39 Larger wmtnr aimFlinn hand h39 a giverquot pileta tn gtrmnzlh atfer Seasons In summer the sun is at a smaller angle more effective heating In winter the sun is at a larger angle less effective heating Seasons vs hemispheres Northern and southern hemisphere have reversed seasons North Pole North Pole I W December June summer in Southern summer in Northern Hemisphere Hemisphere Some common misconceptions what are some other things you have heard or been taught about the seasons Caused by the weather Caused by the dismnce m the sun Weather vs Seasons The changing weather patterns don t cause the seasons The weather d1anges because of the seasons I We wmt m know what it is that causes the difference over the year why is it warmer in Summer and colder in winter Distance to the Sun The distance from the sin d1anges over the orbit If this causes the seasons then it snouid be summer why we ae cioser to the sun I But we are closest to the Sun in Januay A h In rim quotJr variation is closer to the sun This is true but it is a very small amount less than the difference i bit If orbit change was not enough then the d1ange h distance due to tilt is not enough Equinox Sun sets due west Exactly 12 hours of day 12 hours ofnight Once in soring Once in fall Solstice Summer solstice Longest daylight of the year I Sun at noon is highest in sky Winter solstice Shortest daylight of the year Sun at noon is lowest in sky Prep for planetarium lecture Next week we will be in the planetarium Topics Constellations Sky coordinates Motion of sun and stars Differences due to location Notes for planetarium Since it will be difficult to take notes in the planetarium it is dar Iwill provide handouts on the concepts You will fill out worksheet at the end of each lecture Light part 2 PSC 203 Overview In this section How is light created I What can we learn from light Inclass activity Reminder from last time I Think of as many examples light sources that you can think of Spectrum WillWWW 00091 nm 00l Nn lo nm l00 nm OOI cm I cm llm 109m Gamma lays Xrays um unwell Radio waves Radm TV FM AM I Now think about how light is created v H N win 505m 690m mam Spectrogram Shape of Spectra Graph showing the intensity of light at each wavelength Examples on board Characteristics of spectra depends on how the light was generated I So how is light generated Formation of light I light is a form of energy energy has to be transformed into light from some other form sources are categorized by the original energy Incandescence I light created from thermal energy I object radiates its heat as light Light is radiated at all wavelengths Spectrum provides information about the Blackbody Ideal objects which Absorb any light which hits them Reemit light in a characteristic shape depending only on temperature Creates continuous spectrum All wavelengths present tem peratu re T12000K T6000K T3000K xm 250 nm Am z 500 nm K E 1000 nm Brightness gt quot I I I I 0 500 1000 1500 2000 Wovelenglh nm gt Temperature vs brightness Total amount of light generated depends on temperature Hotter object gt more light Cooler object gt less light Temperature vs color I As an object heats it appears to change color from red to white to blue Peak wavelength depends on Temperature T 3 x106 K nmm T 12000K T OOOK T3000K Am z 250 nm xm z 500 nm xm a 1000 nm Brightness gt i I 0 500 1000 1500 2000 Wavelenglh nm gt Incandescent examples I People radiate light because they have thermal energy I Peak wavelength is in infrared I Brightness is fairly low Incandescent examples I Electric stoves radiate light because they have thermal energy I Peak wavelength is in red orange yellow region of the visible spectrum I Brightness is moderate Incandescent examples I Blow torches radiate light because they have thermal energy I Peak wavelength is in blue region of the visible spectrum I Brightness is high Other processes I Not all light is generated by heat w I light created from atomic energy I atom releases energy as light I Light is radiated at specific wavelengths I Spectrum provides information on the atoms Atomic Excitation atoms have energy levels for each electron normally electrons in lowest levels possible can excite electrons into higher levels I to move back into lower levels need to release energy Electron V N High potential energy Electron gains Electron potential loses potential energy and energy and J L J b moves farther moves closer fAror ntucleus 1 p LOW potential p q Xm ictleusf p 0 on p 0 on o of light is energy j light is emitted absorbed at a Nucleus Nucleus Emission spectra when a gas is excited it releases light at specific wavelengths depending on the type of gas Hydrogen Iron Atomic examples Neon lamps High voltage electricity passes through gas Lasers Fluorescent materials Absorption spectra when a cold gas is in front of a continuous source only specific wavelength are absorbed same wavelength produced in emission spectra Continuous Spectrograms I Idealize Spectrograms for each type drawn Emission line hydrogen gas on board Absorption line hydrogen gas Real Spectra Nonsources of light ML I Some light we see appears to come from one source but it is really from another source Spam 3 A gw w wn m I Reflections or scattering I Moon light I Not generated by the moon I Just re ected sunlight Brighlness Soav specllum Inclass activity I Lecture tutorials as time allows Astronomical Time PSC 203 Overview I In this section I How is time measured How do the seasons affect daylight Early time I How was time measured in the oldest times Sun as time keeper We can use the Sun s position during the day to measure time I Sun dial clocks Local noon The time when the sun crosses the meridian highest point for the day I This will be different for every longitude Societies which are spread out need a more uniform way to agree on time Time zones Universal time Stars as time keepers As the earth rotates at night stars can be used like the sun is used during the day m Solar verses sidereal A day is one rotation I But relative to what u If we use the sun solar day I 24 hours on average varies slightly over the year I If we use a star sidereal day I 23 hours 56 minutes To star I I I I l I I Day 2 Noon Earth has now K turned once with respect to the Sun but has made than one full turn with North Pele respect to the star Earth has turned once Day 1Noon with respect to the star Star is back overhead Sun overhead and but the sun ism star overhead Year Definition One complete orbit around the sun Seasons Portions of the orbit around the sun Defined by sun s path as seen in planetarium show and previous lectures Hours of daylight also vary over the seasons December i ri i VI 9 Aphelian JUI39te Solstice 3 39 my 4 7 Solsnce September 3 Equinox Earth orbit No daylight 103 hr daylight 12 hr daylight 4 24 hr daylighl rl 137 hr daylight 1 T3 hr daylight Sunlight 12 hr daylight I 103 hr daylight quotquot 7 No daylight 1 gt aquot 39 l 24 hrdaylight 4quot A gt December June The Su Our Star vs 2n3 Structure uumde er mve enemy tvansrenee thvuuuh vamatmn vamatmn rgt hem er 2H wavE ervuths Overview In Ms semen Hom u mnure m due the Wm WM 2mle mom me m vew ante er sun enevev EEHEvabzd mvuuuh msmn Heme lFumm W In Famdl gelhev mm 2 NAM 2km uutswde er amatva zene enemy tvansrenee thvuuuh mnvemun mnvemun rgt ha 9 m mdev 9 Au 5W2 u bmhnu put er wetev v swb e suface m sun the we auntsdwae m the 5m mmwugwwwgm I mamatuvephmusphae mtsuhd sum nm 5 Wye must aan ums 5n bught n mmmces WEN wnhcut Mas pmmmm ngnehz mm m Inte icr Sh39uctue uw dmsw Huh muaamve DmsW mvmaHv mm mm be seen m Mm h ghext n the Dent 39thmvheve u mobnghu Dvw fup d y Auwzvd Mm can be seen dmng sum amuse Tmpaatue SOHO sea bv madam um um Wmdwae m Aempenlue H mm It the zerlev Dvw ifvzp dh Auwzvd Mm Appearance Ltuk mm mm mm m we sun 2rd dzmbe mtvnusae Photosphere Sun Spots I Very bright visible I Darker cooler spots surface on the photosphere I Need filter to take 39 St39quot E hot picture I tNheeend filter to see quot3 K r 55 5 Si i39x39htu i t quot quotIt 27 leiquotr4 Tl I Features Other wavelengths Chromosphere I As we look in other wavelengths we see other I Looking in UV features besides just the photosphere I Wavelength related to temperature Features I spotchangempg 20041031 1919 Chromosphere Corona Outer edges of atmosphere Overwhelmed by photosphere I Seen in eclipses I Features Acmlty on Ihe Sun THE M mam 5m m2 53mg mm and davk speckth mm The changes ave vefaved m as 3an mum aus bv mnvemnn undaneam 39vevv smaH scab and shun nme 51m Sum mm 9mm 39Watdw mum and mama and mate 7 r 7 Changes Hmawmmnmupmay Omges met momh ang ma 1 phmsmeye mm mm a chvcmusuhae 3an musases and daneasz m 11 V22 myvauhm vde CaHed sum Evde Nance mtatmn and stave 159me m mud n mmmm u H Currentshams mm W m mmm dugy A12 WE m Huh m w pan Bf me we me acumty on me sun rs caused by me temporay coder darker spos on the magneuc e d surface knotmd to ether 39 ast from hours to months dynamo Sunotformauonmdfae Horrirenoes I Gas Extends shave the ham here u Must wsrme an the edges Feemrasv Gas aws a nng the magnet e d thhe pm mrnences Tracaz aumuvsts af amle an the sun s 5uvfate vesu tmq m temvmaw hnqhtemn Mm up mm has a Space 39aused w magneh he d hreakmq and refuvmmq Mass Eyechans quotmums ar gas thmwn m mm Gmmm kunesm Observing Other Stars PSC 203 Overview In this section I What are stars I How are stars different from one another I How can we describe stars I How do we measure properties of the stars Sta rs What are they Massive gas bodies in space Generates light by fusion Defined by fusion at the core Stars when you look at a group of stars do they all look th sa Properties of Stars What properties of stars can we measure or use to describe the stars Your thoughts Inclass activity Brainstorming In groups of 2 3 write down as many things as you can think of to answer What properties of stars can we measure or use to describe the stars Properties of Stars What properties of stars can we measure or use to describe the stars Your thoughts We will look at color spectrum and brightness Color Color I what causes color variation in stars I hint we already studied this in light Color I The color of a star indicates its relative temperature blue stars are hotter than red stars Temperature T 12000K T6000K T3000K Am s 250 nm mm a 500 nm km a 1000 nm Brightness gt l gt I I I 0 500 1000 1500 2000 Wavelenglh rim gt Color I Don t need whole spectrum and Wein s law Instead look at relative amounts of two colors red and blue Color Index blue ted mm mm Notice that the flux through the blue ner exceeds that for the red filler for opposite or the cool star So the hot star is has a blue index and the cool star has a tea index energy wavelength can be measured using filters then relate color and temperature Spectral Type Spectra of stars I energy distribution over wavelengths I Stars generally have absorption spectrum I specific features depend on temperature I Sometimes used instead of color Spectral type I an indicator of a star s temperature based on the appearance of its spectrum lines I specific features grouped into categories I The fundamental classes are from hot to cool 0 B A F G K and M EKGnibmo Subclasses I Spectral classes subdivided with numbers I A0 is hotter than A9 I the Sun is GZ Brightness Brightness I Why do all stars not have the same brightness I 2 factors I Distance I Luminosity Distance I Stars are different distances away from our solar system I These distances are very large I closest star Proxima Centari 424 ly Measuring Distance I Several methods I Parallax I Standard candles Parallax I Miniexperiment I Apparent shift of a star relative to the background due to observer s motion I Large shift close distance I Small shift large distance I No shift very large distance Standard Candles I We need to discuss the how distance affects brightness first Distance verses brightness I the apparent brightness of a body decreases inversely as the square of its distance ld 2d 3d a Distance red 2 AUml 0k 1 yellow OYljx iiiii ti Standard Candles I If you know how bright it would be if it were close I Observe how bright it appears to be I Relate that to how far away it is How much light I How do we describe the inherent amount of light a star puts out I This quantity called Luminosity Luminosity I luminosity the amount of energy radiated per second by a body I units 0 L solar luminosity o 1 L 383 X 1026 watts Luminosity I why do stars have different luminosities I depends on temperature I depends on size Luminosity I depends on temperature at surface 0 hotter objects radiate more energy 0 cooler objects radiate less energy temperature at surface not core is what matters Luminosity I depends on size More area on larger objects omore energy released 0 Less area on smaller objects 0 Less energy released units of size RD solar radius Luminosity Formula I L Luminosity Magnitudes I Started by a very old system I Bright stars 1 I Slightly dimmer 2 I I Dimmest visible to eye 6 2 4 L 47rR CT I R radius I T temperature I R2 gt L4 I T2 gt L16 Magnitudes I Now quantified for apparent brightness I See appendix table 8 I Sun 268 I Sirius 144 I Vega 003 I Progtltima Cen 1109 I Big telescope 24 or lower Remaining Solar System Topics Psrzas overview Teams m be waved i a a MSWEYS m Student Questmns What is an Exoplanel m mums s mm quot1 units 1 mind an snlr man How Many Exoplanels Are There m Now many havzwz Inund Asnl May 12nna mpamnqmm Asnl m 2 2m npumu mm httpulznemmsupl nzsz am How do we f39nd mem Lnnk in affect an stays Gvawtahana Lenswq Exoplanet Properties Mns v me 325 gm Manv dnsem they stays whv n 5 may m rm mg mg dase m stas any ms havem been mm Future work New missions to look for more Earth like planets Keck Interferometer Kepler SIM PlanetQuest Terrestrial Planet Finder The Search for Life Means different things to different people Many viewpoints on the topic What does it mean to you Discuss with neighbor Do you think we will find it Possible Answers Searching for ExtraTerrestrial Intelligence Searching for simple organisms Searching for the right conditions for life Right Conditions What do you need to survive Class brainstorming What does life need to live Liquid water Nutrients Raw materials Energy Life in a Variety of Environments Most life forms live in normal range of temperature salinity acidity etc Some forms live and thrive in extreme environments they are called extremoghiles Live in boiling hot springs freezing water very salty very acidic etc What can life tolerate Transmitted light Life in the Solar System Where would we find conditions that any organism could survive Where could we go and survive Terrestrial Extremophiles and Life in the Solar System Studying terrestrial extremophiles helps scientists understand what is POSSIBLE in the extreme environments on other planets and moons in the solar system Where is Life Most Likely ist Evidence of much water in the past Past Life forms Existing Life form39s Jupiter s Moon Europa A frozen surface protects a saltwater ocean below Saturn39s Moon Enceladus a Water Geysers erupt 39 at the surface Sun ace temp 300 F Liquid H20 at 32 F or warmer just below surface Tidal heating or radioactive decay keeps water in liquid phase Terraforming process of deliberately modifying an object s surface or to be similar to those of to make it by humans discussion The Planet Debate Definitions Adopted by IAU Planet Orbits the sun Large enough to form into a sphere Cleared the neighborhood of its orbit Dwarf Planet Orbits the sun Large enough to form into a sphere Hasn t cleared its orbit Clearing Orbit Examples Ceres In asteroid belt Its gravity doesn t really affect other asteroids Jupiter Has a lot of other objects in its orbit Most all are dominated by Jupiter s gravity Current Dwarf Planets Ceres Pluto Eris Makemake Haumea 40 known but unnamed objects Unknown objects Remaining Debate Historical objection view point Geological objection view point Other objections Class Views Should Pluto still be classi ed as a planet Other student submitted s Some already answered today Asteroids questions Future of the solar system Others from cards The Sky from Earth Planetarium PSC 203 The oelstial sphere as me Sun and stars We eroewe ihev dsmnoe stm caHyme sky was percewed as a sphere WH Me this on m For objects sum can 0t dwrec y p We suH use me same vocabuary Vocabulary Honzon me homoer cwde separaung me sky from me gound zerum rune pomtsuawghtoverhead Me d an rhne from Norm m scum mrough zen m I v Mm Overview n m secnon Mm m we see imm Eanh Haw an Ebleds m the SW muve da va Haw an Etueds m the SW muve veanva Haw du was change at mha mama The aels al sphere MWWWMWNew mmln Coordinates I Just like the curved surface of the earth has a coordinate system I So does the sky 2 systems in fact I Altitude and Azimuth I Right Ascension and Declination I These will be studied in the planetarium Altitude and Azimuth 39 quotx 139 NW 3 x 3 l AJiquotiilli39 Celestial coordinates bleslia39 feloslnlmrlhlmla mgr Spquot 5 hemmedmi Ammoquot 39339 tier 5 l V 21 E Qia VI Anal my Pole Mir Decllmlmn Altitude and Azimuth I Altitude how far above the horizon I 0 on horizon I 90 at zenith I Azimuth how far around horizon I 0 at north I 90 at east 180 at south 270 at west Celestial coordinates I Project Earth39s coordinates out into space I Equator Celestial equator I Poles Celestial poles I Longitude Right Ascension I Latitude gt Declination Overvlew of SC North Pole Overview of sc Equator Motion of the Stars Motion of the stars Depends on locauorv We Wm look atSouth Carohna rst 5c Lama 35 N SC looking south SC looking east Ekars n52 SE 5 35 H52 along ave lm altlmde at eastam human the mndlaw th2 up m at an Eel ln SW male towards the mum SC looking west Move down cows 5 SC looking north Same Sta n52 ls NE and set ln NW I Otlirs Clyde around the north EE ESUE pole mmumpular Star Dams Overvlew ofSC mepamfstaysayeu aemnm eymt mums 39WewdH m lEma 14 mm lScum Aim 43mm mm Alaska 7 m E N Nam p 2 4mm gm Equator Eanmr 39 Stavs WW2 mm Eastm wast mme dwa iv wahaad 39mstead J 35 mwads the sauhan hanmn D mvmmudav stavs 39 Cdzna Ddz ave m H mm H Norm Po e mum uses atzm h mama Stays ave 2H uvmmpu av and wave mm at mstam mums Scum Afrlca lav Nave 7mm set m West emhq eh av tawavds the nmthem hDHZDn mlezd memes he wheh humm Stays h the sauth ave wtumvma amund the sauth 2 25ha W e math Mew pee he Meme Ala lta Stays Nave h m aw avts 7mm east In West emhq the saulhan hahmh Mast stays h the skv ave wtumvmav Navth ebsha Dub 5 h qh h m Mouon of the Sm Scum Afrlca Alaska wmme Sun motion Depends ah heetmh aha Seasan We Wm NS aak at Sauth Camhna39s mew h each Seasan 9c w nte39 SC sprlng msesnsz 525an Reaches aw a hmde at naan Reaches nm emmae at naan Sets m sw Sets n w mm anqev than dav Dav and non euua SC summer SC fa Rxses n NE wees m a Reaches ngn emme at naan Reaches nm altitude at naan Sets m NW Sets n w Dav anqev than mth Dav and non euua EQJatOquot Sun a ans waves Mme avevhead Equator South Carolina 0quot latitude 40 Nlatimde 0 deal 39 w u 2344 daal mama a44 daal odaal Calesual Nonil v Pole 723 44v deal Celesual 5 North Pole 5 N Solarpart lwlmer E 1 a Solar path a wmter 5 5 5 Solarpath atsummei 50mm Solar path a so We Solar paxh at vernal and vemal and Solarpath at summer autumnal auzumnal solsnca equinox e mo Alaska North Pole 71 N latitude Banow Alaska 90 N latitude eNonh Pole c l ual Celesual 11 Pole 0 e 23 44 deal 23 44 deal 0 deal 5 N 0 deal s s s Solarpath at summer Solar 501mg N t S l m t filg am at summer Wlmea solsuae not 3 7 Pa 7 Solarpath at Mme sun always Solarpath at Wlmea solsuae not vemal and below homo vemal and vlslble a sun always 1mm autumnal below horizon equinox equmox South Africa Ecliptic verses equator I My diagram I In March ecliptic on celestial equator I In June ecliptic north of celestial equator I In Sep ecliptic on celestial equator I In Dec ecliptic south of celestial equator Ecllpt c verses quator PSC 203 7 Elementary Astronomy Name Spring 2008 Prelecture Assignment Due January 31 Reading Assignment textbook sections 131 additional handouts Complete the lecture tutorial Star Charts on pages 1920 I suggest using pencil o I will check to see that you attempted all of these questions 0 work it out as best as you can we will discuss the questions in the planetarium to clarify any areas you got confused on Be prepared to work with the star charts in the planetarium based on what you learned in the lecture tutorial Other announcements Thursday January 3151 we will meet in the planetarium at 930am 0 The door into the planetarium will be closed at 945 the door will be left slightly open after that but the ghts will be turned off Be on time to make sure that you can get in safely and nd a seat 0 Make sure that you bring your Lecture Tutorials book and the star maps to lecture on Thursday Links to a star chart maker can be found on the course website at httpphysicsscsueduNjcashastro O O Overview I In this section I How does the Sun change I What causes those changes I How does it affect Earth PSC 203 Activity on the Sun Changes I The sun doesn t stay the same What do YOU see7 m I The changes are referred to as activity 39 WIS I Ma netic eld I For all movie clips in this lecture watch carefully and comment on what you see Twisting of the magnetic field Magnetic Field I the activity on the sun is caused by the magnetic field I the sun39s magnetic field gets twisted and knotted I animation 3 i mi dewluprth mt my min i mm mm M Ma sin and SUI SQOtS temporary cooler darker spots on the surface I caused by magnetic field lines bunching together I last from hours to months SUI SQOtS Magnetic field loops out of Sun Hot gas unable to rise here because Ph h of magnetic field otosp ere l7l roil Martel gm limra1giuimc liltell l iii Connections Sunspots are related to other activity features I mgvie Activity comparison EIT39IEISA EIT IESA 1996 June 1995 The solar cycle Regular changes in level of activity activity increases and decreases in 11 year cycle The number of sunspots on the Sun varies In addition to the Sun39s rotation sunspots disappear from view and then re appear overtime new sunspot groups form and old ones fade away Over short periods of time a few weeks or months this variation in the number of sunspots may seem random However longer observations reveal that the number varies over an 11 year cycle which is related to a 22 year cycle for the reversal of the Sun39s magnetic field SunspolNumher a 7 19m 191D 19m 19m 1940 193 1950 19m 1960 159 m Prominences I gas which extents out from the Sun39s surface and flows along magnetic field lines A Sketch illustrating how magnetic fields support a prominence B Photograph of a prominence Courtesy NOAO Approximately how big is the prominence in B Use the fact that the Sun39s diameter is about 100 times the Earth39s Coolingg sllropped in magnetic field Prominences Prominences I Gas flows along the magnetic eld of the prominences media I At right l This is the largest prominence observed by SOHO Twisting magnetic fields forced this huge eruptive prominence 100000 kilometers above the Sun The plasma is heated to about 150000 degrees C August 27 1997 28 Earths high Flares I outbursts of activity on the sun39s surface I resulting in temporary brightening I Movie clip I Movie clip gm Corona I Outer atmosphere of I Look for changes Sun I yideo gl p Solar Wind CMEs I constant low density ow of gas and I coronal M355 EjeCtlons charged particles off of sun I large amounts of gas thrown out into space I caused by magnetic field breaking and reforming gMEs Affects of the sun I Movie cli I How does the sun affect us I Movie CllQ I Your thoughts I Movie cli Heat and Light I most obviously the sun affects the Earth through the light and heat we receive from it Solar Wind constant low density flow of gas and charged particles off of sun Particles reach Earth Aurora charged particles in solar wind hit atmosphere causes the atmosphere to glow Movie clip usually called the northern or sou ern lights These often colorful and flashing light displays in the night sky are seen at high latitudes near the poles They are caused by the impact of fast moving electrons from outer space our magnetosphere Comets Tail is caused by solar wind Movies I Ii 2 I CED CME impacts coronal mass ejections sometimes aimed towards earth I see gas leave sun proton blast comes soon after main gas takes 34 days to reach us I m Movie clip Strong magnetic changes occur when CME S impact our own magnetosphere These generate a number of effects In one instance a CME knocked out interfered with communications 4 7V n CuS w Emma and lntmmr cm lg Mean an AliiiiI Ei mum lunnsp Curr Eiuziiiniy Grid Dinlplin Ennh Current TElitnmrnunlcaliD cause Disrupan a C do some and changino their orbits lrregula n the ionosphere about 40 00 km above Earth 39 1 radio signal p I back as well as arth communi atiohs lt3 2 minute essayquot Individually What concept in today s lecture was most interesting and why I What concept in today s lecture was confusing The Sun Structure PSC 203 Overview I In this section I What is the sun I How is it structured I What causes this structure I What does the surface look like Structure A mm for Compariwn km lif i i t Core I very center of sun I energy generated through fusion I HgtHe Fusion I Two atoms are forced together to create a heavier atom I Energy is released in the process I This is a nuclear process Radiative Zone I outside of core I energy transfered out through radiation I radiation gt light of all wavelengths Convection Zone I outside of radiative zone I energy transfered out through convection I convection gt hot gas rises cooler gas falls I similar to boiling pot of water Photos here I visible surface of sun in visible wavelengths I not solid surface I so bright it dominates view without filters W I the lower atmosphere of the sun I located above photosphere I this is where most activity occurs I prominences I flares I magnetic loops Corona I the outer atmosphere of the sun I low density high temperature I normally too faint to be seen I photosphere is too bright I can be seen during solar eclipse I SOHO sees by blocking out bright photosphere Interior Structure I What is the interior structure of the Sun I Density I The density is highest at the center I Drops off rapidly toward surface I Temperature I The temperature is highest at the center I Drops off rapidly toward surface 150 l5 million Density lgcm3 Temperulure Kelvin 9 million 5 million i 3 million Interior Structure What causes the interior structure of the Sun to be the way it is Temperature High temperature comes form fusion energy source in core I Also comes from the original formation as gas collapsed to form sun Density Like the atmosphere weight compresses gas below Gas in the center is compressed the most Gas at the edges is not compressed much The Sun s Appearance What does the sun look like Your thoughts Photosphere Too bright to look at I Need a lter to see it I Features Photosphere uuuuuuu on Other wavelengths I As we look in other wavelengths we see other features besides just the photosphere I Wavelength related to temperature I animation 6000 degrees K I Darker cooler spots on the photosphere Still veg hot Need filter to see them Features Sun Spots Granulation I light and dark speckling of the photosphere I caused by convection underneath I very small scale and short time I animation I Looking in UV I Features Chromosphere Chromosphere Prominences I Gas extends above the photosphere I Most visible on the edges I Features Prominences Corona I Outer edges of atmosphere I Overwhelmed by photosphere I Seen in eclipses I Features Overview of Astronomy PSC 203 Topics for the semester Sun Earth Moon39system Observations The solar39system Physical processes in astronomy Stars I Galaxies l The Universe Sun Earlh Moon System ow do these objects move around each other I What astronomical events are related to these motions Observations We will be looking at Constellations I Coordinateson the sky Motions of thestars and Sun Astronomica Time Solar system I What objects are in the solar system I What are the relative sizes and distances in the solar system I What defines a planet Physical Processes I What are some of the basic physics concepts we will be studying I Gravity I Orbital Motion I Optics I Light and Energy Stars I We will study I Observable properties of stars I The life cycle of stars Galaxies I What is a galaxy I What is our galaxy like I What are other galaxies like The Universe I What is the Universe I How is material distributed in the galaxy I How has it changed over time I How might it change in the future 2 minute paper I Briefly write out your thoughts for me I complete sentences legible handwriting I Which of these topics sounds most interesting to you Why I What would be one topic I didn t list that you would want to know more about AslronOmy I Astronomy is I Thestudy of the stars I Space science includes I The study of everything outside of earth s atmosphere History I Astronomy is one of the oldest scientific fields see chapter 1 I In the oldest times they studied things like I When and where events happened in the day and night sky Observational Science I In space science we can t experiment like many sciences I Instead we observe I Wh at s there I What happens Observational methods I To observe we need tools I What type of tools do we use eyes I telescopes I Cameras I The order of mmgs Swze Sca e of me Umva39se Wmuqmut the savesta we Wm he WW 3 theye ahvesue Stab af mew D mch n 51 he mr mma vea Wundaslard the vav aqe dxslarmes ma sues nvu ved m ashammY m m m an Vhe avdevafabyed 2nd mm m
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