Summary - Complete - Astronomy Final Exam Study Guide PDF

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Summary

Astronomy Final Exam Study Guide...

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Astronomy Final Exam Study Guide •! AU!–!Average!Distance!between!Earth!and!Sun7!roughly!93!million!miles! •! Light!Year!–!Distance!a!beam!of!light!will!travel!in!one!year7!5.88!trillion!miles! •! Parsec!–!Based!on!how!far!a!star!appears!to!shift!its!position!when!we!view!it!from! one!side!of!our!orbit!around!the!sun!and!then!view!it!when!we!are!on!the!other!side! of!our!orbit! •! Platonic!YearG!25,800!years!(wobbling!of!North!Pole)! •! Astronomical!Mass!–!Amount!of!mass!in!the!whole!Earth!(6x1024)! ! •! Ancient'Astronomy' o! Stonehenge!–!Circle!of!rocks!constructed!in!England!around!2500!BC.!Used!as!a! calendar!to!tell!what!season!it!is!so!they!would!know!when!to!plant!crops! o! Babylonians!–!Formed!88!pictures!in!the!sky!connecting!the!stars!together! (Constellation)! o! Egyptians!–!Used!the!star!Sirius!to!determine!when!to!plant!crops! ! o! Retrograde'Motion'of'Planets' •! Ptolemy!(Epicycle!and!Deferent)!Planets!move!around!the!Earth!in!a!circle! called!the!Deferent.'It!also!moves!in!continuous!small!circles!called! Epicycles.!Used!to!explain!Retrograde'Motion!but!is!false.!! ! •! Copernicus!–!First!to!suggest!the!Heliocentric'Theory! •! Aberration!of!Starlight!–!One!of!the!proofs!of!the!Heliocentric!Theory! ! •! Kepler’s'Three'Laws'' 1.! Planets!go!around!the!Sun!in!elliptical!orbits!with!the!Sun!off!to!one!side! 2.! As!a!planet!nears!the!Sun!it!speeds!up,!and!when!it!is!farther!from!the!Sun!it!slows! down! 3.! The!Farther!away!a!planet!is!from!the!Sun,!the!longer!it!takes!to!orbit!the!Sun! (T2=D3)! ! •! Electromagnetic'Waves! o! Electromagnetic!Wave!(Light!Wave)'–'Double!transverse!wave!which!can! travel!through!a!vacuum!at!186,282!miles!per!second.!! o! WaveGDisturbance!–!The!material!that!is!being!disturbed!is!called!the! medium.!! o! Wavelength!–!Length!of!one!cycle.!! o! Amplitude!–!Height!of!the!cycle.!Frequency!–!Number!of!cycles!that!pass!a! point!in!one!second.!! o! 1!Hertz!=!1!cycle/second.!!

o! Cycle'–!One!crest!followed!by!one!trough! o! Transverse!WaveG!the!medium!vibrates!up!and!down!with!the!waves!as!they! move!by!(ocean!waves)! o! Longitudinal!WaveG!the!medium!vibrates!parallel!to!the!direction!the!wave!is! moving!(sound!wave)! ! Electromagnetic'Spectrum' •! Radiowave:!0G2!billion!HzE'AM/FM' •! Microwave:!2!billionG1!trillion!Hz' •! Heat!Wave:!1!trillionG!300!trillon!Hz' •! Infared:!300G400!trillion!Hz' •! Red:!400G450!trillion!Hz' •! Orange:!450G500!trillion!Hz' •! Yellow:!500G550!trillion!Hz' •! Green:!550G600!trillion!Hz' •! Blue:!600G650!trillion!Hz' •! Indigo:!650:!700!trillion!Hz' •! Violet:!700G750!trillion!Hz' •! Ultraviolet:!750G100,000!trillion!Hz!(Sun!tan)' •! XRay:!100,000!trillionG!10!million!trillion!Hz7!dangerous' •! Gamma!Ray:!10!million!trillionGbeyond7!highly!dangerous7!can!travel!through! entire!diameter!of!Earth7!goes!through!each!of!us!every!7!seconds' ' ! •! Six'Wave'Occurrences' o! Luminosity!–!Object!that!is!radiating!an!electromagnetic!wave! o! Reflection!–!When!a!wave!bounces!off!an!object7!Angle!of!incident!=!angle!of! reflection! o! Absorption!–!When!a!light!wave!is!kept!by!an!object!and!converted!into!heat! o! Fluorescence!–!Change!in!frequency!due!to!reflection.!Ex.!Day!glow!posters! o! Doppler!Effect!–!Change!in!frequency!due!to!motion.!! o! Refraction!–!The!bending!of!a!light!wave!as!it!moves!from!one!medium!to!another! •! Rule!1G!when!a!wave!travels!from!thin!to!thick!medium,!will!bend!toward! normal! •! Rule!2G!thick!to!thin!medium,!will!bend!away!from!normal! •! Rule!3G!the!higher!the!frequency!of!the!wave,!the!greater!the!bend!(rainbow)! ! ! ! !

! o! Refracting!Telescope!(1/i!=!1/f!–!1/o)!(Magnification!=!Focal!Length!Objective/!Focal! Length!Ocular).!Uses!a!curved!piece!of!glass.!To!magnify!objects!at!a!far!distance,! add!more!lenses.!The!more!magnified!an!object!gets,!the!fainter!it!appears.!! o! Reflecting!Telescope!–!A!curved!mirror!is!used!to!make!an!object!appear!larger.!! •! Newtonian!–!Uses!a!small!mirror!to!reflect!light!outside!the!telescope.! •! Cassegranian!–!Uses!a!large!mirror!to!reflect!light!out!the!end!of!the! telescope.!! o! Increase!objective!lens!to!increase!magnification! o! Radio!TelescopeG!used!to!see!behind!cosmic!clouds7!can!determine!chemical! composition!of!clouds! o! Infrared!TelescopeG!water!vapor!stops!infrared!light!waves,!therefore!must!be! sent!into!space! o! Ultraviolet/XRay!TelescopeG!stopped!by!ozone7!evidence!of!dark!matter! o! Gamma!Ray!TelescopeG!highest!frequency!of!light7!detects!strange!gamma!ray! bursts! ! ! •! Observer’s'Sky' o! Zenith!–!Directly!overhead.!! o! Meridian!–!Cuts!sky!in!half.!East/West! o! Altitude!–!tells!how!high!to!look.!0!is!even!with!the!ground!while!90!is!overhead! o! Azimuth!–!Heading!(tells!which!direction!to!look)! ! •! Celestial!Sphere!–!Imaginary!clear!ball!around!Earth! o! North!Celestial!Pole! o! Polaris!is!located!at!NCP! o! South!Celestial!Pole! o! Celestial!Equator!–!circle!around!the!sky!over!the!equator!! o! Lines!of!Declination–!above!or!below!the!celestial!equator! o! Right!ascension!lines–!at!the!ecliptic7!Numbered!from!1G24!from!east!to!west!with! every!degree!being!15!degrees!more!than!the!last.! ! •! Solar!Day!=!24!hours! •! Sidereal!Day!=!23!hr!56!min!4!sec! •! Sidereal!TimeG!the!right!ascension!on!your!meridian7!spaced!15!degrees!apart!(1G24)! and!numbers!increase!toward!East! o! What is Kent’s Sidereal Time on Feb. 21 at 9:10pm? o! At 7pm = 4:42pm o! Add 2 hours, 10 minutes to 7pm

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o! Sidereal Time = 6:52pm Local!Hour!AngleG!tells!how!far!a!star!is!away!from!the!meridian7!calculated!by! finding!the!difference!between!right!ascension!of!a!star!and!your!sidereal!time!(Right! ascension!–!sidereal!time)! ! ! EarthG'Circumference!is!25,000!miles7!Diameter!is!8,000!miles' 3'Layers'of'the'Earth' Crust!–!20!miles!thick,!light!rock! Mantle!–!1800!miles!thick,!molten!heavy!rocks.! Core!–!2200!miles!thick,!molten!heavy!metals!(Iron!and!Nickel)! ! 3'layers'of'the'Atmosphere'' Troposphere!–!0G7!miles,!most!of!the!air.! Stratosphere!–!7G45!miles,!very!cold!and!thin!air.!Contains!OGZone!Layer! Ionosphere!–!45G200!miles.!Acts!like!a!mirror!for!radio!waves! ! MoonG!average!distance!to!moon!is!237,000!miles! o! ApogeeG!farthest!the!moon!is!away!(summer)! o! PerigeeG!closest!moon!is!to!Earth!(winter)! Phases! •! Full!moon! •! Quarter!moon! •! New!moon! •! Complete!set!takes!29!½!days!called!the!Synodic!Month! Sidereal!MonthG!27!days,!7!hrs,!42!mins,!11!½!seconds! TidesG!as!the!Earth!rotates,!the!shoreline!moves!into!bulge!(tide)! Harvest!MoonGthe!full!moon!that!is!seen!nearest!to!the!time!of!the!autumnal!equinox! ! Origin'of'Moon' •! Spin!Off!TheoryG!Earth!was!spinning!faster!and!some!material!came!off! forming!moon! •! Big!Impact!TheoryG!mostly!accepted!today7!asteroid!hit!Earth!and!took!chunk! off!making!moon! •! Capture!TheoryG!moon!was!a!large!rock!and!was!captured!by!the!Earth’s! gravity! •! Formed!with!Earth!TheoryG!moon!was!formed!out!of!same!composition!as! Earth! Origin'of'Craters'' •! Most!are!on!back!side!of!moon!

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•! Acts!as!a!shield! ! ! ! ! ! Planets' Mercury!–!Craters!come!from!asteroids!and!volcanoes.!Very!hot,!no!water.! Venus!–!Very!thick!atmosphere!that!holds!in!heat.!Rotates!east!to!west!which!is! opposite!of!all!other!planets.!Brightest!object!in!the!sky!not!counting!the!sun!or!the! moon! Earth!–!Only!planet!that!can!sustain!life.!Water!and!vegetation.! Mars!–!RedGbrown!soil!due!to!Iron!in!soil!that!turned!to!rust.!Used!to!have!water!that! carved!out!canyons!and!riverbeds.! Jupiter!–!Mainly!a!gas!planet!with!cloud!belts!of!hydrogen!and!helium.!Gives!off! more!heat!and!light!than!it!receives!from!the!Sun.!Rotates!in!less!than!10!hours.! Jupiter!has!16+!moons,!4!of!which!are!large.! Saturn!–!Bulges!because!it!rotates!in!less!than!10!hours.!Rings!made!of!small!rocks! covered!with!ice.!Density!so!low!that!the!planet!could!float.!Has!20+!moons,!one!of! which!(Titan)!has!its!own!atmosphere.! Uranus!–!Covered!with!blueGgreen!methane!atmosphere.!Axis!is!tilted!90!degrees.! Takes!84!years!to!go!around!the!sun.!Creates!42!years!of!day!and!42!hours!of!night.! Neptune!–!Like!Uranus,!Neptune!is!covered!with!a!blueGgreen!atmosphere.!Neptune! has!clouds!of!methane!droplets.!Had!a!large!dark!spot!but!it!disappeared!a!few! months!ago.! My!Very!Educated!Mother!Just!Served!Us!Nine!Pizzas!(order!of!planets:! M,V,E,M,J,S,U,N,P)! ! Origin'and'age'of'Solar'System' o! 4.5G5!billion!years!old' o! Nebula!HypothesisP!most!accepted7!planets!were!formed!from!the!same! material!that!formed!the!sun!about!5!billion!years!ago' o! Close!Encounter!TheoryG!planets!were!formed!from!material!pulled!out!of!the! sun!by!another!star!that!passed!by!the!sun' PlanetoidG!large!rock!often!the!size!of!a!state! AsteroidG!large!rock!up!to!several!miles!across! MeteroidG!small!rock!down!to!the!size!of!dust!particle!(micrometeroid)! Asteroid!BeltG!a!ring!of!asteroids!located!between!the!orbits!of!Mars!and!Jupiter! Meteor! o! Occasionally!a!meterorid/asteroid!will!collide!with!the!Earth!

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o! As!it!falls!through!the!atmosphere,!it!becomes!very!hot!(air!friction)! o! Starts!to!glow!and!will!leave!a!streak!of!light!in!nighttime!sky! o! Can!be!seen!every!10!minutes! MeteroiteG!meteor!that!struck!the!ground! Parseid!Meteor!ShowerG!takes!place!every!Aug.!10G12! Oort!CloudG!a!ring!of!large!rocks!covered!with!ice7!rock!will!fall!out!and!go!toward!the! sun7!ice!melts!and!leaves!a!cloud!of!dust/ice…forming!a!Comet! ! Light'of'Stars' o! Surface!of!a!star!will!change!to!lighter!colors!as!temp.!increases' •! O!=!Bright!Violet!White!30,000G60,000!Celsius' •! B!=!Bright!Blue!White!10,000G30,000!Celsius' •! A!=!Blue!White!7,500G10,000!Celsius' •! F!=!Green!White!6,000G7,500!Celsius' •! G!=!Yellow!5,000G6,000!Celsius' •! K!=!Orange!3,500G5,000!Celsius' •! M!=!Bright!Red!3,000!Celsius' •! R!=!Red!2,000!Celsius' •! N!=!Red!infared!1,200!Celsius' •! S!=!Infared!1,000!Celsius'

! •! Bohr!Theory!of!the!AtomG!electrons!go!around!atoms!much!the!same!way!as!the! planets!orbit!the!sun! •! When!electron!moves!from!inner!to!outer!shell!(orbit),!light!is!absorbed! •! When!electron!moves!from!outer!to!inner!shell,!light!is!produced! •! Continuous!SpectrumG!all!colors/frequencies!of!light!are!present! •! Emission!SpectrumGbrightly!colored!lines!over!a!faint!continuous!spectrum!in!the! background! •! Absorption!SpectrumG!a!spectrum!of!electromagnetic!radiation!transmitted!through!a! substance,!showing!dark!lines!or!bands!due!to!absorption!of!specific!wavelengths! •! HR!DiagramG!a!graph!made!around!1910!where!the!type!of!star!is!plotted!against!its! absolute!magnitude! •! Apparent!MagnitudeG!brightness!of!a!star!as!it!appears!from!your!backyard! •! Absolute!MagnitudeG!brightness!of!a!star!if!it!were!located!10!parsec!(32!light!years)! away!! •! Distance'to'Stars' o! Parallax!MethodG!used!to!tell!distance!to!close!stars!up!to!100!light!years!away! o! HR!DiagramGworks!for!all!stars!on!the!Main!Sequence!in!our!galaxy!

o! Cepheid!Variable!MethodG!for!every!10!days!it!takes!to!become!bright,!the!star! becomes!2!magnitudes!brighter7!tell!distances!to!nearby!galaxies! o! Doppler!Effect!MethodG!the!faster!a!galaxy!is!moving,!the!farther!it!is!away7!used!to! tell!speed!of!galaxy! ! •! Hubble’s!ConstantG!every!30!miles/sec!the!galaxy!is!moving,!it!moves!3!million!light! years!away! ! Nuclear'FissionG!works!by!creating!a!chain!reaction!that!breaks!apart!complex!atoms! •! Usually!Uranium!235!or!Plutonium! •! Produces!atom!bomb! •! Rapid!reaction! •! If!reaction!takes!place!slowly,!can!produce!energyG!nuclear!power!plant! ! Nuclear'FusionG!combines!simple!atoms!under!high!temps/pressure!to!make!more! complex!atoms! •! Usually!4!hydrogen!atoms!fused!together! •! Produces!Hydrogen!bomb! •! Our!sun!undergoes!Nuclear!Fusion! •! When!fused,!some!of!the!mass!of!the!4!hydrogen!atoms!is!converted!into!an! Xray7!equation!to!find!the!energy!of!Xray!is!E!=!MC^2! ' •! The'Sun' o! Diameter=!865,000!miles7!could!hold!1!million!Earths' o! Core!is!27!million!Celsius' o! Reversing!layerG!layer!of!gas!around!the!core!of!the!sun' •! Layers' 1)! PhotosphereG!outer!layer!of!sun7!' o! Temp!is!5,000G6,000!Celsius' o! Sun!spotsG!strong!magnets!that!block!light!and!thus!appear!as!dark7!come! in!11!year!cycles' o! Solar!FlareG!magnetic!field!between!2!sun!spots7!can!heat!photosphere!to! over!1!million!degreesE'produces!nuclear!fusion!on!surface!of!sun' o! Solar!Wind!(Nothern!Lights)G!a!stream!of!particles!send!out!by!solar!flares! that!produce!auroras!when!they!reach!the!Earth' o! ProminencesG!large!clouds!of!hydrogen!gas!that!arch!up!from!the! photosphere' 2)! ChromosphereG!a!thin!layer!of!gas!above!the!sun’s!photosphere7!can!only!be! seen!during!an!eclipse!of!the!sun' o! CoronaG!extensions!of!the!chromosphere!on!either!side!of!the!sun'

' •! Birth'of'Stars' o! Compression!of!gas,!resulting!in!increase!in!temperature' •! Death'of'Stars' o! The!bigger!the!star!(higher!mass),!needs!more!light!to!combat!against! gravity' o! When!a!star!runs!out!of!fuel,!the!gravity!is!stronger!and!the!star!contracts' o! Builds!up!pressure,!causing!the!star!to!expand!rapidly!into!“red!giant”' o! Planetary!NebulaG!ring!of!gas!thrown!outward!from!the!red!giant' o! If'star'is'1.5'times'the'size'of'our'sun'or'less,!will!turn!into!red!giant,! then!white!dwarf,!then!black!dwarf' o! Electron!DegeneracyG!star!continues!to!contract!until!atoms!touch!each! other' o! If'1.5'times'or'more,!will!turn!into!red!giant!and!explode7!largest! explosion!in!universe!besides!Big!Bang!(Super!Nova!Type!II)' o! Crushes!center!of!supernova!and!temp!increases!to!1!trillion!degrees' o! After!explosion,!outer!part!of!star!is!blown!outward!creating!shock!waves! that!can!vibrate!clouds!of!hydrogen,!which!can!cause!these!clouds!to! contract!at!a!faster!rate!and!causing!new!stars!to!be!born!more!rapidly' o! If'3'times'or'more,!makes!a!black!hole!and!all!neutrons!are!pressed! together' o! After!death!of!star,!electrons!are!pushed!into!nucleus,!combine!with!the! protons!and!becomes!ball!of!neutrons!called!Neutron!Star.!These!can! spin!very!rapidly!and!are!also!called!Pulsar!Stars' •! Black'Hole' o! Exit!coneG!a!cone!extending!upward!from!a!developing!black!hole' o! PhotonsphereG!a!sphere!of!light!formed!around!a!developing!black!hole!9! miles!from!the!black!hole' o! Event!HorizonG!point!of!no!return!located!6!miles!from!black!hole7!will!reach! speed!of!light!if!you!“fall”!into!black!hole' ' •! 4!Variable!Stars' o! BinaryG!bright!star!that!has!a!dark!companion!star!revolving!around!it! (Algol)' o! Cepheid!VariableG!for!every!10!days!it!takes!to!change!brightness,!it!will! become!2!magnitudes!brighter' o! RR!LyraeG!can!become!bright/faint!within!12!hours' o! Mira!VariableG!takes!months/years!to!change!magnitude' ! •! Milky'Way'Galaxy'

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o! 100G200!billion!stars! o! Galactic!NucleusG!center!about!15!light!years!across7!many!stars!with! black!hole!in!center! o! Nuclear!BulgeG!cluster!of!stars!12,000!light!years!across! o! Spiral!ArmsG!chains!of!stars!that!come!out!like!arms!from!nuclear!bulge7! 100,000!light!years!across! o! We!live!in!a!spiral!arm!about!3/5!from!center! o! We!look!at!Sagittarius!when!we!are!looking!at!center! o! Milky!Way!Galaxy!rotates!once!every!250!million!years! o! We!move!about!140!miles/sec! o! In!“The!local!group”!of!galaxies!that!contains!2!large!spiral!galaxies!(Milky! Way!and!Andromeda!M31)!and!22!small!irregular!galaxies! ! Population!I!StarsG!young!stars!usually!found!in!the!arms!of!galaxies! Population!II!StarsG!older!stars!usually!formed!in!center!of!galaxies! Magellanic!CloudsG!clusters!of!stars!seen!in!southern!hemisphere!(one!small,! one!large)! ! Elliptical!Galaxies!(E0GE15)! Spiral!Galaxies!(Sa,!Sb,!Sc,!Sbc,!Sbb,!Scc,!etc.)! Irregular!GalaxiesG!gravity!hasn’t!“shaped”!it!yet! Peculiar/Seyfert!Galaxy!

! Galaxy!Evolution! •! Goes!from!Normal!Spiral!galaxy,!then!Elliptical!galaxy,!then!Barred!Spiral!Galaxy! ! Olber’s!ParadoxG!there!are!infinite!galaxies!in!an!empty!space! ! Cosmology' 1)! Big!BangG!explosion/creation!of!universe!that!occurred!13.7!billion!year!ago! 2)! Steady!State!TheoryG!the!universe!has!always!existed!and!will!continue!forever! and!is!not!changing7!bad!theoryG!universe!is!expanding!(changing)! 3)! Oscillating!TheoryG!theory!that!the!universe!goes!through!cycles!of! expansion/contraction! ! •! Dark!MatterG!matter!we!cannot!see! •! Dark!EnergyG!hypothetical7!known!as!the!“force”!that!is!pulling/pushing!universe! apart!when!it!should!be!contracting7!pulling!on!dark!matter!to!expand!the! universe7!! !

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