galaxies big bang

7/25/2019 Galaxies Big Bang

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Galaxies and the Universe


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What Are Galaxies?

Greek galax= milk William Herschel, 1783: A disk with

the Sn sli!htl" #$%center


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What Are Galaxies?

1&th 'entr": (S)iral *e+lae

*ear+"? -a"+e S#lar S"stems in

.#rmati#n? 1&/0: Galaxies are Stars

1&/0s: Galaxies are like the -ilk" Wa"

2i!!est sin!le increase in #r mental)ictre # the Universe in hmanhist#r"


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Where Are We in #r

Galax"? 4he visi+le -ilk"

Wa" s!!ests #r

!alax" is a 5atdisk

Srr#ndin!#ther !alaxies is

a s)herical hal## Globular StarClusters


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4he -ilk" Wa"s Gl#+lar'lsters


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4he -ilk" Wa" As We See6t


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Anat#m" # a Galax"


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S)iral Arms


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6n -icr#waves, We 'an See

the H+ # the Galax"


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-a))in! the*ei!h+#rh##d


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-a))in! the *ei!h+#rh##d


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-a))in! the

Galax":*#t4here

et


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4he#calGr#

)


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9#wnt#wn: 4he ir!# 'lster:;0 m


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4he#cal

S)er%

clster


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4he'#ma

'lster3;0

m


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ar!e%ScaleStrctre

# theUniverse

t# ;00m


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4ravel t# the Stars?

inetic >ner!" = 1/ -v/

What d#es it take t# !et a 1000%t#ns)aceshi) t# 10@ # the s)eed # li!ht? B3

"ears t# Al)ha 'entariC -=10Dk!, v = 3 x 107msec

> = 1/ x 10Dx & x 101B= BFals Uner!" r#dcti#n #r B


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Ielativit"

S)eed # i!ht is 6nde)endent # S#rce -ichels#n and -#rle", 1887 % S)eed #

i!ht 6nde)endent # Observer

(ne # the -#st Unex)ected Ieslts in

the Hist#r" # Science % 6saac Asim#v '#nclsi#n: S)eed # i!ht is the Same

for All Observers

6m)licati#n: S)ace and 4ime -st'han!e t# ee) S)eed # i!ht'#nstant


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Wh" the S)eed # i!ht is aS)eed imit

>ner!" # a -#vin! +Eect inIelativit":

> = mc/ --------------------- ---------------------- ---------------------- -------------- 1 % v/c/

ne c#nseFence: as v a))r#achesc, >ner!" !#es t# innity

Als#, as we a))r#ach c, >ner!" !#es) very fast


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.el >c#n#m" # a Starshi)

At 0


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An#ther '#nseFence #Ielativit"% Gravitati#nal

enses


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What 9#es 4he Universe ##kike?


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What 9#es 4he Universe##k ike?


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(4he 2i! 2an!

>dwin H++le, Iecessi#n # Galaxies,1&/&

Ied%shit increases with distance

'#smic -icr#wave 2ack!r#nd, 1&D; >stimated A!e # Universe: 1/%1; +


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As .ar t as We 'an See %Ten DaysWith the H++le

4elesc#)e


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A *ew *ame #r the (2i!2an!?

Sky and Telesope, 1&&;C 4he 2i! 2##t

G#ds #!%n

.red Withair 9a" (*#+#d" evernamed an"thin! else ater me, s#wh" n#t?C

What Ha))ens 6 6 sh 4his 2tt#n? #re *ever G#in! 4# Get 6t All 2ack

6n 4here A!ain


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&0@ # the Universe is(-issin!

ter Stars in Galaxies rev#lveaster than ex)ected

What h#lds clsters # !alaxiest#!ether?

'#nclsi#n: 4here mst +e a lot#invisi+le mass in the Universe

*#t reall" (missin!, Est n#n%lmin#s


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Astr#n#mers Are *#t As U)setAs ne -i!ht >x)ect

-A'Hs -assive '#m)act Hal#+EectsC: aint stars, +r#wn dwars,

)lanets '##l n#n%lmin#s !as

-assive *etrin#s?

W6-s Weakl" 6nteractin! -assivearticlesC

-a!netic m#n#)#les

>x#tic #+Eects: strin!s, mini%+lack h#les


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.ine 4nin! the Universe 9ensit"

-ch !reater and the Universe w#ldalread" have c#lla)sed in #n itsel

-ch less and stars c#ld n#t have #rmed

*clear .#rces .si#n im)#ssi+le

.si#n t## eas"

Anthr#)ic rinci)le '#sm#l#!" has t# +e a+le t# ex)lain wh"

we exist


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.ine 4nin! the Universe

6t Est came #t that wa" 6t has t# +e that wa" #r reas#ns we

havent "et disc#vered

-a"+e there are an inJnit" #niverses +t #nl" th#se with certain)arameters devel#) intelli!ent lie

-ltiverseC >n!ineered #r desi!ned


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.ine 4nin! the Universe

9esi!ner? 9#esnt >x)lain An"thin!

6 the 9esi!ner can create a Universe, wh"

is c = 300,000 kmsec instead # B00,000? 6 9esi!ner hadt# have c = 300,000

kmsec, wh"? What wh#?C dictated that,and wh"?

Wh# sa"s 9esi!ner is an"thin! )ictred +"an" reli!i#n?


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-isinter)retin! Ielativit"

4here are n# a+s#ltes S)eed # li!ht is a+s#lte

6t ma" n#t +e )#ssi+le t# +e a+s#ltel"

ri!ht +t it is ver" eas" t# +e a+s#ltel"wr#n!


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Where Will 6t All >nd?

4rilli#ns # "ears: Star #rmati#n ends

10%100 trilli#n "ears: Stars st#)radiatin!

101;K 10/0"ears: lanetar" #r+its deca"

103/K 10B1"ears: r#t#ns deca"?

Heat 9eath?

2i! 'rnch?

2i! 2#nce?

Wh t 9 ' l 6 l


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What 9#es '#sm#l#!" 6m)l" #rhil#s#)h"?

*#thin!

At east, *#t et

6t 6s H#)elessl" rematre 4# 4r" 4# 'reateA hil#s#)h" 2ased #n '#sm#l#!"

We can sa" what the ate # the Universe will+e +ased #n s)eciJc assm)ti#ns

We are a l#n! wa" r#m kn#win! theassm)ti#ns are c#m)lete #r c#rrect

6 "# s))#rt "#r )hil#s#)h" withscience, +e )re)ared #r science t# )r#veit wr#n!


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