Galaxies Big Banged

8/20/2019 Galaxies Big Banged

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Galaxies and the Universe



What Are Galaxies?

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

the Sn sli!htl" #$%center



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"



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



Galaxies and Gl#+lar'lsters



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



4he -ilk" Wa" As We See6t



Anat#m" # a Galax"



S)iral Arms



6n -icr#waves, We 'an See

the H+ # the Galax"



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



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



-a))in!the

Galax":*#t 4here

et



-a))in! the

Galax":*#t 4here

et



4he#calGr#

)



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



4he#cal

S)er%

clster



4he'#ma

'lster3;0

m<l<"<



ar!e%ScaleStrctre

# theUniverse

t# ;00m<l<"<



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• -=10D k!, v = 3 x 107 msec

• > = 1/ x 10D x & x 101B = B<; x 10/0 E#les

• >Fals U<S< >ner!" r#dcti#n #r B<; "ears

• nce "# !et there, "# have t# stop.





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



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





.el >c#n#m" # a Starshi)•

At 0<1 c, ener!" is 0<7@ !reater than*ewt#nian #rmla

• At 0<; c, /B@ !reater

•

At 0<& c, 3 x !reater• At 0<&& c, 1/ x !reater

• At 0<&&& c, B3 x !reater

•

>ach extra & m#re than tri)les the ener!"• Gettin! #r 1000 t#n shi) t# 0<& c takes

1<1 x 10/3 E#les = U<S< ener!" se #r1100 "ears



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

enses



What 9#es 4he Universe ##kike?



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



(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; +<"<

• (2i! 2an! #ri!inall" a derisive term,

c#ined +" .red H#"le



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

4elesc#)e



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



&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



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



.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



.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



.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 had t# 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?



-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!



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



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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