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Chapter12

SpaceExploration

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p

Section12.1

page428Explaining the Early

UniverseGALAXY collection o! stars"

planets" gasan# #$st hel# together %ygravity

&E#'in ($%%le 'as the)rst astrono*er toi#enti!y othergalaxies %esi#esthe *il+y 'ay.

SOLAR

SYSTEM

GALAXY – Milky Way

UNIVERSE

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,eas$ring -istances in $r

Universe• /he #istance to *ost stars !ro* Earth are

*illions o! AUs there!ore0

&#istances 'ithin o$r Universe are*eas$re# in light

years

1 light year = distance lightwilltravel in 1 year

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($%%le s roposal

• E#'in ($%%le notice# that galaxies'ere not staying still %$t they 'ere

*oving a'ay !ro* each other3%ase# on re# shi!t analysis

• (e propose# that the Universe is

expan#ing" an# galaxies are*oving a'ay

!ro* each other•

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/(E 56ES 7 /(E 56G67 /(E

U 69E5SE

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/(E :6G :A G /(E 5Y

• Since there is evi#ence that o$rUniverse is Expan#ing" it *$st havestarte# so*e'here;

• <1=.> %illion years ago there 'as a*assive explosion an# very highte*perat$res < 1 %illion ?C 'erereache#

• 9ery 5api# Expansion o! a tiny vol$*e

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/(E SC6LLA/6 G

/(E 5Y• Closed Universe one that 'ill

expan# so !ar an# is then #ra'n

%ac+ %y gravitational !orces" all the*atter 'ill *eet again in a :igCr$nchB

– /his theory says the Universe goesthro$gh a series o! %angs an# cr$nchesin an ongoing cycle

– C$rrently still expan#ing !ro* the*ost recent explosion

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/(E 56ES 7 /(E 56G67 /(E S LA5

SYS/E,

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ST !!"# CO!!$S$O%

T& O#' • /his /heory says that $rSolar Syste* 'as create#!ro* the spin o!! o!colliding stars ;

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% (U!"#

&')OT& S$S%e*+lae,%e*+la- & clo$#s o!(y#rogen gas an# #$st%et'een stars

& hen p$lle# together %y gravity"stars !or* i! hot eno$gh& A near%y explo#ing star co$l# have

ca$se# a shoc+ 'ave 'hich starte#the process

&As the clo$# %egins to collapse itstarts to rotate

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&4.D %illion years ago" the S$n%eca*e an active star an# the

le!tover *aterial co*%ine# to!or* 8 planets" an# others*aller %o#ies s$ch as *oons"

asteroi#s" an# co*ets.& ot all the planets !or*e# atthe sa*e ti*e or in the sa*e

'ay the inner planets 'ere

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TASK

Read Section 12.1 in the textbookand answer the following questions:

p. ! "s 1#$#%#&#'#(#11#12.

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p. 4== 1. ($%%le notice# that all galaxies are*oving a'ay !ro* each other.

2. ($%%le propose# that the $niverse isexpan#ing in all #irections" an# that the galaxieshave ta+en the sa*e a*o$nt o! ti*e to reach

their present positions !ro* an original startingpoint.

4. /he scillating theory states that the $niverseis close# an# that there is eno$gh *atter in

the $niverse to slo' 3%eca$se o! gravity an#event$ally stop the expansion o! the

$niverse. Accor#ing to this theory" all *atter 'ill*eet again in a :ig Cr$nch.

D. Cos*ic %ac+gro$n# ra#iation is thera#iation le!t over !ro* the :ig :ang expansion.

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p. 4=@

1. /he ne%$lar hypothesis o! solar syste*!or*ation is that the S$n an# planets !or*e#'hen a large ne%$la con#ense# an# 'as

collecte# together %y gravity.

2. $r solar syste* !or*e# *ore than 4.D%illion years ago.

=. 6nner or terrestrial planets an# o$ter or Fovian planets.

4. /he #istances are too great to %e*eas$re# in astrono*ical $nits.

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Section12.2

Galaxies an#

StarsS)$#"! !!$)$T$C"!$r ,il+y ay Galaxy"

Earth is on a spiral ar*"'e see the center onit s si#e at night

So*e o! the ol#est an#largest galaxies areelliptical" *ore thenD H o! galaxies are thisshape

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hat is a starI

Stars are hot %o#ies o!glo'ing gas that vary in

siJe" *ass an# te*perat$re. /he color o! a star is#eter*ine# %y its

te*perat$re0 the hotteststars are %l$e an# thecoolest stars are re#.

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/(E E9 LU/6 7S/A5S/"#0 ST"#S $"%T

ST"#SS*all

:$rn !$el slo'ly K last along ti*e 31 %illion

years5e# #'ar!s event$allychange into very hot" %$ts*all" #i* 'hite #'ar!san# %$rn o$t.

Large" %$rn !$el$ic+ly" last a short

ti*e

5E- G6A /S slo'lyshrin+ into a 'hite#'ar! 'hich *ay coolinto a %lac+ #'ar!

5

SU E5 G6A /S

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/he Li!e o! a Star

Stage 1 stars are %orn in %e*+la an#con#ense into a large glo%$le o! gas an##$st that contracts $n#er its o'n gravity

Stage 2 /he con#ensing *atter %egins toheat $p an# glo' !or*ing )rotostars.

Stage = 6! there is eno$gh *atter thecentral

te*perat$re reaches 1D *illion #egreesan#

n$clear reactions start.

Sta e 40 /he star %e ins to release

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/he -eath o! a Star & hen a star starts to r$n o$t o! hy#rogen !$el

6 it %eco*es a red giant or a s+per giant .

& #ed giants gro' %igger an# !or* a clo$# o! gascalle# a planetary ne*+la . As it cools" it %eco*es

awhite dwar2 'hich 'ill event$ally r$n o$t o! !$el

an# #ie %eco*ing a *lack dwar2 .

&#ed s+per giants *ay s$##enly explo#e 'hichis calle# a s+pernova . A!ter this explosion"le!tover star *aterial *ay !or* a ne+tron star .

A!ter a large *ass star explo#es" a largea*o$nt o! *ass re*ains an# the gravity o! the*ass is soo strong that the gas is p$lle#in'ar#" #ecreasing its vol$*e. Event$ally"the gravity is soo strong that nothing canescape" incl$#ing light. /he *assive star then

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(!"C3 &O!• Sphere o! extre*ely #ense

*aterial 'ith a gravitationalp$ll so strong not even lightcan pass o$t o! it;

• Create# 'hen a SU E5G6A / star collapses in onitsel!

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4U"S"#• 5egion o! extre*ely high

energy 'hich #evelopsaro$n# a s$per*assive %lac+hole as *atter is attracte#intoitsel!

• /his energy*a+es the* the%rightest o%Mects

in the $niverse.

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/he 7$t$re o! Space

Exploration

Careers5elate# to

Space

Engineer

Astrona$t

-octor

Scientist

ilots /echnici

ans

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