tsdiscoveryi
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fortu
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Itwill
othaveaclear
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ewclassificatio
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owmadeupoftheeight“classicalpla
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umberofdwarfpla
etsTheclassicalpla
etsareMercuryVe
usEarthMarsJupiterSatur
Ura
usa
dNeptu
eThedebateoverPluto’sstatusstartedi
1992Aftera
adva
cedtelescopewasse
ti
tospaceastro
omersstartedtofi
dabeltofobjectswhichliesbeyo
dNeptu
eThebeltco
tai
s
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cludi
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ti
uedtheexploratio
scie
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tlydiscoveredatleast41dwarfpla
etsattheedgesofthesolarsystemThereareatleasttwoobjectsofasimilarsizetoPlutoItseemsthateve
iftheIAUhadkeptPluto’sstatusasapla
ettheclassicaltheoryof
i
epla
etsi
thesolarsystemwouldhavehadtobecha
gedbuttheotherwayarou
dMoredwarfpla
etsofasimilarsizetoPlutowouldjoi
thefamilyofpla
etsScie
tistswillprobablyfi
dma
ymoredwarfpla
ets347words
fGoodbyePluto
Pluto
olo
ger1_____totheclassicalpla
etfamily
Plutotur
edouttobeo
lya“dwarfpla
et”
Thefirst2___defi
itio
ofpla
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etmusthaveaclear
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I
4____PlutoisverysmallasaresultitisattractedbyNeptu
e’s5______whe
thetwopla
etsgetcloser
Accordi
gto
6_____a
dwarfpla
et
shouldhave
a
orbit
arou
dthe
Su

I

7____it
must
otbe
asatellite
Plutohaswidelybee
co
sideredapla
etfor8_____yearsThedebateoverPluto’sstatusstartedi
1992
9____a
adva
cedtelescopeastro
omersstartedtofi
doutabeltofobjectslyi
gbeyo
dNeptu
e10_____Plutoattheedgesofthesolarsystem
二，经典背诵
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M6U2TEXT2
预习导学
一1T2T
3T
4T
5T
二．课文阅读ADADr