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TEACHER
RESOURCE
PLANETARIUM
STARDOME OBSERVATORY & TIES ON...
TIVI
FACTS, RESOURCES AND AC
STARS
HOLES, NEUTRON
PART 2 - BLACKIT
ARFS
STARS AND WH E DW
ond part of
isiting the stars in the sec
In this resource, we’re rev
You can find
r.
sta
a
of
cle
ut the life-cy
our star series to learn abo
part one here.
of hydrogen into
verts 700 million tonnes
Every second the Sun con
c2, we can
E=m
n
atio
ium. Using the equ
695 million tonnes of hel
tonnes of energy
st expel about 5 million
calculate that the Sun mu
the energy
to
Sun
ing the size of the
every second! By compar
ut halfway
abo
y
onl
is
it
ted
ula
have calc
it emits, astrophysicists
Sun starts
the
en
wh
rs,
another 5 billion yea
through its lifecycle. In
nt. As the helium
gia
red
a
into
w
gro
will
l, it
running out of nuclear fue
ses where the outer
will undergo thermal pul
core burns out, the Sun
and the core of the
ing a planetary nebula,
layers will spread out, form
size of Earth).
the
out
(ab
white dwarf star
Sun will become a dense
rs, but the
yea
of
disperse over thousands
universe.
The planetary nebula will
the
in
of
w
kno
we
ger than anything
white dwarf will last lon
can continue
times larger than the Sun
Stars that are about ten
y reach iron.
the
il
unt
way
the
elements all
nuclear fusion, creating
the pressure
e
anc
bal
the star can no longer
the star
This is the point where
and
d,
war
out
ng
iati
rad
of energy
of gravity with the force
ire
ent
the
in
– the largest explosion
explodes in a supernova
nts heavier
rks the creation of eleme
spa
on
losi
exp
universe. The
supernovae
are
rs
outer layers of these sta
than iron. The expelled
neutron stars
into
n
dow
se
lap
col
stars can
remnants. The core of the
or black holes.
stars but contain
smaller than white dwarf
Neutron stars are even
massive star.
re
mo
a
e they form from
much more mass becaus
ual
ivid
ind
e
forc
rs
sta
se
the
of
The pressure in the core
ns to
ctro
ele
e
fus
themselves and
atoms to collapse in on
ns to
ctro
ele
no
h
wit
and
ns,
tro
protons. This creates neu
into
trons squeeze together
force atoms apart, the neu
m
ntu
me
mo
r
ula
ang
s,
ink
shr
a dense ball. As the star
to
ses
rea
inc
r
ation of the sta
is conserved, and the rot
.
ond
sec
per
hundreds of revolutions
mic
gets to a point where ato
r
sta
the
of
sity
If the den
gravity
er,
eth
tog
ser
clo
any
structures cannot get
rity with
es. This creates a singula
overwhelms all other forc
Gravity
e.
hol
ck
core becomes a bla
infinite density, and the
than
er
fast
e
hol
ck
bla
a
of
core
is pulling objects into the
led
pul
s
get
re, anything that
the speed of light. Therefo
what is called the event
from
ble
visi
be
to
se
in will cea
escape, not even light.
can
g
hin
not
horizon. From there
e is no stronger than
hol
a black
However, the gravity of
the same
l star. A black hole with
the gravity of the origina
rble, but
ma
of
size
the
ut
be abo
mass as the Earth would
Earth.
ire
ent
tional pull as the
still have the same gravita
SCIEN
CONTE CE
NT/
CURRIC
ULUM L
ASTRON
INK
O
MIC
PHYSIC AL SYSTEMS,
AND PH AL INQUIRY
YSICS C
THE STR ONCEPTS,
UCT
OF MAT URE
TER.
Sagittarius A* is the black hole at the centre of
the Milky Way galaxy. Credits: NASA/UMass/
D.Wang et al., IR: NASA/STScI
Black holes are invisible
because nothing, not
even light can escape.
Credit: NASA and the Night Sky Network
Check out these other resources...
Wikipedia – Stellar Evolution: https://en.wikipedia.org/wiki/Stellar_evolution
HubbleSite Black Holes: http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q3.html
DISCUSSION
POINT
What types of telescopes have
observed black holes, and what
behaviour of matter has been observed
to conclude a black hole may be nearby?
STARDOME.ORG.NZ
09 624 1246
ACTIVITY
PLANETARIUM
STARDOME OBSERVATORY &
F
O
S
E
G
A
T
S
THE FINALEVOLUTION
STELLAR
You’ll need...
Objective...
on and some
life with a ballo
’s
ar
st
a
of
d
en
discover for
To simulate the
ity students will
tiv
ac
is
th
t effect
In
il.
work, and wha
aluminium fo
transformations
e
es
star.
th
t
w
an
ho
illi
s
br
themselve
the once
itational pull of
av
gr
e
th
on
ve
they ha
aluminium
foil
balloons
pump
scales
tape
measures
Instructions...
 BLACK HOLE
MASSIVE STAR
it
star) and cover
lloon fully (the
ar).
st
e
th
of
• Blow up a ba
s
er
lay
il (the outer
fo
m
iu
in
m
alu
with
e scale
al mass using th
ecord the initi
•R
using the
”
ar
st
he
“t
nce of
and circumfere
tape measure.
e
ar by having th
llapse of the st
.
ps
imulate the co
po
•S
it
til
e the balloon un
students squeez
ts of foil to
ee
sh
re
e of the squa
m
eze
so
r
fo
w
llo
A
•
”, but then sque
the “supernova
til
un
on
llo
ba
“explode” off in
ed
ound the popp
ar
il
fo
g
in
ain
m
the re
here.
it is a dense sp
rence.
s and circumfe
ecord the mas
and
•R
ar ” from before 3
st
nsity of “the
de
e
r,
th
e
)π
at
/3
ul
(4
alc
•C
, volume=
e (density=m/v
after the collaps
rence/2π).
r
radius=circumfe
nt that no matte
ould be appare
sh
it
e,
re
tim
is
he
th
sp
y
•B
to their
sure they add on
ill
how much pres
itational pull, w
av
gr
e
or
ef
and ther
that the mass,
ly the density.
not increase, on
rizon using
e of the event ho
t
alculate the siz
•C
2
ius of the even
2GM/c (R=rad
al
rs
ive
un
the equation: R=
G=
,
le
s of the black ho
-2
d
-8 cm3 g-1 s , c=spee
horizon, M=mas
nstant 6.67x10
co
l
na
tio
ita
av
gr
10
/sec).
e
of light 3x10 cm
it would becom
ams, the radius-27
gr
30
is
s
e
as
th
m
d
(If the
x 10 cm, an
uld be about 479
3
a black hole wo
g/cm ).
10
x
be about 9
density would
eum of Nature
the Denver Mus
Adapted from
ator Guide.
ack Holes Educ
and Science Bl
1
2
3
send it to us.
d
an
ity
tiv
ac
ur
yo
of
o
ot
ph
a
ke
Ta
ardome.org.nz
We’d love to see it! education@st
STARDOME.ORG.NZ
09 624 1246