Download The Life of Stars

Hi, kids!
You will learn how stars are made.
You will also learn how stars are your
great – great – great – great – great –
great – great –great –great – great – great
great – great – great – great –great –great
– great - great grandparents!
The Sun Song (classic version)
The Sun Song (rock version)
All stars are “born” in nebulae.
A nebula is an enormous cloud of
hydrogen and helium gas in space.
nebula
One of the “stars” in Orion
is actually a nebula
click to
zoom in
Another famous nebula:
The “Horsehead” nebula
Over time, the nebula’s own gravity
makes the nebula come together into
a ball, called a protostar
nebula
protostar
The pressure inside a protostar is
so strong that hydrogen (H) fuses
together to become helium (He)
H
H
He
H
H
When hydrogen
fuses into helium,
it gives off light
(photons). This is
why stars shine!
Fusion happens billions of times
every second inside a star
H
H
H
H
He
H
HHeH
H
HHe
He
H
H
H
H H
H
H
Stars shine because of nuclear fusion!
H
H
H
H
H H
He
HHeH
H
H
H
He
HH
H
H
He
He
H
H
He
H H
H
H
H
H H
He HH
He
Protostars look like this:
Eventually, protostars give off enough
light to be officially called stars
Don’t forget – a
star is just a big
ball of gas! Our
sun is just a big
ball of gas
Most stars have a “buddy star” – pairs
of stars are called binary star systems
This imaginary
center is called
the “Barycenter”
However, you
wouldn’t be
here without
stars...
X
Every atom in your body
was made by a star!
“The nitrogen in our DNA, the
calcium in our teeth, the iron in our
blood, and the carbon in our apple
pies were all made in the interior of
collapsing stars. We are made of
starstuff” – Carl Sagan
The atoms of everything in this
room, this town, and this planet
were created inside a star!
Stars make all the different elements:
3 helium atoms fuse into 1 carbon atom
He
C
He
He
4 helium atoms fuse into 1 oxygen atom
He
He
O
He
He
Thisrun
starout
is now
a
Eventually stars
of their
a “Red
Giant”
hydrogen fuel, called
from the
center
out–
“cool” stars are red
This star has no
more hydrogen in
its center – only in
its outer edge.
This causes the
star’s exterior to
expand and cool.
Our sun will become a red giant in
about 5 billion years
Oh no, the sun will blow up in
157, 787, 999, 999, 999, 958 seconds !
(2,629,800,000,000,000 minutes)
(43,830,000,000,000 hours)
(1,826,250,000,000 days)
(5,000,000,000 years)
Start count down
Stop count down
Assume 365.25 days per year
Debug: in presentation mode, start countdown. Then escape from presentation mode. Then return to presentation mode. It will work
Mercury and Venus will be destroyed
Is it getting hot
in here or is it
just me?
E
Help!
V
M
Our sun is
currently a
“Main
Sequence”
star – but
will grow
into a Red
Giant!
After all the fusion stops inside a red
giant, the gases float away and only
the
core
remains
This leftover gas is
called a “Planetary
Nebula”
This core is called
a “White Dwarf”
Example of a planetary nebula
Example of a planetary nebula
Example of a planetary nebula
Example of a planetary nebula
The White Dwarf is the burned out core
of the star – like a burnt piece of
charcoal
Eventually, white dwarfs fade to black
as they cool off
Stars smaller than our sun never
become red giants – they just fizzle out
into white dwarfs
Which eventually
burns out completely
into a Black Dwarf
Betelgeuse
Stars much
larger than our
sun become
enormous red
giants
click to
zoom in
A super red giant has intense fusion
in its core – and explodes into a
supernova
A supernova
can be brighter
than a million
stars!
Example of a Supernova
The last Supernova
we observed
without a telescope
was in 1604. It was
so bright you could
see it in the day
time!
The white dwarf inside a supernova
collapses into a neutron star
neutron star
A neutron
star inside
the Puppis
Supernova
You’ll learn
more about
neutron stars
soon…
Really big neutron stars collapse
into black holes
You’ll learn
more about
black holes
soon too…