you will learn how stars are made. you will also learn how stars are your great – – – – –...
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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!
Hi, kids!
The Sun Song (rock version)
The Sun Song (classic 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
nebulaprotostar
When hydrogen fuses into helium, it gives off light (photons). This is why stars shine!
The pressure inside a protostar is so strong that hydrogen (H) fuses together to become helium (He)
H H
HH
He
Fusion happens billions of times every second inside a star
H H
HH
He
H H
HH
HeH H
HH
He
H H
HH
He
Stars shine because of nuclear fusion!
H H
HH
He
H H
HH
HeH H
HH
He
H H
HH
HeH H
HH
He
H H
He
H H
HH
He
H
H
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
This imaginary center is called
the “Barycenter”
Most stars have a “buddy star” – pairs of stars are called binary star systems
XHowever, you wouldn’t be here without
stars...
Every atom in your bodywas 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 SaganThe 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
He
He
C
4 helium atoms fuse into 1 oxygen atom
He
He
He
He
O
Eventually stars run out of their hydrogen fuel, from the center out
This star has no more hydrogen in its center – only in
its outer edge. This causes the star’s exterior to expand and cool.
This star is now a called a “Red Giant” – “cool” stars are red
Our sun will become a red giant in about 5 billion years
Oh no, the sun will blow up in
Start count down
157, 787, 999, 999, 999,
Stop count down
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)
Assume 365.25 days per yearDebug: in presentation mode, start countdown. Then escape from presentation mode. Then return to presentation mode. It will work
M
V
Mercury and Venus will be destroyed
Our sun is currently a
“Main Sequence” star – but will grow
into a Red Giant!
Help!
Is it getting hot in here or is it
just me?E
After all the fusion stops inside a red giant, the gases float away and only
the core remains
This core is called a “White Dwarf”
This leftover gas is called a “Planetary
Nebula”
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
Stars much larger than our
sun become enormous red
giants
Betelgeuse
click to zoom in
A super red giant has intense fusion in its core – and explodes into a
supernovaA 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…
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