Transcript Our Worlds, Other Worlds

SUPERNOVA!
What is a supernova?
How dangerous are they to life on Earth?
How would the universe be different without
supernovae?
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A hundred years
ago, we believed
we lived in a quiet,
safe universe . . .
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Today we know the
universe is filled with
powerful cosmic
radiation our eyes
cannot see:
• Gamma-rays
• X-Rays
• Fast-moving atomic
particles (“Cosmic Rays”)
Much of which originates from monstrous black
holes in the centers of galaxies and from . . .
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Today we know the
universe is filled with
powerful cosmic
radiation our eyes
cannot see:
• Gamma-rays
• X-Rays
• Fast-moving atomic
particles (“Cosmic Rays”)
. . . neutron stars with powerful magnetic fields and
more commonly from . . .
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Supernova!
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Where does the radiation
come from?
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Life of a Butterfly
Caterpillar
Eggs
Pupa
Butterfly
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Life of a Butterfly
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Life of a Sun-like Star
Sun-like Star
Protostars
Red Giant
Planetary
Nebula
Star-Forming
Nebula
White Dwarf
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Life of a Massive Star
Protostars
Massive Star
Red
Supergiant
Star-Forming
Nebula
SUPERNOVA
Neutron Star
Black Hole
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SUPERNOVA!
Click on image to activate movie
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A special effect of
a stellar explosion . . .
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Gamma-Ray Burst (GRB)!
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Is radiation from supernovae
and GRB sources
dangerous to Earth?
How close would they have to be?
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Radiation on Earth
Radioactive sources emit
gamma-rays.
If we are too close to a
radioactive source, like a
chunk of uranium, we
cannot see the radiation,
but it is still harmful to us!
So how far should Earth
be from cosmic radiation
sources to be safe?
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Death from Exploding Stars?!
.
Artist’s
Conception
of the Milky
Way Galaxy
Location of Solar
System
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How close would a Supernova
have to be?
.
Location of Solar
System
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How close would a Supernova
have to be?
.
Location of Solar
System
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How close would a Supernova
have to be to be dangerous?
.
Supernova:
within 30 light
years
Location of Solar
System
Nearest Supernova
Candidate: over 250
light years away!
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How close would a
Gamma-Ray Burst (GRB)
source have to be?
.
Location of Solar
System
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How close would a
Gamma-Ray Burst (GRB)
source have to be?
.
GRB Danger Zone:
within 8,000 light years
Location of Solar
System
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How close is the nearest
Gamma-Ray Burst (GRB) source ?
Nearest detected GRB source:
over a Billion light years away!
.
Our galaxy is about 100,000 light years across
GRB
Danger
Zone
Location of Solar
System
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Earth’s Atmosphere & Magnetic Field
Protect Earth from most high-energy
radiation . . .
But prevent us from detecting it here on Earth
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The high view: getting a better look
XMM-Newton
(X-ray Multi-Mirror Mission)
Suzaku
Swift
GLAST
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Life from Exploding Stars!
Oxygen
Scientists have discovered
that most of the heavy
elements in the universe
are dispersed from stars
that go supernova.
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Life from Exploding Stars!
Silicon
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Life from Exploding Stars!
Gold
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Life from Exploding Stars!
Iron
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Life from Exploding Stars!
Without supernovae
to disperse elements
made in stars, there
would be no planets,
no life as we know it!
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So aren’t you
glad we live in a
universe where
stars explode?
Which stars?
Orion’s stars likely to
go supernova!
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What is a supernova?
How dangerous are they to life on Earth?
How would the universe be different without
supernovae?
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