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SUPERNOVA!

What is a supernova?What is a supernova?

How dangerous are they to life on Earth?How dangerous are they to life on Earth?

How would the universe be different without How would the universe be different without supernovae?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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. . . neutron stars with powerful magnetic fields and more commonly from . . .

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”)

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Supernova!

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Where does the radiation come from?

Gamma-rays

Gamma-rays

Atomic Particles

Atomic Particles

X-raysX-rays

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Life of a Butterfly

Butterfly

Pupa

Caterpillar

Eggs

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Life of a Butterfly

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Life of a Sun-like Star

Protostars

White Dwarf

Planetary Nebula

Red Giant

Sun-like Star

Star-Forming Nebula

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Life of a Massive Star

Protostars

Black Hole

SUPERNOVA

Red Supergiant

Massive Star

Star-Forming Nebula

Neutron Star

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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)!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?!

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Location of Solar SystemArtist’s

Conception of the Milky Way Galaxy

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How close would a Supernova have to be?

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Location of Solar System

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How close would a Supernova have to be?

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Location of Solar System

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How close would a Supernova have to be to be dangerous?

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Location of Solar System

Supernova: within 30 light years

Nearest Supernova Candidate: over 250 light years away!

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How close would a Gamma-Ray Burst (GRB)

source have to be?

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Location of Solar System

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Location of Solar System

GRB Danger Zone: within 8,000 light years

How close would a Gamma-Ray Burst (GRB)

source have to be?

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Location of Solar System

Our galaxy is about 100,000 light years across

Nearest detected GRB source: over a Billion light years away!

How close is the nearest Gamma-Ray Burst (GRB) source ?

GRB Danger

Zone

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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

GLAST

Swift

SuzakuXMM-Newton (X-ray Multi-Mirror Mission)

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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?What is a supernova?

How dangerous are they to life on Earth?How dangerous are they to life on Earth?

How would the universe be different without How would the universe be different without supernovae?supernovae?