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SUPERNOVA! What is a supernova? How dangerous are they to life on Earth? How would the universe be different without supernovae? 1 A hundred years ago, we believed we lived in a quiet, safe universe . . . 2 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 . . . 3 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 . . . 4 Supernova! 5 Where does the radiation come from? 6 Life of a Butterfly Caterpillar Eggs Pupa Butterfly 7 Life of a Butterfly 8 Life of a Sun-like Star Sun-like Star Protostars Red Giant Planetary Nebula Star-Forming Nebula White Dwarf 9 Life of a Massive Star Protostars Massive Star Red Supergiant Star-Forming Nebula SUPERNOVA Neutron Star Black Hole 10 SUPERNOVA! Click on image to activate movie 11 A special effect of a stellar explosion . . . 12 Gamma-Ray Burst (GRB)! 13 Is radiation from supernovae and GRB sources dangerous to Earth? How close would they have to be? 14 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? 15 Death from Exploding Stars?! . Artist’s Conception of the Milky Way Galaxy Location of Solar System 16 How close would a Supernova have to be? . Location of Solar System 17 How close would a Supernova have to be? . Location of Solar System 18 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! 19 How close would a Gamma-Ray Burst (GRB) source have to be? . Location of Solar System 20 How close would a Gamma-Ray Burst (GRB) source have to be? . GRB Danger Zone: within 8,000 light years Location of Solar System 21 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 22 Earth’s Atmosphere & Magnetic Field Protect Earth from most high-energy radiation . . . But prevent us from detecting it here on Earth 23 The high view: getting a better look XMM-Newton (X-ray Multi-Mirror Mission) Suzaku Swift GLAST 24 Life from Exploding Stars! Oxygen Scientists have discovered that most of the heavy elements in the universe are dispersed from stars that go supernova. 25 Life from Exploding Stars! Silicon 26 Life from Exploding Stars! Gold 27 Life from Exploding Stars! Iron 28 Life from Exploding Stars! Without supernovae to disperse elements made in stars, there would be no planets, no life as we know it! 29 So aren’t you glad we live in a universe where stars explode? Which stars? Orion’s stars likely to go supernova! 3030 31 What is a supernova? How dangerous are they to life on Earth? How would the universe be different without supernovae? 32
