Credit: Night Sky Network: http://nightsky.jpl.nasa.gov/download-view.cfm?Doc_ID=276

2. A hundred years ago, we believed we lived in a quiet, safe universe . . .

5. Supernova!

6. Where does the radiation come from? Gamma-rays Atomic Particles X-rays

7. Life of a Butterfly Butterfly Pupa Caterpillar Eggs

8. Life of a Butterfly

9. Life of a Sun-like Star Protostars White Dwarf Planetary Nebula Red Giant Sun-like Star Star-Forming Nebula

10. Life of a Massive Star Protostars Black Hole SUPERNOVA Red Supergiant Massive Star Star-Forming Nebula Neutron Star

11. SUPERNOVA! Click on image to activate movie

12. A special effect of a stellar explosion . . .

13. Gamma-Ray Burst (GRB)!

14. Is radiation from supernovae and GRB sources dangerous to Earth? How close would they have to be?

15. 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? Danger - Radioactive!

16. Death from Exploding Stars?! . Artist’s Conception of the Milky Way Galaxy 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? . Location of Solar System

19. How close would a Supernova have to be to be dangerous? . Supernova: within 30 light years Nearest Supernova Candidate: over 250 light years away! Location of Solar System

20. How close would a Gamma-Ray Burst (GRB) source have to be? . Location of Solar System

21. How close would a Gamma-Ray Burst (GRB) source have to be? . GRB Danger Zone: within 8,000 light years Location of Solar System

22. How close is the nearest Gamma-Ray Burst (GRB) source ? . Our galaxy is about 100,000 light years across Nearest detected GRB source: over a Billion light years away! GRB Danger Zone Location of Solar System

23. Earth’s Atmosphere & Magnetic Field Protect Earth from most high-energy radiation . . . But prevent us from detecting it here on Earth

24. The high view: getting a better look GLAST Swift Suzaku XMM-Newton (X-ray Multi-Mirror Mission) X-rays Gamma-rays

25. Life from Exploding Stars! Scientists have discovered that most of the heavy elements in the universe are dispersed from stars that go supernova. Oxygen

26. Life from Exploding Stars! Silicon

27. Life from Exploding Stars! Gold

28. Life from Exploding Stars! Iron

29. Life from Exploding Stars! Without supernovae to disperse elements made in stars, there would be no planets, no life as we know it!