1. 1 These are a few of my favorite things… Black Holes and stretched space Eclipse Cruise 2009

2. 2 What is a black hole? A massive spacetime curvature singularity, Surrounded by an event horizon (a point or ring of infinite density and tidal acceleration) (a spacetime boundary between causally disconnected regions of the universe)

3. 3 i was considering how within night's loose sack a star's nibbling in- fin -i- tes- i -mal- ly devours darkness the hungry star which will e. -ven tu- al -ly jiggle the bait of dawn and be jerked into eternity. when over my head a shooting star Burs (t into a stale shriek like an alarm-clock) -- e.e. cummings But what is a black hole REALLY?

4. 4 What happens at the event horizon? Be careful where you cross (Euna Lee and Laura Ling, Korea, AP photo)

5. 5 Can matter escape from a BH? Quantum tunneling produces a Particle-Antiparticle pair from the vacuum! http://superstringtheory.com/blackh/blackh3.html Only by dissolving into Hawking radiation!

6. 6 Black holes in Nature The afterlife of giant stars Black hole masses 3-15 solar masses Giant sinkholes in galaxy centers Black hole masses million to billion solar masses

7. 7 How we find black holes (and neutron stars): X-rays! Rossi X-Ray Timing Explorer satellite, launched 1995

8. 8 How do black holes emit X-rays? Rotating gas disk with frictional heating Artistic conception movie 1 Artistic conception movie 2

9. 9 How can we prove these are the BH of Einstein’s theory? Measure the gravitational waves emitted as two black holes merge. Artistic conception 3

10. 10 Prediction of gravitational waves from black hole merger Centrella et al, 2008

11. 11 How to describe gravitational waves Oscillating tides Stretching of space

12. 12 What causes the tides? Why are there two high tides daily?

13. 13 A good try, but wrong Earth’s movement causes the oceans to slosh like water in a bathtub Galileo Galilei, 1622

14. 14 Waving Space Simulated drum head Dan Russell, Kettering U. Cross-section of space “fabric” outside a pair of orbiting black holes

15. 15 How to measure this stretching?

16. 16 Replace rings of particles by 4 swinging mirrors Laser Interferometer Weiss and Drever, 1970s

17. 17 Global network of detectors LIGO LISA VIRGO TAMA GEO AIGO

18. 18 LIGO: Laser Interferometer Gravitational-wave Observatory LA WA 4 km

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20. 20 Why so complicated? Must measure changes in mirror positions to within 1/1000 diameter of a proton! LIGO has succeeded in reaching this goal – and now has to observe patiently for gravitational waves. When will they discover gravitational waves? EB prediction: 2014 or sooner

21. 21 Ultimate success… New Instruments, New Field, the Unexpected…

22. 22 Additional Credits and Information Credits: Rossi X-Ray Timing Explorer figure courtesy NASA/Goddard Space Flight Center LIGO and other gravitational wave images courtesy Nergis Mavalvala Books: The Fabric of the Cosmos, Brian Greene The Elegant Universe, Brian Greene Black Holes and Time Warps: Einstein’s Outrageous Legacy, Kip S. Thorne (more advanced)

23. 23 What causes the tides? Why are there two high tides daily?

24. 24 Gravity weakens with distance

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