Download - These are a few of my favorite things…
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These are a few of my favorite things…
Black Holes and stretched space
Eclipse Cruise 2009
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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)
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i was considering howwithin night's loosesack a star'snibbling in-fin-i-tes-i-mal-ly devoursdarkness thehungry starwhichwill e.-ventu-al-ly jigglethe bait ofdawn and be jerkedintoeternity. when over my head ashootingstarBurs(tinto a stale shrieklike an alarm-clock)
-- e.e. cummings
But what is a black hole REALLY?
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What happens at the event horizon?
Be careful where you cross (Euna Lee and Laura Ling, Korea, AP photo)
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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!
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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
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How we find black holes (and neutron stars): X-rays!
RossiX-Ray TimingExplorersatellite,launched 1995
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How do black holes emit X-rays?
Rotating gas disk with frictional heating
Artistic conception movie 1
Artistic conception movie 2
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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
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Prediction of gravitational waves from black hole merger
Centrella et al, 2008
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How to describe gravitational waves
Oscillating tides Stretching of space
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What causes the tides?Why are there two high tides daily?
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A good try, but wrong
Earth’s movement causes the oceans to slosh like water in a bathtub
Galileo Galilei, 1622
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Waving Space
Simulated drum headDan Russell, Kettering U.
Cross-section of space “fabric”outside a pair of orbiting black holes
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How to measure this stretching?
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Replace rings of particles by 4 swinging mirrors
Laser InterferometerWeiss and Drever, 1970s
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Global network of detectors
LIGO
LIGO
LISA
VIRGO
TAMA
GEO
AIGO
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LIGO: Laser Interferometer Gravitational-wave
Observatory
3030 km(±10 ms)
LA
WA
4 km
4 km
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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
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Ultimate success…New Instruments, New Field, the Unexpected…
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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)
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What causes the tides?Why are there two high tides daily?
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Gravity weakens with distance
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