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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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