LIGO-G W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Listening in on Einstein’s Unfinished Symphony Fred Raab, LIGO Hanford Observatory

LIGO-G W Tuning into Einstein's Unfinished Symphony2 Einstein’s Legacy in Science Annus mirabilis, 1905 »Special Relativity: 1 st installment on a theory of space and time »Theory of Brownian Motion: ends debate on the existence of atoms »Quantum Theory of Light: cornerstone of quantum mechanics »Equivalence of matter and energy: E=mc 2 Opus Magnus: The General Theory of Relativity, 1916 A new form of matter: Bose-Einstein Particles Questioning the reality of Quantum Mechanics »Einstein-Podalsky-Rosen Paradox & hidden variables Unfinished work: »Search for a unified “Theory of Everything” »Detection of Gravitational Waves

LIGO-G W Tuning into Einstein's Unfinished Symphony3 The Essence of General Relativity Space and time are things, not concepts »1905 – Relativity refers to the “relative” interpretations of space and time by moving observers; only the speed of light is not relative »Energy and matter are equivalent and transformable into each other (E=mc 2 ) »1916 – General Theory of Relativity - Space and time affect the motion of objects and objects warp space and time; gravity is the natural movement of stuff flowing through warped space and time. »1919 – Space warp caused by the sun is detected »1950’s and onward– Atomic timekeeping devices reveal time warps Gravity and the speed of light are physical properties of empty space!

LIGO-G W Tuning into Einstein's Unfinished Symphony4 General Relativity: A Picture Worth a Thousand Words

LIGO-G W Tuning into Einstein's Unfinished Symphony5 Mass Warps Space, Affecting Paths of Objects and Light l Presence of mass gives space the appearance of lumpy glass as evidenced by the bending of light l First observed during the solar eclipse of 1919 by Sir Arthur Eddington, when the Sun was silhouetted against the Hyades star cluster A massive object shifts apparent position of a star Einstein Cross Photo credit: NASA and ESA

LIGO-G W Tuning into Einstein's Unfinished Symphony6 The Frontier of Relativity: Gravitational Waves Gravitational waves are ripples in space when it is stirred up by rapid motions of large concentrations of matter or energy Rendering of space stirred by two orbiting black holes:

LIGO-G W Einstein Died Believing Gravitational Waves Would Never Be Detected Never say never…

LIGO-G W Tuning into Einstein's Unfinished Symphony8 Spacetime is Stiff! => Wave can carry huge energy with miniscule amplitude! h ~ (G/c 4 ) (E NS /r)

LIGO-G W Tuning into Einstein's Unfinished Symphony9 Gravitational Collapse and Its Outcomes Present Opportunities f GW > few Hz accessible from earth f GW < several kHz interesting for compact objects

LIGO-G W Tuning into Einstein's Unfinished Symphony10 Supernova: Death of a Massive Star Spacequake should preceed optical display by ½ day Leaves behind compact stellar core, e.g., neutron star, black hole Strength of waves depends on asymmetry in collapse Observed neutron star motions indicate some asymmetry present Simulations do not succeed from initiation to explosions Credit: Dana Berry, NASA

LIGO-G W Tuning into Einstein's Unfinished Symphony11 Gravitational Waves From Orbiting Black Holes and Neutron Stars Sketches courtesy of Kip Thorne

LIGO-G W Tuning into Einstein's Unfinished Symphony12 Emission of Energy by Gravitational Waves Has Been Observed Neutron Binary System – Hulse & Taylor PSR Timing of pulsars   17 / sec Neutron Binary System separated by 10 6 miles m 1 = 1.4m  ; m 2 = 1.36m  ;  = Prediction from general relativity spiral in by 3 mm/orbit rate of change orbital period ~ 8 hr Emission of gravitational waves Hulse, Taylor receive Nobel Prize

LIGO-G W Tuning into Einstein's Unfinished Symphony13 Why go beyond light? Because of where light cannot go. Images of light from Big Bang imply 95% of the universe is composed of dark matter and dark energy. What is this stuff? What was it like at the birth of space and time? WMAP Image of Relic Light from Big Bang First light from the universe

LIGO-G W How can we detect spacetime vibrations? Leonardo da Vinci’s Vitruvian man

LIGO-G W Tuning into Einstein's Unfinished Symphony15 Basic Signature of Gravitational Waves

LIGO-G W Tuning into Einstein's Unfinished Symphony16 Laser Beam Splitter End Mirror Screen Viewing Sketch of a Michelson Interferometer

LIGO-G W Tuning into Einstein's Unfinished Symphony17 New Generation of “Free- Mass” Detectors Now Online suspended mirrors mark inertial frames antisymmetric port carries GW signal Symmetric port carries common-mode info Intrinsically broad band and size-limited by speed of light.

LIGO-G W Tuning into Einstein's Unfinished Symphony18 LIGO (Washington)LIGO (Louisiana) The Laser Interferometer Gravitational-Wave Observatory Brought to you by the National Science Foundation; operated by Caltech and MIT; the research focus for more than 500 LIGO Scientific Collaboration members worldwide.

The LIGO Observatories Adapted from “The Blue Marble: Land Surface, Ocean Color and Sea Ice” at visibleearth.nasa.gov NASA Goddard Space Flight Center Image by Reto Stöckli (land surface, shallow water, clouds). Enhancements by Robert Simmon (ocean color, compositing, 3D globes, animation). Data and technical support: MODIS Land Group; MODIS Science Data Support Team; MODIS Atmosphere Group; MODIS Ocean Group Additional data: USGS EROS Data Center (topography); USGS Terrestrial Remote Sensing Flagstaff Field Center (Antarctica); Defense Meteorological Satellite Program (city lights). LIGO Hanford Observatory (LHO) H1 : 4 km arms H2 : 2 km arms LIGO Livingston Observatory (LLO) L1 : 4 km arms 10 ms

LIGO-G W Tuning into Einstein's Unfinished Symphony20 The International Interferometer Network LIGO Simultaneously detect signal (within msec) detection confidence locate the sources decompose the polarization of gravitational waves GEO Virgo TAMA AIGO

LIGO-G W Tuning into Einstein's Unfinished Symphony21 How Much Will the 4-km Mirror Separation Change? Wavelength of light, about 1 micron One meter, about 40 inches Human hair, about 100 microns LIGO sensitivity, meter Nuclear diameter, meter Atomic diameter, meter

LIGO-G W Tuning into Einstein's Unfinished Symphony22 Core Optics Suspension and Control Local sensors/actuators provide damping and control forces Mirror is balanced on 1/100 th inch diameter wire to 1/100 th degree of arc Optics suspended as simple pendulums

LIGO-G W Tuning into Einstein's Unfinished Symphony23 Vacuum Chambers Provide Quiet Homes for Mirrors View inside Corner Station Standing at vertex beam splitter

LIGO-G W Tuning into Einstein's Unfinished Symphony24 Vibration Isolation Systems »Reduce in-band seismic motion by orders of magnitude »Little or no attenuation below 10Hz »Large range actuation for initial alignment and drift compensation »Quiet actuation to correct for Earth tides and microseism at 0.15 Hz during observation HAM Chamber BSC Chamber

LIGO-G W Tuning into Einstein's Unfinished Symphony25 Seismic Isolation – Springs and Masses damped spring cross section

LIGO-G W Tuning into Einstein's Unfinished Symphony26 Seismic System Performance Horizontal Vertical HAM stack in air BSC stack in vacuum

LIGO-G W Tuning into Einstein's Unfinished Symphony27 Evacuated Beam Tubes Provide Clear Path for Light

LIGO-G W Tuning into Einstein's Unfinished Symphony28 All-Solid-State Nd:YAG Laser Custom-built 10 W Nd:YAG Laser, joint development with Lightwave Electronics (now commercial product) Frequency reference cavity (inside oven) Cavity for defining beam geometry, joint development with Stanford

LIGO-G W Tuning into Einstein's Unfinished Symphony29 Core Optics Substrates: SiO 2 »25 cm Diameter, 10 cm thick »Homogeneity < 5 x »Internal mode Q’s > 2 x 10 6 Polishing »Surface uniformity < 1 nm rms »Radii of curvature matched < 3% Coating »Scatter < 50 ppm »Absorption < 2 ppm »Uniformity <10 -3 Production involved 6 companies, NIST, and LIGO

LIGO-G W Tuning into Einstein's Unfinished Symphony30 And despite a few difficulties, science runs started in 2002…

LIGO-G W Tuning into Einstein's Unfinished Symphony31 Binary Neutron Stars: Initial LIGO Target Range Image: R. Powell S2 Range

LIGO-G W Tuning into Einstein's Unfinished Symphony32 What’s next? Advanced LIGO… Major technological differences between LIGO and Advanced LIGO Initial Interferometers Advanced Interferometers Open up wider band Reshape Noise Quadruple pendulum Sapphire optics Silica suspension fibers Advanced interferometry Signal recycling Active vibration isolation systems High power laser (180W) 40kg

LIGO-G W Tuning into Einstein's Unfinished Symphony33 Binary Neutron Stars: AdLIGO Range Image: R. Powell LIGO Range

LIGO-G W Tuning into Einstein's Unfinished Symphony34 …and opening a new channel with a detector in space. Planning underway for space-based detector, LISA, to open up a lower frequency band ~ next decade

LIGO-G W Tuning into Einstein's Unfinished Symphony35 Closing remark The age of discovery has not ended…

LIGO-G W Tuning into Einstein's Unfinished Symphony36 Recommended Reading “Was Einstein Right”, by Clifford Will. A bit ancient (more than 10 years old) accounting of progress in verifying Einstein’s theory. “Black Holes and Time Warps: Einstein’s Outrageous Legacy”, by Kip Thorne. From basics to time travel in a long, but rewarding read. “Einstein’s Unfinished Symphony”, by Marcia Bartusiak. A highly readable account of the search for gravitational waves.