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What If We Could Listen to the Stars?

LIGO (Laser Interferometer Gravitational-Wave Observatory) aims to open a new portal on the universe by directly listening to the vibrations of space. This unique observatory consists of large detectors that act like huge microphones, enabling the detection of the most violent events in the universe. Explore the mysteries of dark matter, dark energy, black holes, and more through the lens of LIGO's groundbreaking research.

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What If We Could Listen to the Stars?

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  1. What If We Could Listen to the Stars? Fred Raab LIGO Hanford Observatory

  2. LIGO’s Mission is to Open a New Portal on the Universe • In 1609 Galileo viewed the sky through a 20X telescope and gave birth to modern astronomy • The boost from “naked-eye” astronomy revolutionized humanity’s view of the cosmos & astronomers have “looked” into space to uncover the natural history of our universe • LIGO’s quest is to create a radically new way to perceive the universe, by directly listening to the vibrations of space itself • LIGO consists of large, earth-based, detectors that will act like huge microphones, listening for the most violent events in the universe LIGO: Portal to Spacetime

  3. The Laser Interferometer Gravitational-Wave Observatory LIGO (Washington) LIGO (Louisiana) 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. LIGO: Portal to Spacetime

  4. Observatories at Hanford, WA (LHO) & Livingston, LA (LLO) Support Facilities @ Caltech & MIT campuses LIGO Laboratories Are Unique National Facilities LHO LLO LIGO: Portal to Spacetime

  5. Part of Future International Detector Network Simultaneously detect signal (within msec) Virgo GEO LIGO TAMA detection confidence locate the sources decompose the polarization of gravitational waves AIGO LIGO: Portal to Spacetime

  6. Big Questions for 21st Century Science Images of light from Big Bang imply 95% of the universe is composed of dark matter and dark energy. What is this stuff? The expansion of the universe is speeding up. Is it blowing apart? WMAP Image of Relic Light from Big Bang There are immense black holes at the centers of galaxies. How did they form? What was it like at the birth of space and time? Hubble Ultra-Deep Field LIGO: Portal to Spacetime

  7. A Slight Problem Regardless of what you see on Star Trek, the vacuum of interstellar space does not transmit conventional sound waves effectively. Don’t worry, we’ll work around that! LIGO: Portal to Spacetime

  8. John Wheeler’s Picture of General Relativity Theory LIGO: Portal to Spacetime

  9. General Relativity: A Picture Worth a Thousand Words LIGO: Portal to Spacetime

  10. 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: Gravitational Waves LIGO: Portal to Spacetime

  11. 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: Portal to Spacetime

  12. The “Undead” Corpses of Stars:Neutron Stars and Black Holes • Neutron stars have a mass equivalent to 1.4 suns packed into a ball 10 miles in diameter, enormous magnetic fields and high spin rates • Black holes are the extreme edges of the space-time fabric Artist: Walt Feimer, Space Telescope Science Institute LIGO: Portal to Spacetime

  13. Gravitational-Wave Emission May be the “Regulator” for Accreting Neutron Stars • Neutron stars spin up when they accrete matter from a companion • Observed neutron star spins “max out” at ~700 Hz • Gravitational waves are suspected to balance angular momentum from accreting matter Credit: Dana Berry, NASA LIGO: Portal to Spacetime

  14. Catching WavesFrom Black Holes Sketches courtesy of Kip Thorne LIGO: Portal to Spacetime

  15. In 1974, J. Taylor and R. Hulse discovered a pulsar orbiting a companion neutron star. This “binary pulsar” provides some of the best tests of General Relativity. Theory predicts the orbital period of 8 hours should change as energy is carried away by gravitational waves. Taylor and Hulse were awarded the 1993 Nobel Prize for Physics for this work. Detection of Energy Loss Caused By Gravitational Radiation LIGO: Portal to Spacetime

  16. Sounds of Compact Star Inspirals Neutron-star binary inspiral: Black-hole binary inspiral: LIGO: Portal to Spacetime

  17. How does LIGO detect spacetime vibrations?

  18. Important Signature of Gravitational Waves Gravitational waves shrink space along one axis perpendicular to the wave direction as they stretch space along another axis perpendicular both to the shrink axis and to the wave direction. LIGO: Portal to Spacetime

  19. End Mirror End Mirror Beam Splitter Laser Screen Sketch of a Michelson Interferometer Viewing LIGO: Portal to Spacetime

  20. Core Optics Suspension and Control Optics suspended as simple pendulums Local sensors/actuators provide damping and control forces Mirror is balanced on 1/100th inch diameter wire to 1/100th degree of arc LIGO: Portal to Spacetime

  21. One meter, about 40 inches Human hair, about 100 microns Wavelength of light, about 1 micron Atomic diameter, 10-10 meter Nuclear diameter, 10-15 meter LIGO sensitivity, 10-18 meter How Small is 10-18 Meter? LIGO: Portal to Spacetime

  22. Vacuum Chambers Provide Quiet Homes for Mirrors View inside Corner Station Standing at vertex beam splitter LIGO: Portal to Spacetime

  23. Nuclear diameter, 10-15 meter Why is Locking Difficult? One meter, about 40 inches Human hair, about 100 microns Earthtides, about 100 microns Wavelength of light, about 1 micron Microseismic motion, about 1 micron Atomic diameter, 10-10 meter Precision required to lock, about 10-10 meter LIGO sensitivity, 10-18 meter LIGO: Portal to Spacetime

  24. And despite a few difficulties, science runs started in 2002… LIGO: Portal to Spacetime

  25. Binary Neutron Stars:S1 Range LIGO: Portal to Spacetime Image: R. Powell

  26. Binary Neutron Stars:S2 Range S1 Range LIGO: Portal to Spacetime Image: R. Powell

  27. Binary Neutron Stars:Initial LIGO Target Range S2 Range LIGO: Portal to Spacetime Image: R. Powell

  28. Open up wider band What’s next? Advanced LIGO… Major technological differences between LIGO and Advanced LIGO 40kg Quadruple pendulum Sapphire optics Silica suspension fibers Initial Interferometers Active vibration isolation systems Reshape Noise Advanced Interferometers High power laser (180W) LIGO: Portal to Spacetime Advanced interferometry Signal recycling

  29. Binary Neutron Stars:AdLIGO Range LIGO Range LIGO: Portal to Spacetime Image: R. Powell

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