LIGO: The Search for Gravitational Waves
February 27, 2008
The National Science Foundation (NSF) provides funding for large, multi-user facilities that provide researchers and educators with access to the latest technological tools and capabilities. NSF also supports far-reaching areas of science and engineering that hold promise for breakthroughs that will enhance the nation's future in profound, and possibly unpredictable, ways. The Laser Interferometer Gravitational-Wave Observatory (LIGO) is an example of both.
- Take risks to explore the unknown. Investing in leading-edge research and education is a future-oriented endeavor, which involves taking risks. Increasingly, it requires international collaborations and integrating knowledge across traditional disciplinary boundaries. And, as science achieves measurements once considered nearly impossible, it requires technological innovations that were barely conceived of even a few decades ago.
- Study the universe. For many years, telescopes that detect and measure electromagnetic waves, from radio waves to visible light to X-rays, have been the primary means for astronomers and physicists to study the universe. NSF's investment in LIGO has enabled scientists to reach out with an entirely new means of exploration--detectors of gravitational waves. The LIGO project is spearheading the relatively new field of gravitational-wave astronomy.
- Measure faint signals. Gravitational waves, or ripples in the fabric of space-time, are produced by violent events throughout the universe. LIGO is designed to detect and measure these faintest of signals reaching Earth from space and, at the same time, test fundamental predictions of physics. Its instruments are sensitive enough to measure displacements as small as one-thousandth of the diameter of a proton.
- Observe directly. Though Albert Einstein predicted the existence of gravitational waves in 1918 in his general theory of relativity, they have never been directly observed. LIGO is expected to provide the first hard evidence. By measuring the effects of those waves on LIGO instruments, scientists hope to make new discoveries and enrich our understanding ocosmic phenomena such as black holes, supernovae and pulsars.
- Network internationally. Scientists from around the world collaborated on LIGO's design and scientific objectives and participate in analysis of LIGO data. LIGO is the first of an international network of detectors that together will extract the maximum amount of information about the sources of gravitational waves. Running LIGO "in coincidence" with other detectors is essential for ensuring confidence that gravitational waves have been detected and for determining the location and nature of the source.
- Create spin-offs. In addition to its direct objectives, LIGO is reaping far-reaching scientific, technological and industrial benefits. For example, a laser developed for LIGO by LIGO Scientific Collaboration scientists working with industry has many potential applications. Other spin-offs are being realized in areas such as measurement science, seismic isolation, vacuum technology, coatings and optics.
- Educate. Educational outreach ensures that the new knowledge reaches teachers and students, encouraging the next generation of scientists. Opportunities are available for middle schools, high schools, colleges and universities to: analyze LIGO data, contributing to knowledge about phenomena such as gravitational waves, seismic and atmospheric disturbances, and weather; participate in software development; and conduct hands-on research alongside LIGO scientists.
LIGO is the largest single enterprise undertaken by NSF, with capital investments of nearly $300 million and operating costs of more than $30 million/year.
The two LIGO facilities at Hanford, Wash., and Livingston, La., have been constructed and commissioned. LIGO has completed a two-year data run at design sensitivity, being joined at different times by GEO 600 (a German-British detector), and Virgo (a French-Italian-Dutch detector) in a global array. The three LIGO interferometers--two at Hanford and one at Livingston--are currently undergoing an enhancement to give a modest sensitvity increase. A major upgrade, designed to give more than a factor of 10 sensitivity improvement, will begin in 2008
LIGO is operated by a team from the California Institute of Technology and the Massachusetts Institute of Technology. The LIGO Scientific Collaboration consists of more than 550 scientists from more than 40 institutions worldwide.
For more information, see: http://www.ligo.caltech.edu/
LIGO scientists install a suspended mirror in a contaminant-free vacuum chamber.
Credit and Larger Version
Inside the LIGO Equipment Hall at Livingston.
Credit and Larger Version
Diane E. Banegas, NSF, (703) 292-8070, email: firstname.lastname@example.org
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