LIGO detects gravity waves

Written by: Stephen Hsu

Primary Source: Information Processing

Live-blogging the LIGO announcement of detection of gravity waves. Detection of an event in 2015 (initial science run of advanced LIGO) is good news for the future use of gravity waves as an astrophysical probe — it suggests a fairly high density of NS-NS, NS-BH, and BH-BH binaries in the universe. Each time astronomers have developed a new probe (radio waves, x-rays, etc.) they have discovered new cosmic phenomena. The future is promising!

Techno-pessimists should note that detecting gravity waves is much, much harder than landing on the moon. LIGO measured a displacement 1/1000 of a neutron radius, in a noisy terrestrial background, accounting even for quantum noise.

https://www.ligo.caltech.edu/: 9/14/15 detection of BH-BH (~ 30 solar masses) merger at distance 1.3 Gy. The energy in the gravitational wave signal was ~3 solar masses!

Here is the paper  http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102

When I was an undergraduate, I toured the early LIGO prototype, which was using little car shaped rubber erasers as shock absorbers. Technology has improved since then, and the real device is much bigger.

Kip Thorne (from whom I learned General Relativity) has been one of the driving forces behind the effort to detect gravity waves for over 40 years. The picture below was taken during a conference in Eugene back in 2005.

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Stephen Hsu
Stephen Hsu is vice president for Research and Graduate Studies at Michigan State University. He also serves as scientific adviser to BGI (formerly Beijing Genomics Institute) and as a member of its Cognitive Genomics Lab. Hsu’s primary work has been in applications of quantum field theory, particularly to problems in quantum chromodynamics, dark energy, black holes, entropy bounds, and particle physics beyond the standard model. He has also made contributions to genomics and bioinformatics, the theory of modern finance, and in encryption and information security. Founder of two Silicon Valley companies—SafeWeb, a pioneer in SSL VPN (Secure Sockets Layer Virtual Private Networks) appliances, which was acquired by Symantec in 2003, and Robot Genius Inc., which developed anti-malware technologies—Hsu has given invited research seminars and colloquia at leading research universities and laboratories around the world.
Stephen Hsu

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