[astro] the physics arXiv blog

[Eugen Leitl]

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From: the physics arXiv blog <howdy at arxivblog.com>
Date: Wed, 30 Jul 2008 14:29:01 -0500 (CDT)
To: eugen at leitl.org
Subject: the physics arXiv blog
Reply-To: the physics arXiv blog <howdy at arxivblog.com>


[1]the physics arXiv blog

   [2]The painful search for gravitational waves

   Posted: 30 Jul 2008 12:06 AM CDT

   [3]G-wave data 

   Gravitational wave detectors have a sorry history of disappointing
   results.

   Joseph Weber at the University of Maryland first claimed to have
   spotted these waves in 1969. He did it by listening to the way a giant
   cylindrical bars vibrate, thinking that passing gravitational waves
   would cause them to ring like a bell. Nobody has been able to
   reproduce these results and they remain strongly disputed today.

   Various groups still listen out for gravitational waves using
   Weber-like detectors. But the Ferraris in this field are a new
   generation of laser interferometers that are much more sensitive to
   the bending and squeezing of space that these waves cause as they pass
   by.

   The trouble is that none of these detectors has ever spotted a
   gravitational wave either, despite the investment of hundreds of
   millions of dollars. One way of increasing the sensitivity is to use
   two or more interferometers in different parts of the world to look
   for wave simultaneously.

   Now the results of the first  combined search using four detectors
   (three LIGO detectors in the US and the GEO600 in Germany) have been
   published and the results are again disappointing.  They took data
   over a period of month between 22nd February and 23rd March 2005,
   giving them a decent amount of data to play with. But...

     "No candidate gravitational wave signals have been identified"

   says the team, ominously.

   That's embarrassing because these combined searches should be
   sensitive enough to pick up gravitational waves from sources such as
   supernovae and from black holes as they collide.

   So why aren't they seeing anything? One possibility is bad luck, that
   there weren't any events during the the time  the data was being
   taken. That seems unlikely. Another possibility is that the problem is
   closer to home, perhaps in the equipment, analysis or even the theory
   itself.

   Whatever the problem, they don't seem to be able to put their finger
   on it. This data is three years old which means it's been given one
   almighty going over before publication.

   So I wonder how these guys are feeling given that hundreds of millions
   of dollars and several years of work has so far produced zilch.

   Ref: [4]arxiv.org/abs/0807.2834: First Joint Search for
   Gravitational-Wave Bursts in LIGO and GEO600 Data

   [5][arXivblog?i=ocjXOQ] 
   [6][arXivblog?i=fO919J] [7][arXivblog?i=f77YyJ]
   [8][arXivblog?i=MKs9kj] [9][arXivblog?i=01GlpJ]
   [10][arXivblog?i=ANhdDj] [11][arXivblog?i=LOi9LJ]
   [12][arXivblog?i=zAS4kj] [13][arXivblog?i=nqBNvJ] 
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References

   1. http://arxivblog.com/
   2. http://feeds.feedburner.com/~r/arXivblog/~3/350156409/
   3. http://arxivblog.com/wp-content/uploads/2008/07/gw-data.jpg
   4. http://arxiv.org/abs/0807.2834
   5. http://feeds.feedburner.com/~a/arXivblog?a=ocjXOQ
   6. http://feeds.feedburner.com/~f/arXivblog?a=fO919J
   7. http://feeds.feedburner.com/~f/arXivblog?a=f77YyJ
   8. http://feeds.feedburner.com/~f/arXivblog?a=MKs9kj
   9. http://feeds.feedburner.com/~f/arXivblog?a=01GlpJ
  10. http://feeds.feedburner.com/~f/arXivblog?a=ANhdDj
  11. http://feeds.feedburner.com/~f/arXivblog?a=LOi9LJ
  12. http://feeds.feedburner.com/~f/arXivblog?a=zAS4kj
  13. http://feeds.feedburner.com/~f/arXivblog?a=nqBNvJ
  14. http://arxivblog.com/
  15. http://www.feedburner.com/fb/a/emailunsub?id=8632699&key=kesJ612ZsV
  16. http://feeds.feedburner.com/arXivblog
  17. http://feeds.feedburner.com/arXivblog

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-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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