Slashdot Mirror

← Back to Stories (view on slashdot.org)

Gravity Wave Detector Ready For Business

Posted by timothy on from the very-expensive-ripples dept.

Arthur Embleton writes "The BBC has an article about a Gravity Wave Detector. There are two L shaped set-ups. One in Washington, the other in Louisiana. They've got a Laser pointing at a mirror 4km away, watching for the reflection and if it is distorted then it shows that there has been a gravitational pulse, possibly by two Black Holes colliding. The detectors are apparently so accurate they can measure to one-thousandth of the width of a proton! How did they test that it works?"

3 of 53 comments (clear)

  1. "This week's finds" on LIGO by mike_stay · · Score: 4, Informative

    John Baez has some really good info about LIGO in several of his "This Week's Finds in Mathematical Physics" columns. week198 is the most recent to mention it. Baez is a great place to start if you like understanding connections between all kinds of different areas of math & physics (which, of course, includes everything else :)

  2. More info by crapulent · · Score: 5, Informative

    Here are the slides [pdf] from the Oct 2002 NSF review. Lots of pictures, graphs, technical details, etc. for anyone interested. In a nutshell they are aiming to measure strain on the order of 10^-21 over the frequency range of 100Hz - 1kHz. Using two facilities separated by 3000km allows them to search for correlated events and weed out localized noise. IANAP.

    More slides here.

    LIGO home page.

    HTH.

  3. Re:Insulation from vibrations noise... by stevelinton · · Score: 4, Informative
    I wonder how exactly they are doing this - what kind of technology can be used to hold two things 4km away at precisely (give or take a few thousandths of the width of a proton) the same relative position all the time.


    They don't. They damp out a certain amount of vibration via clever mountings, etc.
    Then they make sure that all the rest happens at very specific frequencies. You can think of a guitar string. When you jolt a guitar, the string will "sing" at its tuned note. I think the LIGO mirror supports are incredibly precisely tuned.

    Now they only look for gravity waves at other frequencies, mainly ones away from where seismic noise mostly is.

    Finally, they compare respoonses from two remote detectors and look for "matching" events separated by the speed of light, instead of the speed of seismic waves.