Gravity Wave Detector Ready For Business

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?"

Comments

Really..

[NegativeK]

How did they test that it works?

I think that's the problem. These detectors should work in theory, but gravitation waves are so minute when they get to us that it's _really_ hard to be able to get a reading on them. My bet is the first to provide fairly solid evidence of gravitational waves gets a Nobel.

Re:Really..

[Anonymous Coward]

I betting that's why they build two. You get the same event at the same time on both then say, "What else could it be." I think the hardest problem they will have is that they also made the worlds most sensitve seismic detector. Luckily seismic waves travel much slower than gravity waves.

Re:so many things about it

[lingqi]

no that's not right. the point of the two axis is so that since the gravity stretch / compress effects are vertical / horizontal, you will get different differences between the tubes, therefor costing the light a different amount of time to return. If the light is at constant frequency, this would cause phase shifts between the beams, something you can measure. (this is from their "how it works" website, by the way)

However, I am proposing that since there will be corresponding red/blue shifts in the two shafts, the lights will oscillate the same amount of cycles before merging again, therefore nullifying any potential phase difference, and hence eliminating the possibility of obtaining any result.

I'd think that building these tubes parallel (with a lot of distance between) would be better, because then you would really get phase-shifts from the finite speed of the gravity waves, a positive shift and then a negative shift between the two beams, as the wave affects them sequentially.

Of course, I am just armchair researching - like I said, sure hope they got this right for 300 million dollars.

hmm...

[C21]

wouldn't this work better in deep space. Failing that, wouldn't tossing it up in low earth orbit be better? I can't imagine how theyre going to get past the incredible amount of vibrations, tweaks, tilts that the earth provides.