Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mark Durre on 08/05/2011 19:01:02

Title: How do we detect gravitational waves?
Post by: Mark Durre on 08/05/2011 19:01:02

Mark Durre  asked the Naked Scientists:
   
I love your podcasts (http://www.thenakedscientists.com/HTML/podcasts/)! Keep up the good work.

I have a query about gravitational wave detectors.  I understand the principle of a LIGO type interferometer, but I was wondering how it could get anything other than a null result?  To my (admittedly probably naive) way of thinking, the gravitational wave will change the distance between the mirrors, but won't it also change the wavelength of the light beam?  My analogy is the stretching of space-time in the expansion of the universe, which red-shifts the light from distant sources.  Thus, the "length" of the tube will remain "constant" (i.e. as seen by the light beam), and there would be no fringe changes.

Thanks a lot,

Mark Durré

What do you think?

Title: How do we detect gravitational waves?
Post by: syhprum on 08/05/2011 19:39:29

You are quite correct in saying that the light and the tubes are both affected by the gravitational wave,this article discusses ways around this problem.

http://en.wikipedia.org/wiki/LIGO