Tuesday, February 16, 2016

Einstein and gravity waves.

Gravity waves are not new, Einstein predicted their existance a hundred years ago.  My sophmore physics course (50 years ago) covered them. 
   Gravity is a very weak force compared to the electromagnetic force or the strong nuclear force.  Which makes gravitational waves hard to detect.  Indeed, the detectors only managed to detect the most violent event imaginable, the collision of two black holes. 
   The unscientific newsies have failed to report on a bunch of interesting questions.  Such as how do you figure the distance of the gravity wave source?  It's been reported that the two colliding black holes are billions of light years away.  I wonder how they figure that? 
  What is the signal to noise ratio from the detectors?  Detectors of anything, including gravity wave detectors, tend to output low level random noise all the time.  Signals have to be stronger than the noise to be detected.  How much stronger than the noise was this event?  What causes the noise and could it be reduced in an advanced detector somehow? 
  Do gravity waves propagate at the speed of light?  We all kind of assume that they do, but it would be nice to have some measurements to confirm our ideas. 

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