Gravitational Waves

I like the explanation of how the laser interferometer detection will work, much more clearer than what I've seen before which I just simply "accepted" but didnt quite fully understand. But this time I get it.

So in a nutshell. Two simultaneously synchronised laser beams are fired towards a detector at a very long distance. On their journey they are split up and recombined via mirrors and beam splitters. The distance between source and detector is same for both beams but one beam is flipped so that on their recombining, their interferance pattern should cancel each out and thus the detector should theoretically read ZERO if there are no other outside influences. However, if on occurrence of a gravitational wave interference that is perpendicular to the laser beams, it will cause one beam to stretch and the other to shrink (because one beam has been flipped in its polarity). So the two beams will not exactly cancel out and will result in the photo detector detecting a remaining measurable light wave representation of a gravitational wave.

Neat. Of course, its all highly sensitive and care must be taken to eliminate other earth bound interferences which is biggest engineering challenge...but they look to be on top of that.

Only question to ponder in the mean time is, do gravitational waves exist in the first place? What makes them so sure? Some do not think so, albeit a very small minority and that minority consists of those who suspect a multiverse theory and in turn do not believe in the inflation theory which gravitational waves would prove.