OK we know the gravitational influence of one galaxy acts like a lens to
create a magnified picture of a far more distant galaxy located behind
it. With all those billions of galaxies out there can we say that every
photon has been lens if it started out 13 billion LY from us? How good
is gravity lens focas? How much does this gravity lensing alter the
photon's wave length. When I read about gravity magnified light it
sounds like a good thing. Does it have any negative features? Like
making an image blurry? Bert