Universal constants changing slowly over the lifetime of the universe is one of the things I remember quite well from undergrad physics. Not as anything that ha

Universal constants changing slowly over the lifetime of the universe is one of the things I remember quite well from undergrad physics. Not as anything that has been proven, but as a meachanism to try and fix some of the astrophysics measurements. Of course, the radius of the universe has clearly changed with time- this could mean that a0 did or that c did.