Some of the sun's UV rays can be absorbed by the Earth's surface or bound back off. Although this would be a "good" thing, it is not. These very rays cause the ozone layer to deplete over long periods of time from the rays "breaking it.
The crucifix that the magistrate shows to Meursault is part of a religious philosophy. But it is one that Meursault does not believe in and he is an atheist and finds God meaningless to human existence.