Simplify the following text for a Grade 9 native English-speaking person.
Original: Polarization pattern : Light scattered in a blue sky forms a characteristic pattern of partially polarized light which is dependent on the position of the sun and invisible to human eyes .
Simplified: Polarization pattern : Light scattered in a blue sky forms a pattern of partially polarized ultraviolet light . This depends on the position of the sun , and is invisible to human eyes .