Simplify the following text for a Grade 13 native English-speaking person.
Original: Visible light observations show that the total amount of material in the arcs has remained approximately constant , but they are dimmer in the infrared light wavelengths where previous observations were taken .
Simplified: However , visible light observations show that the total amount of material in the arcs has remained approximately steady , but they are dimmer in the infra-red where previous observations were taken .