I’m sorry if this is a lame question, but
here go’s:
I’m curious as to why objects fade.(e.g. Curtains that have been exposed in the sun)
My first guess is that it has something to do with light (particles or rays for the pedantic) striking the object.
If it makes you feel better, yes, it is a lame question.
Now, you are on the right track with your idea about light. First, think about why things have colour. White light strikes an object, and certain wavelengths of that white light are reflected. That means that other wavelengths are absorbed.
Manufactured objects have colour because of the dyes and pigments used in their manufacture. Dyes and pigments are chemicals that reflect certain wavelengths of light. Therefore, those chemicals absorb other wavelengths.
Think about the energy represented by different wavelengths of light. Blue light is the most energetic, and red light is least. Chemicals that absord blue light look red (basically) because colour is determined by the wavelengths that are not absorbed. Blue light is energetic enough to break down the chemical bonds in the dyes used, so eventually enough bonds are broken to change the chemical into one that does not absord as much blue light. The red colour has faded.
Dr. Fidelius, Charlatan
Associate Curator Anomalous Paleontology, Miskatonic University
“You cannot reason a man out of a position he did not reach through reason.”