I agree with your disagreeing.
You are right, it refers to "rings" so it´s DO in the sentence. So, by the grammar reasoning it would be:Do the rings of Saturn change ?
Does the ring of Saturn change?
Usually they talk about "rings
", I used "ring
" here just to show what happens to DO/DOES when the word "ring" is in the plural or singular form.
Thank you Marcio, for being perceptive and for your always invaluable participation.