I was a little confused about how BBC News knows this. Then I read on and discovered that Saturn has one too.
All the other rings around planets are red due to the size of the particles that reflect the light back.
Blue rings are caused by a moon in the same orbit as the ring particles which strike the moon. The larger ones are captured by the moon and the smaller ones bounce back into the ring structure. Smaller pieces reflect blue light. The moon making Uranus’s blue ring is named Mab.
Still confused, I read they discovered this ring with the Hubble Space Telescope. I was thinking... why would they turn it to look down at Earth?
So, remember, if you moon Uranus will develop a blue ring.
Maybe I’m still confused.