- [Narrator] Saturn's rings are amazingly complex.

- [Narrator] And the more we zoom into them, the more complex they seem to be.

- It is one of the wonders of the solar system.

- [Narrator] Scientists think the rings may have first formed when a moon strayed too close to Saturn, (rocks rumbling) and was pulled apart by its gravity, creating a jumble of trillions of individual fragments of rock and ice.

(mysterious music) So what turns such chaos into the ordered beauty we see today?

NASA's Cassini spacecraft gave us the best view of the rings we've ever had.

- The photographs from Cassini gave us Saturn's rings at all angles.

We saw them reflecting light from the sun.

We saw Cassini look through them toward the sun, just the spectacular beauty of them just mind blowing (static buzzing) - [Narrator] And lurking among the loops of rock and ice.

Cassini imaged one of the most startling moons in the entire Saturn system.

- So Pan is this weird tiny object.

It is only 17 miles across and it looks for me like a walnut, - And it looks like it has a dusting of material around it that could easily break off if you were to touch it.

- [Narrator] Despite its small size, Pan has a big impact on the structure of the rings.

- Pan is a great example of how gravitational interactions can shape Saturn's rings and create the gaps that we see.

- [Narrator] Pan orbits inside a wide track within Saturn's rings called the Encke Gap.

- We think Pan created the Encke Gap by cleaning the orbit and by accumulating all this ring material, dust and ice, around it.

- This ring material has settled specifically on Pan's equator again and again and again, and that meant there is this large ridge around Pan itself.

- It looks like an empanada because so much water, ice from the rings have built up around its equator.

- [Narrator] For millions of years, Pan has been nibbling away, clearing particles out of its orbit, and creating this pathway.

Only that can't be the full story.