Rings Discovered Around a Moon for the First Time

Riding with Robots writes "It turns out that one of the Ringed Planet's moons has rings of its own. The robotic spacecraft Cassini at Saturn has discovered that the icy moon Rhea is orbited by an extensive debris field and at least one ring, the first such system found. 'Many years ago we thought Saturn was the only planet with rings,' said one mission scientist. 'Now we may have a moon of Saturn that is a miniature version of its even more elaborately decorated parent.'"

Comments

Dumb question: Why are they 2 dimensional?

[guanxi]

You get used to seeing them and maybe don't question it, but why do so many structures in 'outer space' -- low gravity, three-dimensional space -- take on essentially two-dimensional forms? Consider rings around planets, planetary systems around stars, and galaxies, at least. They are all flat discs.

I asked an astrophysicist I know and she said, 'that's the way the math works out'. Ah, thanks. Maybe someone here can be more enlightening.

Disclaimer: For all you nitpickers, I know there are more than three dimensions, and that the structures are not truly two-dimensional. Unless string theory applies here, I think we can leave those facts out of the discussion.

Yeah, in mythology they were husband and wife

[dido]

You joke, but Saturn's (Cronus's) wife in mythology was named Rhea. A bit of a coincidence that.