If a material is thicker, it should be less transparent, right? It turns out that in Saturn's rings, that's not always the case. A new examination of the B ring shows that even though it's the most opaque of Saturn's rings, it's not the densest one.
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The puzzling result is not just isolated to this ring, either. Scientists have found similar results in other studies when looking at the gas giant's other rings, NASA said. This latest research comes from using the Cassini spacecraft, which is slowly wrapping up investigations at Saturn since arriving there in 2004.
"Appearances can be deceiving," said research co-author and Cassini co-investigator Phil Nicholson, at Cornell University in New York, in a NASA statement. "A good analogy is how a foggy meadow is much more opaque than a swimming pool, even though the pool is denser and contains a lot more water."
The research team looked at the ring's mass density by studying spiral density waves. These features appear when ring particles move under the influence of gravity - gravity from Saturn's moons as well as the huge gas giant planet itself. Each wave's structure depends on how dense it is, and the effect of gravity. Scientists now know that the B ring is less dense than it appears, but the full reason is still a mystery.