In 2009, astronomers have discovered that there was an outer ring circling Saturn that had not been known to exist, made mostly of extremely tiny dark dust particles, it was very difficult to see. They estimated at the time that the ring was likely over two hundred times the radius of its host planet.
In this new effort, the researchers have studied images taken from NASA's WISE probe and suggested that the ring is actually over 270 times the radius of Saturn, which mean it stretches from almost four million miles from the planet to ten million miles, making it approximately ten times the size of the E ring [until this new discovery, it was the Saturn's largest ring].
Putting it into perspective, if Saturn were merely the size of a basketball, this new outer ring would extend nearly two thirds the length of a football field away from it.
The ring has only been revealed by infrared cameras because the dust particles in it absorb heat from the sun. Some of this particles are extremely small, just microns in size where others are much larger as soccer balls.
Because of the huge distance between the ring and planet, the researchers theorize that the material in the ring is probably very old, perhaps in the billions of years. They also suspect the tiny particles are material ejected from the distant moon Phoebe.
Prior to this discovery, it was believed material ejected from moons at such a distance would form into a new moon, rather than form a ring, but now it appears such theories will have to be rethought. Because of similarities between Saturn's moons and Jupiter's moons, the researchers suspect that, Jupiter may also has a massive unseen ring around it as well.
original source:- Phys.org