The outer rim of the dazzling ring system has a diameter of some 170000 miles. Until modern times, no one knew why the planet's gravity did not pull them crashing down to its surface. In the 1650s, a Dutch astronomer had an idea on this subject. read more
In the 1650s, a Dutch astronomer had an idea on this subject. He suggested that the big beauteous rings must, simply must, be made of tiny swarming particles. For if they were sizeable chunks of material, surely the magnificent circles would collapse and crash down to Saturn's surface. read more
The narrowness of the rings of Uranus and Neptune is believed to be caused by 1. a spiral density wave which confines them. 2. gravitational interactions between ring particles. 3. small shephard moons that orbit near the rings. 4. the smaller mass of Uranus and Neptune as compared to that of Saturn. read more
The rings of Saturn also are in constant orbit around their parent planet. This whirling orbital motion counteracts Saturn's gravity. Instead of falling straight down, their orbital speed causes them to fall in a curved path which takes them around and around. The strength of Saturn's gravity, as in all planets, diminishes with distance. read more