Saturn's ring system is the closest thing we have to the dust and gravel disk that gave birth to earth and other planets 4.55 billion years ago. This protoplanetary disk is formed in the collapse of a nebula composed of ultra-low temperature gas and dust under its own gravity. As the rotating Nebula gradually shrinks, once the sun blows away these gases, the orbiting rubble in the disk is very similar to Saturn's ring system.
mainly introduced in the above text?
shape