Hello Sten and Sandy. Lots of possible reasons. I think the best one is that although there is a lot of junk in the rings left over from when the planet formed, this material cannot collect into very large bodies because of Saturn's gravity, which constantly trys to tear things apart in that part of space. We don't really know. We think it is only aabout 300-400 years old, but why it formed in the first place probably has a lot to do with the kinds of weird wind patterns in the jovian atmosphere.
Smaller storms come and go, and perhaps if one grows large enough it can survive longer.
The color of a star has a lot to do with how hot it is. For yellow stars like our sun, the temperature is 5700 degrees, and for very hot 'blue' stars the temperatures are 20,000 degrees or higher. It changes every day. I think mostly I like being able to stay up to date on what we are discovering every week about space. Its exciting to see, everyday, our understanding of the universe grow stronger and stronger.