Kernel Panic

What is and what causes a kernel panic? Is this when the rotating beach ball shows itself? Also, I am running 10.5.1 and frequently notice the blue bar sliding across the address box stops part way through the page loading process. Why does this happen. I have to quit safari and then go back in to the site. Emptying the cache doesn't help.

See this thread, where I addressed this very question just recently.

http://www.mac-forums.com/forums/showpost.php?p=544755&postcount=3