After trying to get the entire exploding planet work, I came to realize that the planet needs to crack then, explode!

But how do I make the planet crack gradually? Does the shatter node help? Should I put a sphere in the planet and make it a static object while the planet would be a fracture one?

how should I add the explosion after the cracking? Aren't they two different techniques?

I have attached a file in which a tried to generate cracking, but it's done in a terrible way. I have appended a shatter node to the planet object, but when I see the result I see that it's empty inside. Why?

Could anyone, please, enlighten me? I can't find a solution!

Thalie