1. Sun is a big star that provides heat and light to the whole solar system.
2. Sun is 140 miliion km away from Earth.
The appositive phrase is “one of the largest formations of this kind in the solar system”. This is an appositive phrase because the information is not necessary and it describes the pronoun/noun Caloris Basin
If it is in The Grimm story tales it is what they point of view and who wanted to write the story and what characters they wanted in the story.