Had @trufflepig not ranked this post no.3, I'd have ranked it no. 1 of my daily truffle...lol. Fascinating I must say.
However, I don't think the sun gives life to the earth as a planet, I feel the sun is life itself, apart from its role in energy generation, a biologist too will have a thousand things to write about the sun and in a way I feel that differences exists between the suns found in different planets and that's why other planets cannot support intelligent life like the earth we live in.
If science doesn't find a way to manipulate the sun, I don't think life will ever exist in any other planet apart from earth which has a ‘life supporting sun’.
That is an interesting view
The warmth a hen provides to its egg, one of the necessary ingredients required to bring forth a chick, but don't forget to include the egg in the equation. The Sun, no doubt is very important, but the Earth also plays a vital role in the creation and nurturing of life.
About life in other planets, call me a conspiracy theorist, but I deeply believe there is intelligent life in other planets, and in other corners of the universe, but this information is only available to a few sets of people.