1) The Blow up Many people believe that in the future, 1,000,000 years ahead, the sun will have burned off all of its hydrogen and start to burn it's helium, causing the sun to consume earth.
2) My Theory! I believe that the sun was created by God, but if I had to make up a theory, I would believe that the sun got there by having to many campfires, and the smoke went up into the sky, and then a big ball of smoke formed in the sky. Then the smoke ball started on fire and never stopped, and that's how our sun came to be!