The Sun Is Slowly Expanding. How Can We Stop It From Killing Us All? Stephen Hawking has a suggestion.

To avoid this, scientists have theorized about taking advantage of Newton's laws of physics. We could counterbalance an asteroid 100 kilometers (62 miles) wide and 10^19 kilograms (2.2 × 10^19 lbs) in weight around the Earth and Jupiter to slowly edge the Earth out of the Sun's expansion radius over the next billion years.

Another solution suggested by Stephen Hawking is to leave Earth entirely and colonize other parts of our solar system. Unless we find the cure to aging, most of us won't be around to try any of these options — let's hope our descendants don't mess it up.
[link to futurism.com (secure)]