One day soon, Curiosity will wheel around a mound of rock and come camera to face with life on Mars.
The life form will have been waiting for it to arrive, and greet it in English, "What took you so long to get here? Why are you surprised?"
The images beamed back to earth will cause consternation, not excitement. Scientists will have to rethink the universe. Religions will have to rewrite sacred texts and modify their beliefs.
For there, sitting in the middle of a desert, surrounded by artifacts from Earth, will sit a single man, pounding away on an old pre--electric typewriter. Sheaves of paper will be scattered about.
He'll not have on a space suit, because he's able to breathe the atmosphere and survive. He won't be a ghost, but there will be something "unearthly" about him, because there will be no evidence of food or water, and yet he'll continue to thrive.
Most of all, he'll just sit there, furiously typing away, full of enthusiasm and gusto, because he gets to write all the time.
It's not by accident that Ray Bradbury died on this planet, shortly before Curiosity landed on another planet. The Martian Chronicles are fulfilled.