An alien came to Earth looking for a hero. He learned our languages and our ways the best he could in the short amount of time he had. After crunching data and checking with his superiors, he sent out emails to all people who had the word 'hero' in their address.
He got some responses.
You'd be surprised to hear, I know, that this is how the team responsible for defending our solar system was put together, but it's true. Really.