Years went by like this: adventures and games, interspersed with homework and science projects. Bradbury and I spent as much time together as possible, until the day that he told me he was moving away.

"Dad got a job in the U.S.," Bradbury said, in an almost silent voice. "We're moving to Detroit, to work on the Cadillacs."

And the next day he was gone. Gone with his birthmark, gone with his scared sometimes, gone with his infectious energy. It was in the fall of 1985. I remember the year, because in the coming January Christa McAuliffe blew apart over Florida.

I remember the disbelief at school when the principal spoke to us on the public address system. All of us children were crushed, along with children around the world who had been taken from class to watch the first teacher in space. I remember how my parents believed that I was making a sick joke when I told them Challenger had exploded. And on the news on every channel there were replays of the video, and speculation by witnesses and engineers and retired astronauts.