I sat with my dad on the verge of the road, near the car. The night was cold and clear and the stars were falling like rain. "I wonder if there are other worlds," said dad, "Or if this is the only one?" The next day we visited the observatory. We stood in line and, one by one, were allowed to look through the giant telescope. "The planet you can see now is four million light years away," said the guide, "We believe it is...