Go to: LUNAR FLOAT The moon seems to float along the edge of Earth's atmosphere in this digital photo, taken in May by astronauts on the international space station. The hovering satellite, which is actually 250,000 miles beyond Earth, is an optical trick due to different sunlight levels on the atmospheric boundary. It is still daytime on the right side of Earth, but night is beginning on the left. The gradient change is responsible for the illusion, according to NASA. (07/02/03)