... Peering out of the windows of the International Space Station (ISS), astronaut Tracy Caldwell Dyson takes in the planet on which we were all born, and to which she would soon return. About 350 kilometers up, the ISS is high enough so that the Earth's horizon appears clearly curved . Astronaut Dyson's windows show some of Earth's complex clouds , in white, and life giving atmosphere and oceans, in blue . The space station orbits the Earth about once every 90 minutes. ...