Abstract: A method to display the earth as viewed from outer space (or a spaceship) is proposed. The intention of the paper is application to space flight simulators (e.g., reentry to the atmosphere) and the simulation of surveys of the earth (comparisons with observations from weather satellites and weather simulations); it is not for geometric modeling of terrains and/or clouds viewed from the ground, but for displaying the earth including the surface of the sea viewed from outer space taking into account particles (air molecules and aerosols) in the atmosphere and water molecules in the sea. The major points of the algorithm proposed here are the efficient calculation of optical length and sky light, with lookup tables taking advantage of the facts that the earth is spherical, and that sunlight is parallel.