The world's surface
is represented with satellite imagery from the NASA Goddard Spaces Flight
Centre enhanced with 3D terrain data to give a colourful portrayal of the
physical geography of the planet.
The area of the
globe where it is night-time is shown in shadow. The darkness of the
shadow can be set by the user. Where the sun and the moon are both below
the horizon, the night time shadow is darker still.
As
an area moves into the night-time shadow, town and city lights are turned on.