We are so accustomed to seeing satellite pictures of the earth that it seems as if there is nothing left to be discovered. In the daily weather reports on television we regularly see images taken by geostationary satellites and with the help of web-based virtual globes we can zoom in from the full-earth disk to detailed views of any place on the earth in a matter of seconds. Yet, does this truly mean that all the secrets of the earth have now been disclosed? Can we extract all the information we need from existing earth observation data? [...]