A Satellite's-Eye View
Satellite pictures like these will be of increasing value as humans struggle to cope with issues of land use and environmental degradation. A mosaic, this picture is a composite of many high-resolution radiometric images. Such images are made using radiation -- energy -- emanating from the Earth. Reflected sunlight and energy inherent to the biosphere and other features of the planet can be used to effectively and efficiently map the landscape. Land cover such as forest and snow are especially evident in this picture of South America.

This picture comes to us courtesy of the Earth Resources Observation Systems Data Center, an arm of the U.S. Geological Survey.