Decent Look: Look closely at this rather dark view of some part of Earth. What continent(s) are visible?

Look closely at this rather dark view of some part of Earth. What continent(s) are visible?

Posted by nazim Friday, July 17, 2009

As far back as the Apollo program, even before Landsat, scientists and others connected with the space program realized that earth-looking satellites, as their sensors improved, could provide a wealth of data and derived information about the Earth as a whole and about selected regions by operating in a coordinated way. Different spectral intervals, look angles, resolutions, etc. would provide complementary data sets useful in many applications. Thus, early on, the value of acquiring data from fleets of satellites was so compelling that planners began to devise programs that would supply such inputs. One variant would be to have different sensors on the same spacecraft. This next image was made as a composite using data supplied by land, meteorological, and oceanographic satellites that show clouds, land surfaces, and ocean water temperatures. It serves to introduce you to one of the main ideas in this Section: the Terra space platforms that bears five sensor systems which can gather data integrated spatially and in time which are invaluable in monitoring the Earth's natural systems and the impact of humans on such systems.

'Humans' is the keyword in the above paragraph. To the best of our knowledge, Earth is the only planet in the Solar System that supports life (although organic molecules may exist on one or more satellites of Jupiter and Saturn, and perhaps once on Mars [page 19-13]). Life, in all its myriad forms, virtually covers Earth. No matter where we look for it, we find it. Much of our planet's geophysical and biological phenomena take place in a relatively thin shell of fluid (the atmosphere and oceans) that is about as thin in proportion to the Earth as a sheet of paper wrapped around a basketball. Most other relevant life activities stay on the land surface,within an even thinner zone of the uppermost layers of soil and rock. And yet, the complex interactions between the biosphere and the geosphere all take place within that thin shell. Just about everything that concerns us as living beings depends upon the integrity of these shells of land, sea, and air.