Launched on July 23, 1972, NASA's Landsat imaging satellites have been looking down on us, gathering a scientists a broad visual history of the Earth for 40 years. Documenting the changes in our natural resources, the data on has been used for everything from forestry, agriculture, and geology to education and national security.
To help commemorate the anniversary occasion, 5 images were selected from the 120 in the 'Earth As Art' series, which appreciated Landsat's data as sheer beauty, recognizing the planet's palate of color, form and design seen from above.
This image of Lake Eyre, taken on August 8, 2006, shows a Northern Australian desert lake bed - only filled with water three times in the past 150 years.
2 of 5 NASA's Goddard Space Flight Center/USGS
Algerian Abstract Landsat 5
Ridges formed by wind blown sand appear as watercolored streaks in this image from April 8, 1985, taken in the Erg Iguidi area of vast sand dunes across Algeria and Mauritania in northwestern Africa.
3 of 5 NASA's Goddard Space Flight Center/USGS
Meandering Mississippi Landsat 7
Evidence of human habitation on the planet -- towns, roads, fields, and pastures -- are seen as right angled blocks in this image taken on May 28, 2003, and contrast the looping, swirling blues of the mighty Mississippi River.
4 of 5 NASA's Goddard Space Flight Center/USGS
Yukon Delta Landsat 7
These biologic looking patterns of growth are actually the rivers, lakes, and ponds of the Yukon Delta in southwest Alaska on September 22, 2002.
5 of 5 NASA's Goddard Space Flight Center/USGS
Van Gogh from Space Landsat 7
It's almost impossible not to equate the thick, vivid blue and green swirls of this image of the Baltic sea on July 13, 2005 with the distinctive Dutch post-impressionism of Vincent Van Gogh's "Starry Night."
The vibrant greens in the dark water off the Swedish coast are phytoplankton blooms -- the result of currents exposing nutrients to the warm, sunny surface waters, accelerating growth of the biologic colonies.