Forty years ago today, NASA launched its first Earth-observation satellite, Landsat. Data from the program, now on its eighth orbiter, have been used in climate-change studies, in ecology, and to show the effects of population growth.
Scientists have also noticed that some images are just visually amazing. (Particularly when the researchers add color to the pixels.)
Here are two of the most popular, voted on by 14,000 members of the public. The first contrasts the graceful oxbow bends of the Mississippi with the blocklike parcels of land that surround it. The second highlights one of the largest—and least-seen—river deltas in the world: the Yukon Delta in southwest Alaska, featuring a multitude of ponds, sloughs, and other water-forms.
(Credit: NASA’s Goddard Space Flight Center/USGS)