Sunday, July 6, 2014
NASA’s website for the Landsat program quotes the baseball player Yogi Berra, saying “You can see a lot by just looking”. If you’ve never heard of the Landsat program before, that quote pretty much sums it up. There have been eight Landsats since 1972, and their purpose from the beginning was to take photographs of the earth. And by photographing the same place over 40 years, these photos give amazing insights into things like soil erosion, the effects of natural disasters, and the migration of penguin colonies.
Pretty much everyone knows the ‘blue marble‘ image. Taken by the crew of Apollo 17 in 1972, it’s a picture of the earth, framed against the vast emptiness of space. The image is common now, but no one knew what the earth looked like from space until the late 1960′s, when people actually went up there. And though we went up to explore space, there was no denying the sudden appeal of the earth below. For the first time we could really see the earth in all its glory, and NASA and the Department of the Interior decided to see more. So the Landsat program was born.
When Landsat 1 was being designed, a new type of imaging system was installed, which could detect light wavelengths outside the visible spectrum, like infrared. This was helpful in showing things like water saturation in soil. So instead of trying to tell the difference between slightly different shades of green, as you would in a ‘true color’ photograph, the imaging system could use other wavelengths and display saturated areas in pink and dry areas in yellow. The different way of looking meant greater understanding, and some amazing looking images.
WITH THANKS FROM NASA.