"These observations give the strongest evidence to date that water still flows occasionally on the surface of Mars," said Michael Meyer, lead scientist for NASA's Mars Exploration Program, Washington.

One thing scientists learned was that Mars' sky was pinkish in color, not dark blue as they originally thought (the sky is pink due to sunlight reflecting off the reddish dust particles in the thin atmosphere).

The first color image (12A006/001) of the surface of Mars was taken July 21, 1976, at the Viking 1 site, one day after the landing. Immediately displayed on color monitors at JPL, as seen in Figure 1a, the landscape awed observers with its resemblance to that of Arizona. Typical desert colorations of soil and rock, ranging from umber sand to yellowish-brown and olivine-colored rocks stood out clearly under a blue sky. Two hours later, however, the official image was changed to the monotone of orange-red (NASA P-17164), Figure 1b, that, with few exceptions, has prevailed in NASA-published images of Mars ever since, as presented by Mutch et al.[1]. However, a spectral analysis of color images of the Viking 1 site reported[2] a broader palate. The paper made the first, and perhaps only, reported use of JPL’s Image Processing Laboratory to analyze digitally the red, green and blue color channels of the images taken by the Viking 1 lander camera. In addition to studying the color images, their RGB components were transformed into saturation, hue and intensity components to enhance subtle deviations. When these components were equally amplified to produce an equal average sensitivity over the spectral bandpass, the resulting “radiometric” (closest possible approach in appearance to a human observer) images very closely resembled the first color image (12A006/001). Among the range of colors, the paper reported that some of the rocks exhibited greenish patterns that apparently changed between images taken 301 sols apart. Radiometric images of lichen-bearing terrestrial rocks taken and processed through the same system as were the Viking images showed a close resemblance of the lichen colonies to the greenish patches on the Mars rocks. Inclusion in the analysis of three near-IR channels available on the Martian images enhanced the greenness of the patches that were, to the sensitivity of the method, virtually indistinguishable from the lichen colonies on the terrestrial rocks.

Originally posted by whitecastle
reply to post by zorgon

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Ah, but we've just begun looking! I'm quite optimistic there is life in this solar system beyond our world!