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Life on Mars? Some of us feel that it is quite likely that, at least in the past, there has
been life on Mars. There are several observations that seem to point
in that direction. Some years back we got indefinite results from the first measurements that were made on Martian soil. The nutrient solution which was dripped on the soil contained a mixture of both right and left
handed amino acids. Now living organisms on Earth discriminate between
the two. They take the left handed amino acids but not the others. And if, on Mars, we had dripped two separate nutrient solutions, one with right handed amino acids and one with left handed
amino acids, and if one had been used but not the other, then we
might have surmised that their use was through biological metabolism and not
through some unknown chemical reaction. It would also have been nice to know, by which one they chose, whether or not they might be relatives of ours. A similar nutrient solution was dripped on the
soil of Antarctica where the temperature is similar to that on Mars
but where we know that the microorganisms are alive and well. And the results there were the same as on Mars. Although at the present time the atmospheric pressure on Mars is so low that the boiling point of water
there is colder than the freezing point, it wasn't always so. Mars
must have had a heavier atmosphere in the past or there couldn't have been
liquid water there. And there is abundant evidence that in the past there were both rivers and lakes on Mars. Also, with a heavier and wetter atmosphere, Mars would have had a warmer climate than it
has now. But
perhaps the most convincing evidence that there has been life on Mars is the redness of the Martian rocks. In the distant past, the rocks on the Earth were not red. The red is largely iron oxide which
dates only from the time when our photosynthetic relatives had succeeded
in dumping out enough toxic waste to give us an oxidizing atmosphere. The Universe at large has a reducing atmosphere, and before the blue green algae and the rest had dumped out all this oxygen,
the iron in our rocks was soluble in water and washed down into the
ocean. There a microorganism named Pedomicrobium used the oxygen
from the rocks to oxidize the iron and put it away in the bottom of the sea so that we could make Chevvys and ships. We know how we got an oxidizing atmosphere, but without photosynthesis, how did Mars?
It has been suggested that through photodissociation of the water
molecules in the upper Martian atmosphere the hydrogen was allowed to escape. That would leave the oxygen behind. But we're closer to the Sun than Mars is, so why didn't it happen here? It's true
that on Mars the hydrogen would have had escape velocity, but so
does it here in our upper atmosphere. When we check again for life on Mars, it is to be hoped that we will separate the right handed and left
handed amino acid nutrient solutions and drip them on the soil at
the bottom of the deepest canyon where the temperature should be a little warmer and where moisture might be a little more plentiful.
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