Beagle
January 25, 2004, 6:11pm
1
A couple years ago I bought Life by Richard Fortey . He explained that many millions of years of stromatolites building huge towers oxidized * the iron in the soil on Earth, turning it red. That’s a paraphrase. If the soil on Mars is mostly iron and silica, the conventional wisdom, and all the iron is oxidized (?), how did the iron become oxidized without substantial oxygen present at one time? The bulk of the oxygen on Earth is attributed to life, I think.
However their most important role in the history of the earth has been that of contributing oxygen to the earth’s atmosphere. The organisms which construct stromatolites are photosynthetic. They take carbon dioxide and water to produce carbohydrates, and in doing this they liberate oxygen into the atmosphere.
Q.E.D
January 25, 2004, 6:13pm
2
Mars is red because it’s rusty.
Beagle
January 25, 2004, 6:19pm
3
Oh well, that was quick. In case anyone is wondering, this is the crux of it – unless you go with the “oceans and rain” theory:
In 2000, he conducted an experiment with a 100-milligram chunk of labradorite, a mineral commonly found in Martian soil. The sample was placed in a test tube filled with gases common to the Martian atmosphere and chilled to a Mars-like minus 76 degrees Fahrenheit. Finally, Yen and his cohorts pelted the tube with ultraviolet light, to mimic the effects of sunlight. (UV light on Mars is particularly harsh since the planet’s ozone layer is so thin.) After a week, they analyzed the sample for evidence of superoxide ions, negatively charged oxygen molecules that are capable of causing iron oxidization even when there’s no water present. Sure enough, Yen found the superoxides as he’d predicted—a blow to the astrobiologists who’d long believed that Mars’ red hue indicated that water, and perhaps life, must have once been abundant on the planet.
Darn.