Wednesday, August 09, 2006

Life from Mars Via Antarctica?

Rather than talk repeatedly about c change, I will spend a couple of days talking about some other fascinating research.

From the UK Guardian: "(August 6) marks the 10th anniversary of NASA's claim to have discovered life on Mars. Their announcement was based on the study of a meteorite known as ALH84001 that had fallen to Earth 13,000 years previously and remained undetected on an ice sheet in Antarctica until 1984."

From AP: "Ten years later, the results have not been verified. Skeptics have found nonbiological explanations for every piece of evidence that was presented on August 6, 1996. And though they still vigorously defind their claim, the NASA scientists who advanced it now stand alone in their belief." (Shame on you, AP, for beginning sentences with "and")

ALH84001 is so named because it was found in the Allan Hills, an area in the Trans-Antarctic Mountains that is rich in meteorites. Of the few known Martian meteorites, this is the oldest at 4.5 billion years. That is nearly as old as the planets themselves, and may date from a time when Mars was more comfortable for life. Above is an enlarged image of a particle from ALH84001, showing carbonate globules in orange. The 1996 researchers claimed to have found organic hydrocarbons within these globules. However, these compounds are commonly found in other meteorites and in Antarctic ice.

The picture below, taken with an electron microscope, shows tubular forms similiar to Earth bacteria. These formations are 100 times smaller than the bacteria we know. Discovery of magnetite grains was considered even stronger evidence for life. Other scientists claim that these forms can be reproduced without life. Since these photos come via AP, we must ask whether the Martians staged or Photoshopped them!

If Martian meteorites did carry life, we would face the question of whether life evolved on Mars first. Then we all could be Martians! Earth is downhill from Mars in the Sun's gravity well. The answer may wait until humans walk the surface.
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