Tuesday, December 07, 2010

Arsenic and Old Life


From my presentation in Buenos Aires: Meteorite ALH84001, in which signs of fossil life were discovered in 1996.

Last Thursday astrobiology researchers working at Mono Lake in California announced discovery of microorganisms that can thrive on arsenic. This discovery could widen the definition of organic chemistry. Other scientists have already questioned these results. The science of astrobiology has long met with skepticism.

In 1996 NASA scientists found signs of fossil life on this meteorite, picked up from Antarctica in 1984. The rock forming ALH84001 is over 3.5 billion years old. Martian life could be very old, possibly predating life on Earth. Fossils from another world may be one of the great scientific finds of our time.

McKay et al proposed that a combination of features in ALH84001 could best be explained by a biogenic hypothesis:

1) Carbonates formed at relatively low temperatures involving water

2) Possible microfossils (biomorphs) simlar to Earthly bacterial forms

3) Polyaromatic hydrocarbons (PAH) associated with carbonates

4) Nanophase magnetite (Fe304) similar to that produced by bacteria

From time to time others try to attack these discoveries. Recently a paper claimed that the carbonates could have formed by other means, implying that all the findings are invalid. The most convincing evidence, and subject of the most recent work, is nanophase magnetite. As seen in a microscope, magnetites in ALH84001 form crystalline patterns that could not be formed by simple heating. Such patterns are formed by magnetitic bacteria on Earth.

Science thrives on skepticism, and great discoveries are almost always questioned. Several lines of data still point to life on a Martian meteorite. The question may not be completely settled until we have new samples from Mars. Humans may have discovered what they have long wondered about, life from another world.

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1 Comments:

Blogger Ulla said...

As I see it Life is no physical matter, directly. It is some intermediate matter.

"We will then elucidate the issue of decoherence and dephasing, which are believed to be central in the transition between the quantum and the classical world. They are often regarded to be the limiting factors if we want to observe quantum effects on the macroscopic scale of life. -Are nontrivial quantum phenomena relevant for life?" http://www.univie.ac.at/qfp/publications3/pdffiles/Arndt2009a%20HFSPJ%20Quantum%20Bio%20Printed.pdf
http://www.univie.ac.at/qfp/publications3/pdffiles/2009-26.pdf

This is not true for Life, it has tools to create coherence by collapsing resistence, as in high Tc superfluidity.

Life has also tools to neutralize poisons, or store them in its structures. Time is an active operator. And bacterias are extremly creative. Life is mostly very small.

From deep seafloor has amazing creatures brought up, something that cannot be imagined on beforehand. When we cannot do that for earthly creatures, how can we then imagine about creatures from other worlds?

The essence was that the Life code CHONP was broken. O isn't either absolute, and C has many forms. Without O and with lowcomplexity C there is no complex Life, and for the complexity the code seems obligat. Complexity is higher states of Life, evolution.

Maybe the Life code is simply CHN, like the reactive sites, ends of receptors etc. A phase between expansion and compression?

11:12 PM  

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