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Possible Evidence of Martian Bacteria
half-seas-over writes "NASA issued a very interesting press release today. It highlights a recent study that compared tiny magnetite crystals in the Allan Hill meteorite to similar magnetite crystals that are created here on Earth by bacteria (who use the magnetite as a compass). The study (abstract available here (PDF) from this site) uses fairly strict criteria to determine that 25% of the magnetite content of the meteorite was created by ancient (>3.9Gyr ago) martian bacteria... either that or there is some strange natural process that makes very pure, isolated magnetite crystals that we haven't imagined or seen on Earth which is present on Mars. We'll have to wait and see what happens next, 'extraordinary claims require extraordinary evidence' -Carl Sagan."
Ok, lets say we can determine that there were some bacteria on Mars. Aside from exclaiming, "hey that's cool" what would be the big deal? How would this be different from say, discovering bacteria in some otherwise uninhabited place on earth?
Perhaps this might somehow affect our understanding of life on earth or our origins or something... but like, how?
I'm not dissing the pursuit of knowledge for knowledge's sake, but I guess I'm asking this ignorant question-- are we expecting the discovery of bacterial life on mars to have any repercussions aside from the "hey cool" factor and maybe religious fundimentalists having to rework parts of the bible to jam martian bacteria into Genesis? Are there outstanding scientific theories or questions that this discovery might help answer? How might our world change if this ancient bacteria were confirmed to be really martian?
This press release doesn't say anything about finding martian bacteria. What they found is that the crystals showed signs that, on earth, indicate natural bacterial involvement (as opposed to human intervention or a purely chemical/physical process). That doesn't necessarily mean that the crystals were formed by bacteria - Mars isn't earth after all, and it's a little foolish to assume that the same rules apply, particularly in biology. What it shows is that they might have been produced by bacteria, and if so, then there must have been some form of life on Mars.
I know the press release is very definite that the crystals were produced by bacteria, but I think they're being just a tad overconfident at this stage.
The rock is from Mars. Atmosphere isotope ratios are unambiguous in such cases. Every planet has it's own "signature" that, with the right equipment, is possible to detect. This was demonstrated ages ago by Monica Grady and others in the UK.
You're correct that it's easier to get a meteorite from a smaller body, and we do get loads of them (positively identified Martian meteorites number in the dozens rather than the thousans). However, Mars is massive and has had many massive impacts. The amount of material ejected from it's surface means that it would be amazing if none had reached the Earth.
Also, regarding life, it's unlikely that life would have evolved on any body that did not have liquid water. Liquid water has always been unstable on asteroids, whereas there have significant periods of Martian history (likely when the impact occurred) where liquid water was thought to be stable, possibly over hundreds of millions of years. In fact, there are even points on present day Mars where, for a limited period during the year, water can be stable on the surface. Of course, if you believe Fred Hoyle, life could be everywhere, but, based on an Earth model, life seems far more likely to have evolved on Earth and/or Mars.
The evidence for this being a result of biological activity is still highly ambiguous however, which is why we need to get samples back from Mars.
-Karl
Dr Karl Mitchell
Planetary Science Research Group
Environmental Science Department
Lancaster University
UK
According to the press release, this rock is 4.5B years old. Since that is the approximate age of Mars itself, how could it possibly be life? Does this predate any signs of life found on earth so far?
How hard do you want?
They've found a crystal with no known pathway for its creation apart from a directed one.
The three conclusion options are
1) On earth it's directed by microbes, on mars it's directed by God.
2) On earth it's only directed by microbes, on mars the laws of physics permit it to happen without direction
3) On earth it's directed by microbes, on mars it's directed by microbes.
Get out your Ockham's razer - which of the two are you more inclined to pare away?
YAWIAR.
Your head of state is a corrupt weasel, I hope you're happy.