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Murchison Meteorite Still Contentious
An anonymous reader writes "The well-known 1969 meteorite that fell 60 miles north of Melbourne, Australia, remains remarkably contentious today. The 100 kilogram carbon rock : a) contains pre-biotic proteins and 12% water; b) harbors 50 amino acids not found on Earth; c) favors the tell-tale signature of biochemistry based on a dominant left-handed chirality, compared to random or racemic mixtures found in test-tube syntheses. While terrestrial contamination (even interior to the meteor) may discount this so-called 'Murchison meteor', its light isotopes of carbon and nitrogen suggest the left-handed amino acids not found elsewhere on Earth have the same ratios as the right-handed ones. This would not be the case if, say, bacteria was just making the left-handed ones after impact. Seems quite a controversy from down-under."
To me, if you collected about 20 or 30 of these things, it would answer the question rather quickly.
Unfortunately, the theories I've heard suggest that the amino acids form in colder parts of space than here, and not very often, so the probe would have to go a long way, and gollect rather more than 30 rocks (Would you look under only 30 rocks on a beach to find evidence of life? Space is quite big, and life is less common there.) This would be very expensive and probably not vey conclusive, unless it happened that it found some amino acids quickly. A conclusive negative result could not be found this way.
I am TheRaven on Soylent News
On thing seems abundantly clear: There's no life left on the world it came from. I hope ours doesn't pose a base for such a heated debate on some other world species some day.
A feeling of having made the same mistake before: Deja Foobar
...Earth. They could be of terrestrial origian and thrown up a billion years ago or so by volcanic activity or a large meteor collision with earth, eventually arriving on earth again after a billion years of orbiting near the Earth. They could be leftovers from a very early time when left handed and right handed life coexisted on Earth.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
.....compared to random or racemic mixtures found in test tubes on Earth. We have yet had no other "lab" from which to study life and it's building blocks (life as we know it: carbon based and mostly made of water). Therefore, the sudden appearence of such components from the stars might very well appear to be "based on dominant left-handed chirality" when compared to the billions-old formula we have here on our planet.
We also don't know how the environment of space will effect amino acids contained in the rock. Since these amino acids (and other material) are foreign, then how do we know that it isn't natural for them to be collected in such a manner?
Never forget the scientific method. You have to ask questions. After you're done asking questions, submit to your peers for them to ask questions.
It really isn't compelling at all. It's similar to how UFOlogists focus on half truths and anamolies that confirm their theories, while ignoring the evidence that shows how 90-95% of all sightings are reasonably explained (the tons of disconfirming evidence). They also turn their nose up to the community and the world, effectively becoming the closed-minded character that they try to call the real scientists: Real scientists submit their work to thousands of peers and accept feedback and analysis. Psuedoscientists do not, and yet they call the critical thinkers that reject their ideas closed-minded.
OK, rant over.
"How many times will science have a victory over the church before we can finally kill God for good?"
What victory over the church? Science is good for proving that things exist, but it's not very useful for proving that things don't exist. If you're drawing the conclusion that God doesn't exist by what is or isn't on a meteorite, then you're not using science.
Your idea is a valid one and scientists are currently thinking that the best chance to find life in our solar system will be on Jupitor's moon, Europa. However, it is actually extremely difficult to keep the robot probe itself from carrying contamination since modern electronics can't take the extreme heat needed to kill resilient strains which could possibly destroy any life on that planet. Recently scientists have been putting more effort into trying to figure out how to explore Europa without contamination.
Contamination has already been shown to occur easily. The first Apollo mission found the moon to be sterile, but later Apollo missions found strep bacteria from previous missions. Deeply buried in ancient Antarctic ice, Lake Vostok is an enviroment that is thought to contain ancient life forms, but scientists are reluctant to explore the lake until contamination can be prevented. Bacteria has already been found in drilling to just above the top of the buried lake.
Great, the next "In Soviet Russia..."
Impersonating Tycho from Penny Arcade since before there was a PA.
no life on Earth uses left-handed Animo Acids.
Quite the contrary, all life on Earth uses left-handed (levorotary) amino acids. Typing "levorotary" into Google and clicking "I'm Feeling Lucky" returns this short-but-informative article.
Fact: the meteorite contains ammino acids, and chirality that is not generally found in terrestrial organisms.
Fact: This meteroite is HEAVILY polluted with terrestrial organic matter.
Conclusion: While ammino acids are generated in space, they seem to mimic the compositions found when we try to synthesize them in the lab.
Aside: You can produce the same results with some methane gas, water vapor, and ionizing radiation.
Move along, no controvesy here.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
amino acids not found elsewhere on Earth
Read it again, slowly.
It doesn't say "amino acids that do not exist elsewhere on Earth."
Simply that they haven't been found elsewhere, including, I assume, on rocks near the impact crater.
That's why it says "not found", not "non-existent".
What matters for the meteorite is whether these amino acids are common enough on earth to have contaminated the meteorite, and the answer to that is clearly "no".
I think of civilization and technology as a major/minor cycle. Technology doesn't always advance... sometimes it's lost. Sometimes entire advanced civilizations are wiped out and a hunter-gather society emerges in its stead. Now imagine this happening to the whole of civilization. Imagine we DO go to Europa, and leave behind a streptococcus. We then lose spacefaring technology for a period of a million years, then regain the technology to complete the cycle.
The new civilization travels to Europa, and finds... simple creatures with earthlike amino chains! At that point we will have discovered extraterrestrials.
Of course one has to wonder if the earth-europa contamination hasn't already happened millions of years ago by an ancient civilization now forgotten. Or perhaps it was vice versa... spooky.
Gah! Of course there are more amino acids that we don't know. An "amino acid" is a broad set of compounds.
However, the importance is in certain amino acids, and the configuration found in almost every life form we know. The fact that nearly every biologically-used amino acid favors one enantiomer over another in biological systems is of great significance.
There are exceptions to every rule, but it's odd to see our freaky trends differ on a space rock.
I was waiting for the alien autopsy at the end of this article, or a discussion of the gunman in the grassy knoll.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming