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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."
Guess the DNA spiral the other way just like the water in the toilet down under. ;)
And chunks of it are now on sale at Ned Flander's Leftorium.
Fan-diddly-tastic!
I m just a simple caveman, your fire scares me. These pre-biotic proteins you speak of are unfamiliar to me!
here's a couple of reasons I can think off the top of my head:
1) we've got to get the ship someplace where there are "space rocks". a low-earth orbit really isn't going to accomplish that - you'd have to go to the asteroid belt for a ready supply. that's not easy. or, conversly, you land someplace where rocks may have accumulated (ie, the moon, mars).
2) if you send a ship to a place with lots of space rocks, the ship is going to get hit by a lot of space rocks. shielding becomes a problem.
3) if you land some place, you're stuck getting rocks next to where you land (like viking) or you've got to build a way to move around (like pathfinder)
4) building a reliable, completely automated assay for amino acids is not trivial. if it's mobile, that's going to be even less trivial.
"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.
The first Apollo mission found the moon to be sterile, but later Apollo missions found strep bacteria from previous missions.
That's a little misleading. Apollo 12 found microbes inside the camera of Surveyor 3 (which landed three years before). Its not like the strep bacteria are colonizing the moon -- I'm pretty sure that the lunar environment is still sterile.
"The dinosaurs died because they didn't have a space program." - Niven
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.
If a molecule has a carbon with 4 different groups bonded to it then there are two different ways of making the same thing but with different physical layouts eg:
W
|
X -C- Y
|
Z
Or:
X
|
W -C- Y
|
Z
Basicaly these have a "non superimposable mirror image" (no matter how much you rotate them and you can never have all the x,y,x and z's lined up)
Generaly the left handed and right handed molcules have very quite different behaviours, for instance some drugs use only one of the versions, whilst the other version is a poision.
A racemic mixture is a mixture of 50-50 of the left handed and right handed molecules, and generaly chemical processes will produce a racemic mixture.