Posted on 08/24/2005 10:16:24 PM PDT by LibWhacker
Space radiation preferentially destroys specific forms of amino acids, the most realistic laboratory simulation to date has found. The work suggests the molecular building blocks that form the "left-handed" proteins used by life on Earth took shape in space, bolstering the case that they could have seeded life on other planets.
Amino acids are molecules that come in mirror-image right- and left-handed forms. But all the naturally occurring proteins in organisms on Earth use the left-handed forms - a puzzle dubbed the "chirality problem".
"A key question is when this chirality came into play," says Uwe Meierhenrich, a chemist at the University of Nice-Sophia Antipolis in France. One theory is that proteins made of both types of amino acids existed on the early Earth but "somehow only the proteins of left-handed amino acids survived", says Meierhenrich.
Meierhenrich and colleagues have a different theory. "We say the molecular building blocks of life were already created in interstellar conditions," he told New Scientist.
The team believes a special type of "handed" space radiation destroyed more right-handed amino acids on the icy dust from which the solar system formed. This dust, along with the comets it condensed into, then crashed into Earth and other planets, providing them with an overabundance of left-handed amino acids that went on to form proteins.
Magnetic alignment
The radiation is called circularly polarised light because its electric field travels through space like a turning screw, and comes in right- and left-handed forms.
It is thought to be produced when dust grains become aligned in the presence of magnetic fields threading through regions of space much larger than our solar system. Circularly polarised light is estimated to make up as much as 17% of the radiation at any given point in space.
In 2000, an experiment showed that when circularly polarised ultraviolet light of a particular handedness was shone on an equal mix of right- and left-handed amino acids, it produced an excess of 2.5% by preferentially disintegrating one type.
But that experiment was done using amino acids in a liquid solution, which behave differently than those in the solid conditions of icy dust in space. To avoid absorption by water molecules, it was also necessary to use light at a wavelength of 210 nanometres – significantly longer than the peak of 120 nm radiation actually measured in space.
Biased meteorites
Now, Meierhenrich's team has performed a similar experiment. The group shone circularly polarised light at a wavelength of 180 nm on a solid film of both right- and left-handed forms of the amino acid leucine. It found that left-handed light produced an excess of 2.6% left-handed amino acids.
"Going towards greater realism by exploring another wavelength of light and solid samples is definitely a good thing and a logical step forward," says chemist Max Bernstein of NASA's Ames Research Center in California, US, who is not part of the team.
He says the research adds to previous measurements of an excess of left-handed amino acids in two meteorites. "If it is thanks to meteorites that our amino acids are left handed, then the same bias should exist at least across our solar system", he told New Scientist.
Alien life
But other solar systems may harbour right-handed amino acids if they are subjected to the other type of circularly polarised light, says Meierhenrich.
"The chiral amino acids might have been delivered to other planets, to other solar systems," he adds. "The probability that life arose somewhere else is increased with this experimental result."
Meierhenrich will continue to reduce the wavelength of the experimental radiation by using a synchrotron facility, due to begin operating in 2006. But the real test of his theory may come in 2014, when the European Space Agency's Rosetta spacecraft lands a probe on Comet 67P/Churyumov-Gerasimenko.
He designed an instrument for the lander that will measure the handedness of any amino acids it finds. "If we identify left-handed amino acids on the cometary surface, this would underline the hypothesis that the building blocks of proteins were created in interstellar space and were delivered via comets or micrometeorites to early Earth," he says.
:')
Aren't you proud? I said "smart" and avoided usage of the taboo word "intelligent".
;')
Thanks for the ping!
Looks like ambidextrous amino acids riding in on worm holes invaded the solar system. Or maybe they were just switch hitters???
Wow, what a stretch. Was this study performed with 'Federal Grant' money?
First, eliminate the impossible, life coming from non-life.
Then once you have eliminated what is impossible, what you are left with must be true, no matter how improbable. (Sherlock Holmes)
First, eliminate the impossible, life coming from non-life. Then once you have eliminated what is impossible, what you are left with must be true, no matter how improbable. (Sherlock Holmes)
Actually, the Bible is not the default position or null hypothesis here. There needs to be POSITIVE evidence for your position.
Now you're scaring me. :^)
The positive evidence for my position are the laws of Thermodynamics and biogenesis.
In the end, since we are dealing with an untestable Beginning both paradigms must be accepted by faith.
Christians acknowledge that (Heb.11:3).
Evolutionists want to pretend that they are 'scientific'when in fact, they just evade dealing with the ultimate reality of what their system is really teaching, life came from non-life.
Take your pick on what is more believable.
May? hahahahahahahahahahahahahahahahahahahahahaaa!!!!!!!!!!!!!
The article describes the rough scenario for inducing circular and elliptically polarized light in ultraviolet radiation. Based on this description, it is not the orientation of Earth's magnetic field, or the rotational symmetry of the galaxy. It's a phenomena that is preent everywhere in space and is related to the magnetic fields in that location and the type of dust particles oriented in that magnetic field. When UV light passes through a cloud like this, polarization is induced in this light. It is similar to how glare (i.e. reflected light from the sun) outside is linearly polarized and polarizing sunglasses selectively filter out this glare.
This is a chemistry experiment that was performed in the lab and did produce actual date. It is not a model. Unless, ov course, you believe that chemical reactions are selective to their location in our universe, which has been proven false.
Two things. Nothing in the Laws of Thermodynamics prevents the evolution of self-replicating molecules. Secondly, there is no "Law of Biogenesis" except on creationist websites.
And actually, the water down the drain direction isn't fixed in either hemisphere. It all depends on the shape of the drain and the sink. Water will go either way down a drain, depending on how you shape the toilet bowl.
This is easily testable. Watch the next 10 toilet flushes in different toilets you encounter. Sometimes left, sometimes right, just depends on the bowl.
For example, I believe Lactobacillus fermenti can catalyze the conversion of either enantiomer of glutamic acid into the other. That's pretty imprssive - almost the biological equivalent of catalyzing the conversion of matter to antimatter!
Two things, the law of Thermodynamics makes the evolution of self-replicating molecules impossible because you have to start with the molecules themselves
So, where did the molecules come from?
In other words, something cannot come from nothing.
Or do you deny that is a law also?
Funny how you guys always want to start with life.
Second, the Law of biogenesis is just that a law, since life cannot come from non-life.
Until you show that it can, it remains a law.
More fantasy thinking from the sci-fi world of evolution.
If you're asking "where did matter come from" (and it sounds like this is where you are trending), it may be an artifact of the expansion of the universe. Physicist can explain it eloquently, but it has something to do with the gravitic potential energy of the universe translating into matter in accordance with Einstein's equation.
I did Google "Law of Biogenesis." It comes from Pasteur's experiments that show bacteria do not spontaneously generate -- or that life isn't suddenly zapped into existence, which is a blow for creationism, not science. The latter hypothesizes a gradual shading from self-replicating molecules (Google that and you'll get about 300 research papers; it'll make your head hurt) to primitive lifeforms. At no point could you actually point at one of the products and say, "this is life and its parent is non-life." Each would simply be points on a spectrum from non-life to life.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.