The Origin of Life

The origin of life has been one of the most difficult problems facing abiogenesis.  One aspect of this problem is that several life chemicals are only present in either the right or left-handed form.  Furthermore, most organic chemicals are not found in space debris from sampled comets or in nebulae.  Their origin on earth remains a mystery since environments which would be conducive to the formation of some would destroy others.

Jeff’s Call

His phone call came at the worst time. In the morning, I usually have a clinic where I have a busy waiting room filled in impatient patients who always complain about my taking too long with the prior patients. I knew from experience that Jeff frequently was very verbose and insisted on prolonged discussions even the mundane, and I was sure this would be no exception. I asked my secretary to make a telephone appointment later in the day.

I was of course, very interested to hear what news Jeff had to bring; I was fascinated and somewhat humbled that he would want my suggestions about how to handle his new hallucinations since this was not certainly my specialty. I was sure – at least in the beginning – that these must be hallucinations. I have talked with thousands of people and none have ever complained of angelic visitations.  Hallucinations can seem very real, and many people have great difficulty differentiating between reality and hallucinations when they occur.

When Jeff came into my office, he was clearly deeply troubled. During his first visit, Jeff was still cocky, sure of himself and of his command on reality; now, his self-confidence seemed challenged by a new reality. We all face situations where our self-assurance is challenged when the unexpected takes us by the throat and won’t let go. Often, these challenges are rather mundane, such as when a friend whose opinion we value confronts us with our failures, we get fired from a job we envisioned holding until retirement, or we experience the death of a loved one. Life has a habit of striking us in the face when we least expect it; of knocking us to the floor and kicking us in the face when we seem most in control of our circumstances.

Of course, we are truly never in control of our circumstances – it is all largely an illusion. But it is in these challenges that personal growth is possible; but only if we allow this progress to happen.

“Dave, it happened again! Just when I thought I might be finished with this angel-thing, he came again! But this time, he came with specific information and not just generalized platitudes. You see, Dave, this time he challenged me with specific facts – stuff I never even heard of or considered in my wildest imaginings.”

Hallucinations by their very nature are only a reflection of our own consciousness. Hallucinations are common in drug withdrawal – such as with alcohol withdrawal. These patients often view horrific visions of insects coming at them off the wall, or monsters trying to devour them. Usually, they seem very real but of course, are not. In retrospect, alcoholics during their sober moments readily acknowledge these hallucinations reflect their own fears and imaginations but have no cognitive content; that is, they don’t present any original information. The sufferer doesn’t gain any new life insights or factual knowledge from them.  In other words, the alcoholic does not gain specific information from bugs on the wall.

But this is what happened with Jeff. He was very familiar with hallucinations because he was personally experienced with drug abuse. To him, hallucinations were commonplace, almost as common as going to the store or picking up the laundry. But this hallucination imparted new knowledge which could be independently verified, but which Jeff would never have known with his visitations. Jeff recognized this factual content strongly suggested the hallucinations might actually be real, and that his mortality might actually be approaching much quicker than he had previously anticipated.

Jeff realized it is difficult to explain away something like a ‘hallucination’ if it imparts specific, verifiable information that he had no way of knowing previously..

“OK Jeff, try to regain your composure and tell me what happened. It’s at the end of the day, and I have some time to listen. But really, Jeff, you can’t keep running here after every dream!”

“Dave, I know that but come on man, this is only my second time. Maybe I’ll figure out how to handle this stuff but it really scares me.”

“What scares you?”

“Well, what he told me. First off, who remembers all their dreams? I mean, usually, after five minutes my dreams from the night before are all forgotten. But these things; I remember every word, every inflection, and everything that this horrible hallucination put into my head. And you know what? I remember everything from the other dream too. I’ve tried jacking myself up on whiskey to try to forget them – but I can’t! They stay right with me.”

“Calm down, Jeff. Just tell me what happened. Maybe you need a sedative to get over all this stuff. I mean, it’s probably just flashbacks from using all the drugs – especially the hallucinogenic ones – that you’ve had over all these years.”

“Look, Dave, I’m the expert here on hallucinations; I’ve had them all my life, at least the greater part of my life when I’ve been using drugs to escape at night. These are different.”

“How so?”

“Dreams sometimes seem very real when you are having them, but then you wake up and realize how stupid they are, filled with contradictions and unworldliness.  These things are nothing like dreams.  I remember everything – just like the angel said would happen.  I mean I can’t get them out of my head.

The Dream

“Well, tell me what happened.”

Jeff sat down on my office sofa and struggled for a few minutes to regain his composure. I got him a drink of Diet Coke which he eagerly accepted and gulped down immediately. We shared in some small talk about the weather before he felt comfortable enough to begin.”

“Dave, this whole thing began just like the last one. Just after I had gotten to sleep I could visualize the whole room from my bed. It started to brighten up like a thousand spotlights targeting my face. I couldn’t escape the light, and there was no telling where the light was coming from because it seemed to come from everywhere.  The intense brightness was unbearable, something you couldn’t escape.  Do you know what is funny, Dave?  I remember looking all around me and couldn’t see my shadow!  Isn’t that weird?  Then I check out my clothes; even they were white even though I had on dark pajamas.

“That does seem unusual – what do you think that means?”

I knew from my medical training that you could sometimes tease out information by asking their opinion.

“Dave, I have no idea.  Maybe there can’t be any darkness in the presence of this much light.”

It was then that a booming voice started.”

“Son of Earth, I have come here to challenge some of your most cherished beliefs; beliefs which are foolish and wrong, yet beliefs which you have held since your youth which have led you astray. In your foolish diatribe during our last visit, you supposed that life came from nothing and that you are a product of evolution rather than a creation of God.”

“Well, of course. Everybody knows that. Science has clearly established that life came from the spontaneous assembly of chemicals in ancient primordial soup billions of years ago. Furthermore, over the next billions of years, mutations produced gradual changes some of which improved survival.  Gradually, natural selection of these beneficial mutations produced gradual change over time.

Finally, life got more sophisticated until monkeys and apes evolved into man. That is the consensus of scientific opinion which has been proven to be true. Why they’ve even created life in the laboratory – there’s no need for God when science has shown exactly how life came to be.”

“Son of Earth, your foolishness knows no bounds, and your ignorance is astounding.”

“Look, if you’re going to talk to me like that, this dream is finished.”

“Be quiet and listen, for you are as ignorant as you are misinformed.  You will hear my message each night; you have no choice.  What you do with this information is up to you.”

“Dave, when the angel said those words, I could no longer fight back. It was clear he had me in his clutches and wasn’t going to let go no matter how hard I fought. There was no getting around who was in control – and it wasn’t me.”

“Son of Earth, your mind and understanding are too limited for you to grasp all I must tell you in one night; this may take several nights. But be clear of this; you will hear what I have to say, and you will remember what I tell you until your dying day. When you face God in judgment, you will not be able to claim ignorance; nor will you be able to feign forgetfulness for you will remember all I tell you. If you reject my words, you will only be able to accept the consequences.”

“I really didn’t like feeling pushed around. In my line of business, I have bodyguards just in case some customer who feels I may have done him wrong decides to take revenge. There certainly are instances where a broker has been threatened by a distraught customer – especially when they have lost money. I’m not used to being intimidated either – but it was very difficult to fight back from your dreams!”

“Son of Earth, I can see after looking into your mind you have no formal education in organic chemistry. That is a pity, as that means I am going to have to take the time (and you have little time left) to teach you some simple facts. Perhaps that is why you have such silly notions about the creation of life – because of your ignorance of science.”

Jeff looked down for some time trying to gather his thoughts.  I was impressed he was able to tell me how dismissive the angel was with him.  I was sure Jeff had no education in chemistry, or if he did any knowledge was long forgotten.

“First, Son of Earth, let me tell you many organic compounds have a right-handed construction and a left-handed construction; these compounds are mirror images of each other.”

“OK angel, what is an organic compound?”

“Son of Earth, an organic compound is one that contains carbon and is typically found in living things.[1] Examples of an organic compound would be glucose – the simple sugar that is increased in the blood of diabetics.  Another example is the sugar ribose – the sugar that is found in RNA.”

“OK, so what?”

“Life chemistry frequently uses only one of the mirror images of these compounds  – either the right-handed variety or the left-handed variety. Here is an image of an amino acid;[2] as you can see, it is exactly the same organic compound in two distinct forms.”

“OK, angel, I see that there are two forms of the same chemical.”

“These are amino acids which are the building blocks of proteins. It turns out, Son of Earth, that only the left-handed variety of the amino acid is used in life-proteins.”

“Yes – so what?”

“Son of Earth, we will have to have a chemistry lesson so you might understand the importance of this fact. Natural molecules that have left and right-handed variety occur in nature in equal proportions; there is an equal amount of right-handed molecules and left-handed ones. Furthermore, they are functionally identical and behave exactly the same in chemical reactions. However, they are not functionally identical when incorporated into life molecules. Proteins that incorporate right-handed amino acids may not function properly, and molecules of DNA that incorporate the wrong handed ribose molecule will not be able to copy itself.”[3]

“Well then angel, I suppose that some life molecules started out by using only one or the other of the molecules; what’s so difficult about that?”

“First, Son of Earth, you might ask if there is a physical or chemical process in early Earth that might drive an equal mixture of right and left-handed amino acids into only one handedness or the other. Chemically, the answer is no. All attempts to manufacture amino acids in the laboratory produce an equal mixture of one or the other variety. Therefore, prebiotic synthesis of amino acids whether on Earth or anywhere else in the universe would be expected to produce only equal mixtures of the right and left-handed variety.[4]

“Well there must be some way to produce only right or left-handed varieties of amino acids – isn’t there?”

“There are only two viable physical mechanisms for producing a mixture of right or left-handed amino acids is an effect called magnetochiral anisotropy which links chirality (handedness) and magnetism.[5] The two most probable sources of magnetochiral anisotropy are photochemistry (that is light-induced chemistry) with circularly polarized light and parity violations in electroweak interaction (a particle physics phenomenon). “

“OK angel, you are leaving me in the dirt here. What the heck are you talking about?”

“Son of Earth, try to stay with me. You will remember all of this conversation after you awaken from these dreams; therefore, you can do your own research to verify what I am telling you.”

“Whatever.”

“Photochemistry with the correctly tuned wavelengths and sufficiently concentrated can generate significant amounts of either a left or right-handed mixture of amino acids. However, this is purely a laboratory phenomenon because no natural circularly polarized light exists on Earth except for a tiny amount in normal light.

“Angel, maybe that tiny amount could produce a large effect over many years!”

“No, Son of Earth, for the amount of naturally occurring polarized light is far too little to generate an excess of one mirror image of a molecule over another. The other process that can produce large amounts of a one-handed mixture are parity violations in electroweak interactions. Calculations establish that – at best, these violations might produce an excess of one handedness over the other any better than 10^17 (that is, 0.000000000000001 percent).[6]”

“Angel, look – there must be some other way to produce a single-handed mixture of chemicals in nature – we just haven’t found it yet.”

“Son of Earth, your optimism is commendable but your ignorance is great. The best origin of life scientists on earth admits that there is no known way to produce a single-handed mixture. Organic chemist William Bonner noted, “I spent 25 years looking for terrestrial mechanisms for homochirality and trying to investigate them and didn’t find any supporting evidence. Terrestrial explanations are impotent or nonviable.[7] Bonner admitted that the source of single-handed chemicals must be extraterrestrial while reviewing the origin of homochirality.[8]

“Well, of course, angel – that makes perfect sense! Maybe a high concentration of life chemicals of the correct handedness came to earth on a comet or asteroid, or maybe the Earth passed through a cloud of the correct handed molecules sometime during its history. How can you say this didn’t happen? Furthermore, I seem to have heard the discovery of excessive left-handed amino acids in a meteorite – in fact, now that I think about it a little, I’m sure of it!”

“Son of Earth, as you know, there have been many meteorites falling from space upon the Earth; some of these meteorites have been studied to try to determine amino acid content and more recently, chirality. For example, the Murchison meteorite landed in 1969 and about 1,500 pounds were recovered. It was a carbonaceous meteorite composed of a high percentage of carbon compounds. Chemical analysis found it to be the most amino acid laden meteorite in existence. Biochemists determined that was a small (1 to 9 percent) excess of left-handed molecules among six different amino acids.[9] [10] [11] A recent claim for a 33 percent excess in the left-handed configuration for the amino acid alanine[12] resulted from inadequate instrument resolution.[13]

“But still, Angel, this shows it is possible to produce an excess of one kind of amino acid over another!”

“The biochemist Kvenvolden agreed with your assumption and performed a complete reanalysis using more sensitive techniques[14]
to try to determine whether there was an excess or not. Kvenvolden was particularly concerned about whether the meteorite might have become contaminated with earth amino acids. In order to investigate this possibility, he compared the amino acid abundances near the exteriors of the samples with the abundances in the interior of the meteorite and found that the one amino acid (isovaline) for which he was able to accurately determine the ratio of left-handed to right-handed molecules proved to be racemic; that is, no abundance at all.”[15]

“The other meteorite that has been aggressively investigated is the Nakhla meteorite that hit the Nile River Delta in 1911. Similar to Kvenvolden, the latest investigators to investigate chirality noted, “The distribution of amino acids in Nakhla, as well as their enantiomer abundance, is very similar to what we found in a Nile Delta sediment core sample collected off the coast of Egypt, close to where Nakhla fell.”#[16] Even the most pristine meteorite ever discovered – the Tagish Lake meteorite from northern Canada – is not free of contamination problems. Airborne amino acids can significantly contaminate an exposed meteorite left in freezing conditions for only a week.[17] One origin of life specialist concluded,

If we want any information from meteorites about the state of amino acids in outer space, we must capture a meteorite before it hits the ground.”[18]

“All right, Angel, so it seems we can learn little from earthbound meteorites because of contamination by the Earth; still, that does not negate the possibility of extremely pure left-handed amino acids being somehow formed in space!”

“Of course, Son of Earth, some have supposed homochirality might have occurred somehow in space since there does not seem to be any way such mixtures can occur on earth. Some have supposed that intensely circularly polarized ultraviolet light coming from neutron stars or black holes could produce such a solution. However, using 100 percent circularly polarized ultraviolet light, the most successful laboratory experiments were only able to yield a 20 percent excess of left-handed amino acids over the right-handed variety.[19] [20].

“It seems like these scientists were on the correct track – maybe with a little bit more intense light they could have achieved a greater purity of one-handed amino acids over the other.”

“The main difficulty with your assertion, Son of Earth, is that polarized ultraviolet light produces a greater concentration of either right or left-handed chemicals by destruction; that is, to produce a surplus of left-handed amino acids, ultraviolet light destroys the right-handed variety. Furthermore, experiments by the Japanese question whether polarized light can every produce greater than a 20 percent purity of one-handed amino acid over the other.”

“The Japanese noted that the best known astronomical source of circularly polarized light is the synchrotron radiation emitted by neutron stars. The Japanese simulated this radiation in the laboratory and were only able to produce an excess of 1.12 percent of the left-handed compound compared to the right-handed variety.[21]

“Yes, but maybe over millions of years this small difference could build up into greater concentrations of the left-handed variety of amino acids over the other.”

“The problem with your assertion, Son of Earth, is that neutron stars all have large fluctuations in both the degree and the intensity of their circularly polarized light.[22] These fluctuations either destroy whatever homochiral amino acids are produced, or they generate an insufficient amount of excess of one-handed amino acids over the other.”

“But the practical situation is even worse. Neutron stars also produce copious amounts of gamma radiation and X-rays. A molecular cloud close enough to a neutron star to receive adequate ultraviolet light to produce even a little homochirality also receives enough X- and gamma radiation to destroy any amino acids present in that cloud. So in fact, Son of Earth, astrobiologists have no explanation as to how left-handed amino acids re the only amino acids in proteins when they are present in equal amounts in nature.”

“Well, surely we will find an explanation, Angel. Why must you always assert that if science hasn’t figured out how something happened then God must have done a miracle? I mean so far we have made great strides in understanding how the universe began!”

“But Son of Earth – the situation is even worse for a natural explanation than I have explained so far. The only known method for producing an increase in either the right or left-handed form of an amino acid is through circularly polarized ultraviolet light. But it turns out that not only must the light be circularly polarized, but it must also be monochromatic; that is, of only one wavelength. This is called the ‘Kuhn-Condon Rule’” These investigators found that while one wavelength of circularly polarized ultraviolet light might produce a preferentially left-handed configuration, a different wavelength of the same circularly polarized light would produce a right-handed configuration.[23]
[24] What this means, Son of Earth, is that any broadband of ultraviolet light – such as that produced by a neutron star – would destroy the same number of left-handed molecules as right-handed ones. There are no known astrophysical sources of monochromatic circularly polarized ultraviolet light.”

“Well, angel, of course, I have little I can say; whoever studies such arcane stuff as ‘monochromatic circularly polarized ultraviolet light’ in the first place?”

“Son of Earth – if you were truly interested in objectively studying the origin of life science then you would have learned these facts. You might notice that these particular studies were done 80 years ago – they are nothing new.”

“Surely there must be some other explanation for the natural production of enriched single-handed amino acids!”

“Son of Earth, this area has been aggressively studied as you might imagine for those who won’t believe in God are anxiously trying to find a way to naturally create life. Some have supposed there might be some ‘radiation filter’ between sources of ultraviolet light and the Earth which might absorb all but one single wavelength;[25] however, astronomers have been unable to find such a source because, Son of Earth, none exists.”

“Well, OK angel; but how about ultraviolet light from the sun producing left-handed amino acids. All you need is for the sun to produce this kind of light for a short time in order to make enough of this stuff for life to get kick-started!”

“Son of Earth, your protestations continue to show your ignorance. Earth’s atmosphere at the time life started on earth blocked ultraviolet light; there simply was not enough light available to produce any chiral amino acids.”[26]

“But angel, it seems like I heard about amino acids being discovered in space?”

Stardust Spacecraft

“Son of Earth – only one amino acid – glycine – has been found in space.[27] [28] This is the simplest amino acid and by the way, has no right and left-handed forms and none of the other 19 amino acids have ever been found in space. And by the way, none of the sugars used in DNA and RNA have ever been found in space either – not to mention that only the right-handed sugars are used in life molecules.[29] The closest discovery was the finding of extremely low levels of a three-carbon sugar in the Murchison and Murray meteorites.[30]
[31]

“OK Angel, it seems like I heard about a space mission that sampled dust from a comet – and even returned that dust. As I remember, they found some amino acids in the comet! How can you ignore those findings, angel?”

“Son of Earth, you are correct. The Stardust spacecraft returned from deep space where it was able to sample the dust coming from comet 81P/Wild and bring it back to Earth. Investigators found only one amino acid – glycine – that could be attributed to the comet and not to contamination.[32] As we have noted before, glycine has been found in space previous to the Stardust mission and so it is not too surprising it was found from the comet. Furthermore, glycine is the one amino acid that does not have a right or left-handed variety.”

“So maybe just given enough time and enough space – like the entire Universe – perhaps a protein could have spontaneously assembled using only left-handed amino acids in some way we just haven’t considered.”

“There were several other non-important organic compounds discovered which are not life chemicals.  Son of Earth, there is only so much I can teach you in one night – your intellectual abilities are rather limited and I am only able to teach you very little information with every visit. However, if you wish to study some of the theories regarding this mystery you might start with this monograph.”[33]

And with that, the room started slowly to darken until Jeff recognized he was sitting up in bed, looking forward at the wall. While with the angel in the dream, he saw the molecular formulas of amino acids, sugars, and proteins and he was made to understand how they are used and made by living organisms. It had been a long time since Jeff even considered chemistry and he was unsure whether he had even heard about amino acids. After the dream, he could recall everything said, and every chemical formula that was revealed to him in the dream.

“Dave, do you know why this particular dream has me so freaked out?

“No, not really. It was just like a high school chemistry lesson: I mean, nothing really earth-shattering. Any student in a modern biology class would be learning about amino acids and proteins today, and would also have a good working knowledge of DNA.”

“That’s not what I mean. Look, what freaks me out is that this hallucination – angel, whatever, told me facts, verifiable facts, that I didn’t know before the dream.”

“I still don’t get what you mean, Jeff.”

“Well, that means my hallucination maybe wasn’t a hallucination; I mean, hallucinations can’t give you the information you didn’t know previously. Mostly, they just scar you – kind of like ants falling on you from the ceiling, or monsters coming at you from underneath the bed. I’m an expert on hallucinations; with my drug history I’ve certainly had my share over the years!”

“I guess I see your point now.” I wanted to proceed carefully now because I knew Jeff was starting to see the ‘big picture.’ What Jeff was really worried about was that if this were really an angel – and not just a hallucination, then the part about his living only another year would also be true.”

Rosetta Satellite and the Origin of Life

“Dave, look. This was really technical stuff for me; I mean, circularly polarized monochromatic ultraviolet light – who thinks about such things! And so what! I mean, scientists are discovering new things all the time.  For example, the Rosetta satellite sampled the 67P comet and found glycine – the simplest amino acid present.”

I remember hearing about the Rosetta spacecraft.  It landed a small probe on the comet and it was hoped they might find organic molecules – even complex nucleic acids.

“I remember hearing about the Rosetta spacecraft.  It was hoped that sampling of the comet might demonstrate more complex amino acids but none were found.  Part of the study was to evaluate the comet for chiral molecules but none were located.  The only amino acid found was glycine suggesting many of the compounds found on meteors might be earth contamination.”

“So you’re just going to ignore all that just happened? Are you going to try to do some research and see if what you heard in that dream represents reality?”

“Nope, I’m just going to chalk it up as one of those unexplained experiences. I’m having too much fun with my life now; I mean, I have all the money I’ll ever need, but I also have a way to get more just in case. Dave, money is power, and I love power too! But what I am going to try is to lay off the drugs for a while to see if this angel guy won’t show up anymore!”

Jeff said his good-byes and that was it.

It was difficult for me to figure out what to make of Jeff’s experiences. I see a lot of people and hear a lot of stories, but never have I heard about somebody being visited repeatedly by angels. Of course, there is a respected history of angelic visitations throughout history,[34]
sometimes giving information – but usually, this information was about the future, or a certain mission for them to fulfill, and not an intense, verifiable scientific study. Even so, Jeff was unconvinced; he was sure there was some alternative explanation to what he had just experienced – although he was at a loss to find an alternative explanation.

I also was very skeptical. I could tell Jeff was clearly affected by his experience, but what exactly this experience was – who knows.

Certainly, there are thousands of dedicated scientists across the world working on the origin of life problem – maybe one day they would find an answer – perhaps not. As a society, we have learned not to attribute unknowns in science to ‘miracles’ too rapidly; we must remain skeptical of any such claim. However, it is also a possibility that the creation of life on planet Earth was one of the greatest miracles of all.

I found it interesting that scientists became very excited about the discovery of the simplest amino acid in the comet dust.  We have known that glycine is present in space from prior spectroscopic studies of nebulae.  It is a considerable extrapolation to suggest the finding of glycine on a comet supports abiogenesis, but having no other idea as to how this occurred, Carl Pitcher from the NASA Astrobiology Institute noted,

The discovery of glycine in a come supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare.

Jeff’s return

Gradually, over the next few days, I put all of this behind me. I was so busy with patients, tests, trying to figure out what to do next that I just couldn’t do any independent research right then. His last visit, after all, ended with a promise of another visit; if Jeff got another visit then – well, who knows!

I would not have to wait very long.

References

[1] http://dictionary.reference.com/browse/organic+compounds

[2] http://en.wikipedia.org/wiki/Chirality_(chemistry)

[3] Cohen, Jon, “Getting All Turned Around Over the Origins of Life on Earth,” Science 267 (1995), p. 1265

[4] Bada, Jeffrey L., “Origins of Homochirality,” Nature 374 (1997), p. 942

[5] G.L.J.A. Rikken and E. Raupach, “Enantioselective Magnetochiral Photochemistry,” Nature 405 (2000), pp. 932-935

[6] Rikken and Raupach, p. 934

[7] Quoted in Cohen, p. 1265, Bonner made this observation at “Physical Origin of Homochirality in Life,” a conference held in Santa Monica, California, February 1995

[8] William Bonner, “The Origin and Amplification of Biomolecular Chirality,” Origin of Life and Evolution of the Biosphere, 21(1991), pp. 96-111

[9] John R. Cronin and Sandra Pizzarello, “Enantiometric Excesses in Meteorite Amino Acids,” Science 275 (1997), pp 951-955

[10] S. Pizzarello and J.R. Cronin, “Alanine Enantiomers in the Murchison Meteorite,” Nature 394 (1998) p. 326

[11] John Cronin and Sandra Pizzarello, “ Meteorite Amino Acids and the Origin of Homochirality,” Book of Abstracts, 12th International Conference on the Origin of Life and the 9th Meeting of the International Society for the Study of the Origin of Life (ISSOL 1999), July 11-16, 1999, San Diego, California, p. 41.

[12] M.H. Engel and S.A. Macko, “Isotopic Evidence for Extraterrestrial Non-Racemic Amino Acids in the Murchison Meteorite,” Nature 389 (1997), pp. 265-268

[13] Pizzarello and Cronin, p. 236

[14] Keith A. Kvenvolden, “Chirality of Amino Acids in the Murchison Meteorite – A Historical Perspective,” Book of Abstracts, ISSOL, 19998, p. 41.

[15] Kvenvolden, p. 41.

[16] Daniel P. Glavin, et al., “Amino Acids in Martian Meteorite Nakhla,” Book of Abstracts, ISSOL, 1999, p. 62

[17] Sandra Pizarello et al., “The Organic Content of the Tagish Lake Meteorite,” Science 293 (2001), p. 2239

[18] ISSOL 1999 conference quote

[19] Jeremy Baily et al., “Circular Polarization in Star-Formation Regions: Implications for Biomolecular Homochirality,” Science 281 (1998), p. 672

[20] G. Balavoine, A. Monadpour, and H.B. Kagan, “Preparation of Chiral Compounds with High Optical Purity by Irradiation with Circularly Polarized Light, a Model Reaction for the Prebiotic Generation of Optical Activity,” Journal of the American Chemical Society 96 (1974), pp. 5152-5158

[21] Yoshinori Takano et al., “Asymmetric Photolysis of (DL)-Isovaline by Synchrotron Radiation,” Book of Abstracts, 13th International Conference on the Origin of Life and the 10th Meeting of the International Society for the Study of the origin of Life (ISSOL 2002), pp. 302-311

[22] Mark M. McKinnon, “Statistical Modeling of the Circular Polarization in Pulsar Radio Emission and Detection Statistics of Radio Polarimetry,” Astrophysical Journal 328 (2002) pp. 302-311.

[23] Werner Kohn, “The Physical Significance of Optical Rotary Power,” Transactions of the Faraday Society 26 (1930), pp. 293-308

[24] E.U. Condon, “Theories of Optical Rotary Power,” Reviews of Modern Physics 9 (1937), pp. 432-437

[25] Stephen F. Mason, “Extraterrestrial Handedness,” Nature 389 (1987), p. 804

[26] http://adsabs.harvard.edu/abs/2004cosp…35.1076I

[27] http://arxiv.org/abs/astro-ph/0410335

[28] http://adsabs.harvard.edu/abs/2003ApJ…593..848K

[29] http://en.wikipedia.org/wiki/List_of_interstellar_and_circumstellar_molecules#cite_note-apj619-43

[30] George Cooper et al., “Carbonaceous Meteorites as a Source of Sugar-Related Organic Compounds for the Early Earth.” Nature 414 (2001), pp. 879-883

[31] Mark A. Sephton, “Life’s Sweet Beginnings?” Nature 414 (2001), pp. 857-858

[32] http://stardust.jpl.nasa.gov/news/news115.html

[33] https://books.google.com/books?id=TS2Ce-LWCjYC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f;=false

[34] http://www.near-death.com/angels.html