Is saving our atmosphere killing our seas? Biofuels may stifle global warming, but scientists warn that agricultural runoff causes new problems.

Each year in April and May as farmers in the central US fertilize their crops, nearly 450 thousand metric tons of nitrates and phosphates pour down the Mississippi River. When these chemicals reach the Gulf of Mexico, they cause a feeding frenzy as photosynthetic algae absorb the nutrients. It’s a boom-and-bust cycle of epic proportions: The algae populations grow explosively, then die and decompose. This process depletes the water of oxygen on a vast scale, creating a suffocating “dead zone” the size of Massachusetts where few, if any, animals can survive.

The EPA has been working to reduce the size of the dead zone, with a goal of shrinking it to about 5,000 square kilometers—a quarter of its current size—by 2015. But a new study in Environmental Science & Technology shows that other efforts to preserve the environment may be exacerbating the dead zone. Kristopher Hite, a graduate student in biochemistry at Colorado State University, explains the implications of the study on his blog, Tom Paine’s Ghost.

The study examined the implications of a 2007 law that requires the US to annually produce 36 billion gallons of biofuels by 2022. Barring major biofuel production breakthroughs from sources like algae or microbes, most of this fuel will come from crops grown in the central US; the fertilizers and other agricultural waste they produce will flow straight down the Mississippi and feed the dead zone. Hite says the study, led by Christine Costello, found that meeting this goal will make it impossible for the EPA to reach its target reduction in the size of the dead zone. Even if fertilizer-intensive corn is replaced with more eco-friendly crops like switchgrass, the vast increase in agricultural production will cause the dead zone to grow unless preventive measures are taken.

So what can be done about it? The Society for Conservation Biology suggests that increasing the size of wetlands or other buffer zones around the source of the pollution—the farms themselves—could help.

Unfortunately, artificial wetlands have their own negative ecological side effects. As this post at Conservation Maven shows, some created wetlands are dominated by invasive species. Apparently, the heavy equipment used to build the sites also compacts the soil in a way that makes it more difficult for native species to flourish.

But not all human-made wetlands are bad. Conservation Maven also points to a Swedish study which found that less-diverse wetlands dominated by tall plants are actually more efficient at removing nitrogen from runoff than many other sites. So creating wetlands can be a very effective means of removing pollutants from water, even if local biodiversity suffers. The current pace of biofuel development, however, exceeds the capacity of available wetlands.

Hite remains an optimist, pointing to new technology that uses fungi to convert the cellulose in wood chips, corn stalks, and other agricultural “waste” into biofuels. If this can be done efficiently, we could eventually harvest several times more energy from the same amount of cropland. Even while acknowledging that we may still face problems like the Gulf’s dead zone, Hite believes that ultimately technology can help us prevent greater ecological disasters like global warming.

But should Hite even be making this case? How do we decide whether it’s ecologically sensible to produce biofuels or build wetlands? Some have argued that the advocacy of scientists like Hite and websites like Conservation Maven is misplaced. Shouldn’t scientists just be interested in giving us the facts, staying removed from policy decisions and letting the general public and politicians decide how to act? Doesn’t becoming an advocate introduce bias into the scientific process, potentially tarnishing results?

James Hrynyshyn is a freelance journalist and unapologetic environmental advocate who says that many of the best scientists, from Albert Einstein, to Carl Sagan, to NASA’s James Hansen, have also been important policy advocates. On his blog, The Island of Doubt, Hrynyshyn cites a May paper in Conservation Biology by Michael Nelson and John Vucetich, who argue that scientists’ advocacy positions can easily be separated from scientific truths. For instance, late in his life the great chemist Linus Pauling damaged his reputation by peddling vitamin C as a cure-all, but that didn’t take away from his earlier scientific contributions, for which he won two Nobel prizes.

More importantly, Hrynyshyn says, it’s unfair and unwise to restrict individuals—who are interested citizens as well as working scientists—from participating in the political process, especially when those individuals have knowledge and expertise that applies directly to important problems. Conservation biologists can both alert us to potential ecological disasters and offer insight into how to solve them. Why not tap their expertise to help form policy decisions?

There’s much more discussion of ecology—and ecologists’ role in creating environmental policy—at ResearchBlogging.org.

Optical illusions may seem to deceive, but they actually reveal truths about how our brains construct reality

Stare at the red dot in the center of the figure for a minute or two. Before long, the green ring will disappear—it simply seems to fade into the white background. There are no tricks: This is a simple, static image file. The effect has been known for more than two centuries and is named for its discoverer, Ignaz Paul Vital Troxler (1780–1866), a Swiss physician and philosopher. “Troxler fading” is actually related to what you experience when you get “dizzy”: You become so habituated to a phenomenon (spinning in a circle or seeing a green ring in your peripheral vision) that you stop noticing it’s there. Or, rather, you don’t realize that your perceptual system has begun actively ignoring it. It’s only when your circumstances change that you see what the phenomenon has done to your perceptual system. When you stop spinning, the world seems to continue, in reverse. When you look away from the green ring, you see a red ring in the same part of your visual field.

Occasionally an illusion attracts widespread notice online, perhaps because it was posted by a popular blogger, but it’s rare that we see a scientific explanation of how the illusion works. That’s beginning to change. Each year, at the meeting of the Visual Science Society, the Neural Correlate Society holds a contest where vision scientists share their latest, greatest optical illusions. This year’s winner is entitled “The Break of the Curveball” and was created by Arthur Shapiro, Zhong-Lin Lu, Emily Knight, and Robert Ennis. Shapiro, an associate professor of psychology at American University, is also a blogger and an avid baseball fan. (He once referred to pro football games in the early fall during the baseball playoffs as “preseason games that count.”) He has a full explanation of the illusion on his blog, but to my mind an even more impressive illusion is this one. (Click and watch this before continuing!)

When you shift your focus from the red dot to the yellow dot, the motion of the balls rotating around the dots appears to reverse. Again, Shapiro explains the effect on his blog. As with Troxler fading, the effect is due to our perceptual system’s limited ability to process information outside of a central focal region. When you look directly at the red dot, you can see that the surrounding circles are moving in one direction as the shaded patterns inside the circles are moving the opposite direction. But you can’t process all the information about the circles ringing the yellow dot in your peripheral vision, so the pattern moving inside the circles dominates.

But our perception of the world doesn’t rely solely on vision. We use all our senses to build a representation of what the world is really like. Many illusions occur because what we perceive with one sense conflicts with another. Varun Sreenivasan, a graduate student at the EPFL in Lausanne, Switzerland, has written an amazing account of a 2003 study on the “rubber hand effect.” The basic premise is this: If your real hand is hidden behind a screen and you see a fake hand in its place, then you can “feel” it when a researcher touches the fake hand. Neuroscientists K. Carrie Armel and V.S. Ramachandran wanted to see when the illusion broke down.

First, they asked volunteers to place one hand behind a screen. An experimenter scratched the table in front of the screen while either scratching or not scratching the hidden hand. The participants reported “feeling” a scratch on their real hand whether or not it was actually being scratched.

They also experimented with an extremely unrealistic rubber hand and arm, much longer than a real arm. The researchers bent one of the fake fingers back to what would be a very painful position while lifting the volunteer’s real (hidden) finger only slightly. The participants said they felt real pain, which was only slightly less intense with the extra-long rubber arm than with a realistic rubber arm. A measure of skin conductance showed a dramatic a physiological response in the volunteers as well. Clearly the effect of seeing a finger being bent contributes greatly to our experience of pain.

These illusions are not only fascinating to observe and experience, they also tell us a great deal about how our perceptual system functions. We receive so many inputs from the environment that the brain must prioritize which inputs to trust. Illusions represent the boundaries between conflicting inputs to the perceptual system, and by uncovering them—and often explaining them on their blogs—researchers can also uncover how the brain itself works. You can follow that conversation at ResearchBlogging.org.

More on illusion at Researchblogging.org:

• The Hollow Mask Illusion: An incredible phenomenon which makes hollow faces look solid. The Neuroskeptic shows how it works. Dave Munger elaborates on the same research at Cognitive Daily.
• The Waterfall Illusion: The Neurophilosopher shows how a classic visual illusion can also be experienced through the sense of touch.
• Is “déjà vu” an illusion? Christian Jarrett explains how a recent study shows that déjà vu may be caused a fleeting (but recent) glimpse of a scene.

Studying the Strangest Man

Paul Dirac (left) and Richard Feynman. From The Strangest Man. Photograph by A. John Coleman, courtesy AIP Emilio Segre Visual Archives, Physics Today collection.

For more than five years, former physicist Graham Farmelo devoted himself to unlocking the secrets of one of the most important and curious figures of 20th century science, Paul Dirac. He was born in 1902 and died in 1984, and though lionized by his peers for his fundamental work in quantum mechanics (among other things, he predicted the existence of antimatter and won a Nobel Prize when he was only 31), Dirac’s legacy has fared poorly among the general public. During his research, Farmelo found that most residents of the “famous” physicist’s hometown of Bristol didn’t even know who Dirac was. Unquestionably, this is due to Dirac’s reclusive and taciturn behavior; his social quiescence was so extreme that it inspired his fellow physicists to invent an unofficial unit of measure for the minimal number of words a person could speak in polite company: a “Dirac,” roughly one utterance per hour.

But as Farmelo delved deeper into Dirac’s life for his new biography, The Strangest Man, he discovered surprising complexity and contradiction that gives new appreciation to the physicist’s character: Despite what many perceived as a lack of empathy, Dirac married, raised children, and forged several close lifelong friendships. Despite his professed distaste for unscientific reasoning, in his later life he became increasingly obsessed with philosophical, even religious, questions. And despite his love for the rarefied subject of theoretical physics, Dirac also had a passion for “lowbrow” cartoons and comic books.

Farmelo spoke with Seed’s Lee Billings about the process of researching the book and his astonishing hypothesis that could explain, once and for all, Dirac’s enigmatic behavior.

Seed: What motivated you to spend five years writing a book about Paul Dirac?
Graham Farmelo: I used to be a theoretical physicist, and I can say that everyone in that profession is interested in Dirac. He’s often said to be “the first really modern theoretician” or “the theorist’s theorist.” I remember as an undergraduate coming across my first taste of Dirac’s physics, something called Fermi-Dirac statistics, which governs the transistors and electron flow in your computer. I was blown away, a bit like a young music student listening to Beethoven’s “Moonlight Sonata.” Dirac’s first papers on quantum mechanics still look modern, more than those of any of his fellow pioneers. The mathematical imagination and beauty of those articles is amazing. I wanted to write a biography of him to try to communicate the power and scope of his work to non-specialists who are nevertheless curious about science, and to try to understand his remarkable personality.

In my time in physics, I met quite a few “Dirac fanatics,” people who are obsessive about him. I’m speaking to you from the Institute for Advanced Study in Princeton, and I’ve spent several lunchtimes recounting to the physicists here some new “Dirac stories.”

Seed: “Dirac stories?” Can you give me some examples?
GF: Certainly. At the end of a lecture, Dirac agreed to answer questions. Someone in the audience piped up: “I didn’t understand the equation on the top right of the blackboard, professor.” Dirac was silent for more than a minute. When the moderator asked him if he’d like to answer the question, Dirac shook his head and said, “That wasn’t a question. It was a comment.”

Here’s another: Over dinner one evening at Saint John’s College, Cambridge, an American visitor who was desperate to meet the formidable Dirac steeled himself to ask, “Are you going on vacation this summer, professor?” Silence. About 20 minutes later, Dirac turned to the visitor and said, “Why do you ask?”

Seed: He sounds like quite a deep, literal thinker. Did Dirac have any interests outside physics?
GF: Yes, a lot, but he just didn’t talk about them. He read widely, from Tolstoy to John le Carré. Among artists, he loved Rembrandt and Salvador Dali. Like Einstein, Dirac’s taste in music was mainly classical, but in later life he had a thing about Cher. To settle a dispute with his wife, he bought a second television so that he could watch a Cher special while she watched the Oscars.

Seed: The book includes several revelatory passages documenting Dirac’s personal life. How did you research and verify that material?
GF: I devoted a lot of time tracking down Dirac’s surviving friends, people who knew him very well. The most important one I found was his last great friend, Leopold Halpern, an expert on relativity who slept in the open air, refused to wash with soap, and liked to slice open baked potatoes with a karate chop. A few years ago, when Halpern was at death’s door with prostate cancer, he flew across the country to Florida, where Dirac spent the latter part of his life, just so he could row me up Wakulla Springs. He and Dirac used to go rowing every weekend. That was a special trip for me: Even now I’m looking at my arm and there are goose bumps. He showed me places where they talked, even where they went skinny dipping. Two and a half months later, Halpern died.

I spent several months consulting the Dirac archive at Florida State University in Tallahassee, which was virtually untouched. Dirac was an FSU professor for the last 14 years of his life. I found amazing things, not just letters from great physicists like Heisenberg and Schrödinger but also an amazing cache of weekly letters from Dirac’s mother, spanning almost 20 years. Many historians would’ve probably turned their noses up at these, but I found in them a dramatic story that illuminates Dirac’s home life and upbringing. I was also blessed with beginner’s luck when I happened to meet Dirac’s younger daughter at a centenary celebration of his birth. We hit it off well, and one day in her kitchen while I was visiting her, she showed me something like 120 private letters between Dirac and his first serious girlfriend, later his wife. Keep in mind, this man hardly spoke a word, and here he was opening up, writing whole pages—epics for him. I couldn’t believe my luck. Here was Dirac talking about his father with whom he didn’t get along at all, and about what it felt like to be someone conscious, that he was unlike most other people, unable to empathize with them. This is just my opinion here, but I believe he demonstrated many symptoms of what we now call autism, though that condition had not been identified at the time.

Seed: You think Dirac had undiagnosed autism?
GF: I did not go into this book project thinking Dirac was autistic in any way. When I started researching him all those years ago, I barely even knew what the term “autism” meant, and certainly didn’t apply it to Dirac. But as I researched, I encountered rumors about Dirac being autistic, about Einstein being autistic, and speculations that autism was more prevalent in scientists and mathematicians. So during one of my stays at Cambridge, I went to see Simon Baron-Cohen, who is arguably Britain’s leading expert on autism. He knew nothing about Dirac, but, to my amazement, he began describing patterns of behavior that exactly correspond to Dirac’s. Let me stress that this is just a hypothesis, and that I’m personally very skeptical of attempts to psychoanalyze people who are dead. This isn’t theoretical physics; I can’t do a slam-dunk experiment to prove it.

Seed: What were some of the behavioral indicators?
GF: There are many of them: inability to empathize, extreme taciturnity and literal-mindedness, a passion for a routine, narrow interests, a lack of physical coordination, dislike of sudden loud noises, and so on. Many of the “Dirac stories” told by physicists are, in my opinion, actually autism stories. When people are laughing at these things, they forget what they’re actually doing is mocking.

Seed: Do you think those traits might have helped him in his work or given him a unique perspective?
GF: Well, he was certainly as focused as a laser and as logical as a computer. He also had a fascinating way of looking at mathematics. He had a phrase, “My equation is smarter than I am.” He really did think that a good equation could be more intelligent than its creator. There’s a kind of mysticism in that. In the last 15 or 20 years of his life, he became obsessed with the philosophy that, for a piece of mathematics to be useful in fundamental physics, it must be beautiful. For instance, he thought the theory of photon and electron interactions—what we call quantum electrodynamics—was ugly, so he wouldn’t accept it. He had this extremely rigorous sense of beauty, and saw each successive revolution in physics progressing through increasingly beautiful mathematics.

Dirac, to his dying breath, pursued this quest for mathematical beauty. For him, everything apart from that principle was just details. The job of the fundamental theorist was to look for mathematically beautiful laws. That’s why the string theorists are on the right track, even though there aren’t experiments to bear them out at the moment.

Seed: So Dirac would be a fan of string theory, you think?
GF: Well, when people get old, they tend to basically think that everything’s gone to the dogs, and there was an element to that in Dirac, who took virtually no interest in the latest findings in his field. But if you apply his idea about sticking to mathematically beautiful generalizations of past theories and to hell with experiments in the short term, then this philosophy should embolden string theorists, yes.

The Great Blue Hole - Belize Lighthouse Reef

The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 100 kilometres (62 mi) from the mainland and Belize City.

The diameter of the circular reef area stretches for about 1,000 feet and provides an ideal habitat for corals to attach and flourish. The coral actually breaks the surface in many sections at low tide. Except for two narrow channels, the reef surrounds the hole. The hole itself is the opening to a system of caves and passageway that penetrate this undersea mountain. In various places, massive limestone stalactites hang down from what was once the ceiling of air-filled caves before the end of the last Ice Age. When the ice melted the sea level rose, flooding the caves.

For all the practical purposes the over 400-foot depth makes the Blue Hole a bottomless pit. The walls are sheer from the surface until a depth of approximately 110 feet where you will begin to encounter stalactite formations which actually angle back, allowing you to dive underneath monstrous overhangs. Hovering amongst the stalactites, you can't help but feel humbled by the knowledge that the massive formation before you once stood high and dry above the surface of the sea eons ago. The feeling is enhanced by the dizzying effect of nitrogen breathed at depths. The water is motionless and the visibility often approaches 200 feet as you break a very noticeable thermocline.

Almost all the divers who visit Belize are keen to add this splendid dive site to their list of conquests. When they understand what the hole is and how it was formed, it makes the dive all the more exciting. The Blue Hole is a "karst- eroded sinkhole." It was once a cave at the center of an underground tunnel complex whose ceiling collapsed. Some of the tunnels are thought to be linked right through to the mainland, though this has never been conclusively proved. The mainland itself has many water-filled sinkholes that are connected to caves and tunnels.

At some time many millions of years ago, two distinct events occurred. First, there was a major earthquake and this probably caused the cave ceiling to collapse forming the sinkhole. The upheaval, however, had the effect of tilting Lighthouse Reef to an angle of around 12 degrees. All along the walls of this former cavern are overhangs and ledges, housing pleistocene stalactites, stalagmites and columns.

Some of the stalactites now hang at an angle, yet we know they cannot develop at any angle other than perfectly perpendicular. In addition, there are those stalactites which were formed after the earthquake and others which were formed both before and after that cataclysmic event-the top of the stalactite being at an angle and the bottom being perpendicular.

At that time the sea levels were much lower than today and the second major event was to change all this. At the end of the Great Ice Age the glaciers melted and sea levels throughout the world rose considerably. This process occurred in stages. Evidence for this are the shelves and ledges, carved into the limestone by the sea, which run the complete interior circumference of the Blue Hole at various depths.

The Sentence of John L. Brown

Oh, from the fields of cane,
From the low rice-swamp, from the trader's cell;
From the black slave-ship's foul and loathsome hell,
And coffle's weary chain;
Hoarse, horrible, and strong,
Rises to Heaven that agonizing cry,
Filling the arches of the hollow sky,
How long, O God, how long?

THE SENTENCE OF JOHN L. BROWN.

John L. Brown, a young white man of South Carolina, was in 1844 sentenced to death for aiding a young slave woman, whom he loved and had married, to escape from slavery. In pronouncing the sentence Judge O'Neale addressed to the prisoner these words of appalling blasphemy:

You are to die! To die an ignominious death--the death on the gallows! This announcement is, to you, I know, most appalling. Little did you dream of it when you stepped into the bar with an air as if you thought it was a fine frolic. But the consequences of crime are just such as you are realizing. Punishment often comes when it is least expected. Let me entreat you to take the present opportunity to commence the work of reformation. Time will be furnished you to prepare for the great change just before you. Of your past life I know nothing, except what your trial furnished. That told me that the crime for which you are to suffer was the consequence of a want of attention on your part to the duties of life. The strange woman snared you. She flattered you with her word; and you became her victim. The consequence was, that, led on by a desire to serve her, you committed the offence of aid in a slave to run away and depart from her master's service; and now, for it you are to die! You are a young man, and I fear you have been dissolute; and if so, these kindred vices have contributed a full measure to your ruin. Reflect on your past life, and make the only useful devotion of the remnant of your days in preparing for death. Remember now thy Creator in the days of thy youth is the language of inspired wisdom. This comes home appropriately to you in this trying moment. You are young; quite too young to be where you are. If you had remembered your Creator in your past days, you would not now be in a felon's place, to receive a felon's judgment. Still, it is not too late to remember your Creator. He calls early, and He calls late. He stretches out the arms of a Father's love to you--to the vilest sinner--and says: "Come unto me and be saved." You can perhaps read. If so, read the Scriptures; read them without note, and without comment; and pray to God for His assistance; and you will be able to say when you pass from prison to execution, as a poor slave said under similar circumstances: "I am glad my Friday has come." If you cannot read the Scriptures, the ministers of our holy religion will be ready to aid you. They will read and explain to you until you will be able to understand; and understanding, to call upon the only One who can help you and save you--Jesus Christ, the Lamb of God, who taketh away the sin of the world. To Him I commend you. And through Him may you have that opening of the Day-Spring of mercy from on high, which shall bless you here, and crown you as a saint in an everlasting world, forever and ever. The sentence of the law is that you be taken hence to the place from whence you came last; thence to the jail of Fairfield District; and that there you be closely and securely confined until Friday, the 26th day of April next; on which day, between the hours of ten in the forenoon and two in the afternoon, you will be taken to the place of public execution, and there be hanged by the neck till your body be dead. And may God have mercy on your soul!

No event in the history of the anti-slavery struggle so stirred the two hemispheres as did this dreadful sentence. A cry of horror was heard from Europe. In the British House of Lords, Brougham and Denman spoke of it with mingled pathos and indignation. Thirteen hundred clergymen and church officers in Great Britain addressed a memorial to the churches of South Carolina against the atrocity. Indeed, so strong was the pressure of the sentiment of abhorrence and disgust that South Carolina yielded to it, and the sentence was commuted to scourging and banishment.

---

Ho! thou who seekest late and long
A License from the Holy Book
For brutal lust and fiendish wrong,
Man of the Pulpit, look!
Lift up those cold and atheist eyes,
This ripe fruit of thy teaching see;
And tell us how to heaven will rise
The incense of this sacrifice--
This blossom of the gallows tree!

Search out for slavery's hour of need
Some fitting text of sacred writ;
Give heaven the credit of a deed
Which shames the nether pit.
Kneel, smooth blasphemer, unto Him
Whose truth is on thy lips a lie;
Ask that His bright winged cherubim
May bend around that scaffold grim
To guard and bless and sanctify.

O champion of the people's cause
Suspend thy loud and vain rebuke
Of foreign wrong and Old World's laws,
Man of the Senate, look!
Was this the promise of the free,
The great hope of our early time,
That slavery's poison vine should be
Upborne by Freedom's prayer-nursed tree
O'erclustered with such fruits of crime?

Send out the summons East and West,
And South and North, let all be there
Where he who pitied the oppressed
Swings out in sun and air.
Let not a Democratic hand
The grisly hangman's task refuse;
There let each loyal patriot stand,
Awaiting slavery's command,
To twist the rope and draw the noose!

But vain is irony--unmeet
Its cold rebuke for deeds which start
In fiery and indignant beat
The pulses of the heart.
Leave studied wit and guarded phrase
For those who think but do not feel;
Let men speak out in words which raise
Where'er they fall, an answering blaze
Like flints which strike the fire from steel.

Still let a mousing priesthood ply
Their garbled text and gloss of sin,
And make the lettered scroll deny
Its living soul within:
Still let the place-fed, titled knave
Plead robbery's right with purchased lips,
And tell us that our fathers gave
For Freedom's pedestal, a slave,
The frieze and moulding, chains and whips!

But ye who own that Higher Law
Whose tablets in the heart are set,
Speak out in words of power and awe
That God is living yet!
Breathe forth once more those tones sublime
Which thrilled the burdened prophet's lyre,
And in a dark and evil time
Smote down on Israel's fast of crime
And gift of blood, a rain of fire!

Oh, not for us the graceful lay
To whose soft measures lightly move
The footsteps of the faun and fay,
O'er-locked by mirth and love!
But such a stern and startling strain
As Britain's hunted bards flung down
From Snowden to the conquered plain,
Where harshly clanked the Saxon chain,
On trampled field and smoking town.

By Liberty's dishonored name,
By man's lost hope and failing trust,
By words and deeds which bow with shame
Our foreheads to the dust,
By the exulting strangers' sneer,
Borne to us from the Old World's thrones,
And by their victims' grief who hear,
In sunless mines and dungeons drear,
How Freedom's land her faith disowns!

Speak out in acts. The time for words
Has passed, and deeds suffice alone;
In vain against the clang of swords
The wailing pipe is blown!
Act, act in God's name, while ye may!
Smite from the church her leprous limb!
Throw open to the light of day
The bondman's cell, and break away
The chains the state has bound on him!

Ho! every true and living soul,
To Freedom's perilled altar bear
The Freeman's and the Christian's whole
Tongue, pen, and vote, and prayer!
One last, great battle for the right--
One short, sharp struggle to be free!
To do is to succeed--our fight
Is waged in Heaven's approving sight;
The smile of God is Victory.

The Aysmmetry of Life

Left-right inequality has significance far beyond that of mirror images, touching on the heart of existence itself. From subatomic physics to life, nature prefers asymmetry to symmetry. There are no equal liberties when neutrinos and proteins are concerned. In the case of neutrinos, particles that spill out of the sun’s nuclear furnace and pass through you by the trillions every second, only leftward-spinning ones exist. Why? No one really knows.

Proteins are long chains of amino acids that can be either left- or right-handed. Here, handedness has to do with how these molecules interact with polarized light, rotating it either to the left or to the right. When synthesized in the lab, amino acids come out fifty-fifty. In living beings, however, all proteins are made of left-handed amino acids. And all sugars in RNA and DNA are right-handed. Life is fundamentally asymmetric.

Is the handedness of life, its chirality (think chiromancer, which means “palm reader”), linked to its origins some 3.5 billion years ago, or did it develop after life was well on its way? If one traces life’s origins from its earliest stages, it’s hard to see how life began without molecular building blocks that were “chirally pure,” consisting solely of left- or right-handed molecules. Indeed, many models show how chirally pure amino acids may link to form precursors of the first protein-like chains. But what could have selected left-handed over right-handed amino acids? My group’s research suggests that early Earth’s violent environmental upheavals caused many episodes of chiral flip-flopping. The observed left-handedness of terrestrial amino acids is probably a local fluke. Elsewhere in the universe, perhaps even on other planets and moons of our solar system, amino acids may be right-handed. But only sampling such material from many different planetary platforms will determine whether, on balance, biology is lefthanded, right-handed, or ambidextrous.

Marcelo Gleiser is the Appleton Professor of Natural Philosophy at Dartmouth College. His forthcoming book, Imperfect Creation: Cosmos, Life, and Nature’s Hidden Code, will be published by Free Press in 2010.

Interesting Link

http://seedmagazine.com/portfolio/05_rider-on-the-storm.html
http://seedmagazine.com/content/article/molecular_mimicry/