Quantum genesis: How life was born on Earth
Last Updated: 6:01pm GMT 14/12/2007Page 1 of 2
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An Atomic Adam could have lurked at the dawn of creation, according to
Roger Highfield
The birth of the first life on Earth took place in a "quantum cradle" on
the bed of an ocean, according to a provocative new theory of creation.
New research on the mother of all birthdays suggests that the genesis of
life could be explained in part by quantum theory, the framework that governs
the subatomic world which is deeply counterintuitive, mathematical and highly
baffling, even to most physicists.
Magnified image of grains from a rock believed to be the oldest
sedimentary rock sample on Earth
The quantum pioneer Niels Bohr joked that anyone who is not shocked by
quantum theory has not understood it.
Einstein, after helping to erect the theory, battled against it.
Now, despite the fact that no-one can quite agree on what we mean by
life, scientists are pondering whether quantum theory provided the mysterious
spark that turned non living matter into something that can live, thrive and
breed.
While all agree that chemicals somehow crossed a threshold four billion
years ago to turn into something that could replicate, progress has been
frustratingly slow and the origin of life remains one of the great outstanding
mysteries of science.
A few days ago, experts from around the world gathered in Arizona at a
meeting, "Quantum Effects in Biological Nanostructures", to air new ideas about
how this theory could illuminate the ultimate birthday, which took place only
half a billion years after Earth itself was born.
Although there is scepticism that quantum mechanics is midwife of life,
the British physicist Dr Paul Davies, director of Beyond: Centre for
Fundamental Concepts in Science, Arizona State University, Tempe, believes that
important progress was made at the workshop, though he admits it is
"tantalising and less than totally convincing."
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He points out that the idea that quantum mechanics is key to explaining
the riddle of the origin of life was first raised as far back as 1944 by the
Austrian quantum pioneer Erwin Schrödinger's in his book What is life?
Dr Davies said that quantum theory fills a missing link in existing
models of the origins of life, of which there are many. While all traditional
theories suggest chemistry provides the hardware of life, quantum mechanics
could provide the software, he said. "Today the cell is regarded not as magic
matter but as a computer - an information processing and replicating system of
astonishing precision."
In the beginning, Dr Davies speculates that once "Q life", in the form of
self replicating information at the atomic level, got going on Earth, this
paved the way for replicating chemicals, the best known of which is DNA.
"What we don't know is whether life has evolved over billions of years to
the "quantum edge" to exploit those tricks, or whether it's the other way:
quantum mechanics was the midwife of life and a few quantum tricks are left as
a hangover," he says.
Another advantage of quantum theory was put forward to the meeting by
Johnjoe McFadden at the University of Surrey. Even with all the chemical
ingredients needed to build life, the odds of them combining in the right
sequence to create a primitive self-replicating structure are slim, with one
favoured scenario involving the genetic material RNA enzyme requiring more
shuffling of ingredients than the number of electrons in the universe to
achieve a highly improbably combination that is capable of life.
But work on the theoretical properties of quantum computers, which
exploit the exotic properties of the theory, process information orders of
magnitude more rapidly than it can with a traditional computer.
A classical computer shuffles information in the form of binary numbers,
those containing only the digits 1 and 0, which it remembers as the "on" and
"off" positions of tiny switches, or "bits".
By contrast, the switches in a quantum computer can be both "on" and
"off" at the same time. A so-called "qubit" could do two calculations at once,
two qubits would do four and so on. This process of superposition could speed
up the process of sorting through and discarding unwanted chemical structures
to settle on one able to spawn life.
The one problem, said Dr Davies, in this is that, to tap their special
properties, quantum computers must be protected, because any disturbance upsets
them. Its qubits are said to "decohere": to fall completely into one or another
of their possible simultaneous states, to the exclusion of the others, and stop
exploring all possibilities.
Dr Davies said there is already evidence that this may be possible to
overcome in nature, in the process of photosynthesis.
Through the process, green plants and cyanobacteria are able to transfer
sunlight energy to chemical energy with nearly 100 per cent efficiency. Speed
is the key - the transfer of the solar energy takes place almost
instantaneously so little energy is wasted as heat.
How photosynthesis achieves this near instantaneous energy transfer is a
long-standing mystery and recent experiments at The University of California,
Berkeley, suggests the answer lies in quantum mechanical effects. This can
explain the extreme efficiency of the energy transfer because it enables the
system to simultaneously sample all the potential energy pathways and choose
the most efficient one.
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Dr Davies said another study could shed new light on how life was forged
in a kind of quantum crucible. Prof Asoke Nath Mitra, at the University of
Delhi in India, and independent researcher Gargi Mitra-Delmotte, were struck by
how such an environment could be created near undersea volcanoes, where
chambers of iron sulphide could allow quantum effects to occur without
disruption, harnessing the magnetic properties of the iron sulphide mineral
(Greigite) to control the quantum property of entanglement in qubits.
The magnetic field helps offset the way heat accelerates the rate of
decoherence, says Prof Mitra. "Gargi who picked up this general idea and she
very cleverly grafted this vital ingredient into this huge canvas where it
seems to fit best," he adds.
Dr Davies believes that this idea, inspired by an idea proposed by Prof
Michael Russell at the Scottish Universities Environmental Research Centre,
Glasgow, could provide a niche where quantum magic really could be at work,
though emphasises that it remains conjecture at this stage.
Even if we can't reconstruct the precise details of life's emergence,
quantum mechanics could help define what life could do, said Dr Davies.
Proving a quantum mechanical theorem that puts a bound on the probability
that such-and-such a system can replicate to a certain accuracy, and evolve to
a particular level of complexity, might answer one of the biggest issues of
all, says Dr Davies: Was the origin of known life a freak accident, or the
expected outcome of intrinsically bio-friendly laws of physics? Is life a
cosmic phenomenon, or are we alone in the vastness of the universe?"
Meanwhile, chemists are still trying to find what lit the blue touchpaper
of life. Earlier this month, the American Society for Cell Biology was told by
Helen Hansma of the University of California, Santa Barbara that the narrow,
confined spaces between nonliving mica layers could have provided the right
conditions for the rise of the first biomolecules.
http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=A1YourView&xml=/earth/2007/12/14/sciatomic114.xml
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