Tuesday, 29 September 2015

Water on Mars?

My interpretation of the article "Spectral evidence for hydrated salts in recurring slope lineae on Mars" - Nature Geoscience 28 Sep 2015 


Water is essential to life as we know it here on Earth. The presence of liquid water on Mars today has implications for geology, hydrology, the study of the origins and distribution of life in our solar system and beyond, and also for human space exploration.

While the average temperature on Mars is less than -50 degrees Celsius, temperatures of up to 27 degrees Celsius can occur during warm seasons. On certain slopes of terrain, narrow streaks have been observed to appear and grow during these warm periods. A solution of salts in water can lower the freezing point of water by up to 80 degrees Celsius, thereby significantly lowering the evaporation rate of water, and thus increasing the possibility of forming and stabilising liquid water on the surface of present-day Mars.

Brine- a solution of salt in water- has therefore been proposed to explain these streaks, however, no evidence of water or such salts has yet been found. Now, spectral data from the Mars Reconnaisance Orbiter (MRO) has found hydrated salts at all four locations where streaks were observed on the surface of Mars, probably magnesium perchlorate, magnesium chlorate and sodium perchlorate.

These findings strongly suggest that seasonal warm slopes are currently forming liquid water on Mars. While the possible origins of this water are not yet understood, a variety of formation mechanisms in different locations on the planet may be taking place. With respect to the search for microbial life on Mars, this discovery means we will be working hard to further characterise and explore these unique regions of Mars.

While it is good news for planned human settlements on Mars that there may be liquid water present, COSPAR and the Outer Space Treaty aim to protect extra-terrestrial bodies to make future science investigations possible, and in particular to prevent contamination by Earth life of unique areas where extra terrestrial life may exist. So it is likely that these areas where liquid water may be flowing will be out of bounds for human settlement until careful and detailed astrobiological investigations have been made in these areas.

But excitingly, as a result of investigating these unique locations supporting liquid water on Mars, in the next few years we could make one of the most profound discoveries in the history of life on Earth- the discovery of life on another planet.

Monday, 21 September 2015

Why move to Mars?

Watch this space: expanding our imaginations and our world

I find myself living at a very particular point in the almost 4 billion years of the evolution of life on this planet. I feel lucky, no extraordinarily privileged, to be alive right now, when for the very first time, we are able to investigate terrestrial life on scales smaller than the size of atoms, as well as look to the skies for evidence of extra-terrestrial life many hundreds of light years beyond Earth.

This beauty, this complexity, this body of knowledge that we are creating as humans flies in the face of the second law of thermodynamics, which describes how things tend to become more rather than less disordered as time goes on.

In spite of being participants in this physically unlikely era of human information creation, I believe we are often not open to seeing the bigger picture. Perhaps because in this age of information inundation, we feel more comfortable forgetting how much we still don’t know…

I want to be the most improbable human that I can be. I am prepared to give up my life on Earth for the unprecedented contribution I would be able to make to the sum of human knowledge from a new world. I would like to become one of the first citizens of Mars, and today I would like to talk about why.

Quantum mechanics is our most fundamental theory of reality- a description of phenomena occurring in systems on scales ­millions of times smaller than the resolution of the human eye, consisting of objects such as photons, electrons and atoms. To get an idea of just how small…

Micrometer-sized objects, like an individual human hair are visible to the naked eye. A thousand times smaller than that is the width of the DNA molecule, just a few nanometers, the helical structure of which was first observed only in 1952 using an x-ray imaging technique. And atoms are another ten times smaller than that, best observed with a microscope that uses a beam of electrons for imaging.

Quantum biology: You may wonder what connection these fields may have- biological objects like elephants are things that we can see, while quantum theory deals with objects that are far smaller that the resolution of the eye. However, the idea that quantum mechanics may play a role in living systems is by no means a new idea.

On this very day, the 15 August, in 1932, quantum physicist Niels Bohr delivered a lecture “Light and Life” at the International Congress on Light Therapy in Copenhagen, raising the question of whether quantum theory could contribute to a scientific understanding of living systems. In attendance was an intrigued Max Delbruck, a young physicist who later contributed to the establishment of the field of molecular biology. Both of these brilliant scientists won Nobel Prizes for their contribution to our understanding of reality.

The most developed area of quantum biology is the study of the very early stages of photosynthesis- up to less than the first billionth of a second. Only recent developments in an experimental technique called ultrafast spectroscopy have enabled us to image processes that happen on such quick timescales. This very early part of photosynthesis is almost perfectly efficient and we would like to understand how Nature does it so well. It turns out we have to use quantum physics to do so.

Understanding photon by photon, molecule by molecule how photosynthesis works, is a necessary step towards designing and engineering biologically inspired artificial photosynthetic solar cells, with the ability to harness sunlight energy with greater efficiency than is possible with currently existing technology. Quantum biology promises to contribute to the kinds of green renewable energy technologies essential for our continued existence on this planet (and possibly others…)

But in my opinion the greatest possible contribution of the field of quantum biology would be to help us in some way to answer the question that we have asking since time immemorial: What is life? What distinguishes a living system from the matter of which it is made, and how did it come about? While we are instinctively good at telling the difference between a living creature and bunch of inanimate molecules, a precise scientific theory of what distinguishes the two, and how life emerges in the first place from these molecules is something we are still working on. I think it’s funny that this ethanol molecule looks kind of similar to this horse, but I don’t think this is a clue…

I think the fact that we have identified quantum aspects of photosynthesis, one of the earliest living processes to have emerged on Earth, suggests that going down to these tiny scales may help us understand how life emerged in the first place.

What would be really helpful in the quest to understand the fundamental principles underlying the emergence of life would be to find just one other example of the phenomenon… We have not yet discovered any other location where life exists and all organisms on Earth appear to have evolved from a common ancestor.

Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. And the universe is a big place- we measure it in the distances that light travels in a given time, light being the fastest thing that we know of in our current understanding (with a speed of almost 300 000 km/s ). While Mars is just a few light minutes away, light takes around four years to travel to the nearest star, over a thousand to travel to that intriguing recently discovered Earth-like planet called Kepler-452b, millions of years to reach the nearest galaxy Andromeda, and nearly 50 billion years to reach the furthest edge of the observable universe.

There is a theory with a crazy name, panspermia, which says that life on the Earth originated when the chemical precursors of life present in outer space reached this suitable environment. The theory is not so crazy when you consider that many meteorites found on Earth contain a range of building blocks of life- for example over 70 different amino acids have been detected in the Murchison meteorite that fell in Australia in 1969.  Furthermore, we think that quantum mechanics may provide the tools to understanding how these precursors of life emerged in space…

If you’re feeling mentally taxed, you should be, I’ve taken you on a journey from the tiny scales where atoms exist, out to the furthest edge of the universe many billions of light years away, on the quest to understanding life. That’s a big picture! And a picture I spend a lot of time inside as a researcher in the field of quantum biology and more recently in a field I would like to call quantum astrobiology.

The point I want to make is that so far as we can tell, what we are doing here on Earth as living systems and in particular as humans, is very improbable. In a vast universe, so far, we represent the only instance that we know of, where collections of molecules, because that’s what we are, have observed reality, made sense of it through language, and finally found ways to record and communicate this information, which has culminated in the Internet, in my opinion, one of our finest moments. This is an unlikely time and place in the universe in which we find ourselves!

What I find perplexing is that in spite of living in this improbable era of human existence, and even in spite of, for many of us, having the sum of human knowledge at our fingertips, rather than rejoicing in the hugeness of the picture we have of reality, and in the spirit of exploration and discovery of the vastness of what still remains unknown, many people are overwhelmed, unnerved and indeed find it incomprehensible that I want to move to Mars, on a way-way trip. Although some people may have an idea of who they would like to send on such a trip…

Billions of years of evolution of life on Earth have culminated in the possibility of us calling another planet home for the very first time. Untold discoveries lie in wait, including the possiblity of finding evidence of life there, which would be a giant leap in terms of understanding who are we, where we come from and where we are going. I have applied and been short-listed along with 99 others from around the planet with the Mars One Project, to go and live on Mars because I would be prepared to sacrifice a lot for this idea, this adventure, this achievement, that would not be my own, but that of all humanity. Even returning to Earth.

What I would like to point out immediately is that we are all survivors of one-way trips, wherever on the surface of the Earth we happen to currently live. According to the fossil record, homo sapiens emerged in central eastern Africa around 200 000 years ago, and we have been exploring the surface of the Earth ever since. My ancestors made the hazardous 5 month trip from Europe to the Southern tip of Africa in 1688 without any intention or means of return- I am the 11th generation of descendants of Huguenot refugees from France, now proudly South African. And 500 years from now there may well be human Martians telling tales of the perilous one-way journey their ancestors made in the early 21st century from Earth.

All the observations we have made and information we have gathered is the result of having explored the unknown. The technologies that many of us consider so indispensible in our daily lives are often the unexpected result of investigating something new. I like to think of the invention of the heat engine as the eventual technological solution to the bad weather the first African explorers encountered on discovering Europe.

In the same way I hope that the relatively hostile environment on Mars will lead to new technologies that can help us on Earth- to tackle climate change, poor resource management and the poverty in which so many of us live. Life on Mars will be a precious and fragile resource, and I believe that an attitude of deep appreciation for life and all that is needed to sustain it will charactise morality on Mars, and also, I hope, influence the way people think on Earth.

This is what we have always done as humans and what we will continue to do- we observe, we dream and we expand our horizons through the realisation of these dreams. I want to make the best contribution of which I am capable to this grand and improbable era of human information creation. I want to be one of the first conscious minds to know what it is like to live in a totally new world. I want to add to the sum of human knowledge by contributing to the establishment, and possibly the discovery of evidence of, life on Mars.

To conclude, I feel privileged to be living at a time when the opportunity to expand our imaginations and our world further than ever before, is within reach. Why I want to go to Mars is simple: to me the allure of the unknown has always felt far more powerful than the comfort of the known.

A presentation of these ideas at TEDx Cape Town https://www.youtube.com/watch?v=6MryDEd7CE0

Monday, 9 June 2014

What is Life?

Can quantum biology help us to understand what distinguishes a bunch of molecules from a living organism?

In the beginning, during the first billion years (Gyr) after the Earth was formed about 4.5 Gyr ago, intense meteor bombardment left little remains of the original crustal rocks. High energy collisions with meteorites up to 500 km in diameter periodically disintegrated newly formed continental crust and vapourised early oceans, annihilating primitive life forms possibly existing near the surface.

Gene sequencing suggests that the most primitive known domains of life, namely bacteria and archaea, have been evolving separately for as long as 4 Gyr. Deep-sea volcanic vents are candidates for supporting such early life. The oldest fossils of single-celled microbes are dated at around 3.5 Gyr, while the oldest evidence of the more complex multicellular precursors of plants and animals is more recent, at around 2 Gyr. Structurally, it appears that this complexity in fact arose as the happy endosymbiotic result of the invasion of the archaean cell by bacteria!

In the meantime, life has become so prolific and so complex that human life forms have taken up the study of life and its origins. But are we any closer to an answer? Can we state exactly what it is that distinguishes a bunch of molecules from a living organism?

An intriguing experiment by Miller and Urey in 1953 showed that electrical activity in a gaseous mixture of methane, ammonia, water and hydrogen can produce amino acids: the building blocks of proteins. In spite of more recent and remarkable work in viable DNA design, no experiment has yet been able to synthesise from basic components an object that has the characteristics of a living cell.

All living systems are made up of molecules, and the properties of molecules are given by quantum mechanics, our most successful and fundamental theory to date. Living systems are necessarily open systems constantly exchanging energy and matter with the environment in order to maintain the non-equilibrium state synonymous with living. While living systems are therefore fundamentally open quantum systems, the level of complexity typical of biological systems poses a huge computational challenge to such a fundamental description. Furthermore, many of the processes associated with life are sufficiently described by Newtonian physics.

Quantum biology is the applied science of open quantum systems to those aspects of biology where a description in terms of Newtonian physics is insufficient. An important question is whether quantum theory can add anything to biology: We know that molecules are ultimately described by quantum chemistry, but can such a description help us to understand life itself?

The most well-established area in quantum biology is the study of aspects of one of life's oldest processes: photosynthesis. While evidence of quantum mechanical tunneling in electron transfer in purple bacteria was first reported almost half a century ago, more recently the detection of quantum coherence in energy transfer in green sulphur bacteria and marine algae has contributed to a revival of interest in the possibility that the optimality of some biological processes is due to a sustenance of quantum effects in the warm, wet and noisy environments typical of living systems.

As theorists, we are working hard to keep up. Our research in Durban, with collaborators in Singapore and Amsterdam, has involved the application of open quantum systems models of energy transfer to the photosynthetic process, showing how interaction with an environment can in fact enhance transport efficiency. More recently, we have proposed that quantum spin plays a direct role in reducing the yield of potentially destructive states during charge transfer in photosynthesis, constituting a new example of a quantum mechanical protective mechanism in a living organism.

Given that the simplest living systems exhibit functional complexity of a quantum nature when probed at the limits of our instrumentation, that far more complex animals are able to sense subtle changes in their environments with an accuracy described by quantum mechanics, should come as no surprise. The proposal that navigation in the Earth's magnetic field, as well as our senses of vision and smell, and also our cognition, require quantum mechanical description, are exciting developing areas of quantum biology.

The highest achievement of quantum biology would be a contribution to a scientific understanding of what distinguishes a living system from the inanimate matter from which it is constructed, i.e. a theory of life. The test of such a theory would be the synthesis of life itself. In the absence of such a theory and its confirmation, outside of famous works of fiction, quantum biology will, for now, have to fulfill a more practical role.

The primary importance of the field of quantum biology, in its present state, lies in the identification and mimicry of the ingenious feats of engineering taking place in systems ranging from bacteria to birds. If non-trivial quantum effects on a macroscopic scale play a role in getting the job done better in certain processes perfected over billions of years at physiological temperatures and in immensely complex systems, then there exists before our very eyes a wealth of information in the biological world from which to draw inspiration for our own technologies.

Synthetic biology is gathering momentum to become the next big thing in science, with biologically-inspired quantum artificial photosynthetic systems promising to contribute to the development of the kind of renewable energy technologies essential for our continued existence on this planet (and perhaps others!), and this is just the beginning.

As far as understanding what life is, however, we are limited by a lack of precise knowledge of the conditions under which life emerged on Earth, in a possibly singular event. Barring the sudden discovery of evidence of life on Mars by the Curiosity rover or a roving Mars One colonist, for now, we will have to be satisfied with a definition of life as the continual state of change preceding death, and with the knowledge that the rabbit hole goes as least as deep as we are prepared to venture.