Proof of Life?

Mars south polar cap. Image credit: NASA/JPL/MSSS Click to enlarge
Pamela Conrad, an astrobiologist with NASA’s Jet Propulsion Laboratory, has traveled to the ends of the Earth to study life. Conrad recently appeared in James Cameron’s 3-D documentary “Aliens of the Deep,” where she and several other scientists investigated strange creatures that inhabit the ocean floor.

On June 16, 2005, Conrad gave a lecture called, “A Bipolar Year: What We Can Learn About Looking for Life on Other Planets By Working in Cold Deserts.”

In part 2 of this edited transcript, Conrad describes how her work in cold deserts could aid the search for alien life.

“If we were to find life on Mars, and that life lived in the rocks, how would we study it? You can’t answer that question unless you first do some experiments on Earth. And that’s what we’re doing in the Arctic and in the Antarctic.

In the Arctic we looked at a volcano about a 150 to 200 thousand years old, made of weathered basalt. It’s very interesting weathered basalt, because it contains minerals that look very much like some of the unexplainable minerals in the controversial martian meteorite that was described to have fossilized life in it.

In the Arctic site that we went to — Svalbard, Norway — there are polar bears. So when you go to the Arctic, you have to have some training in shooting. They don’t want you to kill polar bears, but they want you to be able to do so if he’s about to kill you. So we started our expedition to the Arctic with a half-day of gun training. It was fun shooting at paper targets, but I don’t know what I’d do if I were confronted with a polar bear looking at me with dinner in his eyes.

There are no polar bears in the Antarctic, but the sea life is abundant and diverse. At McMurdo Base, there are penguins, there are birds called skua, there are a couple of different types of seals. As you go farther away from the base by the shore, you get to places that are desolate. We investigated a place in the McMurdo Dry Valleys called Battleship Promontory. The rocks there are sandstone, and they were originally deposited underwater. Inside these rocks, thriving layered communities of microbes make their existence. They freeze solid during the winter and come back to life during the summer. Of course, the summer at its most exuberant heat wave only gets to be about 10 degrees Centigrade.

NASA’s strategy for looking for life is to first look around quickly, and process a lot of information. When you get to the interesting stuff, you might take a longer amount of time, and do it more carefully with higher resolution. You wouldn’t want to do something really destructive first, because you might destroy the thing you’re trying to study. You want to be as minimally invasive as possible. Some techniques are very invasive: taking a hammer and whacking on a rock and breaking it into pieces certainly makes you unable to look at the basic overall structure, the geomorphology, of that rock. So when you’re looking for life in rock, if you’re trying to be non-destructive, you can’t crack open the rock and look inside. So there has to be some kind of clue of life on the surface of the rock.

Porphyrins are a ubiquitous class of naturally occurring compounds with many important biological representatives including hemes, chlorophylls, and several others. Life anywhere is going to have some sort of electron transport or energy harnessing system. The common ones on Earth are based on porphyrins, which have very specific shapes.

We would like to bring samples back from places like Mars, but right now we don’t know how to do that. In the future, we will do that, but then it would be a very long experiment. We have to develop the technology to do it, we have to get to Mars safely, we have to get the samples, and we have to safely get it back. That’s a complex problem.

Eventually, there will be human exploration. I want to go to every cool place I can, but I don’t think I’ll go to Mars anytime soon. But there are a lot of people who want to go to other planets, and as we listen to the different strategies and paths that NASA takes, I’m sure that that will happen in time. Right now, I’m focussing on things that might prepare us for the type of solar system exploration that we’re doing right now: sending out a spacecraft, landing it, and doing an experiment.

So my team is developing strategies for life detection, using methods that are non-destructive and quick. We survey the landscape with a minimally invasive tool, we look for the contrast in the chemistry of the rock and the chemistry of organisms that might be on or in the rock. We do it in cold deserts because cold deserts are analogous to the kind of environment we find on Mars. Mars is much drier and much colder, but that’s about as close as we can get here.

My group has been working with an optical technique. I like to describe it as the black light you can buy at PetCo, where you shine the light on the carpet to look for dog or cat pee. Only ours is a little bit higher tech and more specific than that, because there isn’t any dog or cat pee in the areas where we go. Our technique is called “laser-induced native fluorescence.” You take a very short wavelength of light – an invisible wavelength deep into the ultraviolet – and you illuminate a spot. If that spot has organic molecules, that spot glows. And the color of the glow tells you something about what kind of molecule it is, how big it is, how complicated it is. And it’s really cool because it’s fast – you can do this in 50 microseconds. Even though ultraviolet light can be damaging, we have a very short blast. So this is a very minimally invasive technique, because it doesn’t harm living things. The microbes that we’ve detected using this method don’t die.

The machine is about the size of a shoebox, and you can take it anywhere you want to immediately tell where you have life and where you don’t.

We’ve used this tool in the Arctic, sticking it into holes to determine whether or not certain minerals have any organic molecules associated with them – the specific organic molecules that might be associated with the presence of microbes. That tells us whether to grab any rocks and take them back to the lab to look for organisms. We’ve also used the tool on a manipulator arm of a deep-sea submersible and detected organic molecules coming out of hydrothermal vents on the sea floor.

In Antarctica, the organisms live in a certain type of rock that has a lot of pore space to hold water. That means they’re better able to maintain hydration. Temperatures in the rock swing, but not as wildly as the outside air because of heat that’s absorbed by the rock during the day. Also, the kind of minerals that make up that rock are transparent to ultraviolet light. If the basis of your food chain is photosynthesis, then you’ve got be underneath a mineral that transmits light.

There are different kinds of organisms that live in the rock. The kind of organism that lives in the pores spaces of rock don’t go very deep — maybe a centimeter and a half if you have a really thick community. But you do see chemical evidence going a few centimeters deeper into the rock.

There are other kinds of organisms that don’t live in the pore spaces. They migrate into the cracks in rocks. They are called “chasmoliths.” They typically do chemosynthesis, that is, they rip out chemistry associated with the rock, and they either oxidize some ion, or reduce some other ion, and this whole cycle of oxidizing something and reducing something is akin to the respiration we do. Since it doesn’t involve photosynthesis, they don’t need light, so they can go deeper into the rock. But the chemistry in the rock influences how deeply they can go — these tiny organisms have a community structure that has a specific set of chemical conditions that support it. If you change that set of chemical conditions, you have a whole different environment. Another limitation is you can’t go too deep and use up too much space, or thermodynamically you can’t continue to do chemistry because you’ll drown in your own poop. That’s an unfortunate state of affairs.

You can tell the difference between one bacterium and another with our instrument, because different chemicals are on the surface of the organisms. Just using fluorescence can tell you the difference between basic types of bacteria. If you have a spore, and you want know what species you have, you use other techniques, like looking at the vibrational properties of the atomic bond.

One of the cool things about looking for microbial life on Earth is that microbes are everywhere. Most of the biodiversity on Earth is microbial, and they can live in challenging environments. You have to give them credit for being clever in terms of coming up with adaptive strategies to cope with stressful environments.

When we think of looking for fossils of past life, we tend to think of stuff like dinosaur bones. Astrobiologists don’t really expect to find dinosaurs on Mars, although I do have a National Enquirer cover that differs.

But you can find fossil structures in rocks, created from organisms that were in the sediment as it was being lithified – made into a rock. You can also try to find chemical fossils, signs that there was life there. There are some chemicals that are really big molecules that are very hardy and withstand a lot. We just have to be clever enough to distinguish the chemistry associated with the rock from the chemistry associated with the living things.”

Original Source: NASA Astrobiology

Zo? Heads Back to the Desert to Search for Life

Zo?, an autonomous solar-powered rover. Image credit: NASA Click to enlarge
Carnegie Mellon University researchers and their colleagues from NASA’s Ames Research Center, the universities of Tennessee, Arizona and Iowa, as well as Chilean researchers at Universidad Catolica del Norte (Antofagasta) are preparing for the final stage of a three-year project to develop a prototype robotic astrobiologist, a robot that can explore and study life in the driest desert on Earth.

The team will direct and monitor Zo?, an autonomous solar-powered rover developed at Carnegie Mellon, as it travels 180 kilometers in Chile’s Atacama Desert. Zo? is equipped with scientific instruments to seek and identify micro-organisms and to characterize their habitats. It will use them as it explores three diverse regions of the desert during its two-month stay, which runs from August 22 to October 22.

The results of this expedition ultimately may enable future robots to seek life on Mars, as well as enabling the discovery of new information about the distribution of life on Earth.

The search-for-life project was begun in 2003 under NASA’s Astrobiology Science and Technology Program for Exploring Planets, or ASTEP, which concentrates on pushing the limits of technology to study life in harsh environments.

Zo?’s abilities represent the culmination of three years of work to determine the optimum design, software and instrumentation for a robot that can autonomously investigate different habitats. During the 2004 field season, Zo? exceeded scientists’ expectations when it traveled 55 kilometers autonomously and detected living organisms using its onboard Fluorescence Imager (FI) to locate chlorophyll and other organic molecules.

“Our goal with this final investigation is to develop a method to create a real-time, 3D topographic ‘map’ of life at the microscopic level,” said Nathalie Cabrol, a planetary scientist at NASA Ames and the SETI Institute who heads the science investigation aspects of the project. “This map eventually could be integrated with satellite data to create an unprecedented tool for studies of large-scale environmental activities on life in specific areas. This concept can be applied to planetary research and also on Earth to explore other extreme environments.”

“This is the first time a robot is looking for life,” said Carnegie Mellon associate research professor David Wettergreen, who leads the project. “We have worked with rovers and individual instruments before, but Zo? is a complete system for life seeking. We are working toward full autonomy of each day’s activities, including scheduling time and resource use, control of instrument deployment and navigation between study areas.

“Last year we learned that the Fluorescence Imager can detect organisms in this environment. This year we’ll be able to see how densely an area is populated with organisms and map their distribution. We intend to have the robot make as many as 100 observations and make advances in procedural developments like how to decide where to explore.”

Zo? will visit a foggy coastal region, the dry Andean altiplano, and an area in the desert’s arid interior that receives no precipitation for decades at a time. At these sites, the rover’s activities will be guided remotely from an operations center in Pittsburgh where the researchers will characterize the environment, seek clear proof of life and map the distribution of various habitats. During last year’s mission, the team carried out experiments using an imager able to detect fluorescence in an area underneath the rover. The FI detects signals from two fluorescent dyes that mark carbohydrates and proteins ? as well as the natural fluorescence of chlorophyll. The FI, developed by Alan Waggoner, director of the university’s Molecular Biosensor and Imaging Center (MBIC), was not fully automated last year. Scientists had to follow the rover and spray dyes onto the sample area. This year, Zo? can spray a mixture of dyes for DNA, protein, lipid and carbohydrates without human intervention.

The Life in the Atacama project is funded with a $3 million, three-year grant from NASA to Carnegie Mellon’s Robotics Institute in the School of Computer Science. They collaborate with MBIC scientists, who received a separate $900,000 NASA grant to develop fluorescent dyes and automated microscopes to locate various forms of life.

The science team uses EventScope, a remote experience browser developed by researchers at the STUDIO for Creative Inquiry in Carnegie Mellon’s College of Fine Arts, to guide Zo?. It enables scientists and the public to experience the Atacama environment through the rover’s “eyes” and various sensors. During the field investigation, scientists will interact with Zo? in a science operations control room at the Remote Experience and Learning Lab in Pittsburgh. Scientists from NASA, the Jet Propulsion Laboratory, the University of Tennessee, University of Arizona, the British Antarctic Survey and the European Space Agency will participate.

For more information, images and field reports from the Atacama, visit: www.frc.ri.cmu.edu/atacama.

Original Source: Carnegie Mellon News Release

Mapping Life on Earth Could Predict Finding it on Mars

Pathfinder’s image of Mars. Image credit: NASA/JPL. Click to enlarge.
A geologist from Washington University in St. Louis is developing new techniques to render a more coherent story of how primitive life arose and diverged on Earth ? with implications for Mars.

Carrine Blank, Ph.D., Washington University assistant professor of earth and planetary sciences in Arts & Sciences, has some insight concerning terrestrial microbes that could lead to provocative conclusions about the nature of life on Mars and other planets.
Carinne Blank (below) has a method she uses to date ancient life forms that could be helpful for specimens from Mars.
Carinne Blank (below) has a method she uses to date ancient life forms that could be helpful for specimens from Mars.

Blank approaches the task by resolving phylogenetic trees. These trees, based upon genetic sequencing data, trace the genetic relationships between what we think of as primitive organisms through trait development. The relationships between early forms of life can illuminate the relationships between organisms present on Earth today ? which fossil evidence and a method called isotopic fractionation have failed to show conclusively.

Blank most recently presented her research at the 2004 annual meeting of the Geological Society of America.

Haves and have-nots
Microorganisms can be divided into haves and have-nots: cells of eukaryotes contain a nucleus, while prokaryotic organisms cells do not. Prokaryotic organisms encompass archeal and bacterial domains of life. Archeal organisms diverge further into euryarcheota and Crenarcheota lineages. By piecing together genetic sequences of the three types of prokaryotic organisms, Blank creates a genetic flow chart, which can be interpreted to trace the appearance of environmental adaptations across billions of years of evolution.

Genes are inherited from parents, but can transfer from one organism to another without reproducing by a process called lateral gene transfer. Modular metabolic genes, which are not critical for cell production, account for most lateral gene transfers between microbes.

“There is a lot we’re beginning to understand in terms of bacterial evolution that is still not quite clear,” Blank said. “What we’re trying to resolve is the evolutionary history of the core of the bacterial cell. The core is that which is not undergoing this lateral gene transfer, or does it extremely rarely.”

Jumping genes
Jumping genes may be a headache for researchers, but they serve an important ecological purpose, helping other organisms to succeed in their habitats, and can illuminate trait development across the tree of life.

“We try to construct the core with gene sequences, and then we look at the distribution of traits such as those involved in metabolism by laying it onto the tree,” she said.

Timely appearances of certain traits among prokaryotes on the tree of life can betray a trend of habitat divergence, facilitated by lateral gene transfer. The emergence of traits corresponding to measurable changes in the known geologic record allow researchers to date organisms with relative certainty. Blank can then use chronological data to analyze niche specialization, “where these organisms like to grow,” among members of each life domain over geologic time.

Habitat divergence among bacteria is consistent with patterns of divergence among the other prokaryotes, Blank’s research shows. She notes a pervasive trend of cyanobacterial organisms diverging from low-salinity environments into marine environments over time.

“We have the ancestral Archeae ? it diverges into two major lineages, the Crenarchaeota and the Euryarchaeota, one which grows in marine environments, the other on continents,” Blank said. “They grow and diverge for perhaps a billion years, and then they start colonizing each other’s environments. The marine Euryarchaeota eventually colonize the terrestrial environments and the Crenarchaeota colonize the marine environments. My point is that it could have taken a very long time for them to come back and to form even more complex ecosystems. So the literal interpretation of these patterns is that early habitat specialization could have lasted for a billion years.”

After mapping early habitat divergences onto the tree, Blank observes that the ancestors of each of the three kinds of prokaryotes inhabited one of Earth’s three types of hydrothermal systems, which include sulfurous steam vents like those which smatter the Yellowstone caldera, hydrothermal deep-sea vents, and boiling silica-depositing springs.

“Is it a coincidence, then, that we have three hydrothermal habitats and three major groups of prokaryotes? We aren’t sure,” she said. “This could suggest that we have some really ancient habitat specialization. These lineages specialize in these three habitats, and diverge in these habitats for many hundreds of million years before they start moving into other types of habitats.”

The ‘peculiar’ ancestor
It isn’t clear why bacteria diversified later, though environmental changes, like periods of global glaciation nicknamed “snowball Earth,” could have provided the impetus that demanded microbial adaptation. Whatever the cause, new adaptive microbial traits can be very different from those of their “peculiar” ancestors. It seems that, on some level, humans and bacteria can relate.

“If we see these major patterns of divergence on Earth, we should expect to see similar patterns on life on Mars, that is, if life ever existed there,” Blank said. “Not the same patterns, because Mars has had a different history, but we should see trends that are analogous. You would expect to see a peculiar ancestor specialized to a unique niche, eventually diverging into descendants that have very different traits than their ancestor did. These descendents would have adapted to changes that would’ve happened in Mars’s history.”

Original Source: WUSTL News Release

Where Does Intelligent Life Come From?

Image credit: Woods Hole Oceanographic
A lot of things had to go well for life to come about. If you go way back, it all begins with a Big Bang universe giving birth to space and time. In that early universe light echoed about, slowed in vibrancy, the primordial elements coalesced then condensed into a first generation of massive breeder stars. After warming to the notion (by gravitational compression), primordial matter began fusing in stellar cores and a lesser form of light moved outward to warm and illuminate a young and potentially ever-expanding Universe.

More time and more space saw many of those early blue stars implode (after living very short lives). Subsequent explosions spewed vast quantities of heavier – non-primordial – atoms into space. Out of this rich cosmic endowment new stars formed – many with planetary attendants. Because such second and third generation suns are less massive than their progenitors, they burn slower, cooler, and much, much longer – something essential to the kind of benignly consistent energy levels needed to make organic life possible.

Although breeder stars formed within a few hundred million years of the Big Bang, life here on Earth took its time. Our Sun – a third generation star of modest mass – formed some nine-billion years later. Life-forms developed a little more than one billion years after that. As this occurred, molecules combined to form organic compounds which – under suitable conditions – joined together as amino acids, proteins, and cells. During all this one layer of complexity was added to another and creatures became ever more perceptive of the world around them. Eventually – after more billions of years – vision developed. And vision – added to an subjective sense of awareness – made it possible for the Universe to look back at itself.

Empirical research into the fundamentals of life shows that a concoction of well-chosen elements (hydrogen, carbon, oxygen, & nitrogen) exposed to non-ionizing ultraviolet radiation forms amino acids. Amino acids themselves have a remarkable capacity to chain together into proteins. And proteins have a rather “protean” ability to give shape and behavior to cells. It is now considered entirely possible that the very first amino acids took form in space1 – shielded from harder forms of radiation within vast clouds comprised of primordial and star-stuff material. For this reason, life may be an ubiquitous phenomenon simply awaiting only certain favorable conditions to take root and grow into a wide variety of forms.

Currently, exobiologists believe that liquid water is essential to the formation and multiplication of organic life. Water is an extraordinary substance. As a mild solvent, water enables other molecules to dissociate and mix. Meanwhile it is very stable and is transparent to visible light – something useful if biotics are to derive energy directly from sunlight. Finally water holds temperature well, carries off excess heat through vaporization, and floats when cooled to solidify as ice.

According to NASA exobiologist Andrew Pohorille, “Water brings organic molecules together and permits organization into structures that ultimately became cells.” In so doing, water acts in an unparalleled matrix enabling organic molecules to form self-organizing structures. Andrew cites one property uniquely associated with water that makes self-organization and growth possible: “The hydrophobic effect is responsible for the fact that water and oil don’t mix, soaps and detergents ‘capture’ oily dirt during washing in water and for a vast number of other phenomena. More generally, hydrophobic effect is responsible for segregating nonpolar (oily) molecules or parts of molecules from water, so they can stick together even though they are not bonded. In biology these are precisely the interactions responsible for the formation of membranous cell walls and for folding proteins into functional structures.”

For water to take the liquid state, it must remain in a relatively narrow range of temperatures and pressures. Because of this only a certain few well-placed planets – and possibly a handful of large moons are favored with the conditions needed to let life live. In many cases it all comes down to a form of celestial real estate – location, location, location…

Early life on Earth was very simple in form and behavior. Though cellular, they lacked a central nucleus (prokaryotic) and other sub-structures (organelles). Lacking a nucleus such cells reproduced asexually. These anaerobes subsisted primarily by creating (anabolizing) methane gas from hydrogen and carbon-dioxide. They liked heat – and there was plenty of it to go around!

The fact that life developed on Earth should not be as surprising as one might think. Life is now considered far more robust than once imagined. Even now hydrothermal vents deep in the ocean eject near-boiling water. Adjacent to such vents life – in the form of giant tube worms and clams – flourishes. Deep under the surface of the Earth mineral-metabolizing anaerobic bacteria are found. Such conditions were thought impossible throughout most of the 20th century. Life seems to spring up under even the harshest of conditions.

As life forms advanced on our world, cells developed organelles – some by incorporating lesser, more specialized cells into their structures. The planet cooled, its atmosphere clarified and sunlight played upon the oceans. Primitive bacteria arose that fixed energy from sunlight as food. Some remained prokaryotic while others developed a nucleus (eukaryotic). These primitive bacteria increased the oxygen content of the Earth’s atmosphere. All this transpired some 2 billion years ago and was essential to support the quality and quantity of life currently populating “the Blue Planet”.

Originally the atmosphere consisted of less than 1% oxygen – but as levels increased, bacteria-eating life-forms adapted to synthesize water from oxygen and hydrogen. This released far more energy than methane metabolism is capable of. The controlled synthesis of water was a huge accomplishment for life. Consider the high school chemistry lab experiments where hydrogen and oxygen gas are combined, heated then explode. Primitive life forms had to learn to handle this very volatile stuff in a far safer manner – putting phosphorus to task in the conversion of ADP to ATP and back again.

Later – roughly 1 billion years ago – the simplest multi-cellular creatures took form. This occurred as cells came together for the common good. But such creatures were simple colonies. Each cell was fully self-contained and took care of its own needs. All they required was constant exposure to the warm broth of the early oceans to acquire nutrients and eliminate wastes.

The next great step in the evolution of life2
came as specialized cell tissue types developed. Muscle, nerve, epidermis and cartilage advanced the development of the many complex life-forms now populating our planet – from flowering plant to budding young astronomer! But that very first organized creature may very well have been a worm (annelid) burrowing through the marine slime of some 700 million years ago. Lacking eyes and a central nervous system it possessed only the capacity to touch and to taste. But now life had the capacity to differentiate and specialize. The creature itself became the ocean…

With the advent of well-organized creatures the pace of life quickened:

By 500 MYA, the first vertebrates evolved. These were probably eel-like creatures lacking in sight but sensitive to chemical – and possibly electrical – changes in their environments.

By 450 MYA, the first animals (insects) joined rooting plants on land.

Some 400 MYA the first vertebrates climbed out of the sea. This may have been an amphibious fish subsisting on insects and plant-life along the shore.

By 350 MYA – the first “iguana-like” reptiles emerged. These possessed strong, hard, jaws in a one-piece skull. As they grew larger, such reptiles lightened their skulls by adding orifices (beyond simple eye sockets). Before dinosaurs dominated the earth, crocodiles, turtles, and pterasaurs (flying reptiles) preceded them.

Primitive mammals go back almost 220MY. Most of these creatures were small and rodent-like. Later versions developed the placenta – but earlier species simply hatched eggs internally. All mammals of course, are warm-blooded and because of this must eat voraciously to maintain body temperature – especially on cold windy nights tracking down faint galaxies along the Eridanus river…

Like mammals, warm-blooded birds require more food than reptiles – but like reptiles – laid eggs. Not a bad idea for a creature of flight! Today celestial birds fly (such as late summer’s Cygnus the Swan and Aquila the Eagle) because real birds took wing some 150 MYA.

The earliest primates existed even during the time of the extinction of the dinosaurs Strong evidence supports the idea that the dinosaurs themselves passed as a group after an asteroid – or comet – impacted the Yucatan peninsula of the United States of Mexico. After this catastrophic event temperatures fell as a “non-nuclear” winter descended. Under such conditions food was spare, but warm-bloodedness came into its own. It wasn?t long however before one type of a “gigantism” soon replaced another – mammals themselves grew to extraordinary sizes and the largest developed in the womb of the sea and now take the form of the great whales.

The end of the “terrible lizards” was not the first mass-extinction of life – four previous die-offs had preceded it. Today, aware of the potential for other such cataclysmic impacts, some of the world’s astronomers keep an eye on near-earth orbiting chunks of debris left over from the formation of the solar system. The smallest types – meteors for instance – put on harmless celestial light shows. Larger meteors (bolides) occasionally spread “flame” and trail “smoke” as they crash to Earth. Larger bodies have left wakes of natural devastation across miles of forests – without even leaving a trace of their own “party crashing” material behind. But larger intruders have little such modesty. An asteroid or comet one kilometer in diameter would spell absolute calamity for a population center. Bodies ten times that size may account for massive die-offs of the type that spelled the end of the dinosauria.

Human beings first walked upright some 6MYA. This probably occurred as the path diverged between proto-chimpanzees and early hominids. That divergence followed a ten million year period of rapid primate evolution and blended into a six-million year cycle of human evolution. The first stone tools were crafted by human hand roughly 2 million years ago. Fire was harnessed by some enterprising member of the human species a million years later. Technology gained momentum very slowly – hundreds of thousands of years have passed without any significant improvement in the tools used by the tribal societies of long past.

Modern humans originated more than 200,000 years ago. Some 125 thousand years later an event occurred that may have reduced the entire human population of planet Earth to less than 10,000 individuals. That event was not extra-terrestrial in nature – the Earth itself probably belched forth “fire and brimstone” during the eruption of a gas-charged magma chamber (similar to that beneath Yellowstone National Park in the western USA). Another 65,000 years passed and the stone age gave way to the age of agriculture. By 5000 years ago the first city-states coalesced within fertile valleys surrounded by far less hospitable climes. Whole civilizations have come and gone. Each passing a torch of culture and slowly evolving technology to the next. Today it has been only a few short centuries since the first human hand shaped lenses of glass and turned the human eye upon the things of the Night Sky.

Today huge mirrors and space probes allow us to contemplate the vast reaches of the universe. We see a Cosmos dynamic and quite possibly thrilling with life more abundant than anyone could possibly imagine. Like light and matter, life may very well be a fundamental quality of the space-time continuum. Life could be as universal as gravitation – and as personal as an evening alone with a telescope beneath the night sky…


1 In fact, the radio-frequency spectrographic fingerprint of at least one amino acid (glycine) has been found in vast clouds of dust and gas within the interstellar medium (ISM). (See Amino acid found in deep space).

2 That life develops from less sophisticated to more sophisticated forms is a question beyond scientific dispute. Precisely how this process takes place is an issue of deep division in human society. Astronomers – unlike biologists – are not required to hold any particular theory on this issue. Whether chance mutation and natural selection drives the process or some unseen “hand” exists to bring such things about is outside the realm of astronomical inquiry. Astronomers are interested in structures, conditions, and processes in the universe at large. As life becomes more salient to that discussion, astronomy – in particular exobiology – will have more to say about the matter. But the very fact that astronomers can allow nature to speak on such issues as a sudden and instantaneous “creation ex nihilo” in the form of a Big Bang shows just how flexible astronomical thinking is in regard to ultimate origins.

Acknowledgment: My thanks goes out to exobiologist

Andrew Pohorille of NASA who enlightened me as to the great significance of the hydrophobic effect on the formation of self-organizing structures. For more information on exobiology please see NASA’s Exobiology Life Through Space and Time official website through which I had the good fortune of contacting Andrew.

About The Author:
Inspired by the early 1900’s masterpiece: “The Sky Through Three, Four, and Five Inch Telescopes”, Jeff Barbour got a start in astronomy and space science at the age of seven. Currently Jeff devotes much of his time observing the heavens and maintaining the website
Astro.Geekjoy.

Are We Alone?

Image Credit: “Seeking” ?1998
Lynette Cook. Used with Permission.
“All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.”
– German philosopher Arthur Schopenhauer (1788 – 1860)

Are we alone? Given the immensity of the Cosmos, a mathematical impossibility. Will we ever come to know we are not alone? That’s a tougher question. But should first contact occur today we could be in for a shock1. So right now may be a good time to prepare. And perhaps the best way to prepare is to imagine the possibility…

Numerous psychological studies have shown that “imagining a thing” makes us more receptive to the possibility. In fact many of the great breakthroughs in scientific thought came about as a result of the proper use of the creative imagination. Sir Isaac Newton saw the motions of all moons and planets everywhere in the simple fall of a ripe apple from the boughs of a tree. Albert Einstein perceived the relativity of all time and space while contemplating the accelerated motion of a trolley car moving away from the face of a public clocktower. We human beings might want to take a few moments and think about how we will respond should ET make an appearence in our small corner of the cosmos.

So, take a moment and relax. (Yes it’s true, deep breathing does help!) Imagine a universe populated with many and diverse forms of intelligent life. Extend yourself through time and space toward distant systems of suns and planets. See simple organisms thrilling to the rhythms of light and matter working in harmony to develop ever more sophisticated life-forms. Follow the earliest interstellar craft as they move tirelessly from system to system toward some distant beckoning beacon of promise. Surf beams of radiant energy flung like arrows from far away lighthouses upon the Ocean of Space.

Someday such imaginings may be confirmed by rock solid science – perhaps SETI will detect an indisputable signal from beyond, or “Michael Rennie” emerges as an emissary from the Galactic Federation of Planetary Systems trailed by Gort – the Wonder Robot.

Given the likelihood that such space-faring or highly communicative intelligences exist, and given all the billions of years for off-world intelligence to develop the means to travel and communicate, plus our own recent efforts to find them out, why don’t we know already?

One, and possibly the very best answer is “We aren’t ready.”

The human imagination also has its down-side: Imagine the initial shock and ridicule as we humans attempt to upright a world overturned by what for many will be an impossible event. Consider also how governments and institutions, groups and individuals, have responded to similar reports in the past. Remember “Mars-rock”? Do we hear much of it now? And what about pilot Hap Arnold’s “flying saucer” report. Can we really say that we have taken clear-headed, scientific looks at such things? Or is our normal response one of incredulity and ridicule? Hmmmm…

To know is to see truth wherever it may be found. No, we’re not saying that UFO’s have visited the Earth. What we are saying is that our response to those who make such claims is often one of ridicule and disrespect. Is it not possible that compassion and open-mindedness would be more appropriate?

So let’s seek truth where it can be found – right here on Earth. We can start by looking for unsuspected signs of intelligence around us2. Let’s take a clear-eyed look at our animal friends by setting aside prejudices concerning their intelligence. Those goldfish in the aquarium can be surprisingly sensitive about things. Walk near the tank during the day and they ignore you. Come feeding time, and you are the most interesting thing in the world to them.

To be sure we are very unlikely to learn that the universe is suffused with intelligence until we get past our own anthrocentrism. It took a lot of hard work (and self-sacrifice) by Copernicus, Kepler, and Galileo just to get western society to finally step “up to the edge” and see that the Blue Planet is most definitely not flat nor does it act as the axis around which all things celestial swing.

And even with the signs of intelligence abounding on our homeworld today we persist in thinking that all creatures exist for us, our amusement, our purposes. Under such conditions can we possibly appreciate how truly intelligent they are? And to be more germane, do we really think ET might want to come out and play with us under such circumstances?

Today we don’t seem to be ready to accept anything other than the myth of being alone. Yes, one way to tell this does have to do with how we relate to other creatures on the Blue Planet, but there are other reasons to doubt our readiness as well. Consider our political institutions; Why is it that our leaders and their associates spend so much time “down-playing” the truth of things, presenting specious arguments to motivate behavior, or putting controversial issues into the spin cycle? Is it because of hidden political or economic agendas? Or possibly because they don’t believe we can handle reality3?

Meanwhile high overhead, ET approaches the Earth – third stone from the Sun – and initiates a scan of the EM spectrum. Newscasts portray crisis after crisis, violence, conflict, bloodshed, environmental degradation. How would you – an intelligent being from elsewhere respond?

Personally, I’d activate the cloaking device.

ET is no dummy – he/she/it is after all an intelligent life-form possessed of advanced technology. One scan of Earth’s broadcast media and ET soon comes to see that this is not a place to be trifled with: The natives are restless. Emotion overrules reason. Reaction upstages proaction. Nations practice deception and ill-will in relationships – internal and external. Angry voices shout each other down – not just on the streets but in the houses of governance as well. We are not a happy bunch.

And yet the future remains always a bright star of possibility. Hope springs eternal in ET’s breast (or left antibular thorax as the case may be…)

ET of course, has seen such things before. Countless worlds of lesser and greater advancement have been encountered. Before ET learned the wisdom of keeping a safe distance, he-she-it actually tried to help a few troubled worlds such as our own. In the end ET may have had to overcome shock, ignorance, even bloody insurgencies. Costs were great, rewards few. Now ET waits – waits for us to pass certain tests – tests defined in some intragalactic protocol: “The Prime Directive”.

So the hailing frequencies are locked down. ET goes stealth. “Subspace” signals are transmitted to ET Central: “Earthlings are still at it. Planet approaching ecological crisis. Species dying off. The few have much, many have little. Schedule re-visit next solar maximum. Report over and out.”

Today our instruments can peer back to the very threshold of the Big Bang – nearly 13.7 million lightyears distant in time and space, millions and millions of galaxies, billions and billions of Suns. Who knows how many planets – many equal to or superior to our own in fecundity and arability. Some populated as yet only by single-cell organisms. Others by beings possessed of no organic form whatsoever. It doesn’t even take the imagination to see the possibility anymore. Those of us interested in astronomy also read and watch science fiction. All the heavy lifting has been done for us. Fantastic lifeforms dwell in fabulous environs undergoing incredible adventures: Star Trek, Star Wars, Babylon Five – you name it – we’ve seen it. And yes, many of us believe in our hearts – but even so, we want to know.

Even now we scan the heavens seeking proof. The SETI project is bringing its array of parallel narrow-band scanning recievers on line. We hope against hope that some not-too-circumspect intelligence is out there broadcasting narrowband signals intentionally (or not) seeking to conclusively demonstrate their presence in our universe.

Will SETI find them out? And if so, how will we respond to the reality?

It is possible to uncover intelligence in this way, but intelligent life-forms not only learn from experience but in advance of experience as well. Do we here on Earth choose to project our presence intentionally into the interstellar medium4?

No – that particular notion has already been discarded and perhaps wisely so. We know what we are like – others could be worse!

Psychology plays a big role in choices made by intelligent creatures. When they don’t trust others, they “down-play” the truth or offer specious arguments. When they make mistakes, they put things in the “spin cycle”. When they see other intelligences doing these kinds of things with great regularity they know that contact is to be avoided. Perhaps this is at essence in first contact protocol. Until truth is welcomed – even at the expense of notions held dear – a world is not ready. Otherwise the cost of engagement is too high, benefits too low, and outcomes too unpredictable – or worse – dangerous.

But we may detect extraterrestial intelligence in other ways. It’s a solid assumption that all advancing technologies pass through a broadband em broadcast phase. During such an era civilizations “leak” evidence of their existence. Unfortunately, even our largest radio telescope would be hard pressed to detect broadband transmissions – such as Earth’s – from as close as the Alpha Centauri system. Meanwhile the window on em broadcast may even be closing here on earth. How many of us watch television programs delivered by antenna today? Less than a half-century ago every house had its own “rabbit ears”. One-hundred years from now we may be EM mute…

We might also intercept a signal in transit between two worlds. Such an event would be serendipitous – luck would play a huge role. First we would have to be more or less line of sight. Why? Because the tighter such a signal is foused the further it travels without attenuation. Although laser (and maser) transmissions do diffract over great distances, we would still need to be well-placed to pick one up. Meanwhile such signals may not necessarily be narrow band in frequency. Why? Because phase-modulated transmission may be the most efficient way to transmit pictures, sounds, and data across space5.

Despite all these barriers to revelation what practical steps can we now take to prepare for some future “first contact”?

Assisted by writers of science fiction and purveyors of motion pictures, we’ve already made a start by imagining the possibility. Animal behaviorists have helped prepare us by investigating various types and degrees of intelligence in the natural world. Psychologists and socioligists have done the same thing in the realms of our own species.

Meanwhile on an individual basis we can all learn to pay more attention to intelligence as seen within our families, among friends, associates – and even strangers. (Perhaps especially strangers.) All this makes us more aware of what intelligence is and how it is communicated.

On the broadest possible levels we must all further our ability to welcome and speak truth – despite any pain it may leave in its wake.

Having done our own personal work, “homeworld work” can go forward. Collectively we can work together to expunge the seeds and uproot the weeds of war on the planet. Although this means holstering our weapons, it also means overcoming a persistent propensity toward propaganda, religious strife, scientific contention, and undue corporate economic advantage.

And of great importance at this time is the need to be more supportive of other homeworld species – irrespective of intelligence. Ecology teaches us that every creature plays an important role in Earth’s biosphere. Perhaps it should become a matter of human education, demographical planning, economics, and political activity to ensure that this particular insight truly guides our choices and behavior. After all so long as we remain exploitative of lesser species no truly intelligent extraterrerestial species is likely to have much to do with us. Scarier still, if there are any “bad boys” out there, they could easily rationalize “taking over the joint”.

So let’s say we clean up our act. What happens next?

Isn’t that enough? To live in a world where truth multiplies, nature is respected, intelligence is recognized, and peace reigns supreme is actually quite appealing in itself – for most intelligences worthy of interstellar relations.

But this article is not about social transformation per se – it’s about the very real possibility of first contact – something that could transpire even before our children take a leading role in the unfolding story of human history.

Are we ready to get ready?

If intelligence can germinate here, it can flower elsewhere. Why, of course, it’s all so – “self-evident!”


1 The 1997 hit movie “Contact” (based on a novel by Carl Sagan) portrayed the many and varied ways in which human beings responded to scientific proof of the existence of advanced extraterrestrial intelligence.

2 According to a BBC News article a captive African grey parrot named N’kisi has a vocabulary of almost one thousand words, shows evidence of a sense of humour, and devises new words and concocts phrases as needed.

3 Irrespective of its overall merits, US efforts to topple an Iraqi dictatorship were found to be based on overstated evidence. (See Conclusions of Senate’s Iraq report) Such misuses of information often occur when a government is unable to speak plainly to its citizens concerning matters of importance.

4 In an article published by the title Quantum Communication Between the Stars? SETI Institute member Seth Shostak recalls the heated response of England’s Astronomer Royal to the ad hoc messaging of M13 during a 1974 ceremonial at the Arecibo radio telescope in Puerto Rico.

5 The narrower the frequency used to transmit data through space the higher the signal-to-noise ratio. The most efficient mode of such transmission is to digitally switch a carrier frequency “on and off”. Such serial modes of transmission however, are very slow at transfering large amounts of data through space in short amounts of time. Such signals are however very useful for saying things like “look at me I am here!”.

About The Author: Inspired by the early 1900’s masterpiece: “The Sky Through Three, Four, and Five Inch Telescopes”, Jeff Barbour got a start in astronomy and space science at the age of seven. Currently Jeff devotes much of his time observing the heavens and maintaining the website Astro.Geekjoy.

Life Might Have Started in Fresh Water

A geomicrobiologist at Washington University in St. Louis has proposed that evolution is the primary driving force in the early Earth’s development rather than physical processes, such as plate tectonics.

Carrine Blank, Ph.D., Washington University assistant professor of geomicrobiology in the Department of Earth & Planetary Sciences in Arts & Sciences, studying Cyanobacteria – bacteria that use light, water, and carbon dioxide to produce oxygen and biomass – has concluded that these species got their start on Earth in freshwater systems on continents and gradually evolved to exist in brackish water environments, then higher salt ones, marine and hyper saline (salt crust) environments.

Cyanobacteria are organisms that gave rise to chloroplasts, the oxygen factory in plant cells. A half billion years ago Cyanobacteria predated more complex organisms like multi-cellular plants and functioned in a world where the oxygen level of the biosphere was much less than it is today. Over their very long life span, Cyanobacteria have evolved a system to survive a gradually increasing oxidizing environment, making them of interest to a broad range of researchers.

Blank is able to draw her hypothesis from family trees she is drawing of Cyanobacteria. Her observations are likely to incite debate among biologists and geologists studying one of Earth’s most controversial eras – approximately 2.1 billion years ago, when cyanobacteria first arose on the Earth. This was a time when the Earth’s atmosphere had an incredible, mysterious and inexplicable rise in oxygen, from extremely low levels to 10 percent of what it is today. There were three – some say four – global glaciations, and the fossil record reflects a major shift in the number of organisms metabolizing sulfur and a major shift in carbon cycling.

“The question is: Why?” said Blank.

“My contribution is the attempt to find evolutionary explanations for these major changes. There were lots of evolutionary movements in Cyanobacteria at this time, and the bacteria were making an impact on the Earth’s development. Geologists in the past have been relying on geological events for transitions that triggered change, but I’m arguing that a lot of these things could be evolutionary.”

Blank presented her research at the 2004 annual meeting of the Geological Society of America, held, Nov. 7-10 in Denver.

Blank’s finding that Cyanobacteria emerged first in fresh water lakes or streams is counterintuitive.

“Most people have the assumption that Cyanobacteria came out of a marine environment – after all, they are still important to marine environments today, so they must always have been,” Blank said. “When Cyanobacteria started to appear, there was no ozone shield, so UV light would have killed most things. They either had to have come up with ways to deal with the UV light – and there is evidence that they made UV-absorbing pigments – or find ways of growing under sediments to avoid the light.”

To study the evolution of Cyanobacteria, Blank drew up a backbone tree using multiple genes from whole genome sequences. Additional species were added to the tree using ribosomal RNA genes. Morphological characters, for instance, the presence or absence of a sheath, unicellular or filamentous growth, the presence or absence of heterocysts ? a thick-walled cell occurring at intervals ? were coded and mapped on the tree. The distribution of traits was compared with those found in the fossil record.

Cyanobacteria emerging some two billion years ago were becoming complex microbes that had larger cell diameters than earlier groups – at least 2.5 microns. Blank’s tree shows that several morphological traits arose independently in multiple lines, among them a sheath structure, filamentous growth, the ability to fix nitrogen, thermophily (love of heat), motility and the use of sulfide as an electron donor.

“We will need lots of analyses of the micro-fossil record by serious paleobiologists to see how sound this hypothesis is,” Blank said. “This time frame is one of the biggest puzzles for biologists and geologists alike. A huge amount of things are happening then in the geological record.”

Original Source: WUSTL News Release

Would We Mistake Signals from ET?

Researchers from the University of Michigan think that the current programs to search for extraterrestrial intelligence (SETI) might not be able to distinguish signals from the noise of nearby stars. They showed how an efficient message sent through radio waves is nearly indistinguishable from the ordinary thermal radiation coming from stars. If extraterrestrial civilizations have been transmitting for a long time, they’ll probably have optimized their communications to save power, and so we won’t recognize it when we hear it.

If ET ever phones home, chances are Earthlings wouldn’t recognize the call as anything other than random noise or a star.

New research shows that highly efficient electromagnetic transmissions from our neighbors in space would resemble the thermal radiation emitted by stars.

University of Michigan physicist Mark Newman, along with biologist Michael Lachmann and computer scientist Cristopher Moore, have extended the pioneering 1940s research of Claude Shannon to electromagnetic transmissions in a paper published last month in the American Journal of Physics called, “The Physical Limits of Communication, or Why any sufficiently advanced technology is indistinguishable from noise.” Lachmann is at the Max Planck Institute in Leipzig, Germany; Moore is at the University of New Mexico in Albuquerque.

Shannon showed that a message transmitted with optimal efficiency is indistinguishable from random noise to a receiver unfamiliar with the language in the message. For example, an e-mail message whose first few letters are AAAAA contains little information because the reader can easily guess what probably comes next?another A. The message is totally non-random. On the other hand, a message beginning with a sequence of letters like RPLUOFQX contains a lot of information because you cannot easily guess the next letter.

Paradoxically, however, the same message could just be a random jumble of letters containing no information at all; if you don’t know the code used for the message you can’t tell the difference between an information-rich message and a random jumble of letters.

Newman and his collaborators have shown that a similar result holds true for radio waves.

When electromagnetic waves are used as the transmission medium, the most information efficient format for a message is indistinguishable from ordinary thermal radiation?the same kind of radio waves that are emitted by hot bodies like stars. In other words, an efficiently coded radio message coming from outer space would look no different from a normal star in the sky.

So, suppose an alien in space decided to pick up signs of Earth life. It would have a pretty easy time of it, since our radio and television signals are zigzagging all over the place and are inefficiently coded and easily distinguishable from stars.

But say a human tries to tune into extraterrestrial life.

“People do this, and when they do, they are looking for non-random stuff,” Newman said. “But what if (the aliens) have gotten it down? With a few hundred years practice at doing this, you’d have discovered the most efficient way to encode your radio messages. So to us, their communication would look just like another star, a hot object.”

After all, Newman said, in the universe’s 12 billion-year history, it’s likely that extraterrestrials?if they exist?have communicated with each other longer than our paltry 80-year history of radio broadcasting. “In which case, they’ve probably gotten very good at this by now.”

Said Newman: “Our message is that, even for the people who do believe this, they’re probably wasting their time. If they did pick up a signal from little green men, it would probably look like a star to them and they would just pass over it and move on to the next thing.”

Original Source: UMich News Release

Life’s There, You Just Need to Dig

Image credit: NASA
A place so barren that NASA uses it as a model for the Martian environment, Chile’s Atacama desert gets rain maybe once a decade. In 2003, scientists reported that the driest Atacama soils were sterile.

Not so, reports a team of Arizona scientists. Bleak though it may be, microbial life lurks beneath the arid surface of the Atacama’s absolute desert.

“We found life, we can culture it, and we can extract and look at its DNA,” said Raina Maier, a professor of soil, water and environmental science at the University of Arizona in Tucson.

The work from her team contradicts last year’s widely reported study that asserted the “Mars-like soils” of the Atacama’s core were the equivalent of the “dry limit of microbial life.”

Maier said, “We are saying, ‘What is the dry limit of life?’ We haven’t reached it yet.”

The Arizona researchers will publish their findings as a letter in the Nov. 19 issue of the journal Science. Maier’s co-authors include UA researchers Kevin Drees, Julie Neilson, David Henderson and Jay Quade and U.S. Geological Survey paleoecologist Julio Betancourt. The project was funded by the National Science Foundation and the National Institute for Environmental and Health Sciences, part of the National Institutes of Health.

The project began not as a search for current life but rather as an attempt to peer into the past and reconstruct the history of the region’s plant communities. Betancourt and Quade, a UA professor of geosciences, have been conducting research in the Atacama for the past seven years.

Some parts of the Atacama have vegetation, but the absolute desert of the Atacama’s core — an area Betancourt describes as “just dirt and rocks” — has none.

Nor does the area have cliffs which harbor ancient piles of vegetation, known as middens, collected and stored by long-gone rodents. Researchers use such fossil plant remains to tell what grew in a place long ago.

So to figure out whether the area had ever been vegetated, Quade and Betancourt had to search the soil for biologically produced minerals such as carbonates. To rule out the possibility that such soil minerals were being produced by present-day microorganisms, the two geoscientists teamed up with UA environmental microbiologist Maier.

In October of 2002, the researchers collected sterile soil samples along a 200-kilometer (120 miles) transect that ran from an elevation of 4,500 meters (almost 15,000 feet) to sea level.

Every 300 meters (about 1,000 feet) along the transect, the team dug a pit and took two soil samples from a depth of 20 to 30 centimeters (8 to 12 inches). To ensure the sample was sterile, every time he took the sample, Betancourt had to clean his hand trowel with Lysol.

“When it’s still, it’s not a problem,” he said. “But when the wind’s blowing at 40 miles per hour, it’s a little more complicated.”

The geoscientists brought their test tubes full of desert soil back to Maier’s lab, where her team wetted the soil samples with sterile water, let them sit for 10 days, and then grew bacteria from them.

“We brought ’em back alive, it turns out,” Betancourt said.

Maier and her team have not yet identified the bacteria that come from the extremely arid environment of the Atacama’s core. She can say they are unusual.

She said, “As a microbiologist, I am interested in how these microbial communities evolve and respond. Can we discover new microbial activities in such extreme environments? Are those activities something we can exploit?”

The team’s findings suggest that how researchers look for life on Mars may affect whether life is found on the Red Planet.

The other researchers who had tested soil from the Atacama had looked for life only down to the depth of four inches. So one rule, Quade quipped, is, “Don’t just scratch the surface.”

Saying that Mars researchers are most likely looking for a needle in a very large haystack, Maier said, “If you aren’t very careful about your Mars protocol, you could miss life that’s there.”

Peter H. Smith, the UA planetary scientist who is the principal investigator for the upcoming Phoenix mission to Mars, said, “Scientists on the Phoenix Mission suspect that there are regions on Mars, arid like the Atacama Desert in Chile, that are conducive to microbial life.” He added, “We will attempt an experiment similar to Maier’s group on Mars during the summer of 2008.”

As for Maier and her colleagues, Betancourt said, “We’re very, very interested in life on Earth and how it functions.”

Maier suspects the microbes may persist in a state of suspended animation during the Atacama Desert’s multi-decadal dry spells.

So the team’s next step is to return to Chile and do experiments on-site. One option is what Maier calls “making our own rainfall event” — adding water to the Atacama’s soils — and seeing whether the team could then detect microbial activity.

Original Source: UA News Release

Is There Life on Europa?

Image credit: NASA
Christopher Chyba is the principal investigator for the SETI Institute lead team of the NASA Astrobiology Institute (NAI). Chyba formerly headed the SETI Institute’s Center for the Study of Life in the Universe. His NAI team is pursuing a wide range of research activities, looking at both life’s beginnings on Earth and the possibility of life on other worlds. Several of his team’s research projects will examine the potential for life – and how one might go about detecting it – on Jupiter’s moon Europa. Astrobiology Magazine’s managing editor Henry Bortman recently spoke with Chyba about this work.

Astrobiology Magazine: One of the areas of focus of your personal research has been the possibility of life on Jupiter’s moon Europa. Several of the projects funded by your NAI grant deal with this ice-covered world.

Christopher Chyba: Right. We’re interested in interactions of life and planetary evolution. There are three worlds that are most interesting from that point of view: Earth, Mars and Europa. And we have a handful of projects going that are relevant to Europa. Cynthia Phillips is the leader of one of those projects; my grad student here at Stanford, Kevin Hand, heads up another one; and Max Bernstein, who’s a SETI Institute P.I., is a leader on the third.

There are two components to Cynthia’s projects. One that I think is really exciting is what she calls “change comparison.” That goes back to her days of being a graduate associate on the Galileo imaging team, where she did comparisons to look for surface changes on another of Jupiter’s moons, Io, and was able to extend her comparisons to include older Voyager images of Io.

We have Galileo images of Io, taken in the late 1990s, and we have Voyager images of Io, taken in 1979. So there are two decades between the two. If you can do a faithful comparison of the images, then you can learn about what’s changed in the interim, get some sense of how geologically active the world is. Cynthia did this comparison for Io, then did it for the much more subtle features of Europa.

That may sound like a trivial task. And for really gross features I suppose it is. You just look at the images and see if something’s changed. But since the Voyager camera was so different, since its images were taken at different lighting angles than Galileo images, since the spectral filters were different, there are all sorts of things that, once you get beyond the biggest scale of examination, make that much more difficult than it sounds. Cynthia takes the old Voyager images and, if you will, transforms them as closely as one can into Galileo-type images. Then she overlays the images, so to speak, and does a computer check for geological changes.

When she did this with Europa as part of her Ph.D. thesis, she found that there were no observable changes in 20 years on those parts of Europa that we have images for from both spacecraft. At least not at the resolution of the Voyager spacecraft – you’re stuck with the lowest resolution, say about two kilometers per pixel.

Over the duration of the Galileo mission, you’ve got at best five and a half years. Cynthia’s idea is that you’re more likely to detect change in smaller features, in a Galileo-to-Galileo comparison, at the much higher resolution that Galileo gives you, than you were working with images that were taken 20 years apart but that require you to work at two kilometers per pixel. So she’s going to do the Galileo-to-Galileo comparison.

The reason this is interesting from an astrobiological perspective is that any sign of geological activity on Europa might give us some clues about how the ocean and the surface interact. The other component of Cynthia’s project is to better understand the suite of processes involved in those interactions and what their astrobiological implications might be.

AM: You and Kevin Hand are working together to study some of the chemical interactions believed to be taking place on Europa. What specifically will you be looking at?

There are a number of components of the work I’m doing with Kevin. One component stems from a paper that Kevin and I had in Science in 2001, which has to do with the simultaneous production of electron donors and electron acceptors. Life as we know it, if it doesn’t use sunlight, makes its living by combining electron donors and acceptors and harvesting the liberated energy.

For example, we humans, like other animals, combine our electron donor, which is reduced carbon, with oxygen, which is our electron acceptor. Microbes, depending on the microbe, may use one, or several, of many possible different pairings of electron donors and electron acceptors. Kevin and I were finding abiotic ways that these pairings could be produced on Europa, using what we understand about Europa now. Many of these are produced through the action of radiation. We’re going to continue that work in much more detailed simulations.

We’re also going to look at the survival potential of biomarkers at Europa’s surface. That is to say, if you’re trying to look for biomarkers from an orbiter, without getting down to the surface and digging, what sort of molecules would you look for and what are your prospects for actually seeing them, given that there’s an intense radiation environment at the surface that should slowly degrade them? Maybe it won’t even be that slow. That’s part of what we want to understand. How long can you expect certain biomarkers that would be revelatory about biology to survive on the surface? Is it so short that looking from orbit doesn’t make any sense at all, or is it long enough that it might be useful?

That has to be folded into an understanding of turnover, or so-called “impact gardening” on the surface, which is another component of my work with Cynthia Phillips’, by the way. Kevin will be getting at that by looking at terrestrial analogs.

AM: How do you determine which biomarkers to study?

CC: There are certain chemical compounds that are commonly used as biomarkers in rocks that go back billions of years in the terrestrial past. Hopanes, for example, are viewed as biomarkers in the case of cyanobacteria. These biomarkers withstood whatever background radiation was present in those rocks from the decay of incorporated uranium, potassium, and so on, for over two billion years. That gives us a kind of empirical baseline for survivability of certain kinds of biomarkers. We want to understand how that compares to the radiation and oxidation environment on the surface of Europa, which is going to be much harsher.

Both Kevin and Max Bernstein are going to get after that question by doing laboratory simulations. Max is going to be irradiating nitrogen-containing biomarkers at very low temperatures in his laboratory apparatus, trying to understand the survivability of the biomarkers and how radiation changes them.

AM: Because even if the biomarkers don’t survive in their original form they might get transformed into another form that a spacecraft could detect?

CC: That’s potentially the case. Or they might get converted into something that is indistinguishable from meteoritic background. The point is to do the experiment and find out. And to get a good sense of the time scale.

That’s going to be important for another reason as well. The kind of terrestrial comparison I just mentioned, while I think it’s something we should know, potentially has limits because any organic molecule on the surface of Europa is in a highly oxidizing environment, where the oxygen’s getting produced by the radiation reacting with the ice. Europa’s surface is probably more oxidizing than the environment organic molecules would experience trapped in a rock on the Earth. Since Max will be doing these radiation experiments in ice, he will be able to give us a good simulation of the surface environment on Europa.

Original Source: Astrobiology Magazine

Life Found Under 1,350 Metres of Rock

Image credit: NASA

A team of scientists have discovered bacteria inside a hole that was drilled 1,350 metres into the volcanic rock near Hilo, Hawaii. The hole began in igneous rock on the Mauna Loa volcano, and then passed through lava from Mauna Kea. At 1,000 metres they encountered fractured basalt glass which formed when the lava flowed into the ocean. Upon close examination, they found that this lava had been changed by microorganisms. Using electron microscopy, they found tiny microbe spheres, and they were able to extract DNA. Scientists are finding life in more remote regions of the planet, and this gives hope that it might be on the other planets in our solar system as well.

A team of scientists has discovered bacteria in a hole drilled more than 4,000 feet deep in volcanic rock on the island of Hawaii near Hilo, in an environment they say could be analogous to conditions on Mars and other planets.

Bacteria are being discovered in some of Earth’s most inhospitable places, from miles below the ocean’s surface to deep within Arctic glaciers. The latest discovery is one of the deepest drill holes in which scientists have discovered living organisms encased within volcanic rock, said Martin R. Fisk, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University.

Results of the study were published in the December issue of Geochemistry, Geophysics and Geosystems, a journal published by the American Geophysical Union and the Geochemical Society.

“We identified the bacteria in a core sample taken at 1,350 meters,” said Fisk, who is lead author on the article. “We think there could be bacteria living at the bottom of the hole, some 3,000 meters below the surface. If microorganisms can live in these kinds of conditions on Earth, it is conceivable they could exist below the surface on Mars as well.”

The study was funded by NASA, the Jet Propulsion Laboratory, California Institute of Technology and Oregon State University, and included researchers from OSU, JPL, the Kinohi Institute in Pasadena, Calif., and the University of Southern California in Los Angeles.

The scientists found the bacteria in core samples retrieved during a study done through the Hawaii Scientific Drilling Program, a major scientific undertaking run by the Cal Tech, the University of California-Berkeley and the University of Hawaii, and funded by the National Science Foundation.

The 3,000-meter hole began in igneous rock from the Mauna Loa volcano, and eventually encountered lavas from Mauna Kea at 257 meters below the surface.

At one thousand meters, the scientists discovered most of the deposits were fractured basalt glass – or hyaloclastites – which are formed when lava flowed down the volcano and spilled into the ocean.

“When we looked at some of these hyaloclastite units, we could see they had been altered and the changes were consistent with rock that has been ‘eaten’ by microorganisms,” Fisk said.

Proving it was more difficult. Using ultraviolet fluorescence and resonance Raman spectroscopy, the scientists found the building blocks for proteins and DNA present within the basalt. They conducted chemical mapping exercises that showed phosphorus and carbon were enriched at the boundary zones between clay and basaltic glass – another sign of bacterial activity.

They then used electron microscopy that revealed tiny (two- to three-micrometer) spheres that looked like microbes in those same parts of the rock that contained the DNA and protein building blocks. There also was a significant difference in the levels of carbon, phosphorous, chloride and magnesium compared to unoccupied neighboring regions of basalt.

Finally, they removed DNA from a crushed sample of the rock and found that it had come from novel types of microorganisms. These unusual organisms are similar to ones collected from below the sea floor, from deep-sea hydrothermal vents, and from the deepest part of the ocean – the Mariana Trench.

“When you put all of those things together,” Fisk said, “it is a very strong indication of the presence of microorganisms. The evidence also points to microbes that were living deep in the Earth, and not just dead microbes that have found their way into the rocks.”

The study is important, researchers say, because it provides scientists with another theory about where life may be found on other planets. Microorganisms in subsurface environments on our own planet comprise a significant fraction of the Earth’s biomass, with estimates ranging from 5 percent to 50 percent, the researchers point out.

Bacteria also grow in some rather inhospitable places.

Five years ago, in a study published in Science, Fisk and OSU microbiologist Steve Giovannoni described evidence they uncovered of rock-eating microbes living nearly a mile beneath the ocean floor. The microbial fossils they found in miles of core samples came from the Pacific, Atlantic and Indian oceans. Fisk said he became curious about the possibility of life after looking at swirling tracks and trails etched into the basalt.

Basalt rocks have all of the elements for life including carbon, phosphorous and nitrogen, and need only water to complete the formula.

“Under these conditions, microbes could live beneath any rocky planet,” Fisk said. “It would be conceivable to find life inside of Mars, within a moon of Jupiter or Saturn, or even on a comet containing ice crystals that gets warmed up when the comet passes by the sun.”

Water is a key ingredient, so one key to finding life on other planets is determining how deep the ground is frozen. Dig down deep enough, the scientists say, and that’s where you may find life.

Such studies are not simple, said Michael Storrie-Lombardi, executive director of the Kinohi Institute. They require expertise in oceanography, astrobiology, geochemistry, microbiology, biochemistry and spectroscopy.

“The interplay between life and its surrounding environment is amazingly complex,” Storrie-Lombardi said, “and detecting the signatures of living systems in Dr. Fisk’s study demanded close cooperation among scientists in multiple disciplines – and resources from multiple institutions.

“That same cooperation and communication will be vital as we begin to search for signs of life below the surface of Mars, or on the satellites of Jupiter and Saturn.”

Original Source: OSU News Release