Tuesday, September 29, 2009

Ancient Australian Trace Fossils Hint at Martian Equivalents

The hope for primitive life on Mars has received a new boost. Early bacteria that lived 2.75 billion years ago shaped caves to live in, and the traces left behind hint at how life might still be inhabiting Mars. In a recent Discovery Channel article, Michael Reilly describes an early Earth with no oxygen in the atmosphere, or ozone layer to protect anything living on the surface from harmful ultraviolet radiation. This is the earliest evidence of subterranean life on Earth. In the article Birger Rasmussen of Curtin University of Technology in Bentley, Australia describes evidence that these ancient bacteria colonized tiny hollows in lake and river sediments.

The tiny hollows were just a centimeter or so tall and a couple of millimeters across, and formed air-tight sheets, which were inflated by methane gas, generated by decaying organic matter, bubbling through the sediments.

This methane could have been a nutrient for the bacteria, or it could have allowed water and nutrients to flow through the cavity. Over time layer upon layer of material built up and formed the laminate fossils Rasmussen's team discovered.

Living in underground cavities allowed the bacteria to escape the UV radiation that scoured the surface. Here was a tiny, protected environment for life.

The team's finding, published this month in the journal Geology, helps substantiate the hypothesis that bacteria colonies might still be hiding out within caves on Mars. Today the Martian surface is desolate, and far too harsh to support life , but recent discoveries of buried water ice revealed by meteor strikes raise tantalizing promise of hidden niches for a simple and hardy life.

The complete article can be found here:

URL: http://www.msnbc.msn.com/id/30649087/

Saturday, August 15, 2009

Transforming Mars

Wikipedia has a fascinating article on how to terraform Mars into a kinder, gentler planet suitable for Earthly life forms:


Another intriguing Martian factoid comes from the continuing studies of data returned from last year's Phoenix lander. The chemical evidence from the ovens that baked the polar soil samples suggests that films of liquid water were probably present in the recent past, an environment that could have supported microbial life (if any existed).

More Earth-like than either Venus (way to hot) or Saturn's moon Titan (way too cold), Mars offers a tempting platform for study, experimentation, and perhaps a future home for life forms that may have initially developed on Mars, and then were spread to Earth on meteoric debris kicked up by comet and asteroid bombardments as Mars itself began to cool and die, it's future stolen from it by its small size and thin atmosphere. Consider this irony: what if Mar's distant progeny were to be the ones to bring life back to this tiny, still-born world?

Friday, July 3, 2009

Ultramicrobacteria on Mars?

Recently I read an article in the National Geographic News about extremely tiny microbes - 10 to 50 times smaller than E coli - reviving after being frozen for 120,000 years at the bottom of a Greenland glacier. They were extracted from a layer of ice two miles deep. Now consider that planetary icebox, Mars, and the speculation about bacteria, or other tiny forms of life, that might have appeared during that planet's all too brief wet period where saline lakes and perhaps seas spread across a planetary surface washed by rain and dusted with snow. As the atmosphere thinned the lakes evaporated and the seas froze and much of the water migrated to the polar caps Mars became a dusty snowball. Glaciers still exist on the surface, some hidden beneath mantles of dust, and some right out on the surface within craters. The next Mars rover, Curiosity, will be exploring and sampling an area hoped to have preserved chemical traces of such early life. A fossil would be too much to hope for, but Earthly discoveries like these make you wonder what ancient surprises might lurk in an Martian deep freeze.

Wednesday, February 4, 2009

Dinosaur Reconstructions

We see best when a window is clean and when it comes to visualizing the past the more information we have the clearer and more accurate our view.

The extraction and preparation of fossils has improved ten-fold from the early beginnings of paleontology. As a teenage my heroes were Charles R Knight, the painter of majestic prehistoric murals, and paleontologists Colbert and Osborne, who patiently studied the cryptic bones extracted from ancient rock. In this dawn of paleontology fossil bones were blasted, teased, or brushed from the rock holding them, slathered in protective rice paper, burlap and plaster and hauled off to museums to be mounted like trophies. With time, fortunately, these recovery and investigative techniques have grown much more sophisticated. Now we know the stony matrix has its own story to tell about the environment where the entombed fossil lived. Pollen grains identify contemporary plants. Fine textured or clayey stone can hint at skin texture, fur or feathers, allowing us to better determine what the fossilized creature was like. And what discoveries have been made in China in just the last decade! Hordes of unhatched and fossilized eggs. Details of skin and appearance that would never had been guessed at years before. Who would have thought these scrambling “reptilian monsters” would have feathered fans on their arms and legs to better flee predators or chase down prey. Who would have suspected that T-Rex hatched out as a downy chick! These new fossils from China have precipitated a renaissance in dinosaur science and understanding.

Below is one of my favorite drawings by Charles R. Knight of an Ornitholestes. The reconstruction was based on the best fossil information of that period. It’s shown as a nimble, active, fleet of foot catcher of birds (itself a daring and radical idea at that time).

Now check out the 2008 painting by Peter Schouten of Ornitholestes hermanni as reconstructed from imprints and bones from the fossil beds of China. Still fleet and nimble, Ornitholestes is now feathered rather than scaled, and arboreal! Although the coloration and patterning is speculative, if we were to see this creature in the wild today it’s highly unlikely we would now mistake it for a prehistoric variant of six-foot lizard.

But for an asteroid and runaway volcanic eruptions in India, dinosaurs might still be dominant today (bad for us), but smarter and more complex undoubtedly. Slain by catastrophe 65 million years ago, a unique alien world vanished with these fascinating creatures. But our window into their lives is becoming less murky as better extraction techniques and CT scans and rare fossil mummies enrich our view. We should have more respect for the budgie by the window – it’s relatives once dined on triceratops.

Sunday, February 1, 2009

Life in Distant Places

Alien life is the science fiction writer’s stock in trade.

For whatever reason, humans appear to be very lonely upon this water-drenched, biologically rich, warm, and pleasantly hospitable planet. Much money, time and energy has been invested in SETI programs to discover distant alien civilizations. Unfortunately these technological analogs of ourselves either do not exist or are reluctant to talk (or indicate their existence) to us, their neighbors. Considering humanity’s blood drenched and competitive past, there may be some wisdom in this reluctance.

Lacking communion with the stars, we have turned our attention with some desperation to neighboring worlds. Enceladus, a moon of Saturn, exhibits warm water geysers jetting from fissures near its south poles, suggesting a possible favorable environment for microbial life. Water is a key requisite for life and apparently Europe, a moon of Jupiter, possesses a planet-wide ocean capped by a thick cap of ice. A hopeful theory is that life could have developed on the sea floor around black smoker geysers that spew out superheated water and minerals, similar to those found Earth’s deep sea. The sun plays no part in this existence, the organisms are nourished by sulphur and metallic compounds dissolved in the super-heated water spewing from the vents in the sea floor. This may be an environment in which primitive unicellular organisms, called extremophiles, might have developed. One is tempted to speculate that with enough time and resources this life could have developed a certain amount of complexity, including bioluminescence, as in my fanciful illustration below.

As for the hope of finding life beyond the Earth, Mars wears the crown. From Percival Lowell’s canals and Ray Bradbury’s dying civilizations, Mars has provided a fertile field for science fiction’s speculations. The discovery of water-modified sediments by the Mars rovers and ice by the recent Polar Lander keeps hope alive.

But the best evidence for possible life now springs from observations of methane emissions from specific areas of the Martian surface that vary by seasons.

Methane production can be a byproduct of endolithic life processes, or the result of mineral reactions.

An "endolith" is a microorganism that
colonizes the interior of any kind of rock. Endoliths exist by feeding on traces of iron, potassium, or sulfur and some live deep in the crust. The Ocean Drilling Program found microscopic trails in basalt from the Atlantic, Indian, and Pacific oceans that contain DNA. Photosynthetic endoliths have also been discovered.

Due to their harsh environment, endoliths exhibit a very slow reproduction cycle, sometimes undergoing cell division only once every hundred years. There is little energy is available for reproduction or growth so they don't. But this inactivity also lets the organisms weather very long ice ages in a dormant state, eventually wakening again to life when the rocks warms.

The majority of endoliths generate organic compounds essential for their every day lives from inorganic matter. Some though have specialized in feeding on their relatives (are we surprised?). Micro-biotopes where different endolithic species live together are called a SLiME (Subsurface Lithotrophic Microbial Ecosystem) – which is not exactly “take me to your leader” material. Curiously, perhaps inspired by watching too many remakes of The Blob, my Hunters of Tharsis series published by Analog in the 1970s also employed a giant unicellular creature lurking in the deep caves of Mars. Whatever, or whoever, it absorbed it opportunistically incorporated their traits and DNA into its own capabilities. And after it ingests a number of human colonists a new race of Martians is born.

Sadly, even if there is microbial life on Mars living deep within the crustal rocks nourished by subsurface melt water rich in sulphur compounds, such life forms will, no doubt, be totally unimpressive to a boots-on-the-ground astronaut explorer.

As for the geologic reasons for the methane on Mars, serpentinization is suggested as the alternate source. This is a low-temperature metamorphic process involving heat and water in which Periodotite rocks are oxidized and hydrolyzed with water into serpentinite. In the process large amounts of water are absorbed into the rock and in the chemical reactions hydrogen gas, sulfates and carbonates are reduced and form methane and hydrogen sulfide. Of course, here’s another glimmer of hope for life, since this hydrogen, methane, and hydrogen sulfide can provide energy sources for chemotroph microorganisms.

Is there any possibility at all for Martian surface life considering the nearly non-existant atmosphere, intense cold, and punishing rain of UV radiation? Perhaps. Dark spots on dunes have been seen in Mars Global Surveyor images taken during 1998 – 1999 of the southern polar region. The spots appear at the beginning of the Martian spring and disappear by the beginning of the winter. A Hungarian team proposes that the spots are colonies of photosynthetic Martian microorganisms, which are dormant (and not visible) beneath the ice cap until Sun returns in early spring and light penetrates the ice. When these microorganisms begin to photosynthesize they heat the surroundings and a tiny chamber of liquid water forms around them. As the surface ice layer thins and melts, the cells dry and turn dark, creating the observed features on the ice. Of course this ice is really, really cold. Dry ice cold! And NASA feels the dark patches are simply basaltic ash fragments that accumulate as a residue due to sublimation of the ice. Only better observations will determine which explanation is the correct one.

Apparently our only planetary neighbors will never be much more sophisticated than the mold we wipe off the grout in our showers. Gort and Klatuu have yet to check in. Still, considering how those movies turned out for us here on Earth, perhaps that’s a good thing.

And my Red-Planet cave-dwelling bug fantasy, tiny and adaptive though he is, will remain just that - fantasy.

Living the Science Fiction Life…

How we end up in life is sometimes determined by our early fascinations.

When I was in high school there was this somewhat disreputable used books store in downtown San Diego that I loved to haunt on weekends. Way in the back, behind the beckoning racks of men’s magazines with their fleshy covers, it offered year long runs of various science fiction magazines like Astounding, Galaxy, Amazing Stories, Planet Stories, and Startling Tales bound in twine and stacked on dusty shelves like unloved and unwanted orphans.

For me it was a treasure trove and I was in my glory. I already had a subscription to Astounding (soon to be transformed to Analog Science Fact & Fiction) but I was mining the past for the purest vein of space opera. I loved the Cartier, Van Dongen, Emsh, Schoenherr and Kelly Freas illustrations and cover paintings as much as the stories. It’s from these exciting (to me) roots that sprang my desire to write, and after many awkward attempts, John Campbell at last bought and published my first short story in Analog in June of 1970. Over the years I’ve had the good fortune to have other pieces accepted for publication by Ben Bova and Stanley Schmidt, culminating in my first novel winning a cover spot (and a majestic painting by Vincent DiFate) when it was serialized in Analog in 1980.

But as much as I loved it, Science Fiction was my secret life. There was a serious side to my writing - I was creating marketing materials and user manuals for computers, atomic clocks, and the software and hardware used for satellite communications.

I wrote Sir Arthur C. Clarke early last year to tell him how much I had enjoyed his writings over the years and remark on the circumstance that here I was now writing for the satellite communications industry that he had first envisioned decades ago. I was living the life that I had read about in those pulp magazines from the Fifties. I was a member of the Planetary Society and Science Fiction Writers of America and fascinated by every space probe that headed out into the darkness of our solar system. My only regret was not having devoted more time to developing my skills in the fiction and fantasy area. I’d let myself fall into a long hiatus when I should have been imagining and laboring on weekends.

During 2009 I plan to remedy this and apply myself enthusiastically once again to that thing that all writers dread – actually sitting down to confront a blank sheet of paper (which, of course, has now evolved into the blank computer screen of the word processor).