Tag Archives: ALH84001

Cosmos 5: Blues for a Red Planet

by Shane L. Larson

More than any other world in the solar system, Mars has captured the imagination of the human race (except maybe for Pluto, but it’s not a planet, right?). Mars has dominated our imaginings of other worlds for more than a century, beginning with H.G. Wells’ masterpiece of invasion, The War of the Worlds.  Since The War of the Worlds was first written, many other tales of adventure, danger and horror have been penned or filmed concerning Mars — Kim Stanley Robinson’s epic Mars Trilogy, the classic 1964 film Robinson Crusoe on Mars, Elton John’s sonorous musings that Mars is no place to raise a family in “Rocketman,” and many many more.

Mars in fiction. (L) The frontpage of the first edition of The War of the Worlds. (C) The poster for Robinson Cruse on Mars. (R) The three volumes of Kim Stanley Robinson's Mars Trilogy.

Mars in fiction. (L) The frontpage of the first edition of The War of the Worlds. (C) The poster for Robinson Crusoe on Mars. (R) The three volumes of Kim Stanley Robinson’s Mars Trilogy.

Ray Bradbury [Wikimedia Commons.]

Ray Bradbury [Wikimedia Commons.]

I was first exposed to Mars in elementary school, through the reading of Ray Bradbury’s The Martian Chronicles, followed closely by viewing the 1979 screen adaptation of those Chronicles starring Rock Hudson. Bradbury’s Mars was a distant frontier, populated by indigenies resisting the influx of pioneers from Earth. Those pioneers were attempting to create a human civilization on Mars, ignorant of the fading race of natives who lived on the red sands before them. Having grown up in the American West, descended from a long line of ranchers who had homesteaded on the front range in Colorado, it was a familiar tale to me cast on a fantastical tapestry of rocket ships and alien landscapes. Bradbury’s tales of Mars are stories humans have always told about the frontier — tales of discovery, of finding out who we are by looking through the lens of our interaction with (and ignorance of) other lifeforms we have discovered.  In this case, the other lifeforms are the Martians.

The word “Martians” has come to mean more than just beings of Mars; the name has become synonymous with any alien species, vaguely if not outright humanoid.  Tales of Martians are often an allegorical mirror of the best ideals and worst fears we have about our own species.  Sometimes Martians are wise and benevolent; some, like the ghosts in The Martian Chronicles are noble and introspective in the face of extinction. Sometimes Martians are implacable and malevolent conquerers bent on owning the Earth, like the invaders in The War of the Worlds.

It was only natural that Mars become a focal point for our musings about other intelligent species.  Since the invention of the telescope, Mars has sung a siren song to the human race. It is the only planet whose surface can be seen through a telescope, giving us tantalizing glimpses of icy polar caps, vast dark plains that change with the Martian seasons, and long sinuous markings that look for all the world like river channels. It is easy to tempt our imaginations with the idea that Mars could be much like the Earth.

Mars, as seen by the Hubble Space Telescope. (L) The Tharsis Bulge, showing the large shield volcanoes of Mars, and the Valles Marineris in the lower right. (R) The large, dark plain of Syrtis Major, as well as polar ice caps and fleeting clouds. [Images by NASA]

Mars, as seen by the Hubble Space Telescope. (L) The Tharsis Bulge, showing the large shield volcanoes of Mars, and the Valles Marineris in the lower right. (R) The large, dark plain of Syrtis Major, as well as polar ice caps and fleeting clouds. [Images by NASA]

By the 1970s we discovered that Mars was indeed much like the Earth — volcanoes and canyons, ice caps and river valleys. Our landers sent pictures of rocky red deserts, studded with boulders and rolling landscapes that terminate at the foot of mountains on the distant horizon.  But Mars is simultaneously unlike its neighbor, the Earth. The volcanoes are the largest known in the solar system; the largest canyon is a rift valley that is large enough to stretch from New York to Los Angeles; craters stud the surface, worn by the ages but not completely disappeared; and there is not an open body of water to be found anywhere on the planet.  Perhaps most importantly, we have failed to find any sign of life anywhere on the planet.  Unlike our home the Earth, Mars may very well be a dead world, if indeed it was ever alive at all.

Panoramas from the surface of Mars, shot by our rovers.  From top to bottom: (1) Ares Vallis from Mars Pathfinder. (2) Lookout Panorama from Spirit, looking up the slope of Husband Hill. (3) Everest Panorama from Spirit, from the summit of Husband Hill, looking out over Gusev Crater. (4) Opportunity's view of Endurance Crater.

Panoramas from the surface of Mars, shot by our rovers. From top to bottom: (1) Ares Vallis from Mars Pathfinder. (2) Lookout Panorama from Spirit, looking up the slope of Husband Hill. (3) Everest Panorama from Spirit, from the summit of Husband Hill, looking out over Gusev Crater. (4) Opportunity’s view of Endurance Crater.

Thus, I was electrified on a summer’s day in 1996 when a stunning announcement was made. Tiny, mineralized structures had been found using high resolution images of a Martian meteorite known as ALH84001 (name decode, from right to left: 001 = first meteorite found, 84 = in 1984, ALH = in the Allan Hills region of Antarctica).  The structures looked very much like microbes one might encounter on Earth, leading to the very real possibility that the mineralized structures may be fossilized infusoria from the planet Mars.

(L) ALH84001 is a chunk of Mars that drifted through space and landed in Antarctica, where it was discovered in 1984. (R) Micrograph images of structures found in ALH84001, highly suggestive shapes like bacteria.

(L) ALH84001 is a chunk of Mars that drifted through space and landed in Antarctica, where it was discovered in 1984. (R) Micrograph images of structures found in ALH84001, highly suggestive shapes like bacteria.

Like all monumental discoveries in science, the announcement generated tremendous debate. The evidence is not completely unambiguous, and there is still much skepticism about what ALH84001 is telling us.  But it opened up the very real possibility that microbial life could have arisen on Mars, suddenly forcing all of our idle speculations and daydreams about Martians into a definite shape and form.  The human brain is fickle, particularly with regard to the kinds of daydreams it finds compelling — a Universe where all the life in the Cosmos consists of Earthlings and a few microbes on Mars just isn’t that exciting!  Microbes, shmicrobes! So it comes as no surprise to me that I have noticed a subtle uptick in the number of adventure stories told not about Mars, but about other worlds in the solar system: Europa near Jupiter, or Saturn’s enigmatic moons, cloud-swathed Titan and cryovolcanic Enceladus.

New worlds where we might search for life.  Left to right, (L) Jupiter's moon Europa, (C) Saturn's moon Titan, and (R) Saturn's moon Enceladus.

New worlds where we might search for life. Left to right, (L) Jupiter’s moon Europa, (C) Saturn’s moon Titan, and (R) Saturn’s moon Enceladus.

Why is that?  Why are we, at least sub-conciously, singing blues for the Red Planet? I suspect it is because we have landed on Mars and mapped the planet in exquisite detail from orbit.  Mars is by no means a fully explored world; we have roved only over 49 km of  Mars, but the planet has a total surface area roughly equal to the land area of Earth.  There is no way our 4 little rovers (Sojourner, Spirit, Opportunity, and Curiosity), and a handful of landers have seen every nook and cranny of the vast Martian frontier.

Our robotic explorers on Mars: (L) Sojourner micro-rover, (C) Mars Exploration Rovers, Spirit and Opportunity are identical, (R) Curiosity.

Our robotic explorers on Mars: (L) Sojourner micro-rover, (C) Mars Exploration Rovers, Spirit and Opportunity are identical, (R) Curiosity.

Never-the-less, we have yet to see indications of any large lifeforms.  Our cameras have sent back no pictures of Martian tapirs, no pictures of many-legged thoats, no pictures of giant sandworms. The net result: we have given up on the idea of there being substantial lifeforms. We’ve seen enough to convince ourselves that if there is life on Mars, it will be microbial.

Don’t get me wrong — without a doubt, the discovery of a single Martian micro-organism will transform biology forever, but it is not what we’re really looking for! Microbes are not what we long to discover — we long to find companions in the Cosmos. The discovery of a single large organism, whether it is the Martian equivalent of a squirrel, or stag beetle, or snail, would tremendously boost our hopes of one day finding life we can communicate with. 

A Europa cryobot submarine mission concept from NASA.

A Europa cryobot submarine mission concept from NASA.

And so, our imaginations have moved on to new unexplored worlds that could still hide the greatest discovery we have ever imagined.  Foremost among these, is Jupiter’s icy moon Europa.  Europa is sheeted in ice, a solid blanket covering a sub-surface ocean.  What lies beneath the ice?  With so much water, could it perhaps harbor life? There must be heat sources to keep the sub-surface ocean liquid. Perhaps the constant squeezing by Jupiter’s gravity has produced volcanic thermal vents that provide the heat to keep the ocean liquid. On Earth, deep ocean thermal vents were discovered by  explorers in 1977 aboard the Alvin manned submersible. Much to everyone’s surprise, the area around the vent was thriving with life, despite the intense heat and high acidity of the water.

Examples of extremophile life. (L) The Sully Vent in the Pacific; extremophile bacteria glean energy from the extreme heat and acidic water [NOAA image]. (R) The Grand Prismatic Spring in Yellowstone; different colored algae are tolerant of different water temperatures, giving the spring its banded appearance [National Park Service image].

Examples of extremophile life. (L) The Sully Vent in the Pacific; extremophile bacteria glean energy from the extreme heat and acidic water [NOAA image]. (R) The Grand Prismatic Spring in Yellowstone; different colored algae are tolerant of different water temperatures, giving the spring its banded appearance [National Park Service image].

The discovery of life around the hydrothermal vents startled us, but scientists soon realized they were seeing an example of extremophiles — lifeforms that have evolved to uniquely survive in an environment that would normally be too extreme for fragile beings such as us to survive in.  This epiphany opened our eyes, and we see extremophiles everywhere on Earth. A famous and prominent example are the microbial algae mats around the thermal features in Yellowstone National Park — the colored bands surrounding a feature like the Grand Prismatic Spring are simply different species of algae, each tolerant of different water temperatures. In most extreme environments, the extremophiles are microbes, so even a planet like Mars could harbor life, despite the cold, despite the aridness, and despite the ultraviolet radiation.

Tubeworms around a hydrothermal vent survive because the bacteria break down the acids, providing a way for the worms to chemically synthesize energy [NOAA image].

Tubeworms around a hydrothermal vent survive because the bacteria break down the acids, providing a way for the worms to chemically synthesize energy [NOAA image].

The discovery of microbial extremophiles has amplified our confidence in the odds that there is life elsewhere in the Cosmos, but it has done little to dampen our enthusiasm for large lifeforms.  In reality, microbial extremophiles should boost our chances of finding more complex organisms, if the conditions are right.  The deep ocean thermal vents are particularly interesting examples when considering life on Europa, not just because there may be similar vents heating the Europan oceans, but because of the ecosystems we see growing around the vents on Earth.  The microbes that thrive in the immediate vicinity of the vents themselves are the base for a very localized ecosystem and food chain. Other, larger, more complex organisms, such as giant tubeworms, also glom onto the thermal vent, feeding farther down the food chain from the microbes who have learned to exploit the extreme environment.  If we could sink a cryogenic robot beneath the Europan ice, maybe we could find a similar, complex ecosystem.

We have yet to explore beneath the ice of Europa. But in the minds eye of our fiction writers the adventure is on, and already we are by-passing microbes in favor of speculation about there being big Europans, complex lifeforms against which we can compare ourselves.  I was first exposed to adventures on Europa by Arthur C. Clarke’s novel, 2010 (and the associated 1984 film starring Roy Scheider), where the Monolith (already a  manifestation of an alien intelligence beyond our own) fosters the growth of big lifeforms on Europa after collapsing Jupiter into a small star.  More recently, we have all been charmed by “Europa Report” which follows an expedition to Europa to discover not only microbial life, but something more.

The depiction of the unambiguous discovery of microbial life is very tell-tale of our desperate desire to not be alone in the Cosmos.  The first discovery of life beyond the Earth will be a monumental event, but the depiction of discovering extraterrestrial microbes in the movies is similar in excitement to the construction of a new frozen yogurt shop down the street.  Discovering alien life should be an Earth shattering event for our culture: we will know for the first time that we are not alone in the Cosmos!  But perhaps our fictional heroes, like us, have become immune to wonder at the discovery of microbes.  They want to discover something more, something bigger.  Microbes, shmicrobes.  Why is Europa a destination in stories now?  Because Mars, at best, will be the home of microbes, so we are searching for new arenas upon which to cast our dreams, fears, and hopes.

I dream of camping on Mars, whether there be Martians or not.

I dream of camping on Mars, whether there be Martians or not. [Illustration by S. Larson]

But despite our civilization’s fleeting wonder about life on Mars, I still often dream about adventures on the Red Planet and what might be found there.  It is still a world full of mysteries, and as worthy of exploration as any corner of the Earth, or any other world in the solar system. What a grand adventure it would be to go hiking across Mars with my daughter, camping near the now dead Spirit rover, to toss rocks over the edge of the Valles Marineris,  and take iPhone panoramas of the vast rocky deserts of the Red Planet.  I would love to spend an afternoon chipping open rocks on the shoulders of the Tharsis volcanoes, looking for some sign of ancient microbial life as we watch dust devils spin lazily on the plains below.

martian-chroniclesIt may yet be true that Mars harbors no indigenous life, but we’ll never know until we ourselves go, and turn over every rock we can find. It will be the work of a lifetime, indeed of uncountable lifetimes if the exploration of the Earth is any kind of indicator.  In the end, there will be Martians, but as Carl Sagan so aptly noted (and Rock Hudson discovered at the end of The Martian Chronicles), the Martians will be us.

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This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

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Where Discoveries Happen

by Shane L. Larson

On a cold spring morning in Virginia, the leaden clouds had cleared off leaving the morning skies a clear deep blue that reminded me of being home in the Rockies.  Surrounded by hundreds of bustling Virginians, I emerged from the Ballston Metro station, and walked down the streets of Arlington.  Nestled amongst the glass and brick towers of this modern suburbia is a broad and nondescript building, not unlike many others on nearby blocks.  But this building is different.  On this building, emblazoned in burnished steel letters on the overhang that covers the entrance, are three simple words: National Science Foundation.

It is not one of the hot destinations for visitors to the Washington DC area.  Ten year olds want to visit the Air and Space Museum; a steady stream of people walk reverently past the Constitution and Declaration of Independence at the National Archives; dinosaurs at the Natural History Museum may as well be alive and walking around; and many sit in the National Gallery immersed in their contemplation of the wondrous works of master painters and sculptors.  I suppose even the Woodrow Wilson House must get more visitors than the National Science Foundation.  But I wanted to come here, to stand in front of this building, and bask in the glory.  When I had previously stopped in front of NASA Headquarters to get my picture next to the sign, there were others who had made the same pilgrimage as me.  We helped each other shoot pictures, traded tales of wanting to visit NASA since we were young, and how we always wanted to be astronauts and work on the Hubble Space Telescope.

But today, under the late winter skies of Virginia, few stopped (well, none really) to share the moment with me, and that is a shame. The National Science Foundation (NSF) is responsible for as many wondrous and profound discoveries as our friends at NASA, but their press is lighter and the visibility of the Foundation is much lower, much to my dismay.  For myself as a young scientist, visiting the NSF is like getting to stand on the pitcher’s mound at Dodger Stadium or visiting base camp on Mount Everest.  I suppose to some, however, it is less grandiose: more like visiting the heaviest ball of twine in Lake Nebagamon, Wisconsin, or like visiting the first Wendy’s in Columbus, Ohio.  But the National Science Foundation is a place of wonders –– it embodies, more than any other edifice of our civilization, the defining character of the human species: the desire to know.  The ineffable quality of our psyche, that usually is glibly referred to as “curiosity”, is what the NSF is all about.  The recognition of curiosity as a tool has evolved into a uniquely human endeavour called “science.”

Since its formation in 1950 by an act of Congress, the NSF has become the hub of a large fraction of the research and development efforts of the scientific community in the United States.  The mission statement efficiently captures their mandate from the Congress: “to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense.”  As is the case for all of us, we encounter instances in our lives when a few short words cannot always capture the deep meanings that some endeavours hold for us.  Our formal language is inadequate to the burdens of our hearts, and to make up for that, we tell stories.  Let me tell you three stories, vignettes about what the NSF does in the hope of illustrating their mission and the role they play in our society.

The Tale of a Scar.  Some of my close friends have often noticed a one inch scar on the outside orbit of my left eye.  It’s my big movie star scar, though it has not served me as well as Harrison Ford’s chin scar.  In 1982, I was a small and admittedly nerdy young kid. I read books on Einstein, I waited breathlessly for every launch of the space shuttle, and I lived and breathed Star Trek.  I was also bullied.  I received my Indiana Jones scar when an older and much larger student took my prized possession of the day, a collected volume of the novels of H. G. Wells.  When I dared to try and get it back from him, he forcibly threw me across the room into a metal desk chair. The result was 8 stitches, less than a quarter of an inch from my left eye.  It was not the first, nor my last encounter with bullies.  Bullying is a vile and pernicious expression of cowardice that many, unfortunately, view as an unavoidable part of childhood. One of the truths of the modern age is that as our lives become more integrated with technology, old forms of pathological behaviour find new forms of expression, not the least of which is bullying. The advent of social media and the globalization of information in our society has attracted the bullies and expanded the scope of their social terrorism.  Now, your children receive the full brunt of an attack not on the playground, but on their small screens at home while surrounded by family and friends; what was once a fortress of protection has been breached by 3G wireless coverage and cell phones.  Research suggests that in today’s world, 20-40% of all youths are the victims of cyberbullies at least once.  Perhaps more startling, the new ranks of cyberbullies are not confined to our children –– adults have increasingly become victims as well.

As our society evolves, propelled into the future by our ever-changing technology, the NSF is there to understand its impact on our culture.  The psychology, practices, and impact of cyber-bullies on our culture, and the role that the technology plays are well within the purview of the science funded by the Foundation (read the first part of three articles here: http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=121847).  As a scientist, I can sit up a little taller, proud that my profession is trying to do something to make the world a better place. But the person really taking notice is the 12 year old kid still trapped inside of me, hopeful that these scientists can prevent some other hopeful young soul from growing up with a very public scar from the dark shadows of their youth.  Sometimes, the mission of the Foundation is to help us protect ourselves.

Time Capsule in the Ice.  Sometimes, the discoveries of the NSF give us an opportunity to think deeply about our existence on this small world.  One of the last great unexplored areas of this planet are the vast, icy reaches of Antarctica.  Protected by international treaty in 1959, the continent cannot be developed for military or commercial resource purposes.  In the United States, our presence in the frozen reaches of Antarctica is managed by the National Science Foundation’s Office of Polar Programs (http://www.nsf.gov/dir/index.jsp?org=OPP).  One small part of the Polar Programs is an ongoing effort called ANSMET — the Antarctic Search for Meteorites (http://geology.cwru.edu/~ansmet/).  ANSMET’s mission is to search the icy surface of Antarctica every austral summer for meteorites.  Meteorites are hunks of rock and metal, fallen to the surface of the Earth from outer space.  Buried in the Antarctic ice after making Earth-fall, meteorites are easy to spot when the Sun warms them each summer, melting the ice around them so they are visible on the surface, a bold dark spot in the vast sea of white.  Since the end of the Apollo era, ANSMET is one of the only ongoing scientific efforts that provides direct samples of extraterrestrial materials.  Scientists are deeply interested in meteorites because they are time vaults, sealed capsules that harbor information about the primordial composition of the early solar system and, sometimes, pockets of the early volatiles from when the planets were born.

In 1984, two scant years after I received my scar, a meteorite team was deposited in the Allen Hills region of Antarctica by the NSF Polar Programs.  The first meteorite the team found that season was given the nondescript name ALH84001.  It is an achondrite, or stony meteorite, similar to basalt found on Earth.  It was returned to the United States, where it was archived with all the other meteorite samples, and analyzed for its age, structure, and composition.  We also determined its probable origin –– Mars.

That might have been the end of the story of ALH84001, but in August of 1996, during a routine micrograph scan of thin slices taken from the meteorite, scientists stumbled on a remarkable and tantalizing discovery –– mineralized structures that look, for all the world, like fossilized bacteria. The micrographs from ALH84001 captured the imagination of the world.  It was the first time the human race had ever had to seriously contemplate the possibility that Earth was not the sovereign haven of life in the Cosmos.  It is one thing to think about extraterrestrial life, to debate it in the backyard on a summer evening with a beer in one hand and a bratwurst in the other.  But to be faced with plausible evidence of the prospects gives one pause.  It reminds us that we are small and the Cosmos is vast, and that there is much we have yet to learn.  This is not a demeaning insight, but an uplifting and inspiring recognition that the Cosmos has created beings such as we, who can ponder the questions of our own existence.  Sometimes, the mission of the Foundation is to help us know ourselves and our place in the Cosmos better.

What Einstein Thought was Impossible.  In 1918, Albert Einstein was working with general relativity, which he had written down several years before.  General relativity was a new way to think about gravity that had resolved some old observational problems in astronomy and had suggested that there were new things for astronomers and physicists to think about.  Einstein was interested in how gravity propagated through the Cosmos –– how did it get from one place to another? What happens when the source of gravity, say a  planet or a star, moves?  In 1918 Einstein was trying to answer this question, and he made a remarkable discovery: gravity propagates in waves, just like light.

Like every good scientist, Einstein did his due diligence and immediately calculated what it would take to detect these waves.  Imagine you lay two rocks on the ground, and measure the distance between them.  Gravitational waves stretch and shrink the distance between points in space (your rocks) as they travel by.  The more separated the rocks, the greater the change caused by the gravitational waves.  So how big of a change did Einstein predict these gravitational waves might cause?  If you have one rock here on Earth, and another rock near the Sun, 150 million kilometers away, the gravitational waves will change the distance by less than the width of an atomic nucleus.  Einstein thought that it would be impossible to measure this effect, and promptly moved on to new projects.

But now, fast-forward a century.  We’ve replaced Einstein’s fountain pen with ball point pens, phonographs with iPods, and linked the world with a global network of computers, fiber cables, and satellites.  Today, immersed in technology undreamed of in Einstein’s day, we can seriously contemplate looking for these gravitational waves.  In one of the most awe-inspiring scientific undertakings ever imagined by humans, the National Science Foundation has been building the Laser Interferometer Gravitational-wave Observatory –– LIGO (http://www.ligo.org/).  The premise of LIGO is to replace your rocks with carefully constructed mirrors and to measure the distance by timing how long it takes laser light to fly back and forth between them.  The observatories that house the mirrors and lasers are enormous, 4 kilometer by 4 kilometer L-shaped installations that make the measurement in two perpendicular directions at once.  When they come online sometime after 2015, we will begin our first serious astrophysical reconnaissance of the Cosmos using gravity as our messenger.  We should be able to detect the collisions of neutron stars, the shrunken dead husks of stars collapsed to the size of a small city; we should be able to listen to the siren song of black holes spiraling together to form new, bigger black holes; and maybe, if Nature lets us, we may hear the faint murmur of gravitational waves from the Big Bang, the whispering signature of the creation of the Cosmos.

The scope of LIGO is awe-inspiring, and more than anything else it reminds us that our species is truly limitless.  It reminds us that our ingenuity and curiosity and perseverance can overcome any challenges, that we can tease any secrets from Nature with enough diligence, and that we can indeed solve any problem that was once thought impossible.  Sometimes, the Foundation reminds us that there is nothing we can’t do.

There are many such tales we could tell like these.  Standing there outside the National Science Foundation on that spring morning, I was thinking that despite everything we know, despite everything we can do, the vast majority of the world is still a complete mystery!  The goal of science is to explore those mysteries and to use the answers to improve our lives.  That is the mission of the National Science Foundation.

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The NSF uses the tagline, Where discoveries happen.  You can explore the vast mosaic of discoveries made by NSF funded science, and their applications to our world at the NSF Discovery site:  http://www.nsf.gov/discoveries/

You can also watch a spectacular array of video summaries at http://science360.gov (also available as an app for your iPad –– Einstein would have loved that!).