Mars on Earth: As Simple as a Walk in the Park

Mars on Earth: As Simple as a Walk in the Park
Aerial photo of Grand Prismatic Spring in Yellowstone National Park – a habitat for microscopic organisms. Image Courtesy: University of Colorado, Boulder

YELLOWSTONE NATIONAL PARK, Wyoming--Homeof the spewing Old Faithful geyser, Yellowstone National Park may also bean analog for happenings even on far-flung worlds like Mars.

This sprawling national park is largelycontained within Wyoming, but also stretchesout into Montana and Idaho. As the world's first national park, Yellowstone is a literal hot spot for geologists andbiologists--a way to inquire into the intricacies of ancient life here on Earthand possible connections to niches for life on Mars.

Yellowstone is basically a very large, still-active volcano. As such, ithas become a scientific teaching tool about the capacity for the living worldto survive and even thrive in super-harsh locations.

Within the park, researchers are studyinghydrothermal habitats that are loaded with heat loving microscopic organismsdubbed thermophiles: "thermo" for heat, "phile" for lover. These thermophilesappear in an assortment of shapes and colors, fed by energy and the chemicalbuilding blocks available in boiling acidic or alkaline hot springs.

Optimum conditions

Scientists now recognize that life on Earthcan dwell in an astonishing number of unusual habitats and under what areconsidered to be extreme physical conditions. Experts keen on finding life inextreme environments--not only on Earth but elsewhere in our solar system andbeyond--met here August 4-7 in a special workshop for journalists.

The meeting was sponsored by the University of Colorado,Boulder's NASAAstrobiology Institute, the Laboratory for Atmospheric and Space Physics, andthe Center for Environmental Journalism.

Specific to Mars, the study ofthermal spring may help focus the exploration strategy for the red planet.

"It's not just to look at thesurface of Mars, but maybe to look at certain places on Mars," said David Des Marais, an astrobiologist at NASA'sAmes ResearchCenter at Moffett Field, California. Des Marais is ascience team member for the Spirit and Opportunityrobots now carrying out extensive and extended field work on Mars. And in akind of all-things-being equal, knowing Mars may help us to become moreacquainted with early Earth, he said.

"Earth is so active. It has beenvery effective at destroying the first several hundred million years of itsearliest record," Des Marais said. "Life could have begun so early in thehistory of the Earth that any record of that origin has been destroyed."

So if indeed there ever was life onMars, "we might get closer to understanding origins by studying samples fromMars than from Earth," Des Marais told workshop participants.

Chemical consequences

Des Marais said that this week'sliftoff of NASA's Mars Reconnaissance Orbiter (MRO) is important to scoping outhabitable cubbyholes on Mars. One of the key attributes of MRO, Des Maraissaid, is teasing out the mineralology of spot "the chemicalconsequences of hydrothermal activity."

Yet with all the tools orbiting andon the surface of Mars, answering the question of whether life took hold--andmay still remain there--is a tough nut to crack.

"I really think this life thing isgoing to take a while to part, by looking at how long it took us to findevidence of early life on Earth," Des Marais explained. "The surface of Mars isequal to the continental area of the Earth. It's going to take a fewiterations."

Giventhe type of environments on Mars and other celestial locales, can scientiststruly expect to play out the whole story by simply digging around here onEarth?

"We definitely can't get the 'whole story' about thepotential for life elsewhere by looking here on Earth," said Tom McCollom, a research associate with the Center forAstrobiology and Laboratory for Atmospheric and Space Physics at the University of Colorado,Boulder.

The reasons are twofold, McCollom observed.For one, there are significant differences in the physical/chemicalenvironments on other planetary bodies that the organisms there would haveadapted to. Secondly, organisms on other planets would have evolved alongpathways so that their biochemistry would likely be significantly differentthan terrestrial organisms, McCollom said.

"On the other hand, there are enough similarities in the physical/chemicalenvironments on Earth and those that occur elsewhere that we can learn a greatdeal about what to expect -- and where to look--by examining certain habitats onEarth, like hot springs and the subsurface," McCollom told "While there will be certain constants from oneplanetary body to the next, the exact nature of the organisms and thebiochemical pathways they use are likely to be quite different."

McCollom said that, because of the lack of oceans on Mars--at least in recenttimes--hot springs like those in Yellowstone serve as a much better analog for possiblehabitats on the red planet.

Necessary first step

"Ofcourse we can't learn everything there is to know about life elsewhere bylooking at life here on Earth," said Bruce Jakosky, Director of the Centerfor Astrobiology at the University of Colorado, Boulderand lead organizer of the workshop.

"Thebest we can hope is to learn something about the range of environments that cansupport life, about how life functions in these different "extreme'environments, and about the chemistry of life," Jakosky said.

Jakoskytold prior to the workshopmeeting that only by looking at how organisms function in differentenvironments can scientists learn about the different ways in which organismsadapt to different conditions. 

"Thisis a necessary first step to deciding which environments on Mars, for example,might be able to support life and then how we would look for life there,"Jakosky said.

Some like it cold

Mars is a freezing, dried up world. Thatsaid, even the polar regions of Mars could well be suitable for life.

"Low-temperature environments are not justfrozen storage...growth is possible," said CorienBakermans, a research associate at Michigan State University's Center forGenomic and Evolutionary Studies on Microbial Life at Low Temperatures.

Bakermans said that the interface between amartian polar cap and the land could prove worthy ofexploration.

"I'm not sure that we have identified the actuallimits of terrestrial life and biomolecules on Earth," Bakermans reported."Every couple of years, we hear about an organism that can go to a highertemperature or a lower temperature. Life is very adaptable. I think we've gotto keep exploring more find the actual limits," she said.

There are many places to continueexploring...and more diversity to uncover, Bakermans said.

Astrobiology education

Each year, approximately three million U.S. and international visitors of all ages travelthrough the diverse environments of Yellowstone National Park.

Catherine Tsairides, Project Director forEducation and Public Outreach at NASA's AmesResearch Center'sAstrobiology Institute, underscored the public educational value of teachingastrobiology at Yellowstone.

An Astrobiology Planning Team has partneredwith Yellowstone to develop projects that havean integrated approach for introducing park visitors to astrobiology. Forinstance, a select number of sites are soon to feature special signage thatspell out the most compelling aspects of astrobiology research within the park.

Yellowstone's hydrothermal resources are to be denoted as extremehabitats that may help explain the history of the Earth and provide clues inthe search for life on other planets, Tsairides said.

Additionally, a central interpretiveelement for the Old Faithful Visitor EducationCenter--groundbreaking in 2006,completion in 2008--will explore Yellowstone'shydrothermal features. The aerospace firm, Lockheed Martin Corporation, hasmade a $200,000 commitment to the Yellowstone Park Foundation for the newhigh-tech center.

Life: hard to find

Probing the family of planets beyond Earthfor signs of present life may come up dry.

"I think life is common...but hard to find,"suggested Norman Pace, an expert in molecular, cellular anddevelopmental biology at the Universityof Colorado, Boulder.

"My own belief is that there isn't any extant [present] lifeanywhere else in this solar system...although I do believe that it's common inour galaxy," Pace said. Studying extremes and the diversity of life on Earth isworthy in its own right, he added, and leads to thoughts about life "in alarger than terrestrial standpoint".

Pace said what constitutes microbial diversity and biochemicalinterplay is a "just scratching the surface" type of scientific pursuit atpresent. "Looking at the microbial world at this time is very much like beingdropped into the Amazon Basin at about 1500 AD...weknow so little."

In agreement is Steve D'Hondt, professor ofoceanography at the University of Rhode Island inNarragansett. He added, however, that life in extreme environments research hasblossomed in the last several years.

"We're at a continuum...but I think we're at anexciting point in that continuum," D'Hondt told

Money, talent and scientific results areconverging to shape the future trajectory of new investigations, D'Hondt said."There is a tremendous amount that we don't know. But we know a whole lot morethan we did a few years ago."

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Leonard David
Space Insider Columnist

Leonard David is an award-winning space journalist who has been reporting on space activities for more than 50 years. Currently writing as's Space Insider Columnist among his other projects, Leonard has authored numerous books on space exploration, Mars missions and more, with his latest being "Moon Rush: The New Space Race" published in 2019 by National Geographic. He also wrote "Mars: Our Future on the Red Planet" released in 2016 by National Geographic. Leonard  has served as a correspondent for SpaceNews, Scientific American and Aerospace America for the AIAA. He has received many awards, including the first Ordway Award for Sustained Excellence in Spaceflight History in 2015 at the AAS Wernher von Braun Memorial Symposium. You can find out Leonard's latest project at his website and on Twitter.