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--Home of the spewing Old Faithful geyser, Yellowstone National Park may also be an analog for happenings even on far-flung worlds like Mars.
This sprawling national park is largely contained within Wyoming, but also stretches out into Montana and Idaho. As the world's first national park, Yellowstone is a literal hot spot for geologists and biologists--a way to inquire into the intricacies of ancient life here on Earth and possible connections to niches for life on Mars.
Yellowstone is basically a very large, still-active volcano. As such, it has become a scientific teaching tool about the capacity for the living world to survive and even thrive in super-harsh locations.
Within the park, researchers are studying hydrothermal habitats that are loaded with heat loving microscopic organisms dubbed thermophiles: "thermo" for heat, "phile" for lover. These thermophiles appear in an assortment of shapes and colors, fed by energy and the chemical building blocks available in boiling acidic or alkaline hot springs.
Scientists now recognize that life on Earth can dwell in an astonishing number of unusual habitats and under what are considered to be extreme physical conditions. Experts keen on finding life in extreme environments--not only on Earth but elsewhere in our solar system and beyond--met here August 4-7 in a special workshop for journalists.
The meeting was sponsored by the University of Colorado, Boulder's NASA Astrobiology Institute, the Laboratory for Atmospheric and Space Physics, and the Center for Environmental Journalism.
Specific to Mars, the study of thermal spring may help focus the exploration strategy for the red planet.
"It's not just to look at the surface of Mars, but maybe to look at certain places on Mars," said David Des Marais, an astrobiologist at NASA's Ames Research Center at Moffett Field, California. Des Marais is a science team member for the Spirit and Opportunity robots now carrying out extensive and extended field work on Mars. And in a kind of all-things-being equal, knowing Mars may help us to become more acquainted with early Earth, he said.
"Earth is so active. It has been very effective at destroying the first several hundred million years of its earliest record," Des Marais said. "Life could have begun so early in the history of the Earth that any record of that origin has been destroyed."
So if indeed there ever was life on Mars, "we might get closer to understanding origins by studying samples from Mars than from Earth," Des Marais told workshop participants.
Des Marais said that this week's liftoff of NASA's Mars Reconnaissance Orbiter (MRO) is important to scoping out habitable cubbyholes on Mars. One of the key attributes of MRO, Des Marais said, is teasing out the mineralology of Mars...to spot "the chemical consequences of hydrothermal activity."
Yet with all the tools orbiting and on the surface of Mars, answering the question of whether life took hold--and may still remain there--is a tough nut to crack.
"I really think this life thing is going to take a while to do...in part, by looking at how long it took us to find evidence of early life on Earth," Des Marais explained. "The surface of Mars is equal to the continental area of the Earth. It's going to take a few iterations."
Given the type of environments on Mars and other celestial locales, can scientists truly expect to play out the whole story by simply digging around here on Earth?
"We definitely can't get the 'whole story' about the potential for life elsewhere by looking here on Earth," said Tom McCollom, a research associate with the Center for Astrobiology 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/chemical environments on other planetary bodies that the organisms there would have adapted to. Secondly, organisms on other planets would have evolved along pathways so that their biochemistry would likely be significantly different than terrestrial organisms, McCollom said.
"On the other hand, there are enough similarities in the physical/chemical environments on Earth and those that occur elsewhere that we can learn a great deal about what to expect -- and where to look--by examining certain habitats on Earth, like hot springs and the subsurface," McCollom told SPACE.com. "While there will be certain constants from one planetary body to the next, the exact nature of the organisms and the biochemical pathways they use are likely to be quite different."
McCollom said that, because of the lack of oceans on Mars--at least in recent times--hot springs like those in Yellowstone serve as a much better analog for possible habitats on the red planet.
Necessary first step
"Of course we can't learn everything there is to know about life elsewhere by looking at life here on Earth," said Bruce Jakosky, Director of the Center for Astrobiology at the University of Colorado, Boulder and lead organizer of the workshop.
"The best we can hope is to learn something about the range of environments that can support life, about how life functions in these different "extreme' environments, and about the chemistry of life," Jakosky said.
Jakosky told SPACE.com prior to the workshop meeting that only by looking at how organisms function in different environments can scientists learn about the different ways in which organisms adapt to different conditions.
"This is 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. That said, even the polar regions of Mars could well be suitable for life.
"Low-temperature environments are not just frozen storage...growth is possible," said Corien Bakermans, a research associate at Michigan State University's Center for Genomic and Evolutionary Studies on Microbial Life at Low Temperatures.
Bakermans said that the interface between a martian polar cap and the land could prove worthy of exploration.
"I'm not sure that we have identified the actual limits of terrestrial life and biomolecules on Earth," Bakermans reported. "Every couple of years, we hear about an organism that can go to a higher temperature or a lower temperature. Life is very adaptable. I think we've got to keep exploring more environments...to find the actual limits," she said.
There are many places to continue exploring...and more diversity to uncover, Bakermans said.
Each year, approximately three million U.S. and international visitors of all ages travel through the diverse environments of Yellowstone National Park.
Catherine Tsairides, Project Director for Education and Public Outreach at NASA's Ames Research Center's Astrobiology Institute, underscored the public educational value of teaching astrobiology at Yellowstone.
An Astrobiology Planning Team has partnered with Yellowstone to develop projects that have an integrated approach for introducing park visitors to astrobiology. For instance, a select number of sites are soon to feature special signage that spell out the most compelling aspects of astrobiology research within the park.
Yellowstone's hydrothermal resources are to be denoted as extreme habitats that may help explain the history of the Earth and provide clues in the search for life on other planets, Tsairides said.
Additionally, a central interpretive element for the Old Faithful Visitor Education Center--groundbreaking in 2006, completion in 2008--will explore Yellowstone's hydrothermal features. The aerospace firm, Lockheed Martin Corporation, has made a $200,000 commitment to the Yellowstone Park Foundation for the new high-tech center.
Life: hard to find
Probing the family of planets beyond Earth for 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 and developmental biology at the University of Colorado, Boulder.
"My own belief is that there isn't any extant [present] life anywhere else in this solar system...although I do believe that it's common in our galaxy," Pace said. Studying extremes and the diversity of life on Earth is worthy in its own right, he added, and leads to thoughts about life "in a larger than terrestrial standpoint".
Pace said what constitutes microbial diversity and biochemical interplay is a "just scratching the surface" type of scientific pursuit at present. "Looking at the microbial world at this time is very much like being dropped into the Amazon Basin at about 1500 AD...we know so little."
In agreement is Steve D'Hondt, professor of oceanography at the University of Rhode Island in Narragansett. He added, however, that life in extreme environments research has blossomed in the last several years.
"We're at a continuum...but I think we're at an exciting point in that continuum," D'Hondt told SPACE.com.
Money, talent and scientific results are converging 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 more than we did a few years ago."
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