In April of 2012, the Journal of Cave and Karst Studies published a white paper written by scientists at the U.S. Geological Survey that suggested the caves of Mars could hold secret answers to the question of life on Mars.
Scientists at the USGS don’t go far as to suggest that there are strange creatures hiding out under the surface of the red planet, but they do suggest that caves may offer insights into whether or not sentient life ever did exist on the planet long ago, and caves could also hold deposits of organic life that are well protected underneath the surface.
You would not expect an examination of the potential for life on Mars to come from the USGS, but in fact the report shows just how invaluable the expertise at the USGS can be when it comes to analyzing subsurface features of the planet, and whether or not conditions underneath the surface could harbor life or evidence of past life.
This fascinating white paper carefully explores the caves on Mars by first examining images from the Mars Odyssey’s Thermal Emission Imaging System and the Mars Reconnaissance Orbiter’s Context Camera, and then looking deeply into those caves by using the High-Resolution Imaging Science Experiment.
The scientists use evidence gathered from the high-resolution images to not only select and examine targets that could harbor life on mars, but also go so far as to calculate slopes and depths of entrances to caves, in order to provide NASA or future explorers with the highest-value candidates for future cave explorations on Mars.
Cave explorations on Mars – sort of makes for a great blockbuster movie idea, doesn’t it?
Lava Tube Mars Caves Still Exist
The USGS authors of the white paper open by observing that the proposal that lava tubes – present under the surface of both the Moon and Mars – originally came from “Oberbeck et al” in 1969, leading to extensive discussions among scientists about the potential uses for such extraterrestrial cave systems for future scientists and explorers.
The existence of such tubes were only speculation, until scientists recently observed them in 2007, thanks to the technical capabilities of the instruments that NASA has set into orbit above the Red Planet.
While past white papers have suggested the presence of such lava tubes throughout Mars, they suggested that the lava tubes have all collapsed. However, through this 2012 white paper, USGS scientists use evidence gathered by orbiting imaging technology to prove that there are many such cave systems that still exist under the surface of Mars, and represent invaluable research opportunities for future Mars explorers.
Evidence of Large Underground Cave Systems
The first evidence for this is presented in the form of a high-resolution image from the context camera, which shows a “distribution of skylight-bearing tube-fed lava flows” and the “volcano-tectonic fracture system” present in the lava plains to the north of Arsia Mons – a crater mountain that’s present throughout the surface of Mars.
While that photo is remarkable, it gets far more impressive as the scientists use THEMIS imaging technology (from the help of the THEMIS scientific team) to reveal clear evidence of a path of “candidate skylight entrances” to the massive, underground cave system.
USGS researchers are interested in such cave systems because they offer a list of potential uses that could turn up either proof of life on Mars, or evidence that life existed there at one point. Some potential future uses of these cave systems offered by the USGS scientists includes:
1. Using robotic explorers to visit Martian caves. This would require the development of technology where a device could explore these caves while also maintaining communications with the surface, to be transmitted to Earth. Another important factor that scientists point out is the fact that current international “planetary protection policies” exist that forbid any activity that could cause microbial contamination of another planet.
2. Using lava-tube caves that have “flat, relatively smooth floors [that are] particularly suitable to host human habitats on Mars. This is because such caves provide future colonists with protection from “all of the hazards that humans would encounter on the surface.” Those hazards include dust storms, micrometeoroids, surface temperature variations, and “all types of incoming radiation”.
3. USGS scientist also propose that such caves could be “potential reservoirs of stable or metastable water-ice deposits, which could be an invaluable resource.” The authors point out that caves that extend deep into the surface could potentially trap cold air and create “isolated microclimates” which could then form cave ice from that cold air.
4. Finally, USGS scientists suggest that since nearly every cave on Earth hosts entire communities of microorganisms, caves on Mars also present one of the “most likely places to find evidence of past or present microbial life on Mars.” However, the scientists suggest that any future exploration of the caves for life on Mars should focus on older cave systems.
The most compelling statement in the white paper is the suggestion that at some point in the past, sentient life on the surface of the planet could have been forced to retreat to the better-protected regions under the surface of the planet.
“Accordingly, older caves, perhaps formed by aqueous processes, where life might have retreated underground as Martian surface became increasingly inhospitable are more likely to contain evidenc eof past or extant life.”
Since the high-resolution imaging technologies only more recently became available to scientists, research like that conducted by the USGS represents humanities very first steps toward formulating missions to the Red Planet to not only seek out life on Mars, but also to actually form a base there for scientific research.
Every year, through the collective efforts of scientists around the world, it appears more and more likely that a future will exist where humans not only land on Mars, but to also begin studying and exploring Earth’s closest planetary neighbor.
What amazing discoveries will come of those explorations? That is the material that science fiction books and movies are made of.
References & Image Credits:
(1) Candidate Cave Entrances on Mars