January 20th, 2013 by James Ayre
There is now strong evidence that water may be present in the crevices of a huge crater on Mars known as McLaughlin Crater, thanks to new images taken by the Mars Reconnaissance Orbiter.
This is adding to the growing body of evidence that suggests that there is substantial water ice located under the surface of Mars, and possibly even liquid water.
The discovery was made after analyzing a collection of images that were taken by NASA’s powerful Mars Reconnaissance Orbiter. The images show good evidence of a previously wet underground environment on Mars. The photos were “focused on the giant McLaughlin Crater, which is about 57 miles wide and so deep that underground water appears to have flowed into the crater at some point in the distant past.”
As of right now, the crater is of course completely dry, but clays are present, as are other minerals generally only created in the presence if water.
“Taken together, the observations in McLaughlin Crater provide the best evidence for carbonate forming within a lake environment instead of being washed into a crater from outside,” said lead author Joseph Michalski, of the Planetary Science Institute in Tucson, Arizona, and London’s Natural History Museum.
One of the primary objective of Martian exploration has been to determine the habitability of the planet, both in the past and as of now. Currently though, and apparently throughout much of its history, the Martian surface has been rather cold, arid, and chemically hostile. Though the chemical hostility seems to vary a great deal depending where on the planet you are, as some recent research has found.
Underground though, could be a completely different story. Ancient (or current) simple life could have very easily survived in Martian water well underground. As simple microbes do on the Earth, and even some species of multicellular organisms do, such as the the Devil’s Worm, that lives incredibly deep underground in a very hot environment.
“On Earth, microbes up to 3 miles or more underground make up perhaps half of all of the planet’s living matter. Most of these organisms represent some of the most primitive kinds of microbes known, hinting that life may actually have started underground, or at least survived there during a series of devastating cosmic impacts known as the Late Heavy Bombardment that Earth and the rest of the inner solar system endured about 4.1 billion to 3.8 billion years ago.”
An important thing to consider also is that “since Mars has less gravity — a surface gravity of a little more than one-third Earth’s — its crust is less dense and more porous than that of our planet, which means that more water can leak underground.”
On the Earth, wherever there’s liquid water, there’s life. Whether that is a common truth or a more uncommon one, elsewhere in the solar system, remains to be seen, but exploring Mars should help to answer it.
“Microbes underground on Mars could be sustained by energy sources and chemical reactions similar to those that support deep-dwelling organisms on Earth.”
“The deep crust has always been the most habitable place on Mars, and would be a wise place to search for evidence for organic processes in the future,” Michalski said.
Currently, there us no way for us to dig deep down into the Martian regolith, but it is possible to see hints of “what subterranean Mars is like by analyzing deep rocks exhumed by erosion, asteroid impacts or materials generated by underground fluids that have welled up to the surface.”
“Such upwelling would first occur in deep basins like McLaughlin Crater — as the lowest points on the surface, they would be where underground water reserves would most likely get exposed.”
Researchers decided to focus on McLaughlin Crater specifically because it’s one of the deepest craters on Mars. And it is very deep, around 1.3 miles deep.
“The mineral composition of the floor of McLaughlin Crater suggests there was a lake made of upwelled groundwater there. Channels seen on the crater’s eastern wall about 1,650 feet above its floor also hint at the former presence of a lake surface.”
“Michalski was actually originally trying to disprove the idea that groundwater breached the surface in many locations on Mars.”
“Lo and behold, there was strong evidence for that process in this crater,” he said. “Science is special because we are allowed to change our minds.”
“The researchers estimate that a lake existed at McLaughlin Crater for an unknown duration between 3.7 billion and 4 billion years ago.”
“That makes the deposits as old as or older than the oldest rocks known to exist on Earth,” Michalski said.
“Mounds seen on the crater floor may have come from landslides or subsequent meteor impacts. These are important because they may have rapidly buried crater floor sediments.”
“That is really cool because rapid burial is the scenario that is most advantageous for preservation of organic material, if any was present at that time,” Michalski said.
“We should give serious consideration to exploring rocks representing subsurface environments in future missions,” Michalski said. “That doesn’t mean drilling, but instead exploring rocks formed from upwelling groundwater, or rocks naturally exhumed from the subsurface by meteor impact.”
As Michalski notes, it seems that there is always news about water being found on Mars, it’s always grabbing headlines, so some people wonder, why is it still important? “‘Why do I hear about the detection of water or possibility of life on Mars all the time?’ The answer is because Mars is habitable in more ways than we ever realized for many years, and we are finding water in many forms and environments on Mars — many more than we predicted for a long time.”
It seems to be a real possibility that life may still persist underground on the planet, or that it did and we may be able to find evidence. And another reason that it continues to grab many people/researchers attention, is because of the increased possibility of terraforming the planet when there is more water present. Many researchers are very interested in possibly terraforming the planet at some point in the future.
The new research was just published online, January 20th, in the journal Nature Geoscience.
Image Credits: NASA/JPL-Caltech/Univ. of Arizona; High Resolution Stereo Camera/Mars Express
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