By Josh Qian, Daily Staff Reporter
Published July 6, 2014
Recent findings from a University study suggest that the shallow subsurface of Mars could be habitable — and also hints at the possibility of extraterrestrial life.
The research, sponsored by NASA’s Exobiology Program, showed through a simulation of the planet’s environment that droplets of liquid saline water could be present on the subsurface of Mars despite its below-freezing temperatures. Liquid water is an essential element for any life form.
Nilton Renno, an atmospheric, oceanic and space sciences professor, led the research efforts after discovering soft ice on the first trench dug by the Phoenix spacecraft when it landed on Mars in 2008.
“This led me to speculate that the soft ice was frozen saline water or brine,” Renno said. “You really need to do a simulation that can convince yourself and the whole scientific community that something is possible.”
He said after the discovery of the soft ice, the biggest challenge for him was to think strategically, secure funding and assemble a group of talented researchers to test his theory.
Renno’s research team consisted of Rackham students Erik Fischer and Harvey Elliott and AOSS research scientist German Martinez.
To test the theory, the team constructed a cylindrical chamber two feet high and five feet long on North Campus to replicate the atmospheric pressure, water vapor content and temperature of Phoenix’s landing site in the polar region of Mars.
During the experiments, the researchers placed calcium perchlorate, the same salt particle that was detected on Mars by both the Phoenix and the Curiosity rover, on a 3-millimeter thick ice layer inside the chamber.
“Our main finding was that absorption of water vapor from the air by salt particles is not efficient enough to create liquid water on Mars, but the salt particles can melt (the ice layer) efficiently, creating significant quantities of liquid saline water in a few minutes,” Renno said. “This implies that droplets of liquid saline water could be ubiquitous on Mars’ shallow subsurface.”
To accurately verify the presence of liquid water, the team shined lasers onto the surface and examined the signature of its reflective light in a process called Raman scattering spectroscopy, which Fischer said presented another challenge for the group because there had barely been any research done on the topic at the time.
Reeno said the findings were completely unexpected.
They could also indicate the possibility of microbial life on the planet.
“A small amount of liquid water, for a bacteria that will be a big swimming pool,” Reeno said. “So a small amount of water is enough for you to create conditions necessary for Mars to be habitable today.”
While the simulation applies primarily to the shallow subsurface, Reeno said he believes liquid water also exists on the surface of the planet’s polar region for several hours during the spring season and early summer.
“Such a cycle could form gullies, flowing, freezing, thawing and flowing again,” Renno said.
He added that simulating and exploring observed liquid flow features on Mars will be the next step for him and his team.