Given the right circumstances, water on Mars could hold more oxygen than previously believed, theoretically enough to support aerobic respiration
A team led by scientists at Caltech and the Jet Propulsion Laboratory (JPL), which Caltech manages for NASA, has calculated that if liquid water exists on Mars, it could—under specific conditions—contain more oxygen than previously thought possible. According to the model, the levels could even theoretically exceed the threshold needed to support simple aerobic life.
That finding runs contrary to the current, accepted view of Mars and its potential for hosting habitable environments. The existence of liquid water on Mars is not a given. Even if it is there, researchers have long dismissed the idea that it might be oxygenated, given that Mars’s atmosphere is about 160 times thinner than that of Earth and is mostly carbon dioxide.
“Oxygen is a key ingredient when determining the habitability of an environment, but it is relatively scarce on Mars,” says Woody Fischer, professor of geobiology at Caltech and a co-author of a Nature Geoscience paper on the findings, which were published on October 22.
“Nobody ever thought that the concentrations of dissolved oxygen needed for aerobic respiration could theoretically exist on Mars,” adds JPL’s Vlada Stamenkovi?, lead author of the Nature Geoscience paper.
Finding liquid water on Mars is one of the major goals of NASA’s Mars program. In recent months, data from a European spacecraft have suggested that liquid water may lie beneath a layer of ice at Mars’s south pole. It has also been hypothesized that water could exist in salty subsurface pools, because perchlorate salts (compounds of chlorine and oxygen) have been detected at various places on Mars. Salt lowers the freezing point of water, which means that water with perchlorate in it could potentially stay liquid despite the freezing temperatures on Mars, where summer nights on the equator can still dip down to -100 degrees Fahrenheit.
That hypothetical salty water is what interested Fischer and Stamenkovi?. Oxygen enters water from the atmosphere, diffusing into the liquid to maintain an equilibrium between the water and the air. If salty water were close enough to the surface of the Martian soil, then it could effectively absorb oxygen from the thin atmosphere.
To find out just how much oxygen could be absorbed, Stamenkovi?, Fischer, and their colleagues Michael Mischna at JPL and Lewis Ward (MS ’14, PhD ’17) at Harvard, did two things: First, they developed a chemical model describing how oxygen dissolves in salty water at temperatures below the freezing point of water. Second, they examined the global climate of Mars and how it has changed over the past 20 million years, during which time the tilt of the axis of the planet shifted, altering regional climates. The solubility and climate models together allowed the researchers to infer which regions on Mars are most capable of sustaining high oxygen solubilities, both today and in the planet’s geologically recent past.
The team found that, at low-enough elevations (where the atmosphere is thickest) and at low-enough temperatures (where gases like oxygen have an easier time staying in a liquid solution), an unexpectedly high amount of oxygen could exist in the water—a value several orders of magnitude above the threshold needed for aerobic respiration in Earth’s oceans today. Further, the locations of those regions have shifted as the tilt of Mars’s axis has changed over the past 20 million years. During that time, the highest oxygen solubilities have occurred within the past five million years.
The findings could inform future missions to Mars by providing better targets to rovers searching for signs of past or present habitable environments, Stamenkovi? says.
The Latest on: Mars
via Google News
The Latest on: Mars
- Celebrating A Year Of Mars InSighton November 30, 2019 at 5:33 am
Taken shortly after landing, this photo shows InSight's instruments still packed neatly on its deck. It’s been about a year since the Mars InSight lander screamed through the Martian atmosphere and ...
- Global storms on Mars shoot towers of dust 50 miles into the skyon November 30, 2019 at 3:01 am
Side-by-side movies shows how dust has enveloped the Red Planet, courtesy of the Mars Color Imager (MARCI) camera onboard NASA’s Mars Reconnaissance Orbiter (MRO). The view from May shows Valles ...
- Alabama HS semifinals: Fyffe, Piedmont, Mars Hill, Lanett return to Super 7on November 30, 2019 at 12:02 am
They said it: “The return felt amazing. I had a rough first half, but to make that play for my team, it was definitely a game changer." -- Zackery Next week: Lanett will play Mars Hill in the Class 1A ...
- Take a Closer Look at the Tom Sachs x NikeCraft Mars Yard 2.0 Re-Releaseon November 29, 2019 at 10:22 pm
Following initial rumors, we now have a closer look at what is believed to be the Tom Sachs x NikeCraft Mars Yard 2.0 re-release. Rumored to be limited to 8000 pairs worldwide, the re-release appears ...
- Turns Out the Heart of Mars Is Cold as Iceon November 29, 2019 at 2:31 pm
If tiny concentrations of carbon dioxide can hold enough heat to create a global warming impact on Earth, why is Mars cold? Its atmosphere is 95% carbon dioxide. The recipe for the temperature of a ...
- 18-year-old with pilot's license is 'certified' for space. She wants to go to Marson November 29, 2019 at 10:57 am
Alyssa Carson standing in front of a Mars mural at the Kennedy Space Center Visitor Complex. Carson, 18-year-old Florida Tech student, has known she wanted to be an astronaut from a very young age and ...
- Gigantic Dust Towers on Mars Could Explain How the Red Planet Lost its Wateron November 28, 2019 at 2:40 pm
Sprawling towers of dust can reach heights of 50 miles during global-scale dust storms on Mars, according to new research. Acting like a space elevator, the phenomenon might explain how water escaped ...
- NASA's Insight Marks First 'Land-iversary' On Marson November 28, 2019 at 4:00 am
NASA celebrated the InSight lander’s first anniversary on Mars in a simple tweet marking InSight’s milestones and thanking the team behind the mission. Among its achievements since it arrived, InSight ...
- Underwater Drones, Mars Rover Parts and a High-Tech Revivalon November 28, 2019 at 2:00 am
On a crisp afternoon in late September, a submarine launched from Governors Island. The 100-pound unmanned vessel bobbed in the waves for a few minutes before dipping briefly underwater, then returned ...
via Bing News