Credit: NASA/JPL/Malin Space Science Systems
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
- Mars Reconnaissance Orbiter releasing one of its last rainbow-colored mapson June 23, 2022 at 1:43 pm
Scientists are about to get a new look at Mars, thanks to a multicolored 5.6-gigapixel map. Covering 86% of the Red Planet's surface, the map reveals the distribution of dozens of key minerals. By ...
- A quick trip to MARSon June 23, 2022 at 12:57 pm
Greetings from Las Vegas, where it’s 105 degrees outside, but it mostly doesn’t matter because you can’t figure out how to get outside. I’m here this week for my first-ever re:Mars. It’s wild being ...
- How NASA Will Keep The InSight Mars Lander Working Until The Very Endon June 23, 2022 at 11:59 am
NASA's InSight lander has been on Mars since 2018, collecting data on the marsquakes that shake the planet. The mission will soon come to an end, although the experts in charge of the lander plan to ...
- Mars Express Gets A Software Update After 19 Years Of Serviceon June 23, 2022 at 9:00 am
An artist's impression of Mars Express. Can you believe a Martian spacecraft has been running a system based on Windows 98 architecture more than a decade after most of us abandoned the operating ...
- Controversy Grows Over whether Mars Samples Endanger Earthon June 23, 2022 at 4:04 am
Planetary scientists are eager to bring Red Planet rocks, soil and even air to Earth, but critics fear the risk of contaminating our world’s biosphere ...
- NASA Mars Rover Snaps Flaky, Funky 'Scientifically Fascinating' Landscapeon June 22, 2022 at 2:10 pm
We know what NASA's Perseverance rover has been up to lately: checking out a piece of foil in a river delta area on Mars. But what about its older sibling, the Curiosity rover? Curiosity has been ...
- NASA's InSight Mars lander to conduct science until it runs out of poweron June 22, 2022 at 12:07 pm
NASA's InSight Mars lander received a reprieve allowing it to conduct science for another several weeks before shutting down as it nears the end of its battery life.
- Mars says CEO Grant Reid is retiring and will be replaced by head of pet care uniton June 22, 2022 at 6:55 am
Mars CEO Grant Reid will step down from his role at the end of September after seeing unprecedented growth, the company announced Wednesday.
- Mars reveals bigger revenues than Coca-Cola as it appoints new chief executiveon June 22, 2022 at 3:47 am
We’ll send you a myFT Daily Digest email rounding up the latest Mars Inc news every morning. Mars, the intensely private chocolate and pet care group, has revealed annual sales of almost $45bn — ...
via Bing News