Science fiction writers have long featured terraforming, the process of creating an Earth-like or habitable environment on another planet, in their stories.
Scientists themselves have proposed terraforming to enable the long-term colonization of Mars. A solution common to both groups is to release carbon dioxide gas trapped in the Martian surface to thicken the atmosphere and act as a blanket to warm the planet.
However, Mars does not retain enough carbon dioxide that could practically be put back into the atmosphere to warm Mars, according to a new NASA-sponsored study. Transforming the inhospitable Martian environment into a place astronauts could explore without life support is not possible without technology well beyond today’s capabilities.
Although the current Martian atmosphere itself consists mostly of carbon dioxide, it is far too thin and cold to support liquid water, an essential ingredient for life. On Mars, the pressure of the atmosphere is less than one percent of the pressure of Earth’s atmosphere. Any liquid water on the surface would very quickly evaporate or freeze.
Proponents of terraforming Mars propose releasing gases from a variety of sources on the Red Planet to thicken the atmosphere and increase the temperature to the point where liquid water is stable on the surface. These gases are called “greenhouse gases” for their ability to trap heat and warm the climate.
“Carbon dioxide (CO2) and water vapor (H2O) are the only greenhouse gases that are likely to be present on Mars in sufficient abundance to provide any significant greenhouse warming,” said Bruce Jakosky of the University of Colorado, Boulder, lead author of the study appearing in Nature Astronomy July 30.
Although studies investigating the possibility of terraforming Mars have been made before, the new result takes advantage of about 20 years of additional spacecraft observations of Mars. “These data have provided substantial new information on the history of easily vaporized (volatile) materials like CO2 and H2O on the planet, the abundance of volatiles locked up on and below the surface, and the loss of gas from the atmosphere to space,” said co-author Christopher Edwards of Northern Arizona University, Flagstaff, Arizona.
The researchers analyzed the abundance of carbon-bearing minerals and the occurrence of CO2 in polar ice using data from NASA’s Mars Reconnaissance Orbiter and Mars Odyssey spacecraft, and used data on the loss of the Martian atmosphere to space by NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft.
“Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2 gas is not accessible and could not be readily mobilized. As a result, terraforming Mars is not possible using present-day technology,” said Jakosky.
Although Mars has significant quantities of water ice that could be used to create water vapor, previous analyses show that water cannot provide significant warming by itself; temperatures do not allow enough water to persist as vapor without first having significant warming by CO2, according to the team. Also, while other gases such as the introduction of chloroflorocarbons or other fluorine-based compounds have been proposed to raise the atmospheric temperature, these gases are short-lived and would require large-scale manufacturing processes, so they were not considered in the current study.
The atmospheric pressure on Mars is around 0.6 percent of Earth’s. With Mars being further away from the Sun, researchers estimate a CO2 pressure similar to Earth’s total atmospheric pressure is needed to raise temperatures enough to allow for stable liquid water. The most accessible source is CO2 in the polar ice caps; it could be vaporized by spreading dust on it to absorb more solar radiation or by using explosives. However, vaporizing the ice caps would only contribute enough CO2 to double the Martian pressure to 1.2 percent of Earth’s, according to the new analysis.
Another source is CO2 attached to dust particles in Martian soil, which could be heated to release the gas. The researchers estimate that heating the soil could provide up to 4 percent of the needed pressure. A third source is carbon locked in mineral deposits. Using the recent NASA spacecraft observations of mineral deposits, the team estimates the most plausible amount will yield less than 5 percent of the required pressure, depending on how extensive deposits buried close to the surface may be. Just using the deposits near the surface would require extensive strip mining, and going after all the CO2 attached to dust particles would require strip mining the entire planet to a depth of around 100 yards. Even CO2 trapped in water-ice molecule structures, should such “clathrates” exist on Mars, would likely contribute less than 5 percent of the required pressure, according to the team.
Carbon-bearing minerals buried deep in the Martian crust might hold enough CO2 to reach the required pressure, but the extent of these deep deposits is unknown, not evidenced by orbital data, and recovering them with current technology is extremely energy intensive, requiring temperatures above 300 degrees Celsius (over 572 degrees Fahrenheit). Shallow carbon-bearing minerals are not sufficiently abundant to contribute significantly to greenhouse warming, and also require the same intense processing.
Although the surface of Mars is inhospitable to known forms of life today, features that resemble dry riverbeds and mineral deposits that only form in the presence of liquid water provide evidence that, in the distant past, the Martian climate supported liquid water at the surface. But solar radiation and solar wind can remove both water vapor and CO2 from the Martian atmosphere. Both MAVEN and the European Space Agency’s Mars Express missions indicate that the majority of Mars’ ancient, potentially habitable atmosphere has been lost to space, stripped away by solar wind and radiation. Of course, once this happens, that water and CO2 are gone forever. Even if this loss were prevented somehow, allowing the atmosphere to build up slowly from outgassing by geologic activity, current outgassing is extremely low; it would take about 10 million years just to double Mars’ current atmosphere, according to the team.
Another idea is to import volatiles by redirecting comets and asteroids to hit Mars. However, the team’s calculations reveal that many thousands would be required; again, not very practical.
Taken together, the results indicate that terraforming Mars cannot be done with currently available technology. Any such efforts have to be very far into the future.
Receive an email update when we add a new MARS article.
The Latest on: Mars
via Google News
The Latest on: Mars
- NASA releases first-ever audio recording from Mars on December 10, 2018 at 8:57 am
David Bowie’s ‘Ziggy Stardust’ alter ego would be impressed … NASA has released the first-ever audio recording from the surface of Mars. The Mars InSight Lander reached the surface of the Red Planet o... […]
- InSight mission to Mars on December 10, 2018 at 7:46 am
Videographic on the InSight mission. Humans can now hear the haunting, low rumble of wind on Mars for the first time, after NASA's InSight lander captured vibrations from the breeze on the Red Planet ... […]
- Hear the wind on Mars for the first time, thanks to the InSight lander on December 10, 2018 at 4:00 am
Since landing on Mars last week, NASA's InSight lander has been taking pictures of itself and its surroundings as it prepares to unload the scientific instruments it brought along to the planet. But t... […]
- Listen to the very first sounds recorded on Mars on December 9, 2018 at 4:10 pm
Is the electric-car revolution a good thing for the environment? Study to explore gas anaesthesia and likelihood of relapse link Replay Video SETTINGS OFF HD HQ SD LO Video provided by Gizmodo Austral... […]
- For the first time, listen to the sound of wind on Mars on December 9, 2018 at 4:01 pm
NASA’s InSight lander touched down on the Red Planet a couple of weeks ago on a two-year mission. It recorded the vibrations of Martian winds moving over its solar panels.Dec. 9, 2018 […]
- NASA Records Sound Of Mars' 'Really Unworldly' Wind For The First Time on December 8, 2018 at 4:30 am
CAPE CANAVERAL, Fla. (AP) — NASA’s new Mars lander has captured the first sounds of the “really unworldly” Martian wind. The Jet Propulsion Laboratory released audio clips of the alien wind Friday. Th... […]
- In 'Trish Trash,' Roller Derby — And Anti-Capitalist Parable — On Mars on December 8, 2018 at 4:06 am
Science fiction always perches on a tightrope of believability, and that tightrope is no fun place to stand. It's ill-defined (what makes something believable, anyway?), badly designed (it changes acc... […]
- Listen to the sound of Mars on December 7, 2018 at 6:14 pm
NASA scientists released audio Friday of rumbles captured by its InSight lander on the surface of Mars. The sound recorded with InSight’s sensors on Dec. 1 comes from vibrations caused by wind that NA... […]
- Hear the Sounds of Wind on Mars, Recorded by NASA’s InSight Lander on December 7, 2018 at 5:41 pm
Before you listen, hook up a subwoofer or put on a pair of bass-heavy headphones. Otherwise, you might not hear anything. When deployed on the ground, seismometers on NASA’s InSight spacecraft will re... […]
via Bing News