How we could warm Mars

The trouble is that tons of these materials would be needed — literally. Previous schemes depended on bringing gases from Earth to Mars, or attempting to mine Mars for a large mass of ingredients that aren’t very common there are both costly and difficult propositions. But the team wondered whether it could be done by processing materials that already exist abundantly on Mars.

Changing the shape of the planet’s dust

Scientists have learned from rovers like Curiosity that dust on Mars is rich in iron and aluminum. By themselves, those dust particles aren’t suitable to warm the planet; their size and composition mean they tend to cool the surface slightly rather than warm it. But if dust particles could be engineered to have different shapes or compositions, the researchers hypothesized, perhaps they could trap heat more efficiently.

The researchers designed particles shaped like short rods, similar in size to commercially available glitter. These particles are designed to trap escaping heat and scatter sunlight towards the surface, enhancing Mars' natural greenhouse effect.

“How light interacts with sub-wavelength objects is fascinating,” Ansari said. “Importantly, engineering nanoparticles can lead to optical effects that far exceed what is conventionally expected from such small particles.”

A step toward feasibility

Mohseni, a study co-author and the AT&T Professor of Information Technology at Northwestern’s McCormick School of Engineering, as well as a professor of physics and astronomy in the Weinberg College of Arts and Sciences and a core faculty member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), believes that they have just scratched the surface.

“We believe it is possible to design nanoparticles with higher efficiency, and even those that can dynamically change their optical properties,” he said.

“You'd still need millions of tons to warm the planet, but that’s five thousand times less than you would need with previous proposals to globally warm Mars,” said Kite. “This significantly increases the feasibility of the project.”

Calculations indicate that if the particles were released into Mars’ atmosphere continuously at 30 liters per second, the planet would warm by more than 50 degrees Fahrenheit. The effect could be noticeable within as soon as months. Similarly, the warming would be reversible, stopping within a few years if release was switched off.

The authors used the Quest high-performance computing facility at Northwestern and the University of Chicago Research Computing Center.

Potential impact and future research

Much work remains to be done, the scientists said. They don’t know exactly how fast the engineered dust would cycle out of Mars’ atmosphere, for example. Mars does have water and clouds, and, as the planet warms, it’s possible that water would increasingly start to condense around the particles and fall back to the surface as rain.

"Climate feedbacks are really difficult to model accurately," Kite cautioned. "To implement something like this, we would need more data from both Mars and Earth, and we'd need to proceed slowly and reversibly to ensure the effects work as intended."

While this method represents a significant leap forward in terraforming research, the researchers emphasize that the study focuses on warming Mars to temperatures suitable for microbial life and possibly growing food crops — not on creating a breathable atmosphere for humans.

“This research opens new avenues for exploration and potentially brings us one step closer to the long-held dream of establishing a sustainable human presence on Mars,” Kite said.