US scientists say it may be possible to use metal nanorods made from Martian iron and aluminum to thicken Mars’ atmosphere, which would trap heat and potentially melt ice under the planet’s surface to provide water to sustain life. The nanorods would be aerosolised – turned into a very fine dust – and blasted into Mars’ atmosphere, amplifying sunlight and blocking heat from escaping into space, the researchers say. Their computer simulations of the approach suggest nanorods could be 5,000 times more effective than other hypothetical strategies, which focus on using greenhouse gases to warm the planet. But don’t book your ticket just yet – they add that their approach would take centuries to work, and isn’t guaranteed to make the planet’s surface habitable.
Journal/conference: Science Advances
Link to research (DOI): 10.1126/sciadv.adn4650
Organisation/s: University of Chicago, USA
Funder: No external funding.
Media release
From: AAAS
Nanorod-based strategy has potential to warm Mars and strengthen its atmosphere over centuriesA novel, theoretical proposal to warm Mars suggests using metal nanorods to thicken the planet’s atmosphere, trap more heat, and eventually melt subsurface water. The model-based research indicates that this approach might be 5,000 times more effective than other hypothetical strategies, which focus on using greenhouse gases to warm the planet, although it would take centuries to work. Martian geoengineering frequently surfaces as a concept in science fiction. However, real-life researchers are also exploring potential techniques to melt and release frozen subsurface water and render the Martian environment friendlier to life. Many of these strategies involve greenhouse gas-based warming, but the planet is sparse in ingredients necessary for greenhouse gas production. Here, Samaneh Ansari and colleagues propose an alternate strategy to warm Mars: aerosolizing 9-micrometer-long nanorods made from available Martian iron and aluminum. The rods are similar in size to natural Martian dust – essentially, a little smaller than glitter – and should be able to soar high when dispersed. Meanwhile, the rods’ other properties should help them settle 10 times slower than natural dust. Ansari et al. evaluated their proposal using a version of the MarsWRF global climate model and another supplemental 1-D model. Results showed these rods would amplify sunlight that reaches the Martian surface and block ground heat from escaping. In fact, a sustained release of 30 liters of nanorods per second could warm Mars globally by more than 30 degrees Kelvin from its baseline and cause ice melt. After a few months, atmospheric pressure would then increase by 20%, creating the conditions to begin a feedforward loop involving the volatilization of carbon dioxide. Notably, the nanorod process would still take centuries and would not definitively make Mars capable of supporting human life. “Raising Mars’ temperature, by itself, is not sufficient to make the planet’s surface habitable for oxygenic photosynthetic life,” the authors caution. “On the other hand, if a photosynthetic biosphere can be established on the surface of Mars, perhaps with the aid of synthetic biology, that might increase the Solar System’s capacity for human flourishing.”