WASHINGTON — The idea of transforming Mars into a more habitable world is a regular feature of science fiction. But is it possible in real life?
Now scientists are proposing a new approach to warming Earth’s neighboring planet by spraying engineered particles—similar in size to commercially available glitter made of iron or aluminum—into the atmosphere as aerosols to trap escaping heat and scatter sunlight toward the Martian surface. The idea is to leverage Mars’ natural greenhouse effect to raise its surface temperature by about 50 degrees Fahrenheit over the course of a decade.
This alone would not make Mars habitable for humans, but the scientists who developed the proposal see it as a feasible first step.
“Re-terraforming refers to modifying a planet’s environment to make it more Earth-like,” said Edwin Kite, a planetary scientist at the University of Chicago who helped lead the study published this week in the journal Science Advances. “For Mars, warming the planet is a necessary but insufficient first step. Previous concepts have focused on releasing greenhouse gases, but that requires large amounts of scarce resources on Mars.”
“The key elements of our paper are a new proposal to use engineered nanoparticles to warm the Martian atmosphere and climate modeling that suggests this approach could be much more efficient than previous concepts,” Kite added. “This is important because it offers a more feasible way to modify the Martian climate, which could benefit future Mars exploration strategies.”
NASA has sent robotic rovers to explore the surface of Mars and the InSight probe to study the planet’s interior. NASA’s Artemis program aims to send astronauts to the moon’s surface in the coming years for the first time since 1972, in preparation for possible future human missions to Mars.
There are many challenges to human settlement on Mars: lack of breathable oxygen, harmful ultraviolet radiation from the thin atmosphere, salty soils hostile to crop growth, dust storms that sometimes cover much of the planet, and more. But the low temperatures are a serious obstacle.
“We propose to show that the idea of Mars warming is not impossible,” said Samana Ansari, lead author of the study and a doctoral student in the Department of Electrical and Computer Engineering at Northwestern University in Illinois. “We hope that our discovery will encourage the broader scientific community, and the public, to explore this intriguing idea.”
The average temperature on Mars is about 85 degrees below zero Fahrenheit. Because of the planet’s thin atmosphere, solar heat from Mars’ surface easily escapes into space. The proposal aims to allow liquid water to exist on Mars, which has water in the form of ice in its polar regions and below its surface.
Scientists have proposed firing tiny rod-shaped particles — nanorods — into the atmosphere at a rate of about 8 gallons per second for years.
“The idea is to either ship the materials or, better yet, ship the fabrication tool and make the nanorods on the planet, since iron and aluminum are abundant on Mars,” Ansari said.
Researchers are well aware of the potential unintended consequences of making another planet habitable. Scientists, for example, are keen to know whether Mars has ever harbored life—or perhaps now, in the form of microbes beneath its surface.
“Although nanoparticles could warm Mars, the potential benefits and costs of this course of action are currently uncertain. For example, in the unlikely event that Martian soil contains compounds that are toxic to all Earth-derived life, the benefit of warming Mars becomes negligible,” says Kite.
“On the other hand, if a photosynthetic biosphere could be created on Mars, it could increase the solar system’s capacity to support humans,” Kite added. “And on the cost side, if Mars harbors established life, studying that life could have such great benefits that it would justify strong protection of its habitat.”
