Enter "frozen smoke". An international team of scientists suggests the use of silica airgel, sometimes referred to as frozen smoke because of its appearance, to heat the surface of the red planet sufficiently to aid life and to melt frozen water. The airgel is an incredibly light material that is already manufactured on Earth and is currently being used as insulation in NASA's Mars rovers.
The study, published Monday in the journal Nature Astronomy, essentially created Mars-in-a-Box to simulate the light that hits the surface of the planet in the lab and a layer of airgel about one inch thick the top lays.
"We used a customized solar simulator to reproduce the spectrum and intensity of sunlight falling on the Martian surface," said Robin Wordsworth, the study's first author. Wordsworth and his colleagues then measured the temperature and how much UV radiation came through the airgel.
He said the experiments were conceived because existing ideas for changing the Martian environment on a global scale seemed "very difficult to achieve." Instead, the team wanted to replicate the effects of Earth's atmosphere on the distant planet on a much smaller scale.
"The Earth's atmosphere increases the surface temperature due to the greenhouse effect and blocks the UV radiation through the ozone layer," he said. "Every solution for the habitability on Mars must do at least these two things."
They found that the thin layer of airgel, which looks like a frozen cloud, did just that. It could block the UV radiation but allow enough visible light to heat the Martian surface beyond the melting point of the water. The airgel tiles were able to raise the temperature by up to 50 degrees Celsius (122 degrees Fahrenheit).
To complement the lab work, the team also performed computer simulations of how the airgel shield would behave when placed over ice deposits on Mars. Their results showed that "Earth-like temperatures" in the range of 32 to 77 degrees Fahrenheit could be achieved during most of the Martian year, ensuring that everyone on the surface had access to liquid water.
So, what's the jam? We can just fly this stuff to Mars and settle there, right?
Not quite. The team emphasizes that if Mars is to become habitable in the near future, there are philosophical and ethical issues that need to be seriously considered, especially if Mars still contains life today. If we started transporting people and invariably microorganisms from Earth to Mars, these invasive species could threaten life already on the planet. We do not yet know that Mars currently supports any life,. The authors note that the creation of a self-contained system, as described in the paper, would not support life outside airgel-shielded regions.
According to Wordsworth, he plans to conduct further laboratory experiments to investigate a wider range of Mars environmental conditions. "In addition to continuing computer simulation work, field research is also planned at Mars-like locations around the world where the research team will use their airgel shields can test the environment.
Originally published on July 15. PT