The idea of terraforming Mars and other planets within the Solar System and beyond has not only deep roots in science fiction, but also a degree of support from researchers and science popularisers, such as the late great Carl Sagan.
One of the key problems with making the Martian surface habitable is that, according to previous work on the topic, even after processing all the sources of greenhouse gas and water present, the atmospheric pressure on the planet would still be only about 7 per cent that of the Earth.
In response, researchers from the Harvard University, NASA’s Jet Propulsion Lab, and the University of Edinburgh have proposed a more regional approach using silica aerogel, which mimics the Earth’s atmospheric greenhouse effect.
The material could be used to erect a number of domes – or even self-contained biospheres – on the surface to kick-start the terraforming process – experiments performed by the team have shown that silica gel could transmit enough visible light for photosynthesis, block hazardous UV radiation, and raise temperatures underneath without any internal heat source.
“This regional approach to making Mars habitable is much more achievable than global atmospheric modification,” said Harvard’s Assistant Professor of Environmental Science and Engineering Robin Wordswoth. “Unlike the previous ideas to make Mars habitable, this is something that can be developed and tested systematically with materials and technology we already have”.
According to Laura Kerber, a Research Scientist at NASA’s Jet Propulsion Laboratory, the effects of silica gel are passive, which makes it a promising contender for building long-term, scalable zones of habitability without the need for lots of moving parts or energy.
“Spread across a large enough area, you wouldn’t need any other technology or physics, you would just need a layer of this stuff on the surface and underneath you would have permanent liquid water,” said Wordsworth.
Moving forward, the team will conduct experiments in Mars-like climates on Earth, such as Antarctica or Chile.
The paper was published in the journal Nature Astronomy.