WHY THIS MATTERS IN BRIEF
If we are going to colonise other planets then somehow we need to make them less inhospitable to life, and this is one step in the terraforming process.
Recently I wrote about a team who created a new strain of artificial nano-bionic plants that could possibly grow natively on Mars, and now another team have made another breakthrough that could help us grow plants in the Martian soil by using a thin blanket of super-light silica. Aerogel, a lightweight material made mostly of air that when 3D printed is 99 percent lighter and 10 times stronger than steel and that I’ve discussed before because of its quirky applications, could be used to heat up the ground and protect it from harmful radiation while allowing enough light through for plants to grow.
There are two primary problems for life on Mars, which are also problems for any potential human exploration: it is very cold, with night time temperatures plunging below -100° C in some areas, and it has no thick atmosphere to protect it from harmful UV radiation. So Robin Wordsworth at Harvard University and his colleagues have come up with a potential workaround.
Their solution is based on a phenomenon called the solid-state greenhouse effect, which happens when sunlight passes through layers of translucent snow or ice and is absorbed. The ice insulates the deeper layers while allowing them to get warmed up by the light.
Instead of snow or ice, Wordsworth and his colleagues tested silica aerogel, which is one of the best thermal insulators we know of. They found that an aerogel panel just two centimetres thick with Mars-like levels of sunlight shining through it could warm the area underneath by more than 50° C. It also blocked more than 60 per cent of UV radiation, and more than 99.5 per cent of the most harmful type, UVC, while letting through the visible light necessary for photosynthesis.
On Mars, the silica aerogel would likely have to be interwoven with other materials to build structures. Its greenhouse effect could melt subsurface water down to depths of several metres, providing not only a safer place for plants and maybe humans but also the start of a water cycle.
“It’s a very different approach to a lot of these global terraforming ideas, but it has the advantage that we could actually do it in the next few decades rather than much further in the future,” says Wordsworth.
It’s also more gentle on the Martian environment, potentially allowing us to terraform areas of Mars without damaging the scientific clues or possible life that may exist in other spots. The next step is to test structures made of silica aerogels in Mars-like areas on Earth, Wordsworth says.
Journal reference: Nature Astronomy, DOI: 10.1038/s41550-019-0813-0