Scientists have proposed a new way to modify the conditions on Mars to create more suitable conditions for life on earth. According to the new concept of terraforming, it is necessary to cover large areas of a surface rich in water ice with domes of silicate aerogel. This will simultaneously increase the temperature under such structures to about zero degrees, block the excess ultraviolet radiation and ensure the passage of enough visible light for photosynthesis. The new idea differs favorably from other proposed options relative ease of implementation, the authors write in the journal Nature Astronomy.
Today, the conditions on Mars are not suitable for terrestrial life: there is very low pressure, average negative temperatures and no significant amounts of atmospheric oxygen. However, on the Red Planet there is a lot of frozen water and the closest to Earth conditions (among the planets of the solar system), so scientists are trying to think of a way to improve them.
First of all, warming at low and middle latitudes by 50 degrees is required, which will allow the average temperature to exceed the melting point of water, as well as a way to protect against excess ultraviolet radiation because of the thin atmosphere of Mars, absorbs too little in this range. To address these issues, many solutions are offered, from the creation of special shelters under the surface to the nuclear bombing of the poles.
Under the leadership of Robin Wordsworth, a new solution is proposed that differs from the previously proposed relative ease of implementation. The idea is to cover large areas with silicate aerogel domes. In this case, the thin layer of soil is suitable for many forms of terrestrial life, including photosynthesis.
Warming with the help of aerogel will be carried out due to the solid greenhouse effect - an analog of heat retention by some gases but in solids. Dark spots in the areas of its poles, i.e. areas of melted ice, temporarily heated by light absorbed by transparent layers of ice and snow, speak in favor of the presence of such a phenomenon on Mars. The solid greenhouse effect is especially strong in transparent materials for visible radiation, but with low thermal conductivity and transparency for infrared radiation. Silicate aerogel has all these properties.
To confirm the theoretical estimates of the authors conducted laboratory studies with the simulation of Martian lighting conditions. With a flux of radiation energy of 150 watts per square meter (the average value for Mars 147 W/m^2, for Earth - 342 W/m^2), the layer of chips made of aerogel thickness of 3 centimeters increased the temperature by 45 degrees, and the tile of aerogel increased by more than 50 degrees with a thickness of 2 centimeters.
Researchers note that in the area of equatorial and middle latitudes of Mars, where the average annual solar energy flow is highest, found many regions with indications of the presence of large deposits of water ice at shallow depths. The second most important condition is the rate of accumulation of dust, as it can cover the awnings of aerogel, completely blocking the light. Modeling has shown that after several Martian years the layer of aerogel will provide a positive temperature all year round at a depth of up to several meters in the most favorable conditions.
The authors note that on Earth at the moment silicate aerogel is produced on an industrial scale, and the conduct of a large-scale experiment on solid-state greenhouse effect in the closest to the Martian conditions on our planet is possible today. In the most favorable case, it will be possible to receive the modified terrestrial organisms, such as sponges and diatomic algae which will not only build own "skeletons" from silicon dioxide but also create a material necessary for the terraforming of Mars in great quantities.