As far as we know, the surface of Mars is not suitable for human habitation-it's too cold there. However, man finally hopes to build an outpost on Mars. This requires a slight warming of Mars, but how?

The ice sheets at the poles of Mars. The average temperature on the surface of Mars is only -55℃, and the temperature at the poles is even lower, which is not suitable for human beings and plants to live in.

Scientists now suggest that a kind of thermal insulation material called silica aerogel can be used to make parts of the surface of Mars more friendly to photosynthetic organisms (that is, plants). This does not mean a reconstruction project in the whole scope of Mars, but perhaps an aerogel "blanket" can make the ice sheet on Mars melt more easily, thus making a small area on the planet more suitable for humans or plants to live in for a long time.

Image of Mars polar ice cap, black capsule wrapped in warm carbon dioxide.

"Fortunately, we have been able to think of other ways to transform the planet," Laura Cobb, a research scientist at NASA's Jet Propulsion Laboratory (JPL), told Astronomy Online. Silica aerosol is an existing small-scale technology, which is far from the basic scientific research field.

Humans have proved their ability to heat the earth, which is due to the greenhouse effect: when a substance (such as carbon dioxide) absorbs sunlight and re-radiates it, the area below it becomes warmer. But it is not advisable to heat the whole planet in this way-past calculations show that at the current level of science and technology, carbon dioxide on Mars is not enough to transform the whole planet. So researchers focus on how to heat a small part of the planet's surface as effortlessly as possible, for example, using this area to establish a research base.

The greenhouse effect. Greenhouse gases (mainly carbon dioxide) in the earth's atmosphere absorb sunlight reflected from the ground (short wave radiation) and radiate back to the ground (long wave radiation), thus warming the ground.

Silica aerogels can cause the greenhouse effect. This material is mainly air and is wrapped in a silicon net. Due to the nature of this material, silica aerogels with a thickness of several centimeters can transmit visible light needed by plant photosynthesis, block harmful ultraviolet rays and warm the shrouded area.

Silica aerogel is the lightest solid in the world, and its thermal conductivity is extremely low, which can be as low as 0.013w/m k after carbon doping.

The team built an experimental device. They used the intensity of Mars shining on the gel to simulate sunlight, and then measured the temperature difference between the top and bottom of the gel over 50 degrees Celsius. Therefore, this material can be used to increase the surface temperature near the poles of Mars. Korbel suggested that tiles made of this material can be installed in a greenhouse-like device.

Mars greenhouse (concept map)

A researcher who was not involved in the study thought it was a "smart and possibly interesting" idea. Bruce Jakosky, a professor at the University of Colorado at Boulder, told Astronomy Online Blog that this technology has not "transformed Mars" as claimed by other news media. Instead, the researchers proposed to heat some areas enough to melt the ice. In a paper published in the journal Nature Astronomy, the team said that there are still other important life limiting factors that greenhouses cannot overcome, such as proper atmospheric pressure. In addition, korbel pointed out that silica aerogels are very brittle, so it is necessary to add another material, such as polymer.

But there are many other things to consider before we consider transforming a part of the surface of Mars to make it suitable for human habitation. Just the act of establishing a base on Mars will lead to a series of discussions about "who will go" and "why"; Moreover, there may be life on Mars, so the existence of people (humans, plants or microorganisms) on the earth will increase the difficulty of searching for them. Korbel himself pointed out that transforming planets will destroy the "primitive" environment that scientists want to study.

Curiosity Mars probe is searching for the existence of life. However, the settlement of Mars may affect the exploration of life on Mars.

Transforming Mars may also be a bad idea. "It's very dangerous," Jagosky said. "This implies that we don't need to maintain the earth's environment. This is not a good idea. " But perhaps building a small building on Mars will allow researchers to avoid all possible bad results while conducting experiments.

In the final analysis, this is just a study to verify the principle, and the idea of human settlement on Mars is still an unpredictable future. But now, researchers hope to test their materials in some harsh environments on earth, such as Antarctica or Chile. And unlike those high-risk technologies that change the whole planet, it seems not so difficult to build a greenhouse with an existing material.

reference data

1. Wikipedia

2. Astronomical terminology

The singer in the cloud

Author: Ryan Mandelbaum

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