📰 Terraforming Mars Could Be Easier Than Scientists Thought

Slashdot reader sciencehabit shared this report from Science magazine: One of the classic tropes of science fiction is terraforming Mars: warming up our cold neighbor so it could support human civilization. The idea might not be so far-fetched, research published today in Science Advances suggests... Samaneh Ansari [a Ph.D. student at Northwestern University and lead author on the new study] and her colleagues wanted to test the heat-trapping abilities of a substance Mars holds in abundance: dust. Martian dust is rich in iron and aluminum, which give it its characteristic red hue. But its microscopic size and roughly spherical shape are not conducive to absorbing radiation or reflecting it back to the surface. So the researchers brainstormed a different particle: using the iron and aluminum in the dust to manufacture 9-micrometer-long rods, about twice as big as a speck of martian dust and smaller than commercially available glitter. Ansari designed a simulation to test how these theoretical particles would interact with light. She found "unexpectedly huge effects" in how they absorbed infrared radiation from the surface and how they scattered that radiation back down to Mars — key factors that determine whether an aerosol particle creates a greenhouse effect. Collaborators at the University of Chicago and the University of Central Florida then fed the particles into computer models of Mars's climate. They examined the effect of annually injecting 2 million tons of the rods 10 to 100 meters above the surface, where they would be lofted to higher altitudes by turbulent winds and settle out of the atmosphere 10 times more slowly than natural Mars dust. Mars could warm by about 10 degreesC within a matter of months, the team found, despite requiring 5000 times less material than other proposed greenhouse gas schemes... Still, "Increasing the temperature of the planet is just one of the things that we would need to do in order to live on Mars without any assistance," says Juan Alday, a postdoctoral planetary science researcher at the Open University not involved with the work. For one, the amount of oxygen in Mars's atmosphere is only 0.1%, compared with 21% on Earth. The pressure on Mars is also 150 times lower than on Earth, which would cause human blood to boil. And Mars has no ozone layer, which means there is no protection from the Sun's harmful ultraviolet radiation. What's more, even once warmed, martian soils may still be too salty or toxic to grow crops. In other words, McInnes says, upping the temperature "isn't some kind of magic switch" that would make Mars habitable. That isn't stopping Ansari and her colleagues from investigating the possibilities.

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