So Can We Terraform Mars or Not?


Sunset on Mars. Image credit: NASA/JPL-Caltech/MSSS)
It seemed inevitable that Elon Musk would eventually get into a Twitter war over whether Mars can be terraformed. When you’re on Twitter, he told Businessweek in July, you’re “in meme war land.” “And so essentially if you attack me,” he said, “it is therefore okay for me to attack back.”

By Brian Gallagher | NAUTILUS

Musk, the CEO and lead designer of SpaceX, wants to “make life multiplanetary,” starting with Mars. The red planet is relatively close to the Earth and once harbored surface seas and rivers, and it still has ice and a subsurface lake. Its weather is surprisingly workable, too. Mars’ surface temperature range (–285 to 88 degrees Fahrenheit) isn’t too far off from Earth’s (–126 to 138 degrees Fahrenheit). The problem is Mars’ atmosphere now has 0.006 bar of pressure, where one bar is the standard atmospheric pressure at sea level on Earth. Not only does this mean that dangerous levels of radiation reach the surfaced unchecked, but humans need at least 0.063 bar to keep our bodily liquids from boiling (this is called the Armstrong limit).

Enter terraforming—changing a planet’s climate, topography, or ecology to be more suitable for life. If we could boost the pressure of Mars’ atmosphere just above that of Mount Everest’s summit (0.337 bar), we could walk on the Martian surface using just a breathing mask—no pressurized space suit required. That might be called weak terraforming: It wouldn’t let plants grow in the soil outside of greenhouses.

For that, a good amount of nitrogen, more than scientists have spotted so far on Mars’ surface, is required. It also wouldn’t let us breathe the Martian air. But Musk thinks that, at the least, weak terraforming is possible: “In fact,” he told an audience at the International Astronautical Congress in Mexico in 2016, “if we could warm Mars up, we would once again have a thick atmosphere and liquid oceans.”

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