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Terraforming Mars might be nearly impossible — but Elon Musk isn’t phased about it

Mars is a barren and desolate place that’s totally inhospitable for life — at least on its surface. At the same time, however, Mars exhibits Earth-like features: the day/night rhythm is very similar to ours (a Martian day lasts 24 hours, 39 minutes and 35 seconds), it has water that can be extracted from its poles and subsurface, and is believed to have once been rich in liquid water.

For these reasons, some scientists have proposed terraforming the Red Planet into our second home in the solar system. The challenges are numerous, however, and according to a new study, it might be impossible to undertake because the planet doesn’t have enough CO2 to sustain a thick-enough atmosphere.

A leaky planet

Terraforming is the process of transforming a hostile, extraterrestrial environment into one suitable for human life. One of the biggest challenges we face in terraforming Mars is the planet’s lung-emptying thin atmosphere, which is just 6/1000th that of Earth’s atmosphere (judging by atmospheric pressure at the surface). Your body would boil if left exposed on the Martian surface — if the extreme cold, UV radiation, and lack of oxygen didn’t kill you first.

In order to both raise the surface temperature and the atmosphere’s thickness, a terraforming project on Mars would have to dump copious amounts of greenhouse gases into the planet’s atmosphere, either by delivering them from Earth — such as CFCs, or Freon, gasses that are 17,700 times more potent than carbon dioxide at trapping heat — or by releasing the carbon dioxide trapped in the ice and beneath the surface. The Martian atmosphere is already 96 percent carbon dioxide.

A new study published in Nature Astronomy, however, suggests that there simply isn’t enough CO2 available on Mars that we could release and bring its atmospheric pressure to terraforming levels. In the most optimistic scenario, we might be able to raise Mars’ atmospheric pressure from 0.6 percent that of Earth’s to 7 percent. Relatively speaking, that’s a huge jump, but still not nearly enough to make life bearable at surface level, according to the new NASA-sponsored study, led by Bruce Jakosky of the University of Colorado, Boulder.

The researchers tallied the amount of easily-vaporizable materials — such as COand H2O — on the planet, the abundance of volatiles locked up on and below the surface, and the loss of gas from the atmosphere to space. About 20 years-worth of spacecraft observational data was used for this study, collected by NASA’s Mars Reconnaissance Orbiter, the Mars Odyssey spacecraft, and NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft.

“Our results suggest that there is not enough COremaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2  gas is not accessible and could not be readily mobilized. As a result, terraforming Mars is not possible using present-day technology,” said Jakosky in a press release.

The various sources of CO2 on Mars and their estimated potential contributions to Martian atmospheric pressure. Credits: NASA Goddard Space Flight Center.

The various sources of CO2 on Mars and their estimated potential contributions to Martian atmospheric pressure. Credits: NASA Goddard Space Flight Center.

The most accessible CO2 deposit is in the polar ice caps. One can imagine vaporizing the ice caps by spraying dust on them to absorb more solar radiation, or as Elon Musk once jokingly said, “Nuke ’em!”. However, this procedure would only contribute enough of the greenhouse gas to double the Martian pressure — to 1.2 percent that of Earth’s.

Mars might actually have a lot of carbon trapped in minerals inside the crust, but these are buried so deep that it would require enormous resources to recover them. What’s more, the extent of these deep deposits is unknown.

In its distant past, billions of years ago, the Martian climate once supported liquid water at the surface. However, back then it used to have a thick atmosphere, which has since been stripped away by solar radiation and solar winds. Rivers, streams, lakes, even oceans seem to once have dotted the Martian landscape but then they vanished — at least some of the water escaped into space, then some more of it may have been boiled away after the Red Planet lost its magnetic field. Now, all of that water and CO2 is gone forever.

The news didn’t seem to shake Elon Musk, one of the most vocal proponents of Mars terraformation. Taking to Twitter on Monday, Musk said there are actually copious amounts of CO2 on Mars.

The SpaceX and Tesla CEO linked to a 1993 paper authored by Robert Zubrin and Chris McKay, which found that “CO2 may be released by planetary warming, and as the CO2 atmosphere thickens, positive feedback is produced which can accelerate the warming trend.” Zubrin chipped in the Twitter thread to clarify.

Whatever the case may be, terraforming is certainly a lofty goal for humanity. But these numerous challenges ought to remind us just how lucky we are to live on such a hospitable planet. If there’s such a thing as paradise, we’re living in it.

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