Silica aerogel could make Mars habitable

A material way to make Mars habitable
Polar ice caps on Mars are a combination of water ice and frozen CO2. Like its gaseous form, frozen CO2 allows sunlight to penetrate while trapping heat. In the summer, this solid-state greenhouse effect creates pockets of warming under the ice, seen here as black dots in the ice. Credit: Harvard SEAS

People have long dreamed of re-shaping the Martian climate to make it livable for humans. Carl Sagan was the first outside of the realm of science fiction to propose terraforming. In a 1971 paper, Sagan suggested that vaporizing the northern polar ice caps would "yield ~10 s g cm-2 of atmosphere over the planet, higher global temperatures through the greenhouse effect, and a greatly increased likelihood of liquid water."

Sagan's work inspired other researchers and futurists to take seriously the idea of terraforming. The key question was: are there enough greenhouse gases and water on Mars to increase its atmospheric pressure to Earth-like levels?

In 2018, a pair of NASA-funded researchers from the University of Colorado, Boulder and Northern Arizona University found that processing all the sources available on Mars would only increase to about 7 percent that of Earth—far short of what is needed to make the planet habitable.

Terraforming Mars, it seemed, was an unfulfillable dream.

Now, researchers from the Harvard University, NASA's Jet Propulsion Lab, and the University of Edinburgh, have a new idea. Rather than trying to change the whole planet, what if you took a more regional approach?

The researchers suggest that regions of the Martian surface could be made habitable with a material—silica aerogel—that mimics Earth's atmospheric . Through modeling and experiments, the researchers show that a two to three-centimeter-thick shield of silica aerogel could transmit enough for photosynthesis, block hazardous ultraviolet radiation, and raise temperatures underneath permanently above the melting point of water, all without the need for any internal heat source.

The paper is published in Nature Astronomy.

"This regional approach to making Mars habitable is much more achievable than global atmospheric modification," said Robin Wordsworth, Assistant Professor of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Department of Earth and Planetary Science. "Unlike the previous ideas to make Mars habitable, this is something that can be developed and tested systematically with materials and technology we already have."

"Mars is the most in our Solar System besides Earth," said Laura Kerber, Research Scientist at NASA's Jet Propulsion Laboratory. "But it remains a hostile world for many kinds of life. A system for creating small islands of habitability would allow us to transform Mars in a controlled and scalable way."

The researchers were inspired by a phenomenon that already occurs on Mars.

Unlike Earth's polar ice caps, which are made of frozen water, polar ice caps on Mars are a combination of water ice and frozen CO2. Like its gaseous form, frozen CO2 allows sunlight to penetrate while trapping heat. In the summer, this solid-state greenhouse effect creates pockets of warming under the ice.

"We started thinking about this solid-state greenhouse effect and how it could be invoked for creating habitable environments on Mars in the future," said Wordsworth. "We started thinking about what kind of materials could minimize thermal conductivity but still transmit as much light as possible."

The researchers landed on silica aerogel, one of the most insulating materials ever created.

Silica aerogels are 97 percent porous, meaning light moves through the material but the interconnecting nanolayers of silicon dioxide infrared radiation and greatly slow the conduction of heat. These aerogels are used in several engineering applications today, including NASA's Mars Exploration Rovers.

"Silica aerogel is a promising material because its effect is passive," said Kerber. "It wouldn't require large amounts of energy or maintenance of moving parts to keep an area warm over long periods of time."

Using modeling and experiments that mimicked the Martian surface, the researchers demonstrated that a thin layer of this material increased average temperatures of mid-latitudes on Mars to Earth-like temperatures.

"Spread across a large enough area, you wouldn't need any other technology or physics, you would just need a layer of this stuff on the surface and underneath you would have permanent liquid water," said Wordsworth.

This material could be used to build habitation domes or even self-contained biospheres on Mars on Mars.

"There's a whole host of fascinating engineering questions that emerge from this," said Wordsworth.

Next, the team aims to test the material in Mars-like climates on Earth, such as the dry valleys of Antarctica or Chile.

Wordsworth points out that any discussion about making Mars habitable for humans and Earth life also raises important philosophical and ethical questions about planetary protection.

"If you're going to enable life on the Martian surface, are you sure that there's not life there already? If there is, how do we navigate that," asked Wordsworth. "The moment we decide to commit to having humans on Mars, these questions are inevitable."


Explore further

Bursts of methane may have warmed early Mars

More information: Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect, Nature Astronomy. DOI: 10.1038/s41550-019-0813-0
Journal information: Nature Astronomy

Citation: Silica aerogel could make Mars habitable (2019, July 15) retrieved 21 August 2019 from https://phys.org/news/2019-07-silica-aerogel-mars-habitable.html
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Jul 15, 2019
Since we seem to be destroying the habitability of Earth, this would only make sense...

Jul 15, 2019
if we finish destroying the Earth's biosphere?
what makes you confident we won't screw up the next planet we inhabit?

cause, stupid is, as stupid does
here's OUR sign!

Jul 15, 2019
what makes you confident we won't screw up the next planet we inhabit?


No guarantees, but the surface of Mars is probably lifeless anyway, so I am not sure how much we can screw that up.

At a more fundamental level, we are not screwing up Earth's biosphere by accident. For the most part it is being done intentionally, for profit of the few and corruption of those in power against the public interest. We can summon plenty of individual intelligence and a healthy amount of technology, so we could be doing a lot better, but on Earth we struggle against corruption to act for the collective good. We might actually have a better shot on Mars because everyone there will want to improve the environment in order to simply survive.

Jul 15, 2019
I find it "funny" that Mars is even on anyone's radar. We can't survive the trip! Send some robots if we have to, but we're going extinct right here at home, and that's a little more important (and unrelated, no one is terraforming Mars in the next 300 years, but we'll be extinct by 2100, almost for sure...).

Jul 15, 2019
So just how much is corruption holding us back, you might wonder? Consider who has the best rockets, SpaceX or all the nations of Earth. The answer is SpaceX. SpaceX has the most powerful and the most cost-effective rockets in the world, better than any nation, even the U.S. Look at the rocket (SLS) and capsule (Orion) the U.S. government is pretending to build. It is a multi-billion dollar scam that in all likelihood will never fly, or will never fly more than a few times just for show. The reason we have not reached Mars is not lack of intelligence, lack of vision, lack of technology or even lack of funding. It is corruption. Nobody is throwing money at politicians to get it done. The fact that SpaceX has a better shot at reaching Mars than the entire world put together is a big hint that something is very wrong.

Jul 15, 2019
So just how much is corruption holding us back, you might wonder? Consider who has the best rockets, SpaceX or all the nations of Earth. The answer is SpaceX. SpaceX has the most powerful and the most cost-effective rockets in the world, better than any nation, even the U.S. Look at the rocket (SLS) and capsule (Orion) the U.S. government is pretending to build. It is a multi-billion dollar scam that in all likelihood will never fly, or will never fly more than a few times just for show. The reason we have not reached Mars is not lack of intelligence, lack of vision, lack of technology or even lack of funding. It is corruption. Nobody is throwing money at politicians to get it done. The fact that SpaceX has a better shot at reaching Mars than the entire world put together is a big hint that something is very wrong.

Jul 15, 2019
Hopefully Wordsworth et al have spent some time thinking about how the harsh environment will effect the long term material characteristics of aerogel. One of aerogel's desirable properties is its lack of density which makes it a good material for capturing particles. One would think that in a hostile environment like Mars with regular dust storms, extremes of temperature and large ambient radiation, aerogel may become saturated with particles and abraded by the constant winds.

Jul 15, 2019
Silica aerogel. An actual usable product. Unlike graphine, carbon nanotubes, quantum dots...

Jul 15, 2019
At a more fundamental level, we are not screwing up Earth's biosphere by accident. For the most part it is being done intentionally, for profit of the few and corruption of those in power against the public interest. We can summon plenty of individual intelligence and a healthy amount of technology, so we could be doing a lot better, but on Earth we struggle against corruption to act for the collective good. We might actually have a better shot on Mars because everyone there will want to improve the environment in order to simply survive.

The Mark ThomASS brays again.
This jackass believes he's saving the world with his wasteful joyriding in his Tesla, despite knowing that most of its power comes from fossil fuels.
Keep braying jackass.

Jul 16, 2019
Something isn't clear to me about this. The paper itself says the experiments were done under 'ambient' pressure and temperature. The latter is a given, of course. We want to see how good the stuff is at raising the temperature. But 'pressure'? One, down-to-earth, atmosphere? Mars, at the surface is a soft vacuum. I need to see how this stuff works with Mars-like soil, and pressure, and temperature, ab initio.

Dug
Jul 16, 2019
I'm wondering how the necessary production equipment and chemicals get to Mars? At what costs? And, what on Mars is likely to offset those costs on a balance sheet? Unless Mars has it's own economy, the only justification of being there is how it benefits the Earth's economy - which adds another layer to the necessary product return shipping costs. From a basic fiscal analysis standpoint it seems we are long time and far way from the necessary economics (not to mention technology or energy) of processing raw materials on Mars that benefit the Earth's economy - and or it's well being. Though I wish it were otherwise, that does seem to be the reality.

Jul 16, 2019
if we finish destroying the Earth's biosphere?


Things are better than ever before in human history. That includes less pollution, though still bad, it's better. And man has ever right to effect this beautiful 'Hell' for the better of humanity. Mother Nature has no right to make all suffer. Funny how only white liberals, out of all races of people, are the only ones that give their race (themselves) negative ratings. All other political white race categories have a positive view of themselves (conservatives, libertarians, independents).

Jul 16, 2019
(conservatives, libertarians, independents).

fake conservatives taking the ruble
conservative is an action not a cheap political slogan
openly betraying America colluding with Fuehrer Putin

fraudulent libertarians,
i've associated with those claiming Libertarian belief
since the Sixties.
claiming loudly ain't doing

fake independents taking the riyadh to agitprop denialist seceit for the saudi ambitions

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