Cliffs in Ancient Ice on Mars


Oct. 15, 2020

Cliffs in Ancient Ice on Mars

Cliffs in Ancient Ice on Mars

Scientists have come to realize that, just below the surface, about one third of Mars is covered in ice. We study this ice to learn about Mars’ ancient climate and astronauts’ future water supplies.

Sometimes we see the buried ice because cliffs form like the one in this image. On the brownish, dusty cliff wall, the faint light-blue-colored ice shows through. Some of these cliffs change before our eyes and boulders of ice can tumble downhill. We take repeat images of these scenes to check for changes like this.

Image Credit: NASA/JPL-Caltech/University of ArizonaLast Updated: Oct. 15, 2020Editor: Yvette Smith

47 thoughts on “Cliffs in Ancient Ice on Mars

        • You’re welcome.

          The remodeling would include an artificial magnetosphere and accreting enough asteroids to get its gravity high enough to retain O2 in its air. Diluting the CO2 with N2 as well might not be in the budget.

          I don’t know how low CO2 ppm would have to go to avoid asphyxiation and intoxication on Mars, but it would require lots of other molecules. Individual tolerance varies, and habituation to higher CO2 is possible, as with smokers. Fatal CO2 concentrations vary between 14.1 and 26%, accompanied by O2 levels from 4.2 to 25%.


          So, at a minimum, Martian air would have to be seven times denser than now, mainly O2, to avoid lethal CO2 concentrations. To get to sea level O2, Mars’ air would need about 20 times its present mass. I assume there is enough H2O on the planet to achieve this, but there’s still the problem of keeping the O2 from escaping to space.

          • If you had an artificial magnetosphere, there would be no need for more gravity to retain an oxygen atmosphere. Just based on kinetic theory, Martian gravity should have retained an oxygen atmosphere. It was Solar wind that stripped Mars’ atmosphere away, something possible only because there was no magnetosphere to deflect the Solar wind – and it took billions of years.

            Just having the water available is enough for an enclosed habitat colony to exist. Planetary engineering is far beyond us right no. Thinking about it, though, is of value. We might be able to discover just how difficult it is for human beings to change an entire planet.

        • Admiral Richard E. Byrd might beg to differ, if he were still alive. His book Alone, describes what he went through during his solo stay at the South Pole in 1934. Staying in a buried habitat at a South Polar weather station, without hope of rescue, he gradually became ill, and it became worse with time. As he approached death, he realized that the flue on his kerosene stove was leaking, and he was experiencing carbon monoxide poisoning. The story of how he survived it is amazing. That he did, in light of the primitive technology at his disposal, is astonishing. One of my favorite books of all time (my parents’ copy is autographed!).

    • For anaerobic microbes underground however, yes. Any surface organisms would have to tolerate cold, drought, radiation and perchlorate-heavy regolith.

    • The Moon also has no magnetic field, no oxygen and poison soil but in common with Mars it has ice. Neither are habitable by humans or any other form of animal or plant life as they exist but if we are to try, the Moon is a heck of a lot closer so why consider Mars?

      • Mars is bigger and has more air and water.

        The Moon has a weak magnetic field and passes through Earth’s strong one during part of its orbit. Like Mars, it may have had a stronger field in the past, when its core was more active. Impacts might also create temporary magnetic fields.

      • If you were standing on the moon and a pebble traveling 20000 mph hit you, you would cease to exist. On Mars, even though it has a thin atmosphere, it would burn up. Mars has a day similar to Earth, so it does not have such huge temperature gradients that the Moon has. Those are two huge advantages over the Moon.

      • Possibly better still, a permanent space station used for mining asteroids. Large enough for artificial gravity due to rotation, with a large central [double wheel] “airlock transfer system” for ore brought in for processing, a permanent expandable Earth-like environment could be created as a step to a generational spaceship. This could actually be useful.

    • Atmospheric pressure that is 99.4% of the way to total vacuum is a big problem. Nothing really to be gained from living on mars to living in a spaceship except a gravitational field.

    • Earth is covered with water, yet has little hydrogen in its air. On average, water vapor is about 0.25% of the atmosphere, but varies from 10 to 50,000 ppm. There are also tiny trace amounts of CH4 and H2.

      The early atmospheres of both planets contained a lot more hydrogen.

      • Mars is considerably further from the sun than Earth. It gets much less sunlight. The average surface temperature on Mars is around -60C. The place could do with a LOT of global warming.

        Mars’ atmospheric pressure is around 6 or 7 psi vs 1013 psi for Earth. So the partial pressure of CO2 is roughly 64 times that of Earth. That’s only 6 doublings — roughly 30 degrees. It needs another 75C or so

        That calculation may be a bit optimistic. Comparison probably needs to be done on a per molecule basis? CO2 molecules are a bit heavier than Earth’s N2, O2.

        I think that Mars might actually be a candidate for terraforming. But not with any technology we have or will have for a long, long time.

          • “Have you got your PSI and Millibars mixed up?”

            Sure have. Thanks

            I also neglected to mention that the 30C warming from 6 doublings assumes 5 degrees Centigrade per doubling — which is very likely quite a bit too high. It’s not like climate science is actually based on much other than unsubstantiated conjecture.

        • –Mars is considerably further from the sun than Earth. It gets much less sunlight. The average surface temperature on Mars is around -60C. The place could do with a LOT of global warming.

          Mars’ atmospheric pressure is around 6 or 7 psi vs 1013 psi for Earth. So the partial pressure of CO2 is roughly 64 times that of Earth. That’s only 6 doublings — roughly 30 degrees. It needs another 75C or so–

          Well there not really any greenhouse effect on Mars.
          Mars: 0.088 psi {wiki} Earth 14.7 psi
          14.7 / .088 = 167
          Or as say less 1% earth pressure. Though in terms density around 64
          Or earth about 1.2 kg per cubic meter, Mars .02 kg
          1.2 / .02 = 60 . And 64 closer as Mars atm is not pure CO2

          But Mars water vapor is only 210 ppm, and if thought greenhouse gases actually warm stuff, and water vapor a more powerful greenhouse gas
          you could regionally increase water vapor- regionally being Mars tropical zone.
          Earth’s tropical zone about 10 times water vapor, likewise one increase Mars tropical zone water vapor to 2000 ppm, 3 doubling or 3200 ppm for 4 doublings.
          But I think better to make lakes on Mars, use the lakes for living in a higher pressure environment, and side effect would be to increase Mars water vapor. Or course with higher water vapor pressure, less evaporation of lakes.
          And just need Mars water to cost as little 10 times more than Earth water.
          Or we worry too much water evaporating in reservoir lakes on Earth, and would slightly more than non problem we have on Earth.

  1. So Heinlein was right. But it wasn’t the Old Ones who built the canals. It will be us, once we move there. And where there is surface ice, there may be subsurface ice.

    It’s times like these that I wish I were 10 years old again, sitting on the floor of the library stacks reading every book on the shelves….

  2. Any chance of humans living on Mars would necessitate them living underground for a long time. Perhaps new technology might one day allow for terraforming and make the surface more habitable for humans but we ain’t there yet and won’t be for a long time.

  3. What is temp of Mars? Mars has great variation in temps but 2 stations could give an average. One 1/2 way between the equator and north pole at an average elevation….and another in the southern hemisphere on the opposite side.

    • Best estimate is an average of -81 F. But it can get above freezing.

      Surface temperatures may reach a high around 68 °F at noon on the equator, and a low of about −243 °F at the poles.

  4. Visiting Mars for scientific study is fine by me, but any thought that there will be or should be colonies there any time in the next millennium is daft.

  5. No one does anything without a possible return on energetic investment. Not the lowliest bacteria, not Elon Musk. When it becomes clear that there is a large return on investment to be realized for the effort and risk of colonizing the moon or Mars, we will go there. Not before.

    So what would start a gold rush to Mars? Hard to say. Just like the age of sailing ship exploration, it would have to be something that produced large benefits for those back on earth. What could it be? What does Mars or the moon have that would enrich our lives on Earth? By a LOT to make the investment worthwhile.

    • Maybe there’s lots of valuable oil and gas in multiple sub surface basins there?

      Oh wait a minute, that’s on a somewhat larger planet, one step closer to the Sun.

      Never mind.

  6. Why not discuss the ancient Martian cities destroyed in 195,960BC, when the 3rd inhabited Planet in our Sol system, Milona was destroyed in a local war, that knocked Mars out of it’s friendly orbit. Tens of millions of humans died on both Planets. Data from Ancient cities? Here’s what Hoagland downloaded, before the crooked scientists at U of AZ could airbrush out evidence in the nasa 1980s photo. Search.”THEMIS Infra-red images of Cydonia ”Ghost Town… and The Darkness by Richard Hoagland from EnterpriseMission website.”

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