The Red Planet
A Natural History of Mars; a review
Two weeks ago I knew more about myths and esoteric ideas about Mars, than I knew about Mars the planet. It is proper to say now, I’m well informed, and almost everything I know about Mars the Red Planet I learned from Simon Morden PHD.
I’m grateful Dr Morden has a background in science fiction, because he brought Mars alive in this book. I feel like I know Mars in an entirely new way, more as it is, not merely something that has been mostly dreamed about by many people over time.
But first a bit about the origins of the Sun and Solar System. A scientific perspective.
About 4.6 billion years ago there was a vast cloud of gas, mostly hydrogen, containing enough matter to make innumerable stars. Undisturbed by any sweeping arm of the galaxy, it was inert, drifting slowly; it might become a few giant stars, or nothing, swept up over time and dispersed by passing clusters of stars.
I was going to try to summarize this set of pages, then it occurred to me, I have never read a more concise, beautiful description of the early coming together of the Sun and solar system.
It’s rare to find such literate descriptions of the origin of things. Most of the book is like that, Morden has a masterful capacity for technical language, with the instincts of a writer of fiction. He admits he had some help limiting his reliance on technical language, from some very capable people; in consequence it reads more like a novel.
A few things I learned about Mars, from Dr Simon Morden, I didn’t know:
When Mars came together, approximately the size that it is now (roughly half the size of the earth,) it was entirely molten, surrounded by a thick atmosphere containing enough water to cover the entire planet a kilometer or more deep.1 Mars exists at the edge of the frozen zone, a lot of the matter that came together to make Mars in the Great Bombardment/Period of Accretion, contained a lot of water Ice. (I admit I’m still unclear where the oxygen came from in the early solar system, for the making of so much water.) As Mars cooled, a crust formed, water vapor became rain, and seas formed. Conditions were forming to support life, similar to Earth.
The first few hundred million years, there was a lot of debris in the solar system. There were a lot of big objects running into bigger objects. Our moon possibly came from such an impact, the earth colliding with a planetesimal. It is called Accretion, the coming together of material in the early solar system, the building of the four rocky planets, bombardment by small and large objects coming together, over hundreds of millions of years.
Mars is oddly formed. Most of the northern hemisphere is a flat former sea bed. The southern hemisphere stands on average about 5Km high, more elevated than the northern plains. The crust of the southern hemisphere is 60Km thick, the northern 30Km. The transition zone between hemispheres, at the former equator, is a gradual slope a hundred kilometers long; this difference between the hemisphere’s is called the Great Dichotomy.
There are competing theories about how the Great Dichotomy formed2, but the best I think is an impact with a planetesimal; it cast all that material from the northern hemisphere to the southern. It threw off into space a lot of the early atmosphere and a lot of the water. It might have shut off the magnetosphere, if there was one.
There are two other very serious impact sites on Mars, the Utopia Planitia, and the Hellas crater, the latter of which punched through the crust into the mantle, shattering the crust of most of the planet. On the polar side, opposite the planet from the impact site of the Hellas crater, is Olympus Mons, the largest volcano in the solar system 22Km tall, 860Km wide by 640Km. Mars lava was a very thin liquid that could flow for hundreds of kilometers.
Even on Olympic Mons, you would not know you were on a volcano, anywhere but maybe standing at the edge of the crater.3 Even there, looking back the way you came, it would only be a gradual slope as far as you could see. Even as you are you are 2 1/2 higher than Everest.
The primary volcanic zone is called Tharsis. It straddles the Great Dichotomy, so large it is almost 25% of the surface of the planet. It stands taller than the tall southern hemisphere by 2 kilometers, “averaging 7Km above datum,” not including the height of the volcanoes. It is so vast and so heavy - there are 11 large volcanos, to 20 km tall - it has destabilized the crust, already shattered from the Hellas impact; along with the unbalanced Great dichotomy, it gives the planet a comparatively unstable spin. Mars has a wide ranging Obliquity, the range of it’s solar tilt, from 0deg to 60dg. Currently it is at 25deg, similar to the Earth at 23deg, relative to the Sun.
Even after three catastrophic impacts, there was a period when most of the northern hemisphere was a vast, deep ocean, while many of the craters and valleys in the south were full of water. Conditions were still good for the formation of life. There are formations in craters that were formerly lakes, Lake Eridania specifically, that appear to be thermal heat vents, the same sort of structure you see in Earths ocean.
But there are no tectonic plates like Earth has, just one thick, solid crust, no recycling of the crust back into the mantle, only volcanoes venting material. Mars core and mantle is not a recycling heat engine like that of the Earth. A solid crust is very insulating, holding heat in. Over time the atmosphere grew weaker, less able to hold heat, the planet cooled. Most devastating for the possibility of life on the surface, Mars has no magnetosphere, so no protection from solar wind. Solar radiation brakes up water molecules in the air, the particles drift higher and higher, are pulled into open space by solar winds. Radiation strips off more and more of the atmosphere. All that volcanism provides heat and atmosphere, but not enough. Three billion+ years of sustained volcanism, all the while emitting sulfur dioxide into the atmosphere, making the water acidic.
The seas freeze solid; the ice gradually sublimates to gas, which accumulates as ice at the poles. There is enough ice at the poles to cover all of Mars to more than twenty meters. It is estimated half the first kilometer of the crust, at least, is water ice.
It is a frozen surface now, to several kilometers. Much of the surface is covered with a fine dust, ground up in the repeating freeze/thaw cycles of Mars over a couple of billion years. The early atmosphere was hot and stormy, there were great rain storms, with nothing to hold the soil. Great Tsunamis from meteorite impacts. Waves were much taller, with so much less gravity than Earth; in a circumpolar sea, the winds build for a long time. That is a lot of flooding, grinding boulders into gravel into soil into dust.
With little atmosphere and almost no atmospheric pressure, there is comparatively little wind on Mars today. But each spring in the southern hemisphere a seasonal wind will rise, in particular areas like the Thaumasia Planum on southern Tharsis, or around the Hellas crater, places where heat tends to gather, wind builds, picking up enough dust to blot out the sun over a great distance. Every ten years or so the dust storm will cover the entire planet, for a period of several weeks.
The entire surface is not covered with dust, but it can be up to 60m thick in some places.
The dust is so fine, and the air so dry, and the atmospheric pressure so low, every dust particle has a static charge. It can come together and make duststone. It would cling to you, you could not wipe it off. It would find it’s way into every gear of every machine. Breathing it, too much at once or too much over time, because you can’t expel it, kills you.
Everything about Mars is hostility to life. That is why many civilizations conceived of Mars the planet as a god of war.
But then, there is Valles Marineris, in the high shelf of the southern hemisphere, dwarfing the grand canyon at 2000Km long and 200Km wide, in many places with sheer cliffs several kilometers tall, like the crust simply gave way and dropped.
It is 7Km deep in places. There is one spot, standing at the rim, you could look 4miles straight down.
Mars also has an highly elliptical orbit, as well as extreme Obliquity. The only planet that has a greater elliptical orbit is Mercury. Compared to the Earth’s orbit, which is only a 3.1 million mile difference from 91.5 and 94.5 mil miles (for an average around 93mil miles), between the Perihelion and the Aphelion, Mars is 128.4 to 158.8, a 30.4 million mile difference. Mars has seasons like ours, but at 1.88 times the days, a 687 day orbit, the seasons are a lot longer, and even if it’s summer, 158.8 million compared to 128.4 miles out is a cool summer - esp without much of an atmosphere, and less than 1% atmospheric pressure.
If Mars comes close to Jupiter, it is pulled even further from the Sun.
It might be though, the simple reason Mars did not support higher life (maybe now very simple life and far underground,) is the low mass of Mars. If you think of mass as the energy content within a physical body, the mass of Mars is only 1/10 the mass of Earth.
Also, warrior/builder types who want to conquer it. There’s no native iron on the surface, for building things, it was all pulled to the core of Mars when it was molten. There are “iron-bearing minerals, silicates and oxides,” but there is no free oxygen to have made that iron rust. It isn’t iron oxide that makes it the Red Planet.
The red color of the planet is haematite, that is suspected to come from the gradual breaking up of the “Medusae Fossae Formation…composed of loosely cemented volcanic ash and pyroclastic material,” with just the right chemical composition, constantly eroding for billions of years.
“Sand and other fine grains, when blown by the wind, move through a process known as saltation: Essentially a grain flicks up from the loose surface, is carried a short distance and then lands again…Each tiny impact abrades both it and whatever it strikes…It is during these collisions chemistry can occur….Mill a mixture of nine-parts quartz sand and one part magnetite in a carbon dioxide atmosphere long enough and you’ll end up with haematite dust.”
Mars Exploration
I don’t have any idea where the science is, regarding settling on Mars. Morden does not really discuss it, except to remark how challenging it is. Elon Musk, or John Carter is surely more versed in that than I am; but my feeling is, the science isn’t there yet, and not really even close. Sounds like a job for AI/Grok. But then, despite the progress of AI, It seems very good at propagandizing compiling and organizing, but not necessarily good at invention?
Elon is suggesting un-crewed flights as early as late 2026, with crewed flights in the early 2030’s, with a self-sustaining settlement by 2055.
To reiterate, the technical challenges: There is no magnetosphere, so no protection from direct solar radiation; the dust is arguably more of a problem, for mechanics and the health of people; it is very cold, with the average temperature at -70F (on the equator in the summer it might be 70F during the day but -100F at night;) low gravity we already know, is not good for the body, the human body is designed for earth gravity and atmospheric pressure - Mars gravity is only 38% of Earth’s and the atmospheric pressure is less than 1% - even the very structure of DNA starts to falter under such conditions.
But hey, it is a frontier like we have not had in a long time, I understand the draw, and I sincerely hope Elon et al figure it out. Who knows, maybe the DNA changes make you stronger, after a few generations you come back and conquer Earth?
As to Mars, this post is barely a simple sample of the information in The Red Planet, by Simon Morden PHD. I highly recommend it. It is remarkably informative, intelligent and an easy read. It has opened up a new way of thinking for me, about the entire solar system, and I am hungry to know more. It is a fine diversion too, and maybe a bit of a meditation, in a world going mad with wars and rumors of war?
Later in July I will write about the esoteric perspective on Mars.
Ok, right up front, Morden did not say how much water vapor was in the atmosphere of Mars in it’s beginning when it was molten, I surmised it, based on how much he says there is now, and how much was lost by the Great Dichotomy impact and the loss of the magnetosphere. But Mars still has a LOT of water, and it used to have a LOT more.
The other competing theory for the Great Dichotomy is, there are no tectonic plates, like the earth has. The Great Dichotomy might be, the (former) north and south poles are subduction zones, the crust flowing into the mantle in the North, flowing out of the mantle to become crust
Standing at the edge of crater of a volcano on Mars, you cant see the other side. Looking down, it might be a greater drop than anywhere on Earth. And almost everything behind you as far as you could see would be a nearly flat, empty lava field.
Mars is a dead world, but interesting. At least the folly of humanity will not survive there if we ever get to explore it.