Life Could Have Evolved On Mars, That Was A Major Advance In Understanding.


The most important point with Mars is the following, and it is already established, except for what would be one gigantic scientific surprise pertaining probably to biology. Life Could Have Evolved On Mars.

Imagine just this: that Mars would have been twice larger in radius. The martian radius would then be 6,800 kilometers, ten percent bigger than Earth. Assume next that Mars had been of the same density as now. Thus its mass would be 2^3 = 8 times its present mass. Now the gravity on the surface would be different. From the [mass/(distance)^2] law of gravity (which is older than Newton, and true to this day), one sees Martian gravity would become 8/(2^2) greater. In other words, two-thirds of Earth’s gravity.

So a bigger Mars would have found it easier to keep its atmosphere… and in particular the most potent greenhouse gas, water vapor. 

In the last decade, the extent to which water was present on Mars has surprised everybody. The memory of water is all over Martian geology (marsology?). It’s not just the traces of rivers and ripuarian plains as above, but also enormous amounts of sediments, carbonates and silicates… The drama of mars was that water was robbed by Solar Wind and the dreaded Coronal Mass Ejections… (The latter could total our present electric and electronic technology.)

 Martian rocks look normal, like Earth surface rocks: there are carbonates, sediments, and normal-looking lava. Yet… Think about that. Martian density is a tad below 4 grams/((cm)^3): 3.93 g/cm³. Earth density is 5.51 g/cm³

What’s the origin of the difference? The core of the Earth has lots of iron… but not just that. Earth is actually the densest planet: it is denser than Mercury (5.43) and Venus (5.24). The gas giants are of course much less dense, denser than water by a third (Jupiter) or two-third (Neptune)… Saturn, if one could put it in a tub on Earth, would float, with only ⅔ immersed…

I have long viewed the core of the Earth as a giant nuclear reactor, and my good friend the geophysicist Mark Jellinek, a Miller Fellow, became very angry about this, and we stopped seeing each other because of this scientific debate, where he defended the status quo, which was then that the Earth was releasing heat mostly from contraction (as Jupiter does, supposedly) and latency. Since then the consensus has gone my way. My approach was that of a physicist

This Earth Nuclear Reactor is life giving, because it enables Earth to generate a powerful magnetic shield which wards off the 400 kilometers per second solar wind, and probably reduces the atmosphere robbing potential of Coronal Mass Ejections (CME).  

Venus has no self-generated magnetosphere… differently from Mercury, Jupiter, or Saturn; Mars is too small to have a churning metallic core, so has no magnetosphere, thus CMEs tear the Martian atmosphere away, in particular water. Instead Venus has an induced magnetosphere. A pathetic device that could not prevent Venus from being deprived of all its hydrogen, hence water, torn by the solar wind, especially during Coronal Mass Ejections CME.  

Having not much magnetosphere on Mars is a bit less of a problem: Venus is 100 million kilometers from the Sun, Mars, 240 millions kms. So solar radiation on Mars, per surface area, is one sixth of that of Venus… Venus is a torrid hell, from too much greenhouse, while Mars is too cold, from not enough greenhouse.

Superficially, Venus and Earth are sister planets, both rocky, with roughly the same mass. However there is a huge difference, deep inside: Earth has a giant metallic churning core, and Venus doesn’t. This means that habitable planets to generate life need more than the right mass: they need the right core. I have made that argument many times

Now back to our twice-bigger, eight times more voluminous Mars. Suppose now we endow it with a big radioactive, high density core: we could get to the same mass and gravity as Earth. Then there would be a magnetic field (there is plenty of Iron, Fe56, on Mars, that’s why it’s red!), the CMEs would have been less of a problem, the CO2 and H2O would have been retained…. However with plenty of H2O, Mars would have frozen over, sent back the radiation to space, and it would be a shiny crystal snowball…

Not easy to win at terraforming… NASA agrees that terraforming Mars by using Mars itself is impossible with present technology … However, what NASA did not consider is that a foreseeable technology would be just to harness the solar wind, or get water from Jupiter (not its satellites which have plenty… and we need it there)

The main point of this essay is this: at first sight a larger Mars could have sustained life… Supposing that some of the mass which went to Venus had gone to Mars… However, a more refined analysis shows that Earth also found, and stole the radioactive core necessary to generate a magnetic field making the sustainable evolution of life possible. Ergo, the Solar System had just enough for one Earth where it happens to be …

Some have argued that discovering life on Mars would be a gloomy event: it would show that life is common in the universe…. as I think and this essays shows. What the pessimists say is that then, if life is common, there have been plenty of technological civilizations in the galaxy, but no galactic empire, so all these civilizations were crushed by a mysterious event, a systemic occurrence. But the gloomists’ logic is too rapid. Life on Mars now gone or near extinctions proves instead my point: there may be hundreds of billions of habitable worlds in the galaxy… So what? The evolution of life on Earth took more than four billion years. On Mars, the evolution of life may have been sustained for a billion years, and then the planet got dessicated, hostile to life… A typical case in my view [1]… Forty billion Earths does not mean that more than one could develop animals, let alone a civilization beyond stones and sticks.

Ah, last but not least. A big discovery overall, is that from the poles of Mercury to the ice mountains of Pluto, the Solar System turns out to be surprisingly inhabitable… because it’s full of water in many unexpected places. It is imaginable life could have developed on Europa, even Enceladus… And certainly Mars. It’s all there for the taking… Although microbial Martians would be a serious problem… there is little doubt that, armed with fusion, we can settle, say, Ceres…. All we really need is to fabricate compact thermonuclear reactors, to generate all the energy colonization and terraforming will need (although on Mercury, solar panels will do just fine).

Scientific understanding proceeds in subtle ways. The more we understand about Mars, the more we understand about life, and that is just the beginning. Life probably started there, and then degenerated, as life sustaining water was torn away. The Martians existed for a while, but they were biologically retarded… How similar was that life? Did we, Earth life, originate there? What consequences for life throughout the galaxy? And for civilization, looking backwards and forward?… Not even Pluto is the limit…

Mars will double the real estate readily accessible to humans…

Patrice Ayme 

***

[1] The fate of Mars can enlighten the Drake equation. At first sight we have a planet, Mars, where life died after a billion years. Also life may have got started on Venus, and died there for a similar reason (no magnetic shield). We don’t know how many times a planet is both in the radioactive belt and the habitable belt. Being really gross about it, we can say that, even in an hospitable star system as Sol’s there was (1/3)^4 ~ 1/100 that life lasted long enough to evolve animals…

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4 Responses to “Life Could Have Evolved On Mars, That Was A Major Advance In Understanding.”

  1. ianmillerblog Says:

    There is plenty of water on Mars; the problem is it is basically there as ice because it is too cold. Radar has shown massive deposits. Further, there is good evidence that in the last 4 billion years, only a few cm of water have been lost to space, and that mainly as hydrogen. In my opinion, the reason Venus has so little water is that it used most of it up making its atmosphere. The current volatiles had to be accreted as solids (there is clear evidence that they did not come from comets – the 36 and 38 argon levels are 20,000 times too low, and they did not come from chondrites – C/N ratio all wrong, there should be 10 times more xenon, and a number of other isotopes, on Earth at least, are all wrong for Earth to have got volatiles from chondrites). Given that, water plus heat made the atmosphere, and in doing so on Venus the chemical isotope effect is the cause of the high D/H ratio. Venus probably accreted about 1/6 the amount of water bound to silicates and aluminosiicates than Earth (because it was hotter, closer to the Sun) and has not lost that much atmosphere to solar winds.

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    • Patrice Ayme Says:

      Very interesting Ian, thanks… Mars studies first claimed it was the Solar Wind which tore away the water… Then, no, not that, but the Coronal Mass Ejections… Hmm… A few weeks ago, dust storms were pointed out: they heat up and raise the Martian atmosphere… But THEN:
      Something hilarious happened. Within literally minutes of publishing the present essay, a paper came out in the electronic version of Science Mag: a team headed by the excellent Eva Scheller at CalTech, a graduate student, came out with what you just said: most of the water is stuck inside the frozen ground of Mars. I actually wrote an essay to explain this, but did not publish yet. It fits my PLANETARY NUCLEAR ENGINE obsession…
      That Venus water would have created the Venusian monster atmosphere? Hmmm….
      The atmosphere of Venus is composed of 96.5% carbon dioxide, 3.5% nitrogen, and traces of other gases, most notably sulfur dioxide.
      Sulfur dioxide: 150 ppm
      Carbon dioxide: 96.5 %
      Carbon monoxide: 17 ppm
      Average surface pressure: 93 bar (1,350 psi)
      What happened to the hydrogen? Solar wind + CME AND the lack of a MAGNETIC SHIELD (presumably from MO NUCLEAR ENGINE)!
      I want to add the NUCLEAR ENGINE as a mandate for habitable with self sustained biological evolution planet.
      https://patriceayme.wordpress.com/2016/02/22/is-this-why-we-are-alone/

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  2. ianmillerblog Says:

    The atmosphere of the rocky planets, and especially Venus, could not be achieved by accreting gas. It is a bit lengthy to explain that, but I did so in my ebook “Planetary Formation and Biogenesis”. But basically the first question is, that apart from Mercury, how did rocks stick together? (Mercury was close enough to the star that the silicates became sufficiently molten that they stuck together on contact during stellar accretion. Further out all that could accrete were boulders, maybe even asteroids, then further out, stones. At abgout 1500 degrees C, which happened a little outside 1 AU, aluminosilicates could phase separate and at 1550 iron melted and could form globs. The boulders/rocks would then collide, form dust, but if stones could meet together with aluminosipicartes between them, that would act as a cement with water. So the reason Earth formed continents and has lots of water is that it was in the right place to set cements. Venus was hotter, and the stones were bigger, so it is short of granitic material (there may be two small continents) and it accreted about 1/6 the amount of water.

    The carbon and nitrogen were accreted as carbides, nitrides, etc, and these reacted with water to give off hydrogen and make first methane and ammonia, and eventually CO2 and N2. The reason Venus has such a high D/H ratio is the chemical isotope effect during this hydrolysis, in which one hydrogen is given off and one is retained. The bond to deuterium is about 3 kJ/mol stronger than that to hydrogen because of zero point energy (deuterium is heavier) so it is preferentially retained. Hydrogen that gets into the atmosphere is lost to space, as it is on Earth

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    • Patrice Ayme Says:

      So let me see if I understand a few points relevant to my thought systems:
      1) You say Venus was always drier: it was too close to the Sun during accretion. It accreted 1/6 of the water? Is that from a model?
      2) What interests me is that 90 bars of CO2. I want to see if, given enough energy, one could terraform Venus. If I am not mistaken, CO2 penetrates basalt making… limestone as calcium carbonate or magnesium carbonate:

      In carbon storage experiments tied to geothermal power plants in Iceland, 90% of injected carbon dioxide (CO2) transformed into minerals in just 2 years. Standard carbon storage methods can take thousands of years to do the same.

      “We are basing our methods on this natural process which is part of the big carbon cycle where all carbon on Earth derives from and ends up in rocks,” said one of the lead researchers, Sandra Snæbjörnsdóttir. She is the head of CO2 mineral storage at CarbFix.

      “By mineralizing, we are permanently getting rid of the CO2. We can walk away from it. We don’t have to monitor it for the next decades or so. The permanent storage is the key here,” she said.

      Now what they do is dissolve CO2 in water and then inject this partly acidic mix… Methinks the same happens naturally on Earth, from a mix of plate tectonics and abundance of water. Probably Venus comes short on both. (Why? We ll no magnetic field… Although some say that’s due to the lack of rotation; for Earth, it’s not clear how the magnetic field exactly arises…)

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