(2019 Archived) - ARGUMENT - I: The Low Martian Gravity vs. the Earth-Like Venusian Gravity
Having written this in 2019, and originally published in 2021.. when I was 15 and 17, there would be inaccuracies that I would correct here. Having removed it, I'm publishing again, for sake of completion so that the efforts wouldn't have gone to vain: Most of this still stands true, with nitrogen, Earth-like gravity is one of the best arguments for Venus, in colonization.
Gravity is one of the fundamental forces of nature – one which we outspokenly take for granted. Over a course of billions of years, we and most organisms have evolved and adapted to the persistent and consistent pull of the Earth’s steadfast gravity of 1G (9.806 ms-2).We evolved to be so finely-tuned to 1G; that is, our physiology would have a tough time dealing with stronger, weaker or even absent gravity. The same is relatable for many other life-forms who call the Earth home. The ‘gravity’ of an object is determined by its mass and density. The different planets of the solar system and other celestial bodies of our cosmos have different masses and densities. As a result, they have different gravities [10].
The below table depicts the gravitational accelerations and gravity relative to Earth, of the planets of our solar system. The gas giants with the ‘*’, have their gravities measured from their cloud-tops. The table reveals the ringed gas giant – Saturn to have the most Earth-like gravity of 1.0650G [10]. Thus, Saturn is the most gravitationally ideal alien-world for Earth-life. Saturn would be followed by Venus and Neptune, for being gravitationally Earth-like. In a different approach, Venus the 3rd-most gravitationally Earth-like body in the entire solar system, with her gravity being 0.9040G [10]. It is owing to Venus’ Earth-like mass and density.
Planet | Gravity | |
Gravitational Acceleration (ms-2) | Relative to Earth (G) | |
Earth | 9.806 | 1.0000 |
Mercury | 3.700 | 0.3800 |
Venus | 8.870 | 0.9040 |
Moon | 1.620 | 0.1654 |
Mars | 3.711 | 0.3800 |
Jupiter* | 24.79 | 2.5280 |
Saturn* | 10.44 | 1.0650 |
Uranus* | 8.69 | 0.8000 |
Neptune* | 11.15 | 1.1400 |
Mars has a gravitational acceleration of 3.711ms-1, which roughly translates to 0.38G [10], or 38% of the Earth’s gravity. But, what is so bad of such a low gravity? How amok would it be for the human body? Well, I’m afraid that, it is low-enough so that it does have some undesirable effects to the human physiology, with bone decalcification and loss of muscle-tone being the major consequences. Further consequences include: vision problems, formation of kidney stones (by crystallization of calcium oxalate), electrolyte imbalance due to demineralization and fluid-loss, nasal congestion, reduced stimulation of taste and olfactory receptors, desynchronysis, and increased risk of osteoporosis which could manifest itself as fractures in later-life[11, 12].
Moreover, bone mineral-loss appears to be proportional to mission duration. That is, if an astronaut were to spend an entire lifetime on Mars – Let’s say that he would end-up quite fragile and ill. That is even only for a static colony of immigrants from the Earth.
The effects could prove to be disastrous for a reproducing colony on Mars: Every single zygote, foetus and embryo of every to-be human offspring had been raised and nourished in wombs under the steady pull of Earth’s 1G. This delicate yet gradual process with regard to human embryology, like the human himself, had evolved to happen under the influence 1G. A little more or a little less could disrupt the process – in ways that would haunt your dreams. The most concerning consequence would be for immature weakened bones, and vision problems from birth. The true Martian would be born unfit for surviving the other constraints of lower gravity, which he would be forced to live in, with no other choice.
It wouldn’t be a hard time for the new-born, but equally as hard for the mother: Miscarriage might turn out to be common-place with maternal mortality sky-rocketing. Maternal mortality and production of offspring is quintessential for the continuation of a civilization, perhaps even the species as a whole. When maternal mortality is high and successful childbirth low – Martian civilization would fall as soon as it began, unless there were to be constant immigration from Earth (which would be unfeasible on the longer run). Even if Martian parturition were successful enough, the congenital physiological anomalies along with being raised in gravity unsuitable to be raised-in, would wreak havoc on the true Martian’s lives. But, what if the Martians were able to adapt and evolve a healthy physiology for the low Martian gravity. It is by far possible – given enough time. Such an evolution would require thousands, perhaps millions of years to come into action [1]. Even if one-day, there were humanoids evolved to Martian gravity – it would require the suffering of countless generations before. Frankly, I’m quite sentimental and sympathetic on anyone who would have to spend an entire lifetime on Mars – They are up to a total world of unsentimental and unsympathetic pain and torture.
But, although the Venusian gravity is the 3rd-most Earth-like, it isn’t purely Earth-like. Surely there should also be a similar phenomenon on Venus, isn’t it? The Venusian gravity is only ~90.4% that of the Earth, what about the remaining 10%? Won’t it have an effect? Theoretically it should, and to an extent it might. But Mars has a missing 62%, and it means that Martian gravity is still worse than Venus’, specifically six-fold. The effects of the 62% are far worse that the 10%, and thereby – the effects of lost gravity wouldn’t be as adverse as on Mars. As a matter of fact, it might not make a pennyworth of difference to the Venusians themselves – the difference might only be slightly noticeable [10].
The story on Venus, on the other hand is totally different – especially regarding maternal mortality, successful childbirth and up-bringing. Unlike any other children from across the inner solar system (Except the Earth), the Venusian newborns would be much more well suited to live and be-raised. They would be born free from the sorrows of being-raised in an inappropriate gravitational field, and the constraints that hinder life unavoidable. Maternal mortality would likely be more-or-less similar to that of the Earth.
But, what if we were to create an artificial form of gravity on Mars? If we were to create an artificial gravity of 1G, we would be fine. Wouldn’t we? The concept of artificial gravity is quite out of the ordinary, and exploits the equivalence principle – Simply, the exploitation of the inability of the human body to tell apart gravity and uniform acceleration - to create the illusion of gravity [13]. This would most probably be done using circular accelerating motion, which would create a centripetal force (Further exploration on this interesting topic would be better when done by self-research), like a centrifuge. But, we are still quite naïve with regard to some aspects of artificial gravity and it is a concept which needs more research, with much more things to learn about it [13]: For example, (1) we are still quite unaware of the level of artificial gravity needed for good health. Similarly, (2) we would have trouble finding the optimum level of artificial gravity, as it varies from person to person. Moreover, (3) we are unaware of how long humans can tolerate spin in a short-arm centrifuge, and (4) How to deal with the different spin-tolerances of different people [13].
Basically, spin tolerance is an essential factor with regard to putting the Martians under artificial gravity, as the centrifugal motion disturbs their vestibular systems; if anyone were to have a defective vestibular system, he would find himself to be quite dizzy and nauseous under the effects of artificial gravity [13]. The same is true for those who have their vestibular systems pushed to the very limit. I believe that the AG-centrifuges on Mars would have short arms, as those of those with ideally longer arms would have questionable feasibility. However, in a centrifuge with smaller arms; the gravity acting onthe Martian’s soles would be higher than that at their hips, which in-turn would be lower at their heads. The different effects of these gravities can wreak havoc on the astronaut’s body. To make matters worse, the Coriolis Effect would add into the effect of creating confusion and nausea [13].
Still I believe that the reason which makes artificial gravity quite unfeasible is its cost. AG-machinery and centrifuges would bequite very expensive to create, transport and maintain. Basically, it would bemuch more feasible to live in a planet with Earth-like gravity than to live under artificial gravity in aLow-gravity world.
I would like to conclude this argument with the word that the Venusians and their decedents would fare better in their cloud-cities owing to Venus’ Earth-like gravity. True; the Venusians would still have to go through exercise and physical work-out to maintain their physiology – However, it wouldn’t be as much of a dire situation as at Mars. Mars, with its lower gravity, would torment the physiological wellbeing of the Martians with a repertoire of anomalies. Similarly, Artificial gravity - though might be fundamental in space-time odysseys of the distant future, isn’t as much a feasible countermeasure for low Martian gravity primarily for its cost, but also for some of its side-effects.
Nevertheless, there is certain jollity of being in low gravity; I mean who wouldn’t like the feeling of being able to jump thrice as high? However, that jollity would be short-lived: The Martians might enjoy the low gravity at first, but later, as the weeks pass-by, it would turn out to be one of their greatest nightmares. But surely, gravity isn’t everything – there are other factors that are needed to be taken into consideration in the colonization of either world. Until then; because (1) Venusian gravity is Earth-like and physiologically sound, (2) Martian gravity is critically-low and physiologically unsound, and (3) the alleged artificial gravity for Mars, at present, is un-experimented and costly – I would like to conclude this argument with the message that Venus is gravitationally more ideal for human colonization.
[10] Williams, M. (2016, January 1). How strong is gravity in other planets? Retrieved from (https://phys.org|news/2016-01-strong-gravity-planets.html).
[11] Wikram, L.A. (2006). Human Performance Considerations for Mars mission [Paper available online and for download at https://www.apu.edu/static/src/sites/research-science/downloads/human performance mars mission.pdf]
[12] Dunbar, B. (2018, June 11). The Human body in space. Retrieved from (https://www.nasa.gov/nrp/body_in_space).
[13] Walker, R. (2017, April 17). Why not simply create a ship with artificial gravity for the journey to Mars? Retrieved from (https://www.quora.com/why-not-create-a-ship-with-artificial-gravity-for-the-journey-to-mars).
Achinthya Nanayakkara (30.03.2025)
Originally published - 2021 (now removed)
Originallly written - 2019
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