The red wanderer in our sky, Mars - once an omen of strife and misfortune due to its color, now a beacon to the hopes and dreams of mankind - holds the promise of a second home, a "boundless" frontier, and a new Earth if we dare to make one. Mars is exotic enough to be our greatest challenge yet, but not so hostile to make our aspirations on the Red Planet foolhardy. It is the testing ground, where humanity emerges both physically and psychologically into its role as a species committed to spreading itself into the entire solar system. While it may seem a relatively cold, frozen, dead world at first glance, look more closely and you will see something completely different: A world yet to be born. We conclude the Mars sub-series by looking at the history of the planet from humanity's perspective, its potential future as another home for mankind, and its long-term fate as a physical body.
The progress of our adventure so far (current in bold):
1. The SunSections of the Mars sub-series (current in bold):
4. Earth (Vol. 1)
5. Earth (Vol. 2)
6. Earth (Vol. 3)
7. Earth (Vol. 4)
8. Earth (Vol. 5)
9. Earth (Vol. 6)
11. Mars (Vol. 1)
12. Mars (Vol. 2)
13. Mars (Vol. 3)
14. Phobos & Deimos
25. Tethys, Dione, and Rhea
28. Rings & Minor Moons of Saturn
30. Moons of Uranus
33. The Kuiper Belt & Scattered Disk
35. The Stellar Neighborhood
I. ContextV. Past Relevance to Humanity
IV. Natural & Artificial Satellites
V. Past Relevance to Humanity
VI. Modern Relevance to Humanity
VII. Future Relevance to Humanity
VIII. Future of Mars
IX. Catalog of Exploration
Although the ancients noted the strange motions of the planets in Earth's sky, they had no incling that these "wanderers" were fundamentally different objects from the other points of light in the heavens. The other planets of the solar system were simply believed to be stars of some extraordinary mystical significance, and were thought to orbit the Earth along variously complicated epicycles (i.e., sub-orbits) to explain such phenomena as Mars' apparent retrograde motion - the fact that it appears to move backwards in the sky as a result of Earth passing it in orbit around the Sun. The path of Mars as seen from Earth:
It's important to say, however, that ancient astronomers were not barbaric fools coming to ridiculous conclusions for believing in an Earth-centered universe - they were highly intelligent people working from what they knew in order to understand what they saw. And what they "knew," from intuitive experience, was that Earth does not move and the heavens do - and in the case of Mars, what they saw of its motion indicated epicycles. Epicyclic motion was plainly witnessed, as in the photograph above, and it would take profound conceptual leaps to understand that what was being seen was something totally different than what it appeared. Such leaps were in the future, but direct deduction from observation produced geocentric models on the part of Greek, Roman, and medieval astronomers such as this 14th century work by Ibn al-Shatir, which were generally accepted at face value until the Copernican Revolution in the 16th century:
So, for thousands of years, Mars was believed to be a "star" wandering in an odd, epicyclic path around the Earth. Those less concerned with objective behavior attributed far more significance to its color than to its motion, leading several independent civilizations to associate the red planet with war, violence, and chaos, naming it the "fire star" (in China) or "star of the god of war" in Greece, Rome, and India. It should be noted that ancient astrologers - mystics who attribute abstract meanings to astronomical objects - did not claim the planets were gods or primal forces themselves, but merely that they were indicators of the moods and intentions of those gods based on entirely arbitrary associations between celestial alignments and human occurrences. In other words, planet Mars was the omen of the god of war, not the god himself.
The position of the star of Mars, along with the other planets, would thus be worked into astrological tables and charts, and used by priests and augurs to interpret standard omens as seen in the innards of animal sacrifices. As such, the status of the red planet became somewhat ambiguous with the rise of Christianity and Islam and the attendant demise of the Egyptian, Greco-Roman, and ancient Mesopotamian gods. Aside from insisting on a geocentric model of the universe, neither the Catholic Church, Orthodox Church, or the main sects of Islam attached any particular religious significance to the planets, and this perhaps opened up some room for scientific observers to explore new ideas. The fact that religion continued to insist on this one aspect of astronomy, however - that Earth is the center of everything - may ironically have allowed more logical thinkers to zero in on what was actually going on, and take closer looks at the formerly obscure idea of putting the center of motion elsewhere.
VI. Modern Relevance to Humanity
With the Copernican Revolution and the waning power of religion to stifle science, we can draw a sharp boundary between the ancient and modern relevance of astronomical bodies to humanity. At that point, relevance becomes a matter of increasing understanding and evidence rather than religious ideology, superstition, and fallacious correlation. Once it became generally accepted that both Earth and Mars orbited the Sun, humanity set off on a path toward realizing that they were two examples of the same type of object. However, it's not nearly as clear when people started understanding that Mars was a world with a human-relatable surface environment rather than a star: The concept, although idly explored in philosophy in ages past, seems to have evolved along with the increasing ability to gather evidence since Galileo.
What is known is that by the middle of the 17th century, astronomers were already making crude maps of the planet based on light and dark regions seen through telescopes, and were able to deduce both the fact and rate of rotation by changes in these features over time. A sketch by Christiaan Huygens in 1659, most likely depicting Syrtis Major:
Compare it with a Hubble Space Telescope image of Syrtis Major - the frame of reference appears to be tilted somewhat clockwise in the HST image from whatever orientation Huygens was observing:
By the 18th century, astronomers had seen the Martian polar caps, noted their seasonal variations, and correctly deduced that they consisted of ice. Observations had also been made of the Martian atmosphere, so by then it's reasonable to say that the academic community understood what they were dealing with was something vaguely like Earth and the Moon, and not some entirely different class of object. They had also more or less constrained the size and distances of the planet to figures reasonably close to reality.
In fact, the environmental similarity between Earth and Mars was greatly exaggerated in the first few centuries of this understanding, with astronomers concluding - again, reasonably, given that the only world we knew was Earth - that Mars had a human-breathable atmosphere and was likely inhabited by intelligent civilizations. There would have been no evidenciary basis to claim at that point, or even to hypothesize, that Mars had an unbreathable atmosphere, that it was far thinner than Earth's atmosphere, or that the planet would later prove to be completely barren of any obvious life let alone cities. The sophistication of observations and science was not yet such that even the Moon could be ruled out as an abode for intelligent life, so to that point in history everything we knew - i.e., this planet - said that people live on planets, and thus there were assumed to be people on that one too.
It was during the 19th century that scientific understanding about our solar system first began to percolate into popular culture, firing the imaginations of Jules Verne, H.G. Wells, and a number of less distinguished authors who took far more liberties with fact and probability. As non-scientists came to understand that the heavens were full of actual places and not just abstract objects, an entirely new genre of fiction was born to fill these settings with adventure, drama, exotic creatures, and foreign civilizations: Science fiction, or as it was initially known, "science romance."
Verne's most popular works were relatively local, concerning exotic Earth-bound locales, the ocean, underground environments, balloon travel, and the Moon, but all nonetheless added to the sense that an alien environment should be full of life and strange people, since that had been the experience of humanity throughout its history exploring (or more often, invading) strange lands. Wells' vision, however, was less romantic despite being equally confident of the core premise - although his Martians were a malevolent and aggressive race bent on conquering Earth, that too was simply a projection of human history on to the rest of the solar system: He merely reversed the roles, making humanity the indigenous population targeted for conquest. No one could blame these visions: There was no scientific reason to rule them out at the time.
This assumption about Mars being alive and populated persisted throughout the 19th and well into the mid-20th century, aided and exacerbated by faulty conclusions drawn from otherwise valid evidence. For instance, Italian astronomer Giovanni Schiaparelli famously produced detailed maps of the Martian surface in 1888 depicting dark, linear features he called by the Italian word for "grooves" - canali:
Unfortunately, the nuances of translating Italian to English were not the strong suit of one Percival Lowell, who did not understand that although "canali" can mean "canals," it doesn't necessarily - it just refers generally to the physical concept of linear depressions that could just as well be natural canyons. The mistranslation, along with Schiaparelli's arbitrarily connecting albedo features with straight lines, led Lowell to believe the Italian was announcing the discovery of an advanced Martian civilization that had built a world-girdling network of canals. Lowell's subsequent drawings of the Martian surface were interpreted through this assumption, and he connected dark features with straight lines where none were actually in evidence:
Most likely the entire misunderstanding was based on a faulty interpretation of the Valles Marineris canyon system, which is a vaguely linear scar running across an entire face of Mars. Ironically, this led to some accidental insight into the true nature of Mars, as it led Lowell and other adherents of his beliefs to envision the planet as a desert world whose inhabitants had built engineering marvels to irrigate their civilization. Their error was in greatly underestimating just how much of a desert it is.
Other astronomers of the period did not go as far in their assumptions, but continued to believe that dark areas were seas, and that the planet was most likely inhabited - they just didn't insist on it with the same fervor and romantic sentiment as Lowell, and had largely dismissed the "canali" as optical illusions by the turn of the century:
However, the idea of Martian civilization persisted in popular culture, and exploded into public awareness with the 1938 radio broadcast of an adaptation of War of the Worlds read by Orson Welles. The realism of Welles' acting and the structure of the teleplay convinced some listeners that they were hearing an actual news broadcast, and thought an actual Martian invasion was underway.
By this time, the scientific community had already begun to rule out the idea of civilizations on Mars - once the Earth's own atmosphere was finally factored out, the spectrum of light from Mars showed little evidence of water. Meanwhile the temperatures were found to fluctuate radically between night and day, and gas chemistry was understood well enough that scientists were able to find little or no molecular oxygen in the atmospheric spectrum. The public, though, still lived in the worlds painted for them by Verne and Welles, and to a lesser extent in the burgeoning world of pulp fiction where fantasy writer Edgar Rice Burroughs had envisioned a Mars (called "Barsoom" by its inhabitants) full of exotic creatures and swashbuckling adventures.
Scientists still hoped that some forms of life could exist on Mars, but classic works like Ray Bradbury's The Martian Chronicles (1950) and Robert Heinlein's Stranger in a Strange Land (1961) were already more or less obsolete when published. Oddly, the former would prove to be a better augur of later themes in science fiction, as its story concerns humans colonizing the Red Planet and coming to think of themselves as Martians, whereas the typical theme up to that point (and also in Heinlein's novel) is to focus on native civilizations or their impact on Earth.
In 1964, when the unmanned Mariner 4 probe sent back clear images of a surface that looked in black and white similar to the Moon, even the lingering hopes of complex Mars life were dashed. More than a century of speculation and romantic fantasy went up in smoke with the first interplanetary probes, and people were left with dreams of both Venus and Mars shattered - one a smog-choked furnace hellhole, and the other a cratered, frozen desert with nothing even resembling life visible at any level. Subsequent probes only reinforced these findings:
We should not underestimate how demoralizing this revelation was: Entire generations of scientists, science fiction authors, and laymen who found the topic fascinating had grown up with stories of Mars as the setting of vast adventures and bizarre beings, only at the moment of humanity's triumphal emergence into space to find the setting of their dreams a Great Big Empty, hostile to all known life and barely survivable by automated spacecraft. Still, some modicum of hope was held out that maybe, just maybe there was more going on than met the eye, and those hopes held out until 1974 when the twin Viking landers touched down on the surface, sent back full-color images of utter desolation, and appeared to find no chemical evidence of life whatsoever.
There have been subsequent doubts about the interpretation of those findings, but at the time they were a devastating blow to interest in Mars overall, and the next probe sent to the Red Planet wasn't launched until nearly two decades later. In the interim, a new vision began to coalesce among science fiction authors interested in the setting: Mars as the "New America," where political and economic refugees, entrepreneurs, scientists, revolutionaries, heroes, and villains would go to act out the next stage of human history rather than partaking of someone else's. Some of these visions have come to favor a libertarian bent, focusing on Mars as a frontier where Wild West-like stories can play out; others have emphasized the possibility for progressive social, cultural, and political ferment, as well as possible engineering projects on a massive or even global scale.
Probably the most potent and seminal Mars-related science fiction since mankind met the reality of the planet is Kim Stanley Robinson's Hugo- and Nebula Award-winning Mars trilogy, consisting of Red Mars (1992), Green Mars (1993), and Blue Mars (1996). They have been described as utopian, despite depicting plenty of vile human behavior, and are in my opinion the greatest examples in fiction of the new vision for Mars: One where it serves as the setting for humans to build new civilizations rather than merely passively experiencing ones that already exist. Mars today is seen as a place where human beings will some day be able to make their own destiny, for better or worse.
On a personal note, I still remember how I felt as a 13-year-old walking into the book store and seeing Blue Mars in hardcover on the shelf after having read Red and Green Mars during the previous year. With every page, it was like I was witnessing the fruits of centuries of labor along with the characters, and experiencing the boundless possibilities they were finally beginning to realize. There are plenty of horrific and tragic moments in the books, but I won't deny they're utopian because they do make the reader believe that anything is possible when people are intelligent, courageous, and optimistic - which, when you get down to it, science fiction is supposed to do, and precious few examples have done lately.
Some of the lower-brow pop culture depictions of the current paradigm have ranged from godawful and embarrassing - e.g., Ghosts of Mars (2003) - to inaccurate and pointless (two out of three stages of the original 1993 Doom computer game claim to be set on the moons of Mars, despite showing external scenery from China) - to awesomely fun and entertaining, like Total Recall (1990). The film adaptation of the graphic novel Watchmen contains several scenes on Mars that are quite visually striking and relatively accurate.
Still, film and television depictions of Mars run toward the dystopian - even in the Star Trek universe or Babylon 5, Mars is not considered an interesting or worthwhile setting, but either a backwater due to better locations being available or a place whose hardships have caused its culture to become harsh. Usually the Mars cities depicted in film and TV are grim industrial landscapes both internally and externally, although it's easy to write this fact off as producers being cheap with the background scenery. There seems to be some baseless assumption that Mars would be dominated by mining concerns simply because its landscape is rocky and arid, overlooking the fact that most likely a significant number of people would be going there in order to pursue social, technological, and perhaps political achievement.
Worse still, earnest attempts to make serious films about human exploration of Mars - e.g., Mission to Mars (2000) and Red Planet (2000) - have resulted in some of the worst, most embarrassing movies of all time. I still vividly remember going to see Mission to Mars with high hopes, and leaving the theater feeling like my intelligence, taste, credulity, patience, and reverence for the subject had all been brutally assaulted at my own expense. That travesty may have been one of the contributing factors of the ongoing failure of both film and TV to pursue an adaptation of the Mars trilogy - one that had at one point been slated for production by the Sci-Fi channel (now "Syfy," I guess because any association to science would be false advertising for most of its programming).
Returning to Mars exploration, the world eventually got over its disappointment and started sending probes once again for two main reasons: One reason that NASA has focused on overwhelmingly is to pursue scientific understanding of the history of the planet, and whether and to what extent it might harbor microbial life or have done so in the past. The elephant in the room, that governments seem to find politically dangerous to acknowledge for some reason, is the second reason: That ultimately human beings will be living there, and these probe missions are intended as scouts to enable eventual colonization. NASA does not officially recognize human colonization of space as part of its agenda, although its employees are allowed to speak in the abstract about what "maybe" possible some day via the agency's efforts. To the extent they seek to enable a human presence, it is invariably characterized as scientific missions rather than as the establishment of a new branch of civilization for its own sake and the overall enrichment of humanity.
With the successes (in many cases ongoing) of the Pathfinder rover in 1997, the Mars Global Surveyor orbiter 1999-2006, 2001 Mars Odyssey (2001 - present), Mars Express (2003 - present), the Mars Exploration Rovers (2003 - present), the Phoenix lander, and the Mars Reconnaissance Orbiter (2006 - present), humanity has learned the the planet is not quite as grim as had been thought in the dark days after Viking. Water ice is pervasive in the form of permafrost, and occasionally warms up enough to liquify and seep out of the ground for a few moments before boiling off into the thin atmosphere. Images of the Red Planet as a diverse and dynamic place are seen throughout Vol. 2 of this sub-series. Meanwhile, indirect evidence continues to mount that microbial life may be occurring under the surface.
In August of this year, the Mars Science Laboratory with its massive Curiosity rover is slated to land on Mars and begin the most thorough investigation ever attempted for the planet. Unlike previous post-Viking missions, it will be able to provide conclusive answers about whether life on Mars exists, whether it can exist, and how useful the soil might be to future human attempts to work with it - at least about the parts of the planet that it visits. However, the Curiosity lander will attempt to land using a novel technology that lowers it to the surface from a hovering descent module via a cable, so there is risk in this mission over and above the immense difficulties of landing and operating on Mars. And back on Earth, the budget priorities of the Republican Congress have eliminated funding of any follow-up lander mission in planning, so it is unclear what the findings of the Curiosity rover would be used for unless that situation greatly changes.
One bright light for Mars at the moment is the existence and continuing success of SpaceX - a commercial launch company founded with the explicit purpose of eventually colonizing Mars, and which continues to pursue the technological and economic changes in the industry that will bring it about (e.g., radically reduced launch costs, reusable rockets, and safe human transport to Earth orbit). The fact that the company is still tightly controlled by its founder, Elon Musk, means that its resources remain committed to this mission even as the company grows substantial industrial capability and grudgingly wins political support away from its aimless and future-indifferent Big Aerospace competitors.
An envisioned variant of SpaceX's Dragon spacecraft currently in orbit, called Red Dragon, would employ a souped-up version of the craft's thrusters to land on Mars as a high-volume platform for robotic experiments. The landing system would be similar to the one also being pursued to give Dragon the capability for powered landing back on Earth after an orbital mission, and also as an escape system to remove a manned Dragon from its Falcon 9 rocket in an emergency on the pad or in flight. The fact that this escape system is one of the prerequisites to win NASA contracts to deliver astronauts to the ISS means that a number of different capabilities would be opened up by the system, known as the SuperDraco thruster. A promotional video for SuperDraco, showing test fires and animations of a launch escape and an Earth landing:
What SpaceX is trying to do here is pretty obvious: The same spacecraft they intend to use for carrying astronauts would be used on an unmanned basis to land on Mars, and would do so using the same thrusters that would serve as an escape and landing system for orbital crew missions. The leap to a human Mars mission would be shorter than it's ever been, although still definitely a leap - a lot of hardware would have to precede the astronauts to Mars, and a lot of other hardware would have to accompany them as a habitat module (obviously they can't spend months cooped up in a capsule).
This brings up another project SpaceX is pursuing - it's heavy-lift rocket, the Falcon Heavy: A launcher intended to drastically reduce the cost of launching human Mars mission hardware, and along the way handily steal the entire market for launching big satellites away from United Launch Alliance (a monopoly partnership between Boeing and Lockheed-Martin). Even so, the costs would be massive, so funding would have to await a Congress willing to pass federal budgets above Third World levels. But with the continuing progress of SpaceX in Earth orbit (knock on wood), a human future on Mars has never seemed more imminent.
VII. Future Relevance to Humanity
Humanity not only needs frontiers, but frontiers that occupy the crucial middle ground between an environment that isn't challenging - in which case it is likely already swarming with people and life - and one that is so challenging that the best efforts people could bring to it would go unrewarded. Fortunately, the lines defining these categories shift over time to our advantage due to technological evolution and practical experience, so new environments become survivable that would have been too challenging to our ancestors. Before people started wearing animal furs and building their own shelters, they largely stuck to the tropics in their migrations - warm, wet climates teeming with food sources to be hunted or gathered. But once we put on clothes, and especially once we could build fires, people started showing up on steppes, in tundra, on mountains, and in comparatively cold, bitter places like Northern Europe.
Today, living in Norway or Alaska is not much of a challenge by historical standards unless you deliberately live away from the cities and modern comforts. And the process has worked in the other direction as well: The most hellacious of desert furnaces, once inhabited by a few hyper-adapted indigenous peoples, are now covered in housing developments thanks to the advent of air conditioning - a phenomenon likely to accelerate as solar power ramps up. Even swampy, stagnant, hot-humid climates are made more livable by the ability to control indoor humidity as well as temperature. The inherent costs of living in an ideal climate may be lower than going somewhere more challenging, but ironically that fact makes them crowded and causes costs of living to actually be higher than going elsewhere, so you end up with people always moving outward to more and more challenging environments.
But that, in itself, is not the frontier - that's what follows the frontiers, and is dragged forward by the people who, for whatever reason, seek them out. They often learn what is needed to survive in a new environment by watching the people around them die, and may themselves become an object lesson for their successors. No matter how intelligently one goes about it, and no matter how much prior information you go into it with, pursuit of a frontier ultimately requires simply that people gamble with their lives - the more who do so, the faster the limits and opportunities of an environment will be fleshed out in the shape of catastrophes and unexpected bounties, and the more quickly humanity as a whole evolves into the new niche through technological adaptation.
So there are always those two sets of frontiers - ones that will reward ingenuity and persistence, and ones that will hate you no matter how hard you try - and it really isn't possible to be certain of where the boundary between them is except through effort. Once, the ice and snow of the North was a hateful realm that built violent, hateful societies because they never found respite except in pillaging more prosperous regions. Now some of the mildest cultures on Earth live in frigid Boreal climate. Once, the desert furnace made desperate, fatalistic warrior cultures who saw life and death in the bitterest and starkest terms. Now it sprouts shopping malls and suburban Potemkin villages. Mars, in terms of the other environments of the solar system, is that middle ground between where we are and where the absolute limit lies, and seems like a place that would reward effort.
In the entire solar system, it is by far the easiest non-Earth object on which to establish an independent, self-sustaining civilization starting from where we are right now technologically and economically. Although it is farther away than the Moon in distance, its gravity is much closer to that of Earth (1/3 as opposed to 1/6 g), it has an atmosphere - good for micrometeorite protection, thermal insulation, aerobraking, use of parachutes on descent, slightly less bulky spacesuits, and eventually balloons and aircraft could be used - its water ice resources are far larger, it possesses far more diverse mineral resources, temperatures are much less radical, and it has a day/night cycle close to the one we evolved under. It's close enough to the Sun that solar panels are still practical as a power source, and has soil that scientists believe would be able to support some forms of vegetable growth in a UV-shielded, pressurized greenhouse.
Without radically advancing the state of technology, the two options for our first Second Home boil down to the Moon or Mars, and for the reasons stated Mars is far more habitable on an ongoing basis even though the Moon may be easier to reach. There are substantial hurdles to overcome in getting the people and materiel to Mars to establish a self-sustaining colony, but once they're surmounted, the expense is retired - they do not continue to be a problem over time, whereas a lunar colony will always have to deal with the fact that its days and nights are two weeks long, freezing the night side and burning the day side at temperature extremes Mars does not even approach; it will always have to deal with the fact that there is zero natural protection against micrometeorites, that every centimeter of a descent from orbit has to be powered (absent some distant prospect like a lunar space elevator), that the environment is hard vacuum, that minerals are limited in both quantity and diversity, and water ice is largely limited to craters in the polar regions. That doesn't mean we can't explore the Moon at the same time we're exploring Mars, but colonization is another matter.
Futhermore, Mars is in the best position to be terraformed, since its gravity can hold on to a lot more atmosphere over human timescales than is currently there; it has literally oceans of water trapped as ice; and vast amounts of oxygen are locked in various compounds in its rocks (Total Recall got that right, although obviously you're not going to create a breathable atmosphere in seconds - more like centuries or millennia). As I noted in the Luna diary, we could also terraform the Moon, but it would be a radically unstable and unpredictable process - Mars would involve fewer unknowns, and would require a lot fewer external resource inputs to make habitable. In fact, mainly what is needed is heat, which humanity produces in abundance just by existing in its modern technological state. Global warming would be a good thing on Mars, although additional efforts would be needed to change the chemical composition of the air and introduce photosynthetic microbes to build and maintain oxygen.
An artist's conception of Mars in the process of terraformation, by Daein Ballard:
You can see how the radical dichotomy in elevation between the Northern and Southern hemispheres would play out once there are rising bodies of liquid water on the planet. But even in the absence of terraformation, the case for Mars is overwhelming - its resources would simply be put to work expanding both the scale and diversity of internal ecosystems until terraforming is a moot point because you're essentially "outside" even in a sealed and pressurized environment. The waste heat of civilization would gradually change the climate toward habitability anyway, thickening and moistening the air, and making it possible for liquid water to exist in some places at some times. And even if no effort was made to introduce life into the natural environment, it would eventually find its way out there from everyday human activity and adapt into new niches.
From there, the utility of Mars to humanity goes beyond being a frontier and Second Home, and becomes also a secondary basis from which to launch subsequent colonization into the rest of the solar system. Think about this: Europe was colonized from Central Asia tens of thousands of years ago. England was colonized and turned into a unified kingdom by the Normans (who just a few generations earlier had been Vikings) a thousand years ago. England, via its imperial state the United Kingdom, colonized North America only a handful of centuries ago. Although obviously the scale is far different, it would fit the pattern if this country were to spearhead the colonization of an entirely new world, and then that world's civilization later expanded even further into the solar system in even less time.
And it isn't some misguided historiography that causes me to think this will happen, but rather the basic economics of Mars: The fact that it has 1/3 the gravity of Earth doesn't mean it's merely 2/3 easier to get back into space from its surface - it's many, many times easier, and all the more so because its atmosphere is thin. Once you have an industrial base on Mars, it would be far easier and cheaper to build things there and send them anywhere else than to build them on Earth. It would be far cheaper for Martian humans to leave their world and go anywhere than for Earthlings to do so, and probably the competence and adventurous spirit of the frontier would burn much brighter and more recently in their culture than those of our successors on this planet. This means that a Martian civilization would be able to expand more quickly into the rest of the solar system than Earth powers acting directly: As in history, every frontier is always just a stepping stone to another frontier.
In particular, Mars is also closer to the Main Belt asteroids, which are unimaginably richer and more numerous than the ones which lurk around Earth's environs, and its two moons are both very similar in size and irregular shape to asteroids. Once a suitable level of space operations technology is achieved, the Main Belt asteroids cease being a challenge and instead become a Garden of Bounty the likes of which has never been realized in human history - and very likely it would be Martians paving the way. From there, the gas giant moons, and then who knows what? Each subsequent step outward would accelerate the wealth, diversity, and technological achievements of the last, and humanity could spend millennia exploiting just the Main Belt without even coming close to exhausting its resources and potential habitats. But that's a step beyond Mars, and a topic for a subsequent entry in this series.
Suffice it to say that by colonizing Mars, we would not just be colonizing Mars - we would be putting a down payment on Everywhere. And there is also the less tangible factor of having wealthy, dynamic, innovative offspring civilizations ready to save you in the event of natural or man-made catastrophe: In the 1940s and the Cold War, Europe certainly came to appreciate the investments it had made in the Americas - nothing else would have saved it from the wanton destruction of one mad dictator or the bottomless oppression of the nightmare state that inherited most of the ruins. Some day the nations of Earth including the United States may need some external power to play that role in our affairs, and Mars seems the likely candidate.
Eventually, over the very long term - call it millennia - Earth and Mars are similar enough compared to the rest of the solar system that we would very likely end up with a lot of shared history and kindred culture. It's possible our world would be revered as the Mother of their civilization, but equally possible it would be disdained as the muck out of which something better had arisen - perhaps both to some extent, depending on where a given person's ancestors came from and where they ended up on Mars (there would certainly be regional cultural differences). Perhaps there would be real, lasting political and economic unity at some point - possibly as a defensive measure, possibly just to enable trade - but it seems reasonable that the similarity of the worlds, especially after Mars is fully inhabited, would lead to free-flowing populations who ultimately see themselves as part of the same identity.
This would be especially true if Mars is terraformed, making it the second Blue Marble - and perhaps just one of several if Venus, the Moon, or some gas giant moons are likewise transformed. I doubt if people who went on to colonize the outer solar system would see much of a difference between the inhabitants of Blue Marbles, walking freely under a warm open sky with the Sun shining down, life spilling around them carelessly. But that too takes the scope beyond Mars, because it ceases to be a frontier once the originating cultures are brought up to speed and the new ones become placid.
VIII. Future of Mars
Eventually, it's likely that if humanity continues to grow and thrive, the solid bodies of the solar system would eventually be completely devoured for raw materials - although we're talking about very distant timelines like 10,000 to 100,000 years. However, as I also mention for the other inner planets, there is a possibility of non-economic factors coming into play and resulting in their preservation as something like theme parks, museums, religious sites, or wildlife preserves. Regardless of what humanity does with Mars, it would experience a relatively brief period of Earth-like warmth due to solar expansion at some point in the next few billion years, but the ultimate death of the Sun would obliterate it due to the rapid expulsion of mass from the star: Mars would be sand-blasted away to nothing.
IX. Catalog of Exploration
1. Past & current probes:
Mars 1960A (USSR, 1960 - failed flyby)
Mars 1960B (USSR, 1960 - failed flyby)
Sputnik 22 (USSR, 1962 - failed flyby)
Mars 1 (USSR, 1962 - failed flyby)
Sputnik 24 (USSR, 1962 - failed lander)
Mariner 3 (USA, 1964 - failed flyby)
Mariner 4 (USA, 1964 - flyby)
Zond 2 (USSR, 1964 - failed flyby)
Mariner 6 (USA, 1969 - flyby)
Mariner 7 (USA, 1969 - flyby)
Mars 1969A (USSR, 1969 - failed orbiter)
Mars 1969B (USSR, 1969 - failed orbiter)
Mariner 8 (USA, 1971 - failed orbiter)
Cosmos 419 (USSR, 1971 - failed orbiter)
Mariner 9 (USA, 1971-72: Orbiter)
Mars 2 (USSR, 1971-72: Orbiter, failed lander and rover)
Mars 3 (USSR, 1971-72: Orbiter, failed lander and rover)
Mars 4 (USSR, 1973-74:Failed orbiter)
Mars 5 (USSR, 1974: Orbiter)
Mars 6 (USSR, 1974: Failed lander)
Mars 7 (USSR, 1974: Failed lander)
Viking 1 (USA, 1974: Orbiter and lander)
Viking 2 (USA, 1974: Orbiter and lander)
Phobos 1 (USSR, 1988: Failed orbiter and lander)
Phobos 2 (USSR, 1989: Orbiter, failed lander)
Mars Observer (USA, 1993: Failed orbiter)
Mars Global Surveyor (USA, 1997-2006: Orbiter)
Mars 96 (Russia, 1996: Failed orbiter, lander, and penetrator)
Mars Pathfinder (USA, 1997: Lander and rover)
Nozomi (Japan, 1998: Failed orbiter)
Mars Climate Orbiter (USA, 1999: Failed orbiter)
Mars Polar Lander (USA, 1999: Failed lander and penetrators)
2001 Mars Odyssey (USA, 2001-ongoing: Orbiter)
Mars Express (Europe, 2003-ongoing: Orbiter)
Beagle 2 (UK, 2003: Failed lander)
Spirit (USA, 2004-10: Rover)
Opportunity (USA, 2004-ongoing: Rover)
Rosetta (Europe, 2007: Flyby)
Mars Reconnaissance Orbiter (USA, 2006-ongoing: Orbiter)
Phoenix (USA, 2008: Lander)
Dawn (USA, 2009: Flyby)
Yinghuo-1 (China, 2011: Failed orbiter)
2. Future probes