Thank the Little Green Men

 Mars is a much different place than scientists once envisioned.

This is the story of a strange chain of events, of how the search for mythical Martians led to the greatest discovery of modern cosmology:

In 1877 an Italian astronomer, Giovanni Schiaparelli, turned his telescope to Mars and saw what he thought were lines or grooves on the surface of Mars. To describe them Schiaparelli used the Italian word "canali," which means "channels." Schiaparelli continued his observations into the 1880s; his writings on the canali on Mars became widely known and were translated into other languages.

Unfortunately, when his writings were translated into English the word canali was translated not as "lines" or "channels" but as "canals." However, the English word "canals" does not imply something of natural origin, but is typically interpreted as something artificial. The obvious conclusion by many readers was that Mars had artificial canals, and artificial canals implied intelligent Martian canal builders.

It was a simple mistake in translation, but word of the implied "evidence" of intelligent Martians spread like wildfire. There was fervent speculation about the presumed Martians, and it eventually led to writings such as H.G. Wells' famous "War of the Worlds," which fired the imagination and shaped our views about "aliens" to this day



One person who was fascinated by the assumed Martians was a young man from
Massachusetts named Percival Lowell. Lowell was an heir of a very wealthy family, and he was so taken with Mars and Martians that he personally funded the building of a professional observatory expressly for the purpose of studying Mars. (The Lowell Observatory in Flagstaff, Arizona is still operating and today is one of the world's leading observatories.)

Lowell did a lot of observing himself, but he also hired a professional staff for the observatory. In 1901 he hired a promising young astronomer from the American Midwest named Vesto Slipher. Slipher was to stay at the Lowell Observatory for the next 53 years and excelled as one of the great observational astronomers of his time. (It's an unfortunate twist of fate that Slipher is not often cited for his many discoveries. The only reference many lay readers ever hear about him is that he was the one who hired another earnest young Midwesterner, a Kansas farm boy named Clyde Tombaugh, who went on to discover the planet Pluto.)

One of Slipher's many discoveries was that "spiral nebulae" (what we today know as galaxies) appear to rotate and most appear to be "red-shifted," meaning that the light from these galaxies appears to be shifted toward the red end of the spectrum.

(Think of the whistle of a train rushing away from you: Because the sound waves are "stretched out," the pitch of the whistle is lower. In the same way, the light waves from a fast-receding galaxy are "stretched out," and therefore appear redder, red light having a lower frequency than blue.)

No one knew quite what to make of this "red shift," and the most obvious explanation - that all these galaxies in every direction were rushing away from us at enormous speeds - seemed incredible.

Vesto Slipher published papers on his findings, and in August of 1914 he presented his work to a conference at Northwestern University in Illinois. In the audience was a remarkable young man: At the age of 24 he had already been a star athlete, a Rhodes scholar and earned a law degree, but had decided that instead of practicing law he would return to the university and pursue a doctorate in astronomy.

That young man was Edwin P. Hubble (1889-1953) , and he would take his doctorate just in time to ship out to
France to fight in World War I. (He excelled in the military as he had in everything else, being quickly promoted to captain and eventually to major.) Upon his discharge from the Army, Hubble went off to the Mt. Wilson Observatory and started working with the new 100-inch telescope, then the largest in the world. With the new telescope Hubble achieved a tremendous breakthrough: He became the first to measure the distances to the "spiral nebulae," establishing them not as small objects within our galaxy but huge galaxies like our own and very, very far away.

About the time that Hubble was establishing the sizes and distances of galaxies, a Belgian graduate student with an unusual resumé -- an ordained Catholic priest with an undergraduate degree in civil engineering and a doctorate in mathematics -- was working at the Harvard Observatory, and he attended a lecture by Edwin Hubble on his research. Hubble's findings were establishing what became known as Hubble's Law, a mathematical relationship indicating that the farther a galaxy is from us, the faster it is moving away.

This seemed to imply that the Universe was expanding in every direction, and the priest-turned-physicist, George LeMaitre, came up with an interesting explanation by pondering a very simple thing: If everything in the Universe is rushing outward, what if we play the "movie" backward, all the way back to the beginning?

To LeMaitre the obvious conclusion was that the "movie played backward" would show everything coming together at a point. This indicated that the Universe must have started at a single point at a given time, an extremely compact mass that exploded and sent everything rushing outward, resulting in what Hubble was seeing.

Thus it was that LeMaitre, an obscure nobody in the world of science, came to formulate what we now know as the Big Bang theory.

(It turned out he was not the only one: A Russian physicist, Aleksander Friedmann, had come up with it independently, but Friedmann died soon thereafter and has never been as widely recognized.)

It took some time for the new theory to catch on. LeMaitre did not hold a scientific post and was unknown to the academic community. He published his theory in an obscure journal, which meant no one paid much attention to it. And when the theory was finally recognized and publicized, it was at first roundly criticized by Einstein for poor physics and by others for being too close to the Christian view of creation. But in time Einstein came to recognize the value of LeMaitre's insight, and subsequent refinements and observations came to establish it as the foundational view of the development of the Universe.

Despite a few modern critics and some apparently contrary evidence, the Big Bang theory remains the widely accepted explanation for the structure we see in the Universe. But it's interesting to ponder how it came to us, at the end of a long chain of events that started with a simple mistranslation and a starry-eyed search for "little green men" on Mars.



The word Martian is applied to a hypothetical native inhabitant of the planet Mars. Historically, life on Mars has often been hypothesized, and the notion that the planet harbours or once harboured life continues to the present day, having such proponents as Courtney Brown. While it is possible that there is or once was life on Mars, there are no scientific data to support the notion.


The idea of intelligent Martians was popularized by Percival Lowell and in fiction, especially by Edgar Rice Burroughs' John Carter (Barsoom) Series, H.G. Wells' The War of the Worlds and Ray Bradbury's The Martian Chronicles. Despite the observation by Alfred Wallace that Mars' atmosphere was too thin to support an Earth-like ecology, various depictions of a Martian civilization were popular throughout the 20th century. The first pictures of Mars returned by space probes dashed hopes of contacting Martians, although dubious claims of past Martian civilizations have continued into the twenty-first century.


Wells' Martians

In The War of the Worlds, H.G. Wells describes the Martians as octopus-like creatures; the "body" consists of only a head with eyes, v-shaped lipless beak-like mouth, and two brunches with a total of 16 tentacles. They have no male or female differences; a Martian is born by "budding" off its parent. The Martians also consist of just a brain, lungs, heart and blood vessels; they had no organs for digestion. The ear, located in the back of the head, was believed to have been useless in our atmosphere.


Wells also mentions that, apparently, there were two distinct species of Martians. One is the species that attacks Earth and the second (briefly described) appears to have existed only as a source of nutrition for the superior race (much like the relation between the Eloi and Morlocks in Wells' novel The Time Machine). Skeletons of the subordinate race were recovered in the Martians' transport cylinders. This species was bipedal and similar to humans. Since the Martians had no digestive track, they were able to sustain themselves by injecting blood from this sub-race directly into their veins. Two or three of these creatures were brought by the Martians and were killed before they landed. This explains why the Martians seemed to prefer the blood of humans.


Many adaptations of the Wells novel also incorporate Martians as the invading race, though with some descriptive differences. However, because science has revealed that the planet is devoid of anything that can come and take over Earth, the concept of using Martians is sometimes dropped as it is no longer deemed realistic. The Steven Spielberg adaptation and the syndicated TV series are the most prominent examples of this, though the series does tie the invasion force with Mars, using it as a temporary base, making them pseudo-Martians.


The real Martians


Because of the prevalence of stories containing Martians, the idea of the Martian has become the default identity of extraterrestrial characters in popular culture. If Mars is colonized in the future by humans, the generations descended from the settlers may well be called Martians. Some members of the Mars Society, an organization devoted to such colonization, semi-humorously describe themselves as "Martians in exile".

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Mars, life on

Has there been life on Mars in the past? If so, does it exist there still today? These questions remain open and of keen interest to the astrobiologist. Conditions on the surface of Mars would once hve been much more conducive to the survival of life as we know it. The average temperature was higher, the atmospheric pressure was greater, and there was plenty of surface water – though exactly how much and how long it remained are important unresolved issues. Given the ability of hardy microorganisms known as extremophiles to thrive in what appear to us to be very harsh conditions on Earth, the possibility of present-day Martian microbes certainly can't be ruled out. Such creatures could have evolved several billion years ago, when Mars was more similar in its climate to Earth, and then gradually adapted as the environment turned less friendly. In particular, microbial survivors on the Red Planet may have retreated underground where it is warmer, probably wetter, and better shielded from the Sun's harsh ultraviolet rays. The prospects for residual life on Mars appear to have been raised by the announcement, in 2004, of the discovery by the Mars Express orbiter of trace amounts of methane and ammonia in the Martian atmosphere.


Early speculation

Although advocates of pluralism from the 17th century on had built a case for Martian life on purely philosophical and theological grounds, it was William Herschel who first made astronomical observations of the planet that were detailed enough to be relevant to the debate. From his telescopic studies in 1783, Herschel concluded:1


The analogy between Mars and the earth is, perhaps, by far the greatest in the whole solar system. The diurnal motion is nearly the same; the obliquity of their respective ecliptics, on which the seasons depend, not very different; of all the superior planets the distance of Mars from the sun is by far the nearest alike to that of the earth ... If, then, we find that the globe we inhabit has its polar regions frozen and covered with mountains of ice and snow, that only partly melt when alternately exposed to the sun, I may well be permitted to surmise that the same causes may probably have the same effect on the globe of Mars ... I have often noticed occasional changes of partial bright belts ... and also once a darkish one, in a pretty high latitude... And these alterations we can hardly ascribe to any other cause than the variable disposition of clouds and vapors floating in the atmosphere of that planet.

Writing in 1870, Richard Procter 2 took Herschel's Mars-Earth parallels further and argued vehemently for advanced Martian life based on the assumption that Mars was well supplied with both water and atmosphere:

Shall we recognize in Mars all that makes our own world so well fitted for our wants – land and water, mountain and valley, cloud and sunshine, rain and ice, and snow, rivers and lakes, ocean currents and wind currents, without believing further in the existence of those forms of life without which all of these things would be wasted? ... it is yet to speculate ten thousand times more rashly to assert ... that Mars is a barren waste, either wholly untenanted by living creatures, or inhabited by beings belonging to the lowest orders of animated existence.

The astronomical evidence seemed to continue to favor life following Giovanni Schiaparelli's announcement that he had seen regular linear markings on the surface, though no one could have imagined how far speculation over his canali would lead. By 1892, Camille Flammarion 3 had leapt to the conclusion that:

[T]he present inhabitation of Mars by a race superior to ours is very probable... The considerable variations observed in the network of waterways testify that this planet is the seat of an energetic vitality ... [We] may hope that, because the world of Mars is older than ours, mankind there will be more advanced and wiser.

In the fertile imagination of Percival Lowell, this portrait of an intelligently-populated planet attained its most elaborate form. Though Lowell's Mars was far less hospitable than Procter's, this was seen by him as no barrier to its habitation. On the contrary, the difficulties imposed by the environment had led the Martians to engage in such heroic hydrological schemes that evidence of them was visible from Earth. By the early years of the twentieth century, professional opinion was shifting inexorably away from the notion of advanced life on Mars. Increasingly, Mars seemed too dry, airless, and cold to support anything more than primitive vegetation. Yet, as late as 1936, one of the founders of the British Interplanetary Society, felt able to write: 4

On Mars, the crumbling remains of ancient civilizations may be found, mutely testifying to the one-time glory of a dying world.

Indeed, in the very decade that the Space Age began, Willy Ley and Wernher von Braun's The Exploration of Mars 5 contained a haunting illustration by Chesley Bonestell of the ruins of a Martian temple. That dream, of finding the remnants of a long-dead race, quickly vanished as close-up pictures arrived in 1964 from the first successful Mars probe, Mariner 4, of a crater-strewn wilderness seemly not unlike that of our own Moon. However, in 1971, Mariner 9 brought renewed hope of finding past and even extant biological activity, with its images of what appeared to be dried-up river channels. Such was the revival of optimism that only a few weeks before the first Viking landing, Carl Sagan and Joshua Lederberg went so far as to suggest 6 that: "Large organisms, possibly detectable by the Viking lander cameras, are not only possible on Mars; they may be favored." In the event, nothing so spectacular was found, although the Viking result's are still open to a variety of interpretations, both chemical and biological.


Post-Viking developments


The discovery on Earth of a number of meteorites from Mars has opened up a couple of extraordinary possibilities. One is that some of these rocks actually contain evidence of past Martian life in the form of fossils and biogenic chemical signatures. The other possibility, which remains valid whatever the final verdict on the fossils claim, is that microorganisms could travel between worlds aboard material shot into space during asteroids collisions. Life may have been seeded on Mars from Earth. Or, more extraordinarily, it has been suggested that life may have evolved first on Mars and then come to Earth by the process of ballistic panspermia.7 According to this idea, Mars afforded a safer haven for primitive life during the early, violent bombardment phase of the Solar System, between about 4.6 and 3.8 billion years ago. Whereas the Earth was probably hit repeatedly by objects up to 500 kilometers across which would have vaporized the oceans and created a deadly steam atmosphere, fewer giant impacts would have taken place on Mars (because it is a smaller target) and the absence of large amounts of surface water would have saved the planet from being as severely steam-sterilized. Any Martian thermophiles living just a few hundred meters below the surface, it has been suggested, would have been able to survive the trauma of collision with a 500-km-wide object. Furthermore, because of Mars' relatively cool interior and low gravity (allowing cracks, in which microbes could reside, to extend further down into the planet's interior) thermophilic subterranean organisms may have existed in a wide habitable zone extending to depths of several thousand meters. On Earth, by comparison, although thermophiles 1 km below the surface might have survived an ocean-boiling impact this would have left an uncomfortably narrow habitable zone – much below 1 km and microbes would probably be cooked by the planet's hot interior.8, 9




Herschel, W., "On the Remarkable Appearances at the Polar Regions of the Planet Mars, the Inclination of its Axis, the Position of its Poles, andf its spheroidal Figure; with a few Hints relating to its real Diameter and Atmosphere," Philosophical Transactions of the Royal Society of London, 74, 233 (1784).

Procter, Richard. Other Worlds Than Ours. New York: P. F. Collier (1900) (first published 1894).

Flammarion, Camille. La planète Mars et ses conditions d'habitabilité. Paris: Gautheir Villars et Fils (1892).

Cleator, P. E. Rockets Through Space, p. 195. New York: Simon & Schuster (1936).

Ley, Willy, von Braun, Wernher. The Exploration of Mars, New York: Viking (1956).

Sagan, C., and Lederberg, J. "The Prospects for Life on Mars: A Pre-Viking Assessment," Icarus, 28, 291 (1976).

Sleep, N. H., and Zahnle, K. "Refugia from Asteroid Impacts on Early Mars and the Early Earth," Journal of Geophysical Research, 103, no. E12, 28529 (1998).

Goldsmith, Donald. The Hunt for Life on Mars, New York: Penguin Books (1997).

Hansson, Anders. Mars and the Development of Life, 2nd ed. New York: John Wiley & Sons (1997).