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Markkula Center for Applied Ethics

Environmental Activists, Heroes, and Martyrs

Portrait of Chris McKay

Portrait of Chris McKay

Chris McKay

Microbes, Morals, and Mars

Michael Turgeon was a 2016-2017 Environmental Ethics Fellow at the Markkula Center for Applied Ethics.

For 99% of human history, the heavens were utterly inaccessible. While the night sky has always had a profound effect on human culture, and while heavenly bodies have helped drive centuries of scientific investigation into the inner workings of our universe, it was not until very recently that humans were able to travel through the vacuum of space and actually put a boot on the fine dust that covers the lunar surface. Humans have sent spacecraft with cameras and sensors all around the solar system, exploring the moons of Jupiter, the thick atmosphere of Venus, and even the cold outlying bodies like Pluto. In fact, Voyager 1, launched in 1977, has left the solar system entirely, and is still sending us radio signals from interstellar space[1]. Suffice it to say, humans have their fingerprints on many places in the solar system, and another major milestone in our exploration seems imminent: putting a human on Mars. Considering the rapid progress of modern space technology, notably developments such as SpaceX’s reusable rocket[2], space travel is getting cheaper, long flights for astronauts are seeming more feasible, and to many a human settlement on Mars seems not only realistic, but inevitable. However, exploring and settling another planet is obviously an unprecedented endeavor, and thus it comes with unprecedented moral considerations. Mars represents a pristine environment, nearly untouched by humans, and may even harbor life of its own. While we know enough from probes and rovers to (mostly) discount the notion of little green men on the red planet, microbes are a different story. Microscopic life on Mars is at least plausible enough that it deepens the moral conundrum facing space-age environmental ethicists, and deciding on the proper way to approach our neighbor planet is no easy task.

One pioneer in Martian environmental ethics is NASA physicist and astrobiologist Christopher McKay. McKay currently works at NASA’s Ames Research Center in Mountain View, California, and has investigated the most extreme environments on Earth (such as Chile’s Atacama Desert and the Antarctic Dry Valleys) as analogues of the Martian surface, with hopes of learning more about what kinds of life could exist there. But for McKay, Mars was not always on his radar, and it took a series of fortuitous events to turn his sights to the red planet. McKay studied physics in college, but was not particularly interested in space until he discovered an old telescope in a lab closet, which later inspired him to build his own. He started graduate school at the University of Colorado in 1976, and was amazed by the findings of Viking 1 and 2, Mars landers that showed a planet with the elements needed for life (at least in the past), yet no evidence of it being there[3]. An internship four years later ignited his interest in biology, as he joined an expedition to the Antarctic Dry Valleys, a small part of the continent that is actually not covered by ice. While he expected to find nothing but barren rock, upon close inspection he discovered that the desolate landscape was actually teeming with microbes just below the surface[3]. As it often happens in science, the curiosity of unexpected results drives progress and passion, and McKay was hooked. His first job after getting his doctorate in 1982 was to study planetary atmospheres with NASA Ames[3], but he soon pushed his career towards astrobiology and to this day focuses on exploring the possibility of life on Mars.

McKay and other astrobiologists have learned that life on Earth is hardy; microbes have been found thriving in extreme temperatures, pressures, and chemical environments, and if anything this research shows us that life in the extreme Martian environment is certainly possible[4]. However, McKay believes that the most likely home for Martian life is a few meters below ground, away from the radiation bombardment on the surface. The possibility of life underground complicates matters even further, as actually digging down and launching a thorough investigation would be exceedingly difficult until the contaminating hands of humans are already there. In response, McKay has been at the forefront of Martian ethics, and has attempted to establish an ethical framework for how we approach Mars going forward.

At the heart of McKay’s framework is the idea of the “Cosmic Golden Rule;” if we encounter life elsewhere in the universe, whether microbes or otherwise, we should treat it as we would want a race of proportionally more intelligent beings to treat us[5]. If we do encounter life on Mars (or elsewhere), we should not be quick to cast it aside for the sake of human interests because it potentially sets a bad example on the cosmic stage and also sets a precedent for further exploration we want to avoid. Across millennia of exploring and colonizing our globe, humans have rarely upheld the sanctity of life when encountering a new place, and our own planet and own species has suffered because of our carelessness. If we do not further develop our ethical frameworks pertaining to exploration, use, and settlement, we are doomed to repeat our mistakes throughout the galaxy.

McKay openly admits when elaborating his framework that he wants to uphold the intrinsic value of life, even microbes[5]. As members of the expansive tree of life, humans have a duty to respect the other branches of the tree because of our shared connection, a connection that might be quite special in the greater context of the universe (see Carl Sagan and the Fermi Paradox). Despite his belief in intrinsic value, McKay also recognizes that this motivation is more nebulous when it comes to microbes; however, he also believes that extraterrestrial microbes could carry extrinsic value as well (the term he uses is “instrumental” value). Microbes on Earth, such as nitrogen-fixing soil bacteria, are incredibly important for healthy ecosystem function, and thus microbes on other planets may play similar roles, or could have similar benefits for future human endeavors that are difficult to foresee now. Still, though, he thinks that ideally we should allow alien ecosystems to develop and evolve on their own, and if anything, humans interaction should foster the development of this life rather than exploit it for our own gains.

However, an especially important consideration in this scenario is the origin of alien life; discovering life that shares a common ancestry with ours has profoundly different implications than a “second genesis,” where an entirely new lineage of life spontaneously came into existence on another planet. McKay upholds the sanctity of life in either case, but the latter perhaps commands more respect and caution. If microbes on Mars were genetically related to species on Earth, then perhaps contamination would not be quite as much of an issue and human activity would not have to be restricted. On the other hand, if a whole new tree of life is evolving on a separate planet, human activity could interrupt delicate chemical processes, introduced microbes could outcompete native ones, and the entire Martian lineage could be compromised. This scenario is exactly what McKay is trying to avoid[5].

Additionally, the question of a “second genesis” harkens back to the Fermi Paradox. Mathematically speaking, even if the creation of life from non-life is a rare event in the universe, the ubiquity of hospitable planets and the vast amount of time these planets have existed means that evidence of intelligent life should be obvious, yet the only intelligence we have witnessed is our own. Many believe this conundrum implies that intelligent life tends to hit a “Great Filter” and destroy itself before it can expand and populate the galaxy, and that humanity may be doomed to a similar fate[6]. Our seemingly poor galactic prospects motivated those like Carl Sagan and still motivates those like Elon Musk to pursue space travel and the goal of spreading the human race, for example, to a settlement on Mars. However, another possible solution to the Fermi Paradox is that the spontaneous creation of life is actually so rare that it statistically negates the wide array of opportunities it may have. In this scenario, humans are pioneering space exploration rather than racing against the clock, and the future of our species may appear a little brighter. However, a “second genesis” means that not only is life on Earth not alone, but life came about elsewhere in our own solar system on a planet with comparatively much less favorable parameters; in this case, the Great Filter seems very much in our future, and the stakes of colonization would become much higher. If we do discover a “second genesis” on Mars, then we will have reached a point where we may need to choose between one lineage of life over another. If this case becomes a reality, then environmental ethics will need to resolve perhaps its most important question, and the answer we reach may decide the future of the human race. And following in the footsteps of Chris McKay and other forward-thinkers, it would be best for both parties if we consider this question preemptively.


[1] Dunford, Bill. "Voyager 1: First to Interstellar Space." National Aeronautics and Space Association, n.d.<>

[2] Wall, Mike. "SpaceX Rocket Could Be 100-Percent Reusable by 2018." N.p., 10 Apr. 2017 <>

[3] Nadis, Steve. "Alien Worlds on Earth." Discover, 04 Feb. 2014 <>

[4] David, Leonard. "Q&A with Chris McKay, Senior Scientist at NASA Ames Research Center." N.p., 20 July 2015. <>

[5] Randolph, Richard O., and Christopher P. McKay. "Protecting and expanding the richness and diversity of life, an ethic for astrobiology research and space exploration." International Journal of Astrobiology 13.01 (2014): 28-34.

[6] Urban, Tim. "The Fermi Paradox." Wait But Why. N.p., 21 May 2014. <>